napire2012v2

NAPIRE 2012
Native American and Pacific Islander
Research Experience Program
La Selva Biological Station
Las Cruces Biological Station
Las Alturas Biological Station
Costa Rica
Coordinated by:
Wendy R. Townsend, PhD
Robert E. Godshalk, PhD
4 June – 30 July 2012

NAPIRE 2012 2
Table of Contents
Staff.................................................................................................................................................4
Scientific Mentors..........................................................................................................................5
Students ..........................................................................................................................................8
Course Activities – Lectures and Seminars .................................................................................13
Daily Schedule..............................................................................................................................14
Welcome to San Jose!..................................................................................................................23
La Selva Biological Station (OTS)..............................................................................................24
Dole Banana Plantation ..............................................................................................................27
Bribri Indigenous Reserve..........................................................................................................29
Las Alturas Biological Reserve...................................................................................................33
Ngöbe Indigenous Reserve..........................................................................................................36
Brunka Indigenous Reserve........................................................................................................38
Las Cruces Biological Station (OTS)..........................................................................................40
Special Occasions-Birthdays, 4th of July, Christmas in July.......................................................46
Student Research Presentations.................................................................................................48
Student Research Reports: .........................................................................................................51
Agouti of Las Cruces Biological Research Station ...................................................................51

Comparison of predatory behavior between male and female Dipoena spiders.......................64

A comparison of the community structure of aquatic insects between streams of the tropical
and temperate regions................................................................................................................74

Density and distribution of agouti at Las Cruces Biological Research Station, Wilson
Botanical Garden.......................................................................................................................84

Acoustic sound space competition in the Neotropics between bird and cicada communities ..93

Effects of climate change on biomass allocation to leaves and specific leaf area along an
elevation gradient ....................................................................................................................101

Induced Response by Pheidole bicornis ants to the threat of herbivore damage....................108

Measures of tropical premontane reforestation success: early tree species survival, growth and
the influence of policy.............................................................................................................115

The assessment of understory succession in tropical premontane reforestation: invasive and
native plant cover in relation to canopy cover.........................................................................125

Leaf litter input and decomposition of neotropical riparian zones..........................................134

Changes in carbon sequestration by reforestation of abandoned Costa Rican pastures: a carbon
inventory using aboveground biomass measurements ............................................................141

The relationship between colony size of Pheidole bicornis and damage due to galls and
folivory in Piper sagittifolium.................................................................................................152

Size dependent survivorship in tropical restoration plantings in different climates................162

Macro-consumer roles in benthic organic matter processing in an upland tropical stream ....170

Territoriality in the Orange Billed Sparrow: convergence of male and female roles..............176

NAPIRE 2012 3
Function of songs in the Orange-Billed Sparrow (Aurremon aurantiirostris): Evidence for sex-
role convergence......................................................................................................................188

Aquatic insect colonization in early, mid, and late successional streams in a tropical forest.196

2012
NAPIRE
Photography
Contest
–
Students
.....................................................................
203

Landscapes and Ecosystems:...................................................................................................203

Water Themes:.........................................................................................................................204

Plants: ......................................................................................................................................205

Invertebrates: ...........................................................................................................................207

Herpetofauna: ..........................................................................................................................208

Birds: .......................................................................................................................................210

Mammals .................................................................................................................................211

Natural Phenomena .................................................................................................................213

People: .....................................................................................................................................215

Humor......................................................................................................................................217

Cultural Encounters.................................................................................................................218

Student Research .....................................................................................................................220

Photo
Exhibition
–
Staff
.................................................................................................................
222

Landscapes and Ecosystems:...................................................................................................222

Water Themes:.........................................................................................................................223

Plants & Fungi:........................................................................................................................224

Invertebrates: ...........................................................................................................................226

Herpetofauna: ..........................................................................................................................229

Birds: .......................................................................................................................................231

Mammals .................................................................................................................................233

Natural Phenomena .................................................................................................................235

People: .....................................................................................................................................236

Humor......................................................................................................................................237

Cultural Encounters.................................................................................................................238

Student Research .....................................................................................................................239

NAPIRE 2012 4
Staff
Robert Godshalk, PhD – Co-coordinator
Herpetology, crocodilian conservation
Gainesville, FL
caiman@ufl.edu
Fern Lehman, MS - TA
University of Georgia
fern.lehman@gmail.com
Wendy R. Townsend, PhD – Coordinator
Community Natural Resource Conservation
Santa Cruz, Bolivia
Wendy.townsend@ots.ac.cr
Rhiana Jones – TA
New Mexico State University
reevamp@hotmail.com

NAPIRE 2012 5
Scientific Mentors
Richard Bigley, PhD
Forest ecology, management & restoration
Evergreen State College
bigley@evergreen.edu
David Baumgardner, PhD
Entomology, fresh water ecology
Texas A&M University
dbaumgardner@tamu.edu
Frank Camacho, PhD
Fresh water ecology, aquatic food webs,
productivity relationships
University of Guam
dr.frank.camacho@gmail.com

NAPIRE 2012 6
Karin Rita Gastreich, PhD
Behavioral ecology, arthropods, plant- animal
interactions, Piper spp
Avila University
Kansas City, MO
Karin.Gastreich@avila.edu
Leslie Hay-Smith, PhD
Tropical ecology, mammology
Malone University
Canton, Ohio
lahaysmith@gmail.com
Patrick Hart, PhD
Ornithology, forest bird ecology &
conservation, bird songs
University of Hawaii – Hilo
pjhart@hawaii.edu

NAPIRE 2012 7
Michael Heppler
Writing excellence, graduate school & grant
application expertise
Oklahoma State University
rabbito76@yahoo.com
Jaqueline Mohan, PhD
Forest ecology, climate change, forest
restoration
jmohan@uga.edu
Shafkat Kahn, PhD Student
Forest ecology, climate change, forest
restoration
Shafkat1@uga.edu

NAPIRE 2012 8
Students
Adams, Brandi-Leigh
Kapiolani Community College
bladams@hawaii.edu
Alforeza, Severino
Northern Marianas College
severino.alforeza@student.nmcnet.edu
Albini, Briana
Univ. of Hawaii - Hilo
bdalbini@hawaii.edu
Fairbanks, Cedric
Leech Lake Tribal College
cefairbanks@students.lltc.edu

NAPIRE 2012 9
Hall, Robert
University of Washington
robert12892@gmail.com
Irvine, Aliah
Univ of Hawaii – Manoa
aliah@hawaii.edu
Hardison, Alex
Oklahoma State University
alex.hardison@okstate.edu
Kernak, Michelle
Northwest Indian College
mkernak@stu.nwic.edu

NAPIRE 2012 10
Leon-Guerrero, Naomi
University of Guam
naomisouthswell@gmail.com
Martinez, Paul
Northeastern State University
martin56@nsuok.edu
Lockwood, Jolene
Fort Berthold Community College
jolenelockwood@hotmail.com
Norman, Rachel
Univ. of North Carolina – Chapel Hill
rnorman@live.unc.edu

NAPIRE 2012 11
Pillman, Steve
University of Guam
stevepillman@gmail.com
Sanders, Andrew
University of Arkansas
ajs005@uark.edu
Sala, Evailaufaumalu
University of Hawaii – Hilo
esala@hawaii.edu
Torivio, Emilio
Southwestern Indian Polytechnic Inst.
torivio_emilio@yahoo.com

NAPIRE 2012 12
Tupu, Josephine
American Samoa Community College
jtupu@yahoo.com
Yazzie, Alanna
San Juan College
asyazzie86@my.sanjuancollege.edu

NAPIRE 2012 13
Course Activities – Lectures and Seminars
Topic Speaker
Risk Management and Safety in Costa Rica Wendy R.Townsend, PhD
Undergraduate Education at OTS Jennifer Stynoski, PhD
History of Costa Rica Robert Godshalk, PhD
Indigenous People of Costa Rica Wendy R.Townsend, PhD
Geography of Costa Rica Robert Godshalk, Phd
Research, Education and Outreach at La Selva Carlos de la Rosa, PhD
Introduction to La Selva Kenneth Alfaro, Naturalist
La Selva orientation & birding walks Naturalist Guides
La Selva nocturnal walks Naturalist Guides
Introduction to Tropical Ecology & Biodiversity Wendy R.Townsend, PhD
Introduction to Tropical Plants Orlando Vargas
Abiotic Factors in Tropical Ecosystems Robert Godshalk, PhD
Traditions in the Bribri Culture Bribri Shamans
Indigenous Groups in Costa Rica Rafael Angel Cabraca
3 Bribri Cabecar Legends Jairo Morales
Agrosylvopastoral Systems/ Cacao Tour ACOMUITA Women Association
Sustainable Wood Production in Bribri Territory Several Local Participants
Amphibian Research at La Selva Maureen Donnelly, PhD
Monitoring Biodiversity Johana Hurtado, PhD
Intro to Research Design, Statistics & Analysis Jane Zeikova, PhD
Group Project Presentations – Design & Statistics NAPIRE Students
Introduction to Bats & Tent Bat Biology Bernal Rodriguez, PhD
Changes in vegetation due to peccaries Kelsey Reider
Forest Structure & Dynamics Wendy R.Townsend, PhD
Climate Warming Effects:Herbivory in Temperate Forests Fern Lehman, MSc
Plant-animal Interactions Wendy R.Townsend, PhD
Understory Birds and the Changing Landscapes Mathew Fagan
Leaf Litter Ant Research in La Selva Terry McGlynn, PhD
Dendrobatid Research at La Selva Ralph Shapiro, PhD
Parental Care in Oophaga pumilio Dart Poison Frog Jennifer Stynoski, PhD
Banana Plantation Operations Dole employees
Ethics - Falsification, Fabrication, Plagiarism Robert Godshalk, PhD
Introduction to Las Cruces Zak Zahawi, PhD
Las Cruces Orientation Rodolfo Quiros, MSc
Writing Workshop – Introduction to the Process Michael Heppler
Ethics – Oceanic Nations and climate change Fern Lehman. MS
Introduction to Las Alturas Zak Zahawi, PhD
Writing Workshop – Manuscript guidelines Wendy R.Townsend, PhD
Ethics – Case Studies discussion Robert Godshalk, PhD
Indigenous Health Services in Coto Brus Pablo Ortiz, MD
Role of Science for Indigenous Rights in the Amazon Wendy R.Townsend, PhD
Ethics-Global Population and Womens’ Education David Baumgardner, PhD
PowerPoint Workshop–Preparing your Presentation Wendy R.Townsend, PhD

NAPIRE 2012 14
Daily Schedule
June 3 4 5 6 7 8 9
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
6:30 - Bird walk7:00 to
7:59
La selva botany
Dr.Orlando vargas,
Canopy tower visit
Tirimbina Bat
Reserve
8:00 to
8:59
8:00 travel to OTS
Office
Bus leaves 8 AM Travel to
La Selva Biological
Station
Introduction to the
Tropics -Ecosystem
Challenge setting the
rules
9:00 to
9:59 Intro to NAPIRE
2012 Johanna Hurtado
Camera Traps
10:00 to
10:59
11:00 to
11:59
History of Costa Rica
Dr. Robert Godshalk
Meet your rubber boots!
12:00 to
12:59
Picnic lunch OTS Almuerzo
13:00 to
13:59
Visit to Costa Rican
National Museum
Room Assignments
Introduction to Tropical
Ecology Dr. Townsend
and Dr. Godshalk
Indigenous Costa
Ricans and Human
Ecology in the
Amazon, Dr. Wendy
Townsend
Abiotic and Biotic
Characteristics of the
tropics
14:00 to
14:59
Orientation walk15:00 to
15:59
Dr. Ralph Shapiro and
Dr. Jennifer Stynoski
16:00 to
16:59
Folkcrafts fair
Dr. Carlos de la Rosa, La
Selva Station Director,
Research and
environmental education
activities at La Selva
17:00 to
17:59
Student Introductions
Dr. Terry McGlynn
Leaf Litter ants
18:00 to
18:59
Dinner
19:00 to
19:59
Pizza at hotel
Inaugural Dinner
Maria Bonita
Restaurant
Student Introductions
Presentations
Night Walk
Ethics night
Video Night (non-
obligatory)
20:00 to
20:59

NAPIRE 2012 15
10 11 12 13 14 15 16
June Sunday Monday Tuesday Wednesday Thursday Friday Saturday
6:30 Breakfast
7:00 to
1159 Ecosystem
Challenge
Activities
Kelsey Reider,
Changes in vegetation
due to peccary
populations
Group Research Group Research Group research
Powerpoint posters
of results NAPIRE
Students
Travel to Finca
Educativa
Talamanca
Mountains
12:00 to
12:59
Lunch
Lunch Finca
Educativa
13:00 to
13:59
Visit to Banana
Plantation
Introdution to the
Scientific Method
Wendy Townsend
Group Research
Basic statistics
Statistical
Distributions
Presentations
Ecosystem
Challenge and Leaf
cutter ant research
results
Acomuita Women's
Cooperative
Chocolate farm and
factory
14:00 to
14:59
Designing our
research, Developing
Research Questions
15:00 to
15:59
16:00 to
16:59 Mathew Fagan
"Understory birds
and the changing
landscape of the
San Juan-La Selva
Biological
Corridor."
17:00 to
17:59
Dennis Wasko
"Spatial ecology
of the terciopelo
(Bothrops
asper)"
Rafael Angel
Cabraca Indigenous
Territories of Costa
Rica, Cosmovision
of Bribri and
Cabecar Indians,
18:00 to
18:59
Dinner
19:00 to
19:59
Our literature source:
Dr. Jane Zelikova
Introduction to leaf
cutter ants
Dr. Maureen
Donnelly
Herpetologist ( joint
lecture with REU in
conference room)
Dr. Steven M.
Whitfield, La Selva
frogs
Community
Resource
Management in
Latin America
Dr. Lilian Painter
Ethics Discussion
Working with local
people
Historias Bribri
Cabecar, Jaime
Morales The
begining of the sea,
The jaguar and the
sea, The Usekra
20:00 to
20:59

NAPIRE 2012 16
17 18 19 20 21 22 23
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
6:30
Preparation of
research plan
7:00 to
7:59
7:30 Travel to Las
Cruces
Possible Study
Site visits
Possible Study Site
visits
Research Plan and
sample data spread
sheet
8:00 a
8:59
8:30 leave to
Kashabri
Conical House
8:00 to Shiroles Monte
de Sion school
NAPIRE Cultural
Exhange
Research Mentor
Training and
Planning Session
Hotel Students
free time
9:00 to
9:59
10:00 to
10:59
11:00 to
11:59
12:00 to
12:59
Traditional
Lunch-
Kashabri
Lunch at Finca
Educativa
Students lunch
where they want
Lunch on the
Road
Lunch at Las
Cruces
13:00 to
13:59
Medicinal
Garden,
Traditional
Chocolate
Grinding
Visit to Community
Forestry and Carpentry
Shop
Meetings Students
and Research
Mentors
14:00 to
14:59
Intercambio
con Niños de la
comunidad
Kashabri 14:30 leave for San
Jose
Arrival Las Cruces
Communications
Workshop
Communications
Workshop
Communications
Workshop
15:00 to
15:59
Distribution of
rooms
16:00 to
16:59 Orientation to Las
Cruces17:00 to
17:59
18:00 to
18:59
Diner
Buffet Dinner at
Hotel Rincon de
San Jose
Diner
19:00 to
19:59
Edeline Gallardo
Biodiversity in
Indigenous
territories
Pizza at Hotel
Mentors arriving
Introduction to Las
Cruces Zak
Zahawi
Mentor
Introductions
part 2
Ethics Discussion
20:00 to
20:59
Mentor
Presentations
part 1

NAPIRE 2012 17
24 25 26 27 28 29 30
June/July Sunday Monday Tuesday Wednesday Thursday Friday Saturday
6:30 Breakfast
7:00 to
11:59
Leave to Las Alturas Hike to La Amistad
Clean up and
packing
Individual
research
Individual research Individual research
1
12:00 to
12:59
Box Lunch Box Lunch Box Lunch Lunch
13:00 to
13:59
Presentations
Student Research
Project Plans
Activities Las
Alturas
Leave Las Alturas
back to Las
Cruces Communication Workshop
14:00 to
14:59
Communication
Workshop
Project Plan
15:00 to
15:59
16:00 to
16:59
17:00 to
17:59
Poster summary of
Literature Consulted
due
18:00 to
18:59
Dinner Dinner Las Alturas Dinner Las Cruces Dinner
19:00 to
19:59
Cultural Exchange
community of Las
Alturas
Simposium
Global warming
effects on leaf
herbivory and
quality in eastern
temperate forest
species, Fern
Lehman "
Ethics Night Video Night
20:00 to
20:59

NAPIRE 2012 18
1 2 3 4 5 6 7
July Sunday Monday Tuesday Wednesday Thursday Friday Saturday
6:30
7:00 to
7:59
Individual
research
Individual
research
Individual
research
Individual
research
Individual
research
Individual research Individual research
8:00 a
8:59
9:00 to
9:59
10:00 to
10:59
11:00 to
11:59
12:00 to
12:59
Lunch
13:00 to
13:59
14:00 to
14:59
Communication workshop
15:00 to
15:59
16:00 to
16:59
17:00 to
17:59
written methods
section due
18:00 to
18:59
Dinner
19:00 to
19:59
SIMPOSIO TBA Ethics Video Night
20:00 to
20:59
4th of July
Barbecue

NAPIRE 2012 19
8 9 10 11 12 13 14
6:30
7:00 to
7:59
Brunka visit Individual research Individual research Individual research Individual research Individual research
8:00 a
8:59
9:00 to
9:59
10:00 to
10:59
11:00 to
11:59
12:00 to
12:59
Box Lunch Lunch Las Cruces
13:00 to
13:59
Deadline SACNAS
Thursday
Simposium TBA
DEADLINE for
SACNAS
14:00 to
14:59
Brunka visit
Communication workshop15:00 to
15:59
16:00 to
16:59
17:00 to
17:59
written background
section, literature
review
18:00 to
18:59
Dinner Las Cruces
19:00 to
19:59
SIMPOSIO TBA Ethics Video Night
20:00 to
20:59

NAPIRE 2012 20
15 16 17 18 19 20 21
6:30
7:00 to
7:59
Individual
research
Individual
research
Individual
research
Individual
research
Individual
research
Individual
research
8:00 a
8:59
Intercambio Cultural
Ngobe
9:00 to
9:59
10:00 to
10:59
11:00 to
11:59
12:00 to
12:59
Lunch Lunch at La Casona Lunch Las Cruces
13:00 to
13:59
14:00 to
14:59
communication workshop
15:00 to
15:59
16:00 to
16:59
17:00 to
17:59
written results
and analysis
section due.
18:00 to
18:59
Dinner
19:00 to
19:59
SIMPOSIO TBA Ethics Night Video Night
20:00 to
20:59

NAPIRE 2012 21
22 23 24 25 26 27 28
6:30
Individual
research
Individual
research
Individual
research
Draft final
paper due Presentation Practice
7:00 to
7:59
NAPIRE Research
Simposium
8:00 a
8:59
Rachel Norman
Cedric Fairbanks
9:00 to
9:59
Alanna Yazzie
Emilio Torivio
10:00 to
10:59
Break
Alex Hardison
Jolene Lockwood
Paul Martinez
11:00 to
11:59
Paul Martinez
Jolene Lockwood
12:00 to
12:59
Lunch
13:00 to
13:59
Powerpoint
Presentation
workshop
Presentation Practice
1:30 Michelle
Kernak
Final Paper
Due
14:00 to
14:59
Robert Hall
Aliah Irvine Clean up and
Exit Interviews,
Assesments,
3rd Progress
Report,
Evaluations
15:00 to
15:59
Communication Workshop Conclusions and
discusions
NAPIRE Research
Simposium
Eva Sala
Briana Albini
16:00 to
16:59
Severino Alforeza
Steven K Pillman
Break
Brandi Leigh Adams
17:00 to
17:59
Naomi Leon-Guerrero, Josephine Tupu
18:00 to
18:59 Christmas in
July Dinner
and Gift
Exchange
Dinner
19:00 to
19:59
SIMPOSIO
TBA
Closing Celebration
20:00 to
20:59

NAPIRE 2012 22
29 30
August Sunday Monday
6:30
7:00 to
7:59
7:30 Leave Las
Cruces
Bye-Bye (sniff
sniff). Students
and Mentors
return home
8:00 a
8:59
9:00 to
9:59
10:00 to
10:59
11:00 to
11:59
12:00 to
12:59
BOX LUNCH
13:00 to
13:59
14:00 to
14:59
15:00 to
15:59 Free Time Moravia
Crafts Fair
16:00 to
16:59
17:00 to
17:59
Bus to Hotel Rincon
de San Jose
18:00 to
18:59
19:00 to
19:59
Closing Dinner and
Awards Ceremony
Antojitos

NAPIRE 2012 23
Welcome to San Jose!

NAPIRE 2012 24
La Selva Biological Station (OTS)

NAPIRE 2012 27
Dole Banana Plantation

NAPIRE 2012 28
Tirimbina Biological Reserve (Bat Conservation)

NAPIRE 2012 29
Bribri Indigenous Reserve

NAPIRE 2012 33
Las Alturas Biological Reserve

NAPIRE 2012 36
Ngöbe Indigenous Reserve

NAPIRE 2012 38
Brunka Indigenous Reserve

NAPIRE 2012 40
Las Cruces Biological Station (OTS)

NAPIRE 2012 45
Special thanks to all the home institution support staff, some present here:

NAPIRE 2012 46
Special Occasions-Birthdays, 4th of July, Christmas in July

NAPIRE 2012 48
Student Research Presentations

NAPIRE 2012 51
Student Research Reports:
Agouti of Las Cruces Biological Research Station
Brandi-Leigh H. Adams
Kapiolani Community College
Honolulu, Hawai’i
Abstract
Agoutis (Dasyprocta punctata) play an important role as seed dispersers in forests for
their scatterhoarding behavior. The overall goal of this study was to better understand agouti
behavioral food ecology. The objective was to evaluate the species of plants agoutis display
food behaviors over within Wilson Botanical Garden (WBG) at Las Cruces Biological Research
Station. Additionally, with a student colleague and assistants we evaluated the density and
distribution of agouti at WBG. In my study, several research methods were employed to study
agoutis including daily observations over ten minute intervals during designated time periods
within GPS plotted viewsheds. Line transects and agouti census surveys were also conducted to
better determine agouti density in Wilson Botanical Garden. For fruit and seed information, I
conducted interviews with the Las Cruces taxonomist. Likewise, a fruit and seed analysis was
conducted to determine fruit/seed availability to agouti within WBG. Camera traps were also
employed within viewsheds in target areas where agouti were observed eating or foraging to
evaluate agouti activity.
Results from our viewshed surveys, line transects, and census surveys indicate that the
number of animals present within WBG is approximately 18-22 agoutis. We also found that
agouti are not evenly distributed throughout WBG because our data showed higher observations
of agouti activity within certain viewsheds. Data also demonstrated that agoutis have a wide
diversity of fruits and seeds available at Wilson Botanical Garden but agoutis are not displaying
food behaviors over many of these species. My research indicated that individual observations
of agoutis do not correlate with the measured fruit/seed density within our viewsheds. The
results of this study are important to Las Cruces Biological Research Station because it provides
a better understanding of agouti behavioral ecology. The results of this research study can
provide information to be used beyond Las Cruces to show the importance of agoutis to
ecological systems in the Neotropics as seed dispersal agents.
Introduction
The agouti (Dasyprocta punctata) is a meso-sized rodent that is unique to the tropics and
is a member of the suborder, Cavimorphs (Kricher 1999). Agoutis are omnivorous but are
mainly dependent on fruits and seeds with a “preference for large seeds” (Jorge and Peres 2005).
Agoutis are approximately 50 cm in size and 3-6 kg in weight and are strictly ground-dwelling
rodents (Wainwright 2002, Jorje and Peres 2005). Agoutis eat in a manner similar to squirrels,
where they sit on their haunches watching for predators, freeing their forepaws for manipulating
food (Janzen 1983). Agoutis easily penetrate hard seeds with their sharp incisors and fruits are
calorically rich, nontoxic, and easily accessible food items for their diet (Kricher 1999).
From an ecological perspective agoutis are important agents of seed dispersal because
they scatterhoard seeds and fruits. Scatterhoarding is the process of collecting more food than
the agouti can consume at the time and burying the food in a widely scattered pattern to be dug

NAPIRE 2012
52
up later in times of food shortage (Kricher 1999). Benefits of scatterhoarding include increased
probability of survival for adults and their offspring in times of food shortages, optimized
foraging and eating, and improved foraging for limited resources (Guimaraes et al. 2005).
However, the agouti may not return to retrieve the buried fruits and seeds, thus contributing to
dispersal of seeds which germinate to become trees. Agoutis will disperse small and large seeds,
thus contributing to forest community dynamics and directly influencing the distribution of seeds
and inevitably adult trees (Enzo 2004).
The agouti population at Las Cruces Biological Research Station (LCBRS) near San
Vito, Costa Rica is likely an agent of seed dispersal within the Wilson Botanical Garden.
Unfortunately, no database is available to show what species of plants (i.e. seeds and fruits) the
agouti forage and scatterhoard (Federico Oviedo, personal communication: 2012). This
information is useful to LCBRS because it provides a better understanding of the behavioral
ecology of agouti and the dispersal of seeds which can provide insights to forest restoration in
the Coto Brus county of Costa Rica. Agoutis are accessible and easily viewable at LCBRS due
to protection within the garden from hunting and habitat destruction. Therefore, I focused on
agouti behavioral food ecology within WBG in my research study. The objective of my research
was to determine the fruit and seed species that agouti forage, eat, and scatterhoard.
Additionally, my research colleague and I evaluated the density and distribution of agouti within
WBG. After surveying the WBG area and speaking to ecologists and taxonomists, it was
apparent that a unique variety of fruits and seeds are available for agouti, which is distinctly
unique from other geographical areas where agouti have been studied. I hypothesized that
agoutis display food behaviors over a small group of fruit and seed species (<15) throughout
WBG. My alternate hypothesis was that agoutis do not display food behaviors over a small
group of fruit and seed species (<15) throughout WBG.
Methods
Our study was conducted at Las Cruces Biological Research Station, which is located in
the Coto Brus region of Costa Rica. This study was specifically located within the Wilson
Botanical Garden (WBG) of Las Cruces. Las Cruces is classified as a tropical pre-montane rain
forest according to the Holdridge Life Zone system, and it receives approximately 4,000 mm of
rainfall annually. Las Cruces is located about 1,150 m above sea level and the average monthly
low temperatures range from 15-21 C. The average monthly high temperatures range from 21-
26 C. Habitat structure within WBG is unique as a wide diversity of plant species is present in
the garden. Many of these species are not native to Costa Rica. The materials used to conduct
this study included: a map of WBG, pink and orange flagging, binoculars, Ziploc bags to hold
fruit/seed specimens, pencil/pen, field notebooks, data sheets, sharpies, camera, GPS, camera
traps, compass, 1x1 m quadrat, 2 dice, clipboard, and a digital watch.
We divided WBG into 25 view sheds, which were delineated by markers. The viewsheds
were selected based on visibility of animals within each sector. Each viewshed was assigned a
number from 0 – 24, which was written on the flagging to designate the viewshed boundaries.
Boundaries were chosen where visibility was at a maximum within a 2-meter radius from each
viewing station. Viewing stations were separately marked from the boundaries with orange
flagging so the station was easy to identify. The entire garden was plotted with a few exceptions
due to dense vegetation or buildings. All plotted sections of the garden were monitored to
minimize bias in data collection. The view sheds were mapped using GIS.

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On a daily basis all viewsheds were divided between 2-4 observers who stood at the
designated viewing station, moving within a 2-meter radius to observe and document agouti
behavior within the viewshed. Over a 10-minute period, observers scanned the viewshed to count
agouti, document behavior, and record the amount of time spent eating and/or foraging (if it
existed). When an agouti was observed foraging or eating, observers documented or collected a
food sample when feasible using one of the following methods: (a) use of binoculars to identify
the fruit/seed being eaten, (b) use of camera traps near trees where fruits and seeds drop and at
the compost pit to get photos of agouti activity, and (c) observing and collecting seeds and fruits
that agouti were observed either foraging for and/or eating when in our viewsheds.
To further reduce research bias, observers alternated plots daily. Observations were
conducted at different times of the day between 5:00am – 6:00pm to assess agouti activity
throughout the day. This time period of 5:00am – 6:00pm was divided into six activity periods
during which we would conduct our surveys. However, dominant viewshed sampling was
conducted during the agoutis’ expected peaks of activity (5:00-8:30am and 4:00-6:00pm).
To collect further data on agouti density, line transects were conducted twelve times to
increase reliability of density counts and as a comparative method. Observers walked transects
10-20 m apart and tallied agoutis in the appropriate size class. We also collected census data on
six separate days in our viewsheds with 25 individuals observing all viewsheds at the same time
from 7:30-7:45am. During these censuses we documented the same information we collected in
our daily viewshed surveys.
In addition to conducting daily viewshed observations, a method of analyzing fruit/seed
density and distribution within viewsheds was developed. For each viewshed (with the
exception of viewshed 13), the center of the viewshed was estimated and a 1x1 m quadrat was
placed on the ground. The fruit/seed density within the 1x1 m quadrat was calculated according
to a density scale we developed (see below). Pink flagging was then placed in the center of that
quadrat and the point was recorded with GPS. Following this, we designated north, south, east,
or west from the center point using a compass. Once the bearing was found, we used a
randomization method of rolling 2 dice and the sum rolled indicated the number of meters we
would travel from the center point to the bearing on the compass. Using the 1x1 m quadrat, we
measured the distance in the given direction to travel. From this point, we recorded the fruit/seed
density within the quadrat and calculated the center point using GPS. Next, we returned the
quadrat to the center point that was designated by the pink flagging and repeated the process for
all compass directions (i.e. north, south, east, and west). This method gave us a total of five
quadrat surveys and GPS points within each viewshed. Viewshed 13 only had a single GPS
point that represented the compost pit, due to the fact that the fruits/seeds within this plot are
clearly concentrated within a single pit. The density code and scale developed is as follows:
Table 1: Fruit/Seed Density Code
Density code Translation
0 No seed/fruits on the ground
1 ≤10 seeds/fruits on the ground
2 11-50 seed/fruits on the ground
3 51-100 seeds/fruits on the ground
4 >100 seeds/fruit on the ground

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Finally, interviews were conducted with the Las Cruces taxonomist, Federico Oviedo, for
a total of 6 hours. F.Oviedo identified fruit and seed samples that were collected in the garden
and also identified plants on garden walks that agoutis were observed eating and/or were strong
candidates for consumption due to size and abundance of fruits or seeds. Plants identified were
flagged and all the species of fruits/seeds were given a code beginning with “F” followed by a
number (e.g. F1, F2, F3)
Analysis
The GPS points of our viewsheds were sent to the Las Cruces GIS Manager, Mauricio
Pancho to be overlaid on the pre-existing map of WBG. From the GPS points taken at each
viewing station in each viewshed (for a total of 25 GPS points), M.Pancho used the GIS
function, “Thiessen Polygons” to calculate the viewsheds. Slight changes were made to four
borders, as the Thiessen Polygons did not accurately represent those four borders. Areas of
WBG where no agouti observations were made were grayed out on the map. Data collected
from daily view shed observations, walking transects, agouti census viewshed observations,
fruit/seed density, camera trap photos, and fruit/seed identifications obtained from interviews
with Federico were inputted into six separate Excel spreadsheets, respectively. Statistical tests
used to analyze our data were descriptive statistics such as sums, means, and standard deviations
in Excel. We also conducted a Chi Square Goodness of Fit, and regression analysis in a program
called Minitab.
Results
The agouti census data was organized into a table showing the total agouti observations
from each day as well as the average number of agoutis, thus displaying the estimated agouti
density (Table 2).
Table 2: Agouti Average From Census Survey Data
Date Total Mean
5-Jul-12 15 1.50
7-Jul-12 20 1.70
17-Jul-12 21 1.10
19-Jul-12 13 1.58
20-Jul-12 19 1.57
21-Jul-12 22 1.63
110 1.51
Avg. # of agouti 18.33
St.
Dev. 3.60
Density
per
hectare
2.57

Data from line transects also was also organized into a table similar to Table 2, and also
shows the average number of agoutis observed from this method (Table 3).

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Table 3: Agouti Average From Walking/Line Transect Data
Transect Total Obs. Mean Obs.
AM Transects
67 0.59
Avg. Total 15
PM Transects
30 0.58
Avg. Total 12
Avg. for AM & PM 8.08
St.
Dev. 2.57
The number of individual agouti sightings from the daily viewshed observations was
converted into a histogram according to number of agouti sightings per viewshed to show agouti
distribution within WBG (Fig. 1).
Fig. 1: Histogram showing the number of agouti observations per viewshed. Data shown here
was analyzed from the daily viewshed survey method only.
The sums and means of the agouti observations from daily viewshed surveys were also
calculated to discern agouti distribution within WBG. A color-coding system was created
according to the number of agouti observations within viewsheds and this information was sent
to M.Pancho to be added to our viewshed map. Based on the color code, each viewshed was
shaded with a specific color. Each color represents the number range of agouti observations
within a given viewshed. In terms of agouti distribution within WBG, we found that the total
0
20
40
60
80
100
120
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
NumberofAgoutiObservations
Viewsheds
Agouti Observations at WBG Per Viewshed
St. Dev. of total
agouti obs:
22.98

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number of agouti observations were highest in viewsheds 12, 13, 14, and 22. The total number
of agouti observations were lowest in viewsheds 2, 3, 4, 5, 8, 23, and 24 (Fig. 2).
Fig. 2: Map of WBG with agouti distribution according to the number of agouti observations per
viewshed.
We also ran a Chi-Square Goodness of Fit test to see if agouti distribution was equally dispersed
throughout all viewsheds (Figure 3). Our resulting Chi-square value was very high (252.78) with
a low P value of 0.000, demonstrating that our data was highly significant. This indicates that
agouti distribution based on the number of observations is not even across the viewsheds of
WBG.
Fig. 3: Chi-Square Goodness of Fit chart
Category 2731057713241
300
250
200
150
100
50
0
Value
Expected
Observed
Chart of Observed and Expected Values
DF = 4
Chi Square Value
= 252.78
P Value = 0.000

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The same data from the daily viewshed observations was also organized according to
agouti activity periods to demonstrate which periods in the day agouti are most active. Our data
shows that agouti have two peak activity periods between 5:30-8:00am and 4:00-6:00pm (Fig 4).
Fig. 4: Graph of the number of agouti observations according to activity period.
Information from the interviews with F.Oviedo on the different species of fruits and seeds
available to agouti with WBG is projected below (Table 4). Altogether, we identified 37 species
of fruits and seeds within WBG that agouti were observed eating or may potentially eat based on
observations in the field and F.Oviedo’s expertise. Species with an asterisk (*) next to its name
are species of fruits and seeds that were not in fruit at the time our study was conducted. The
categories “Compost” and “Other” are included because, although no codes were given to these
categories (as the specific species cannot be identified), this information was still documented
during our research when an agouti was observed eating or foraging for these categories.
Table 4: Fruit and Seed Identification Database & Agouti Consumption Behavior
0
50
100
150
200
250
300
350
400
5:30-8:00am 8:00-10:00 10-12:00pm 12:00pm-2:00pm 2:00-4:00pm 4:00-6:00pm
#ofAgoutiObservations
Activity Periods
Agouti Activity Periods - WBG
Fruit/Seed

Code
Name
of
Fruit/Seed

Viewshed

found
in

Sure
of

consumption

Unsure
of

consumption

F1
Ruagea
glabra

1,
7,
11
X

F2
Juglands
olanchana
4,
10,
11
X

F3
Syagrus
coronata

9,
12
X

F4
Zalacca
sp.

22
X

F5
Areca
sp.

22

X

F6
Pinang
sp.

22
X

F7
Eriobotrya
japonica
9
X

F8
Psidium
guajava

20
X

F9
Ficus
tonduzii
18
X

F10
Carica
papaya
9
X

F11
Phytelephas
aequatorialis
22

X

F12
Attalea
butyraceae
3

X

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Fruit/Seed

Code
Name
of
Fruit/Seed

Viewshed

found
in

Sure
of

consumption

Unsure
of

consumption

To analyze what fruit/seed species agouti consume within WBG, we calculated the
number of observations from our daily viewshed surveys which included agouti eating those
fruits or seeds we identified. Of the 37 species identified, we observed agoutis eating 10 of those
species. The number of observations of agouti eating compost and other items that cannot be
classified as fruit/seed species were also included in (Figure 5).

F13
Inga
densiflora
24
X

F14
Citrus
aurantiacus

18,
19
X

F15
Dypsis
decipiens
9
X

F16
Psidium
littorale
5,
9

X

F17
Hyophorbe
lagenicaulis
5
X

F18
*Bactris
sp.
5
X

F19
Areca
vestiaria
4
X

F20
Ficus
auriculata
4
X

F21
*Iriartea
deltoidea

11
X

F22
*Areca
sp.

11
X

F23
Quercus
sp.

12,
Lab
X

F24
*Tagua
12
X

F25
Matisisa
cordata
12
X

F26
Syzygium
malaccense
6
X

F27
Wettinia
sp.
12
X

F28
Attalea
iguadummat
14
X

F29
*Drospyros
ebenaster
16
X

F30
Ficus
imbricata
17
X

F31
Socratea
exorrhiza
18
X

F32
Quercus
rapuruherensis
18
X

F33
*Salaca
edulis
19

X

F34
Livinstona
sp.

22
X

F35
Vochysia
guatemalensis
22
X

F36
Arenga
sp.
22

X

F37
Diospyros
sp.
22

X

-‐-‐
Compost
13
X

-‐-‐
Other
-‐-‐
X

NAPIRE 2012
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Fig. 5: Graph of the number of observations of agouti eating fruit/seed species we identified.
Data collected from the fruit/seed density and distribution analysis is shown in Table 5
(see below). Means of fruit/seed density were calculated for each viewshed and a scaling system
was created to differentiate between viewsheds of high, medium, and low fruit density. It
appears that fruit density is greatest in viewshed 4, 8, and 13 according to the density means
calculated.
Table 5: Fruit/Seed Density Means Per Viewshed
Viewshed
Density
Sum
Density
Mean

11
0
0.0

23
0
0.0

15
1
0.3

18
1
0.3

21
1
0.3

24
1
0.3

17
2
0.7

19
2
0.7

12
3
1.0

14
3
1.0

16
3
1.0

0
4
1.3

1
4
1.3

2
4
1.3

3
4
1.3

20
4
1.3

5
5
1.7

6
5
1.7

9
5
1.7

22
5
1.7

22

2
1
0
0
0

7

1
0
0
0
0
0
3
0
0
0
0
0
1
0
0
0
0
0

7

0

6

0
0
0
0
0
2
0
0
0

70

6

0

20

40

60

80

Total
ObservaAons

Food

EaAng
ObservaAons
From
Daily
Viewshed

Surveys

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Viewshed
Density
Sum
Density
Mean

7
6
2.0

10
6
2.0

4
8
2.7

8
8
2.7

13
4
4.0

The fruit/seed density data and corresponding GPS points were given to M.Pancho, who
added this data to our viewshed map. This includes the color-coding for each viewshed for the
number of agouti observations. The color-coding system previously discussed in the methods
section (see Table 1) has also been included in this map. Each square on the map represents the
1x1 m quadrat areas where fruit/seed density was calculated (Figure 6).
Fig. 6: Map showing the density and distribution of fruits/seeds in WBG in relation to the
volume of agouti observations within each viewshed.
When analyzing this map, it appears there is no relationship between the fruit/seed
density and distribution and the number of agouti observations within each viewshed. A linear
regression was also conducted which demonstrated no correlation between agouti activity and
fruit/seed density within viewsheds. The negative T value of -0.22 and the P value of 0.828
confirmed that our values were not significant, thereby indicating that there is no relationship
between the number of agouti observations and the fruit/seed density and distribution within
viewsheds (Fig. 7).

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Fig. 7: Chart of regression analysis of fruit/seed density in relation to
agouti observations per view shed
Data collected on foraging and scatterhoarding behavior of agoutis within WBG was not
sufficient to give an in-depth analysis of these food behaviors. However, we found that, out of
the 622 agouti observations from our daily viewshed surveys, 21 of those observations were of
agouti scatterhoarding. This calculates to approximately 3.38% of our total observations.
Additionally, 219 out of the 622 observations were of agouti foraging, which calculates to
approximately 35.21% of our total observations. Compared to a study done on agouti
(Dasyprocta ruatanica) on Roatan Island, researchers found that agouti spend 15.4% of the time
they spent observing agouti behavior on sniffing and digging, which can constitute finding or
making scatterhoards as well as foraging (Lee et.al. 2000).
Discussion
After analyzing our data, we found that we cannot reject the null hypothesis that agoutis
display food behaviors over a small group of fruit and seed species (<15) throughout WBG. A
full database of the fruits and seeds available to agoutis within WBG would need to be created
and tests would need to be run to see how many of these species agouti actually eat. Clustered
sampling of the fruit and seed species is one method to implement a test for this hypothesis. We
were able to reject the alternate hypothesis that agouti do not display food behaviors over a small
group of fruit and seed species (<15) throughout WBG because we observed that agoutis
consume 10 species of fruits and seeds in our study. However, this does not mean that further
research should not be conducted, as our results do not fully represent agouti food behaviors
within WBG. It is also important to note that the presence of the compost pit within WBG may
be affecting how many fruit and seed species agoutis consume. Future research should evaluate
the effects of the compost pit on agouti food behavior.
As a recommendation to improve to these methods, we suggest more time to conduct this
research. At least a full year should give future observers a better idea of agouti food behaviors
9876543210
100
80
60
40
20
0
IV Fruits
DVAgouti
Scatterplot of DV Agouti vs IV Fruits
Regression:
T = -0.22
P = 0.828
Analysis of Variance:
F = 0.05
P = 0.828

NAPIRE 2012
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within WBG. Having at least a year is particularly important if researchers want to study the
effects of the compost pit because our study was conducted during a very busy season at Las
Cruces. During the summer there are many visitors, which means more food is being prepared.
Therefore, the compost pit has a larger volume of food compared to other times of the year. It is
important to see if agouti food behavior changes when the volume of the food in the compost pit
is lower.
For daily viewshed surveys I recommend conducting more surveys during the non-peak
activity periods. We only conducted four surveys in each of the non-peak activity periods.
Additional surveys during those times would bias the results less. In regards to the walking
transects, future researchers should conduct the same number of transects in the mornings as the
evening to balance the sampling. Improvements to census surveys are to establish individuals
prescheduled to do observations for every day that a census is conducted, run one “practice
survey” to get observers accustomed, have observers report to their stations 5 minutes before the
actual survey is to begin, and make sure all observers have their watches synchronized. For the
fruit and seed density and distribution survey, I suggest taking more sample points within each
viewshed or developing a clustered method of surveying. Since fruit and seed distribution is not
sporadic, (i.e. fruits and seeds fall from their mother trees and they do not fall very far from
them) it is a better idea to have a clustered survey method. Future researchers should spend more
time with the taxonomist to achieve a full database of species within WBG that produce
fruits/seeds to better this research project. Lastly, camera traps should be set to take more videos
instead of photos, because we had difficulties with the sensors on the cameras.
The continuation of research regarding agouti behavioral food ecology is important to the
scientific world because agoutis disperse small and large seeds via scatterhoarding, thus
contributing to forest community dynamics (Enzo 2004). By understanding agouti food
behavior, we can better understand their role as agents of seed dispersal and how this can
contribute to forest restoration in later secondary growth of reforested areas.
Literature Cited
Aliaga-Rossel, E.R. 2004. Landscape use, ecology and home range of the agouti (Dasyprocta
punctata). Word processed and bound thesis, 103 pages, 6 tables, 22 figures.
Guimarães Jr, P.R., Gomes, B.Z., Ahn, Y.J., and Galetti, M. 2005. Cache pilferage in red-
rumped agoutis (Dasyprocta leporina) (Rodentia). Mammalia 69 (3-4): 427-430.
Janzen, D.H. 1983. Costa Rican natural history. University of Chicago Press: Chicago.
Jorge, M.S.P., Peres, C.A. 2005. Population density and home range size of red-rumped agoutis
(Dasyprocta leporina) within and outside a natural Brazil nut stand in Southern
Amazonia. Biotropica 37(2): 317-321.
Kricher, J. 1999. A Neotropical companion: an introduction to the animals, plants, & ecosystems
of the new world tropics. Princeton University Press: Chichester, West Sussex.
Lee, T.E., Rhodes K.R., Lyons, J.L., Branan, D.K. 2000. The natural history of the Roatan
Island agouti (Dasyprocata ruatanica), a study of behavior, diet and description of the
habitat. The Texas Journal of Science.
Wainwright, M. 2002. The natural history of Costa Rican mammals. Featherstone, D, (ed). Pp:
178-180. Zona Tropical, Miami, Florida.

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Acknowledgements
Many thanks to NSF for funding the program under which my study was conducted, to
OTS and NAPIRE for providing me with the space and means of conducting my research, and to
KCC STEM staff for encouraging me to apply for NAPIRE and face the challenges of
conducting fields work and scientific research.
Thank you to Dr. Leslie Hay Smith, Dr. Patrick Hart, Dr. Frank Camacho, and Dr. Wendy Kuntz
for being my mentors and guiding me through the many aspects of conducting my research.
Thank you to Dr. Wendy Townsend, Dr. Robert Godshalk, Fern Lehman, and Rhiana Jones for
being a supportive staff and providing an excellent learning environment for myself and all the
NAPIRE students.
Thank you to Federico Oviedo, Rodolfo Quiros, and Mauricio Pancho for their help in the field
and for creating the maps for my research project.
Research Assistants: Cedric Fairbanks, Johanna Hay Smith, Jesse Hay Smith
Research Volunteers: Rachel Norman, Aliah Irvine, Steven Pillman, Naomi Leon-Guerrero,
Robert Hall, Severino Alforeza III, Eva Sala, Michelle Kernak, Jolene Lockwood, Alanna
Yazzie, Briana Albini, Andrew Sanders, Analisa Shields-Estrada, Madeline Sides, Luke
Frishkoff, Shafkat Kahn, Dr. David Baumgardner, Dr. Karin Gastreich, Dr. Richard Bigley,
Benjamin Bigley, Galen Bigley, Susan Hart, Violet Hart & Carlos Gonzalez
Photography: Joshua Pang-Ching & Dr. Leslie Hay Smith

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Comparison of predatory behavior between male and female Dipoena spiders
Briana Albini
University of Hawai’i at Hilo
Hilo, Hawai’i
Abstract
There is little scientific knowledge about the predatory behavioral differences between
male and female Dipoena spiders. This research will increase the general spider predatory
behavior knowledge for the greater scientific community by adding more information on non-
dimorphic spiders. This research was conducted at Las Cruces Biological Station in Coto Brus
County, Costa Rica. Based upon some preliminary observations and literature research, I
hypothesized that male and female Dipoena spiders would have different hunting characteristics.
12 male and 32 female spiders were caught along the Rio Java, Wilson, and Melissa trails as well
as within the botanical garden. Each spider had 3 behavioral observation tests. The first was to
watch reactions when a Pheidole ant was introduced. The second was to observe behavior when
another ant species (OAS) was introduced. The last test was to view behavior when 10 Pheidole
were inserted into a Petri dish. I predicted female spiders would be more aggressive towards
Pheidole in both the individual Pheidole ant and multiple Pheidole insertion observation, while
males may be more aggressive towards other ant species. A chi-squared test was done on each of
the three tests. For the single Pheidole observation, there was no significant difference between
male and female behavior. However, the Chi-squared test did indicate that females are
significantly more likely to attack multiple individuals, as well as other species. For the single
Pheidole and the 10 Pheidole test, males had a slower initial attack time than females. Males
also, on average, attacked fewer ants during the 10 Pheidole treatment and number of bites was
also lower during the single Pheidole treatment. Males did not attack during OAS treatment.
Female initial attack during OAS trial was slower than during single Pheidole trial. Overall,
these results indicate that male and female Dipoena do differ in predatory behavior under certain
circumstances.
Introduction
Most of the spiders known throughout the world are generalist, but there are some spiders
that specialize upon specific prey such as ants (Pekar 2004). Spiders that specialize on ants are
called myrmecophagic. Predatory behavior in myrmecophagic spiders has been studied in several
different spider families such as Thomisidae, Zodariidae, and Theridiidae. In Pekar’s paper,
which looks into predatory behavior and prey preference of two European spiders, he observes
that after Zodarion rubidium attacks an ant, it quickly retreats a safe distance away (2004). For Z.
rubidium, capturing ants is risky especially as ants become aggravated during an attack; hence
the spiders need to move away to a safe distance (Pekar 2004). Of the two European spiders
Zodarion germanicum and Zodarion rubidum, males attacked and subdued less ants than females
in general (Pekar 2004). Predatory habits between male and female spiders of any species has
only been looked at rarely, such as in Yeargan & Quates’ (1997) paper which looks into adult
male Bola spiders hunting tactics compared to female Bola spiders. Bola spiders are different
from Dipoena because Bolas have extreme dimorphism (Yeargan & Quate 1997) while Dipoena
males and females are similar in size.

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65
Some myrmecophagic spiders can choose from a variety of ants while others will only
feed upon a selected species of ant (Pekar 2009). Two species of spiders that seem to be
exclusively myrmecophagic are the Theridiid Dipoena and a Thomisid Aphantochilus (Umeda et
al. 1996; Castanho & Oliveira 1997 as cited Pekar 2009). There are some myrmecophagic
spiders that show preference for a certain genera or species of ants (Pekar 2009). Dipoena spp. is
one of the myrmecophagic spiders that show preference for a specific ant species.
Within the Piper ant-plant system, Dipoena spiders exclusively feed upon Pheidole
bicornis (Gastreich 1999). They capture ants at the entrance holes of the hollow petiole where
the ant colony resides (Letourneau & Dyer 1998). Differences in predatory activity between male
and female spiders have not been documented for Dipoena spp. As ant specialists, Dipoena spp.
females may be more aggressive towards P.bicornis ants then males. It has also been observed
that female Dipoena spp. will take down multiple P.bicornis if possible (Gastriech per., comm.).
The null hypothesis for this research is that male and female Dipoena spp. will have the
same hunting behaviors and the alternative hypothesis is that male and female Dipoena spp. will
have different hunting behaviors. I predicted females will be more aggressive towards Pheidole
ants in both single and multiple ant introduction tests because females may be more territorial for
leaves or they may have greater nutritional needs. I also predicted males will be more aggressive
towards other ant species based upon the plausibility that males may need to travel between
plants to find mates and may be willing to eat what is available between plants.
Methods
This experiment was conducted at Las Cruces Biological Station from June 28 to July 20,
2012. Specimens were collected in primary forests along the Ridge trail, Wilson trail and also in
secondary forests along the Rio Java trail. Twelve male and thirty-two female Dipoena spp.
(spiders) were collected and observed.
Collection of spiders, leaves, and ants were conducted in the morning until approximately
noon. Leaves were clipped with scissors at the base of the petiole to also gather ant colonies
living inside. These ants were later used as food supplies for spiders. Not all petioles collected
had ant colonies in them. Leaves, with spiders still on them, were placed in individual Ziploc
bags. They were carried in a larger plastic bag to reduce possible damage or shock to spiders.
Dipoena spp. were only collected from Piper ﬁmbriulatum and Piper obliquum.
Leaves were modified using a pair of scissors to fit into Petri dishes. All modified leaves
included an intact base, where the spiders’ webs normally reside. After collection, individual
Dipoena spp. were housed in Petri dishes with their modified leaf. The Petri dishes were sealed
with two pieces of masking tape. Each spider then had an initial observation to clean the Petri
dish of dead ants, check if each spider was of the genus Dipoena and to check the sex of each
spider. Each Petri dish was labeled with the sex and ID number of each spider. One Petri dish
contained the petioles with ant colonies. This Petri dish was cleaned of old colonies and dead
ants after new colonies were collected.
Three experimental observations were conducted. The first was to observe behavior of
spiders when a single Pheidole bicornis was inserted into the spider’s Petri dish. The second was
to view the spiders’ response to introducing another species of ant into the Petri dish. The final
observation was to study the spider’s reaction to 10 Pheidole bicornis ants. After capture and
placement into Petri dishes, Dipoena spp. were left for 24 hours or more without food. After the
time period, one Pheidole bicornis (ant) was inserted to observe Dipoena spp. behavior. Pheidole
bicornis were placed into Petri dish by butterfly forceps. They were placed into the center of the

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Petri dish. Observation time ran for 30 minutes and measurements were taken in one minute
intervals. Measurements taken were initial insertion time (called drop time), spider behavior, ant
behavior, attack time, time of spinneret attachment (which indicates the end of attack), distance
between spider and ant, and number of bites during attack.
Twenty four hours or more after the initial experiment, a different species of ant was
introduced to the Petri dish. Ants were collected by setting out a food trap in locations around
botanical garden (near lab). Collection began every morning before observations started. Ant
species may be different but were similar in size and color. The ants used were also similar in
size to P. bicornis. Observation time lasted for 30 minutes, and was conducted in the same
fashion as the previous experiment.
After another 24 hour period, a final observation was conducted to test whether or not
Dipoena spp. hunt multiple P. bicornis. 10 P. bicornis were introduced into Dipoenas’ Petri dish
at one time. Distance between ant and spider was not recorded during the 10 Pheidole tests.
Observation time for the multiple P. bicornis went for 45 minutes each. The extra time was given
to allow more viewing opportunity of behavior for 10 ants and the attacking spiders.
Results
In the single Pheidole tests, female and male spiders were equally likely to attack the
single Pheidole based upon a p-value of 0.60 from a Chi-squared test (See figures 9 & 10). The
female average time for initial attack is 4.93 ± 4.04 minutes (SD, N=11 spiders). For males, the
average time for initial attack is 15.63 ± 12.03 minutes (SD, N=4 spiders) (See Figure 1). The
female average completion time for attack is 11.33 ± 6.41minutes (SD, N=7 spiders). Male
average for completion time for attack is 10.21 ± 10.55 minutes (SD, N=2 spiders) (See Figure
2). Lastly, female average number of bites during attack is 3.64 ± 1.57 (SD, N=11 spiders). For
males, the average number of bites during attack is 2.25 ± 1.50 (SD, N=4 spiders) (See Figure 3).
In the single Other Ant Species test there was a Chi-squared p-value of 0.05, which
means females were more likely to attack other ant species than males (See figures 9 & 10).
None of the males attacked the other species of ant, so no averages could be collected. The
female average for initial attack time was 9.16 ± 6.41 minutes (SD, N=8 spiders). The average
time to complete attack for females is 10.43 ± 6.00 minutes (SD, N=4 spiders). Finally, the
female average for number of bites is 1.88 ± 1.13 (SD, N=8 spiders).
In the 10 Pheidole ant test, the Chi-squared test resulted in a p-value of 0.02, showing
that males are less likely to attack 10 Pheidole ants, while females are more likely to attack
multiple ants (See figures 9 & 10). For males, the average time to start an attack was 21.16 ±
16.52 minutes (SD, N=3 spiders). Female average time to start an attack was 5.79 ±6.74 minutes
(SD, N=15 spiders) (See Figure7). The males’ average number of ants attacked during the
observation was 1.67 ± 1.15 (SD, N=3 spiders). The average number of ants attacked by females
during observations was 4.44 ± 2.50 (SD, N=15 spiders) (See Figure 8).
Based on these numbers, females who attacked in the single Pheidole trial, on average,
had a quicker initial attack than females who attacked during the Other Ant Species trial (See
Figure 4). In the single Pheidole trial, females who attacked had a slightly longer duration to
complete an attack than females attacking during the Other Ant Species trial (See Figure 5).
Females in the single Pheidole observation had more bites, on average, to their ant than females
in the Other Ant Species trial (See Figure 6).
In two instances, ants overwhelmed and killed female Dipoena spp. In both observations,
one ant made a frontal approach toward the spider, while another ant began an attack from

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behind the spider. Both observations had ants attacking the spider’s legs and then the body. Both
spiders had an initial attack on them by ants passing by in what was called a ‘conflict’ since the
spider did react to the ant’s presence but did not show signs of intending to attack the ant; attack
being defined as the spider biting the ant and more importantly spinning thread upon the ant to
stop its mobility. Instead, during the conflicts, the two spiders did react to being touched and
bitten by ants by running away.
Fig. 1.
Fig. 2.
0

2

4

6

8

10

12

14

16

18

Male
Female

Single
Pheidole
Average
Initial

Time
of
Attack

Male

Female

9

9.5

10

10.5

11

11.5

12

Male
Female

Single
Pheidole
Average
Duration

of
Attack

Male

Female

Time(min)Time(min)

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68
Fig. 3.
Fig. 4.
0

0.5

1

1.5

2

2.5

3

3.5

4

Male
Female

Single
Pheidole
Average
#
of
Bites

Male

Female

0

1

2

3

4

5

6

7

8

9

10

Single
Pheidole

Female

OAS
Female

Average
Initial
Time
of
Attack

Single
Pheidole
Female

OAS
Female

Time(min)

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69
Fig. 5.
Fig. 6.
9.8

10

10.2

10.4

10.6

10.8

11

11.2

11.4

Single
Pheidole

Female

OAS
Female

Average
Duration
of
Attack

Single
Pheidole
Female

OAS
Female

0

0.5

1

1.5

2

2.5

3

3.5

4

Single
Pheidole

Female

OAS
Female

Average
#
of
Bites

Single
Pheidole
Female

OAS
Female

Time(min)

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70
Fig. 7.
Fig. 8.
0

5

10

15

20

25

male
female

10
Pheidole
Avg
Time
to
Initial

Attack

male

female

0

1

2

3

4

5

male
female

10
Pheidole
Avg
#
of
Ants

Attacked

male

female

Time(min)

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71
OBSERVED VALUES:
Single Pheidole Ant
Male Female
No 8 15
Yes 4 11
Single Other Ant Species
Male Female
No 12 23
Yes 0 8
10 Pheidole Ants
Male Female
No 9 8
Yes 3 15
Fig. 9.
Chi-squared Results
Single Pheidole P-value
0.60
Single OAS P-value
0.05
10 Pheidole P-value
0.02
Fig. 10.
Discussion
Contrary to my hypothesis, male and female spiders were equally as likely to attack a
single Pheidole, showing no predatory differences within this situation. For this test, I made a
prediction that females would be more aggressive in their predatory behaviors towards ants than
males. My prediction was not supported from the results; instead both sexes were equally likely
to attack.
For the single other ant species observations, the null hypothesis was rejected, which
meant that for other ant species there was a difference between male and female hunting
behaviors. The prediction made for this test stated that males would be more aggressive than
females towards other ant species. The opposite trend was found from the results. None of the
males attacked the other species of ant, but some females willingly attacked the other ant species.

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One reason as to why this result happened may be that females have greater nutritional needs
then males.
In the final 10 Pheidole observation test, the null hypothesis was rejected, and there was a
difference between male and female predatory behavior. The initial prediction for this test was
that females would be more aggressive towards multiple Pheidole, and based upon the results
this prediction was accurate.
There were some non-significant trends within the single Pheidole observations. For
example, males seemed more reluctant than females to initiate an attack. Males and females did
have similar duration times for attack, but male duration time was slightly shorter. Also, females
had a higher amount of bites per attack than males. No males attacked during the single Other
Ant Species tests, which was interesting because I was expecting the opposite to happen. For the
OAS tests, I thought males would attack more willingly then females, but all males refused to
attack. During the 10 Pheidole trials, females had quicker times to initial attack and they were
more willing to attack greater number of ants than males. Basically during the 10 Pheidole trials,
males would take longer to initiate an attack and would attack fewer ants than females.
Overall, females were more willing to attack ants in all three trials. Female aggression
towards ants may be greater than males because females have greater nutritional needs. Some
females laid egg sacks during the duration of research, which may have also increased
aggression. The trends could also be due to the fact that the sample size for females was about 3
times larger than the male sample size. This may have been fixed if more time was allotted to
find male Dipoena spp.
During the 10 Pheidole ant test there were two interesting and rare observations. Two of
the female spiders were attacked and killed by the ants. There are a couple of plausible reasons
as to why the ants had successful kills upon both spiders. The first is that the spiders’ size was
smaller than the worker ants’ size and therefore the spider was easily overwhelmed when
P.bicornis attacked. The second plausible reason that the spiders were killed was because they
could not use their silk threads to drop down to safety like they could do naturally on a Piper ant-
plant system. In a Petri dish, spiders are completely susceptible to attacks from ants.
To date, Pheidole bicornis ants have not been observed to kill Dipoena spp. These two
observations, then, imply that a risk does exist for Dipoena spp. as ant specialists. There are four
main prey groups that have high risk for specialty predatory spiders; ants are one of them
(Nentwig 1986). Predators that can enter into a niche with low competition and a nearly
unlimited food resource, will usually take the high risk that comes with a dangerous prey
(Nentwig 1986). In a natural state, Dipoena spp. risk may not be as great because they can
escape an ant attack with their silk lines, but within this experiment, they could not escape and
risk may have increased.
An issue with observations for the 10 Pheidole test, is that some attacks upon ants were
missed or could not be viewed due to ants and spiders wandering under the leaf in-between the
one-minute observation times. To minimize any possible disturbance to spiders, Petri dishes
were not supposed to be lifted to view underneath the leaf unless it was time to do a one minute
observation and only if spider cannot be viewed. Any attacks that occurred under the leaf in-
between the observation times could not be viewed. New observation styles could be applied to
increase viewing ability during the 10 Pheidole treatment.
The retreat distance after a spider attacks an ant should also be measured, if research
upon predatory behavior of Dipoena spp. continues. During each trial that had a successful

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73
attack, the spiders were observed to move back a safe distance away from the ant. This may be
due to the risk of attack from the ant.
Another test I would recommend for future research upon Dipoena spp. predatory habits
would be to use 10 Other Ant Species trial. This test could be used to compare results from both
the single Other Ant Species and the 10 Pheidole trial. Also it would be interesting to see how
aggressive other ants would be towards spider and vice versa.
Literature Cited
Gastreich, Karin R. 1999. Trait-mediated indirect effects of a theridiid spider on an ant-plant
mutualism. Ecological Society of America. Web. 27 July 1999.
<http://userwww.sfsu.edu/~parker/bio840/pdfs/Gastreich1999IndEff.pdf>.
Letourneau, D. K., and L. A. Dyer. 1998. Density Patterns of Piper Ant-Plants and Associated
Arthropods: Top Predator Trophic Cascades in a Terrestrial System. National Science
Foundation. Web. 27 July 2012. <http://wolfweb.unr.edu/~ldyer/letdy98b.pdf>.
Nentwig, Wolfgang. 1986. Non-webbuilding Spiders: Prey Specialists or
Generalists? Oecologia 69: 571-76.
Pekar, Stano. 2004. Behavior of Two European Ant-Eating Spiders (Araneae,
Zodariidae)." American Arachnological Society 32: 31-41. American Arachnological
Society. Web. 06 July 2012. <http://www.jstor.org/stable/3706334>.
Pekar, Stano. 2009. Capture efficiency of an ant-eating spider, Zodariellum asiaticum (Araneae:
Zodariidae), from Kazakhstan. Journal of Arachnology 37: 388-91. Bio One. American
Arachnological Society, 2009. Web. June-July 2012.
<http://www.bioone.org/doi/full/10.1636/Hi09-08.1>.
Yeargan, K. V., and L. W. Quate. 1997. Adult male bolas spiders retain juvenile hunting
tactics. JSTOR. Springer, 1997. Web. 6 July 2012.
<http://www.jstor.org/stable/4221815>.

Acknowledgements
Thank you to OTS NAPIRE, NSF, and LSAMP for making this program and experience
possible. Also thank you to my mentor, Dr. Karin Gastreich for guiding me through this
experience. I also would like to show my appreciation to my peers, Aliah Irvine and Steve
Pillman, for helping me out throughout this adventure. Another big thanks goes to Dr. Wendy
Townsend and Dr. Robert Godshalk, and all the other NAPIRE staff who guided me this
summer. One last thank you to everyone who supported me this summer.

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74
A comparison of the community structure of aquatic insects between streams of the
tropical and temperate regions
Severino P. Alforeza III
Northern Marianas College
Saipan, Commonwealth of the Northern Marianas Islands.
Abstract
This research is focused on establishing a model of the community structure (Functional
Feeding Groups) of aquatic insects within streams of the Neotropical region. The current model
on community structure is based off of a study done in the temperate region (e.g. River
Continuum Concept). This groundbreaking research showed the composition of the functional
feeding groups (FFG) within streams. Further research is needed to develop a community
structure model for Neotropical streams. Our research was done at the Las Cruces Biological
station, Costa Rica. 10 sampling sites were chosen among varying 1st-3rd order streams within
the biological station. Elevation stands at above 1000 meters above sea level with diurnal
temperatures ranging from 13-26° C. A Surber sampler was used to collect the benthic
macroinvertebrates for each of the four replicates per sampling site. Identification of the aquatic
insects are done to the lowest taxonomic level possible and then placed into their respective
functional feeding group (shredders, scrapers, collectors, and predators). The results of this
fundamental research showed minimal difference in the functional groups collectors, scrapers,
and predators which showed consistency in their abundance throughout all ten sites. However,
the shredders showed a significant difference in their portion of the FFG model for the tropics
(Tropical-4%, Temperate-36%). Collectors were abundant regardless of the shredder's absence,
formulating the question of who or what is shredding the Course Particulate Organic Matter
(CPOM). Further research could be done to explain what other organisms play the functional
role for shredders within tropical streams.
Key words: Community Structure, Functional Feeding Groups, Tropical, macroinvertebrates,
stream, shredders. aquatic insects.
Introduction
Vannote et al. (1980) introduced the “River Continuum Concept” to explain the structure
and function of lotic ecosystems. This established a model that explains how energy flows and
nutrient cycles throughout varying streams orders, from the narrow headwaters to the lower
reaches of the river. It also depicted the relative change in the structure of the Functional Feeding
Groups throughout the stream orders. This ground breaking research was important in many
respects, but was focused upon temperate ecosystems. Little is known about the structure and
function of aquatic insect communities in tropical ecosystems. Wantzen et al. (2006) noted that
“most of our current models for stream nutrient dynamics, decomposition, and regulation of
community structure have been derived from extensive and detailed research on lotic systems in
the temperate zone." Research into the community structure of lotic tropical systems is needed,
along with a greater understanding of the flow of energy and nutrient cycling.

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75
Although the Neotropical region contains the greatest concentration of biodiversity
(species) on planet Earth, there is insufficient knowledge concerning aquatic insect community
structure and functions in streams and rivers of the tropical region (Springer 2008). For
example, the processing of leaf litter in temperate streams is well understood (Yule et al. 2009).
In contrast, the decomposition process in tropical streams has been little studied, and the relative
roles of shredders vs. microbial and physical breakdown are under debate (Wantzen et al. 2008).
The five functional feeding groups are first the scrapers/grazers who consume algae and
others of the same type; second the shredders consume Course Particulate Organic Matter
(CPOM) such as leaf litter and wood; third the collector-gatherers, which collect FPOM from the
stream bottom; fourth the collectors-filterers, which collect FPOM from the water through a
variety of filters; and fifth the predators, which feed on other consumers. These groups play an
important function to the ecosystem and nutrient cycling. Understanding these systems are
important, however if there is no current knowledge to the structure of these aquatic insect
communities then not much can be done to study it.
The objective of this paper is to gain insight into the community structure of aquatic
insects within pre-montane streams of the tropical region, and compare this structure to that of
temperate regions. This will hopefully provide the first documentation of a functional feeding
group (FFG) model that could be used as reference for other studies of similar interest. And
second, to examine the different shredder groups which compose the community structure, and
make inferences as to their importance in the role of leaf litter decomposition.
Methods
Study site
Ten sampling sites were chosen among streams located within the Las Cruces Biological
Station, Costa Rica (Table 1, Fig. 1). Elevation at the grounds of the Las Cruces Biological
Station are above 1000 meters with temperatures ranging from 13-26° C at daytime. The
biological station receives approximately 4000 mm of annual precipitation. The areas of our
sampling sites are within a pre-montane wet forest according to the Holdridge life zone
classification system.

NAPIRE 2012 76
Table 1: Physical Characteristics and Location of Sampling Sites
Stream
Flow
Stream
Width-Ave
Temp
Riparian
Cover
Substrate
GPS
(coordinates)
Elevation
Stream
Order
1-Cusingo River-
Water Trail
0.319 m/s 2.1336 m 20˚ C 25-50% Sand /Gravel
N 08˚ 47' 30''/
W 82˚ 57' 44''
1110 m 2
2-Rio Java- Ridge
Trail
0.508 m/s 5.4864 m 19.4˚ C 50-75% Gravel/Cobbles
N 08˚ 47' 12''/
1120 m 3
W 82˚ 57' 58''
3-Rio Java- Melissa
Trail
0.15 m/s 4.2672 m 21.7˚ C 25-50% Cobbles/ Boulder
N 08˚ 47' 24''/
W 82˚ 57' 56''
1095 m 3
4-Cerro Creek- Loop
Trail
0.406 m/s 1-5 m 20˚ C
75-100%
(84%)
Gravel/Cobbles
N 08˚ 47' 07''/
W 82˚ 58' 02''
1165 m 2
5-Culvert Creek-
Water Trail
0.43 m/s 1-5 m 20˚ C 25-50% Sand/Gravel
N 08˚ 47' 13''/
W 82˚ 57' 46''
1115 m 2
6-Rio Java
Headwaters (west
Border)
0.476 m/s 1-5 m 19.4˚ C 75-100% Gravel/Cobbles
N 08˚ 47' 07''/
W 82˚ 58' 10''
1319 m 1
7-West Java River-
Gamboa Trail
0.472 m/s 1-5 m 20˚ C 25-50% Cobbles/Boulder
N 08˚ 47' 18''/
W 82˚ 58' 25''
1243 m 2
8-Gamboa River-
Melissa Trail
0.425 m/s 10.363 m 20˚ C 75-100% Cobbles/Boulder
N 08˚ 47' 34''/
W 82˚ 58' 14''
1284 m 2
9-Yiguirro River 0.43 m/s 1-5 m 21.1˚ C 75-100% Cobbles/Boulder
N 08˚ 48' 00"/
W 82˚ 58' 21"
1023 m 2
10-Java River 0.3 m/s 10 m 20˚ C 0-25% Cobbles/Boulder
N 08 48' 10"/
W 82 58' 21"
1000 m 3
Table 2: Total Number of specimen at each site

NAPIRE 2012 77
Fig. 1: Percentage distribution among Functional Feeding Groups of all sampling sites.
Sampling Design and Specimen Collection
Forty quantitative samples were taken of benthic macroinvertebrates, four replicates per
site, using a Surber sampler. Debris collected within the sampler, was then preserved in a 500 ml
Nalgene bottle filled with 75% ethyl alcohol. Samples were then taken to the lab to be sorted
with the use of a dissecting microscope.

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Physical Data Collection:
Physical data of the stream was also collected (Table 1). Stream flow was determined by
timing how long it took a plastic float to move a fixed distance. Stream width was measured at
five sites. Temperature was recorded using a thermometer. Riparian cover was estimated using
a convex mirror. Dominant substrate was determined as described by Kaufmann et al (1999).
Latitude and longitude were recorded using a Garmin GPS, and recorded as degrees, minutes,
and seconds. Stream orders were determined by examining maps provided by the GIS laboratory
at Las Cruces.
Taxonomic Identification:
Identification of each individual macroinvertebrate was meticulously done within each
replicate sample and was taken to the lowest taxonomic level possible (generally genus) using
available published literature. Unfortunately very little specific information is given for each
country of the region and no taxonomic keys are presented (Springer 2008). Functional feeding
groups were determined based upon information provided in "An Introduction to the Aquatic
Insects of North America, Fourth Edition", by Merrit and Cummins (2008).
Analysis:
Microsoft Excel was used to create the various charts that created the model of the
aquatic insect community structure, and graphs that compared the Functional Feeding Groups of
these aquatic insects. After all samples are sorted and organized, we will do a comparison
between previous studies of aquatic insect community structures of temperate streams to the
results that we had towards Neotropical streams.
Results
A total of 1222 specimens were collected and identified from the 10 sampling sites
(Table 2). A total of eight orders, 33 families, and 50 genera were identified.
The functional feeding groups were determined at each site. Predators generally
accounted for 15% to 20% of all specimens collected at each site. The most common functional
groups were the collectors (filters and gathers), generally accounting for approximately 50% of
all organisms at each site. The least abundant functional group were the shredders, ranging from
0% to 16% of individuals at each site.
The taxa richness and diversity was closely looked (Figures 2 & 4 ) at where collectors-
gatherers had a total of 27 taxa from 4 orders, 6 families, and 15 genera. The collectors-gatherers
group's abundance totaled to 636 specimen, which accounts for a little more than half of all the
specimen collected. The predators group followed closely behind amounting to 21 taxa from 6
orders, 14 families, and 15 genera and a total abundance of 169 specimen. Scrapers/grazers
came next with 18 taxa from 4 orders, 5 families, and 9 genera; the abundance of the
scrapers/grazers was second just behind the collectors, totaling to 223 specimen. Collectors-
filterers had 5 taxa from 2 orders, 3 families, and 5 genera; total abundance was 156 specimen.
The shredders groups showed the lowest amount of abundance in relation to diversity. The
shredders was composed of 6 taxa from 3 orders, 6 families, and 4 genera; their abundance
totaled to a low 38 specimen.

NAPIRE 2012 79
Fig. 2: Taxa Richness (diversity) of each Functional Feeding Group
Fig. 3: FFG abundance counted by specimen within all 10 sampling sites.

NAPIRE 2012 80
Fig. 4: Functional Feeding Group Averages within the 10 sampling streams of Las Cruces, Costa Rica
(Neotropical Region).
Fig. 5: Functional Feeding Group distribution within streams of the Temperate Region
(River Continuum Concept- Vannote et al.)-Percentage Labeled
Predators

16%
Shredders

4%

Scrapers/
Grazers

15%

Collectors-‐
Gatherers/
Filterers

65%

FFG
Averages
for
10
Sites

Percentage,

Predators,
10%

Percentage,

Shredders,
36%

Scrapers/Grazers

6%

Collectors-
Gatherers/
Filterers
48%
River
Continuum
Concept
FFG
Model

NAPIRE 2012 81
The percentages for each functional feeding group throughout all the ten sites were fairly
similar except for the shredders which were not consistent, showing an absence in three sites
(Figure 1).
Discussion:
Functional Feeding Group (FFG) Distribution and Comparison
Our goal was to compare the community structure within streams of the temperate region
as shown in the River Continuum Concept (RCC) and what the results of this research will
reveal for the functional feeding group distribution for the tropical region. This research has
shown what the community structure is composed of within tropical streams. The River
Continuum Concept has given a model for the community structure within streams of the
temperate region. A new model was created for the percentages of each Functional Feeding
Group comprising the community structure of aquatic insects within tropical streams. (Figure 4)
Surprisingly, the model created from the RCC and the one that this research generated
were not as similar as expected (see Figures 4 and 5). One would think that the similar physical
conditions for the areas of sampling (similar order streams-headwaters) would create a fairly
similar environment for the invertebrate species to exist, especially temperature wise (Table 1).
The Collectors (Gatherers and Filters) were fairly similar with their groups making up almost
half (48%) from the RCC model, and 65% from this research's model. Predators were not too far
apart with the RCC model showing 10% while the tropical streams showed that the group
composed 16% of the model. Scrapers were not too far apart with the RCC model showing 6%,
while 15% of them composed the FFG model within tropical streams. The shredder group of this
research's model were relatively low, averaging out at only 4% from all the specimen collected.
This is in comparison to the model set by the River Continuum Concept which showed that
shredders amounted to 36%. The huge difference is apparent with the shredder functional groups
of the tropics and the temperate region.
Shredders Negative Abundance
The main shredder, a beetle (Coleoptera) from the family Elmidae and the genus Lara,
amounted to a total of 17 individuals throughout all ten sites. Other shredders found within our
samples, but less, were true flies (Diptera) family Tipuliidae and genus Tipula, and caddisflies
(Trichoptera) from the families Brachycentridae (genus Micrasema), Calamoceratidae,
Odontoceridae (genus Marilia). This low amount of shredders did not support a hypothesis from
a paper titled " Shredders in Malaysia: abundance and richness are higher in cool upland tropical
streams." (Yule et al 2009)
Yule et al. (2009) hypothesized "the possibility that shredders might be more common in
cooler highland than in warmer lowland streams." Highland streams flow through montane rain
forests and are more similar to temperate streams (Yule et al 2009). So they tested their
hypothesis by examining the invertebrate communities in 12 sites of pristine forested headwater
streams in across a range of altitudes from 55 to 1560 m above sea level. Their results showed
that shredder abundance increased with altitude. Shredder abundance and species richness were
highest at sites in the Cameron Highlands, where the air and water temperatures and the species
richness of the leaves in the riparian vegetation were lowest, and conditions resembled those in
temperate forested streams. (Yule et al 2009). This result was different to what we have come
up with which proved to be interesting that shredders were relatively low while none even
existed within some of the ten sampling sites.

NAPIRE 2012 82
A major role of shredders in stream ecosystems is the conversion of large organic plant
substrates (coarse particulate organic matter, CPOM) such as leaf litter into smaller particles
(Cummins et al. 1989). Shredder feeding has been estimated to account for 20-30% of leaf litter
processing (Petersen and Cummins. 1974), this can possibly affect the growth of FPOM feeding
collectors. (Short and Maslin. 1977). Now why was there a shortage of shredders, and what
organism or physical action matches the role of the shredders? How is there a high amount of
collectors without the abundance of shredders and their role of breaking down CPOM to produce
FPOM (Collector's food source), and what is creating this FPOM enough for them to sustain and
expand their numbers? Who or what is breaking down these CPOM? These are interesting
questions to possibly answer in further research which could be done within the Neotropical
region. With our limited time and resources, we were not able to look into these subjects to
further understand their occurrences.
Decomposition processes in tropical streams have not been as thoroughly examined, and
the relative roles of shredders vs. microbial and physical breakdown are under debate. (Wantzen
et al 2008.) Shredders, other than the aquatic insects, are the crabs, snails, or shrimps. Little to no
crabs, snails, or shrimps was found within each samples. One crab was found in one the samples
while a two to six small snails were identified within some sample, and no shrimps were in any
of the samples.
Further research can be done to look into this apparent difference in shredder
communities of the tropical and temperate region. Such research would require one to study the
roles of macroconsumers, bacteria and fungi, and also the physical destruction of leaves (e.g.
stream flow smashing leaves against stream substrate).
Literature Cited:
Cummins, K.W., M.A. Wilzbach, D.M. Gates, J.B. Perry, W.B. Taliaferro. 1989. Shredders and
Riparian Vegetation. BioScience, 39: 24-30.
Kaufmann, P.R., P. Levine, E.G. Robison, C. Seeliger, and D.V. Peck. 1999. Quantifying
Physical Habitat in Wadeable Streams. EPA/620/R-99/003.U.S. Environmental
Protection Agency, Washington, D.C. 14
Merritt, R.W., K.W. Cummins, M.B. Berg. 2008. An Introduction to the Aquatic Insects of
North America, Fourth Edition. Kendall/Hunt Publishing Company.
Petersen, R.C., and K. W. Cummins. 1974. Leaf processing in a woodland stream. Freshwater
Biology. 4: 343-368.
Rosemond, A.D., C.M. Pringle, A. Ramirez.. 1998. Macroconsumers effects on insect
detritivores and detritus processing in a tropical stream. Freshwater Biology. 39: 515-523.
Short, R. A., and P. E. Maslin. 1977. Processing of leaf litter by a stream detritivore: effect on
nutrient availability to collectors. Ecology 58:935-938.
Springer, M. 2008. Aquatic insect diversity of Costa Rica: state of knowledge. Revista de
Biología Tropical. 56: 273-295.
Vannote, R.L., G. W. Minshall, K. W. Cummins, J.R. Sedell, and. E. Gushing. 1980. The River
Continuum Concept. Can. J. Fish. Aquatic science. 37: 130-137.
Wantzen, K. M., A. Ramirez, K.O. Winemiller. 2006. New vistas in Neotropical stream ecology.
The North American Benthological Society 25:61–65.
Wantzen, K. M., C. M. Yule, J.M. Mathooko, and C. Pringle. 2008. Organic-matter dynamics
and processing in tropical streams. Academic Press. 43–64.

NAPIRE 2012 83
Yule, C.M., M.Y. Leong, K.C. Liew, L. Ratnarajah, K. Schmidt, H.M. Wong, R.G. Pearson, L.
Boyero. 2009. Shredders in Malaysia: abundance and richness are higher in cool upland
tropical streams. The North American Benthological Society. 28:404–415.
Acknowledgements
This research was made possible by funding from the National Science Foundation
(NSF). I give my great appreciation for the organization and coordinating done by Dr. Wendy
Townsend and Dr. Robert Godshalk. This research paper was substantially improved by the
editorial and comments provided by my research mentor Dr. David Baumgardner, so my
gratitude goes out to him for all his mentoring and assistance with my research project. I would
like to thank Mr. Carlos Gonzalez for the transportation that he provided for our further study
sites and for moral support and company throughout the entire research experience.
I also appreciate the Dr. Frank Camacho and Steven Pillman for accompanying me and
assisting me in my collection of macroinvertebrates. Special thanks to my roommates Emilio
Torivio and Cedric Fairbanks for the fun and exciting times that we have had all throughout the
research experience.
I give the greatest thanks to God who blesses me with so much, and for all this, I give the
most highest gratitude to him.

NAPIRE 2012 84
Density and distribution of agouti at Las Cruces Biological Research Station, Wilson
Botanical Garden
Cedric Fairbanks,
Leech Lake Tribal College
Cass Lake, Minnesota
Abstract
The objective of my study was to evaluate the density and distribution of the agouti
(Dasyprocta punctata) at Las Cruces Biological Research Station. I evaluated the abundance and
density of the agouti at Wilson Botanical Garden (WBG) compared to other studies in Central
America (Enzo 2004, Jorge and Peres 2005). Wilson Botanical Garden is a unique area because
of the diversity of palms, shrubs and trees that produce many fruits. A compost pit for kitchen
refuse is also present which provides an important source of food for the agoutis at WBG. The
data from my study demonstrated that agoutis are aggregated in the vicinity of the compost at
WBG. We observed an overall density estimate of 2.57 agoutis per hectare. Additionally, they
demonstrate two peaks of activity in the morning and afternoon with the highest activity level
occurring in the morning hours between 5:30am-8:00am.
Introduction
The Central American Agouti is a medium-sized rodent with the Latin name Dasyprocta
punctata. Dasyprocta is Greek for bushy-rumped and the meaning of punctata is “spotted.”
These names refers to the behavior of the agouti because when it is startled it raises the rump
hairs to appear bigger than its true body (Reid 1997)
The diet of agoutis consists mainly of fruits and seeds, but agoutis are omnivores. When
food is scarce the agoutis will eat insects and fungi. Agoutis are scatter hoarders and play an
important role in the environment they live in. Scatter hoarder means that the agouti eats the
fruits and seeds from trees and plants, but they do not eat all of the seeds they bury and these
seeds are called caches. This helps disperse seeds of trees and plants and contributes to forest
diversity (Wainwright 2002). The seed caches are spread across the home range of the agouti.
When the agouti create a cache they bury the seed, pat it down, and then place a leaf on the seed
location with its forepaws. The agouti creates a cache through scatter hoarding for seasons when
food is scarce, so they can dig up their caches to eat the seeds. The agouti does not always find
their caches, so this helps to regenerate other forest plant.
The geographical range of the agouti spans from Mexico to Ecuador in South America.
They live from sea level to 2400 meters above sea level (Reid 1997). Agouti can survive in
different forest types but they prefer denser forests. Agoutis are diurnal, which means they are
active in the day. However, they appear to have higher levels of activity in the morning and at
dusk (Enzo 2004). During the day when it’s hot the agouti can be observed resting in the shade
of trees and plants.
Agoutis are territorial, but will share their territory with a mate (Reid 1997). The agouti
can use several dens in their territory but does not rest at the same location for lengthy periods.
The range of agoutis is different for males and females. The male home range is twice as big as
the females. The home range of males on average is 2.02-4.36 hectares and the female’s average
is 1.0-2.41 hectares (Enzo 2004).

NAPIRE 2012 85
Research Question and Hypothesis:
Question: What is the density and distribution of agouti at Wilson Botanical Garden?
Hypothesis: Agouti are equally dispersed at Wilson Botanical Garden
Methods
Las Cruces Biological Research Station, Wilson Botanical Garden
The Wilson Botanical Garden at Las Cruces Biological Research Station is unique
compared to other habitats of the agouti in its Neotropical range. The WBG consists of seven
hectares of landscaped and carefully maintained plants from around the world. The vegetation at
WBG consists of many types of fruits and seeds that agouti readily consume and scatter hoard
throughout the garden.
At Wilson Botanical Garden a compost pit exists where staff deposes of kitchen scraps from
previous meals. The staff dumps the kitchen waste into the compost pit and the agouti make
frequent trips to remove kitchen scraps from the pit, and take it to a nearby location to consume
the left-overs.
To lay out plots to study agouti, our research group utilized an existing map from Las
Cruces Biological Research Station and Wilson Botanical Garden. We divided the WBG into
plots or view sheds, and identified stations to observe the visible area of the view shed. Each
view shed had a station that was a permanent location, where we moved within a two meter
radius to see the entire view shed to survey agoutis. This viewshed map was developed in GIS
(Fig 1).
Fig 1. Viewshed map for agouti surveys at Wilson Botanical Garden.

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