Here I would like to inform you in host selection process by the parasitiods.I hope It would increase your understanding on the steps involved n the host selection process.............................

1. WELCOME
SSNAIK
TNAU

2. TERM PAPER PRESENTATION
ON
STEPS IN HOST SELECTIONSTEPS IN HOST SELECTION
PROCESS OF PARASITOIDSPROCESS OF PARASITOIDS
COURSE TEACHER: Dr. S. SRIDHARAN, Professor
ENT 822 - ENTOMOPATHOGENS
CPPS, DEPT. OF AGRL. ENTO., TNAU,
COIMBATORE-641 003
NAME :SABHAVAT SRINIVASNAIK
ID. NO: 2015800506
YEAR : I Ph. D, 2015-2016
DEPT.: AGRICULTURAL ENTOMOLOGY

3. Introduction
Conclusion
PART I
PART II
PART III
INDEX
Steps involved in host selection process

4. INTRODUCTIO
N
PART I

5. PARASITOID
Parasitoid “An insect parasite of arthropod is parasitic only in
immature stages, destroys its host in the process of
development and free living as an adult (or)
Parasitoid is an insect that feeds on the body of
another insect or arthropod during the larval stage
of the their life cycle and adult is a free-living insect,
no longer dependent on the host” -Ramesh , 2010

6. TYPES OF HOST SELECTION PROCESS
1.Host selection process by herbivore/phytophagous insects
2.Host selection process by parasitoids

7. HOST SELECTION PROCESS-TERMS
1. Host
2. Herbivore/ phytophagy
1. Host/prey
2. Parasitoid/predator
3. Phytophagy

8. HOST SELECTION PROCESS- A CONCEPT
 “Host selection process is the manner by which the hosts are actually
found and further development of the host parasitic relationship by
crossing many physical and biological barriers in a habitat ”
 Parasitoid and host are two components
 Two components must meet each other
 Seasonally, Geographically and Ecologically coincident
 Must cross Physical, Psychological and Physiological/Nutritional
barriers

9. HOST SELECTION PROCESS- A LIMIT
 Potential parasitoids and hosts separated by the time and space
 Laboratory readily develop host-parasitoid relationship on the
factitious host species/unnatural
 Limits its parasitism- fraction of the host species in nature
(Salt,1937)
 A distinct and consecutive steps and its operation restricted to few
 Basis for the study of the host searching behaviour


10. STEPS IN HOST SELECTION PROCESS
PART II

11. Salt’s (1934) steps in HOST SELECTION PROCESS
1. Ecological selection
2. Psychological selection
3. Physiological selection
1. Host habitat finding
2. Host finding
3. Host acceptance
4. Host suitability
 Host habitat finding and host finding comes under ecological selection
 Host acceptance come under psychological selection
 Host suitability comes under physiological selection

12. 1. HOST HABITAT FINDING
 Most of the species habitat not coincided
 First activity seeking the habitat or the environment irrespective of the host
 Aysia manducator attracted towards the meat with/without the maggots
(Laing, 1937)
 Nasonia viripennis attracted to the infested meat only (Jacobi 1939)
 Preoviposition period no attraction to the host, Eg.,Opius flecheri (Nishida,
1956)
Opius flecheriNasonia viripennis

13. 1. HOST HABITAT FINDING…
 Parasite of the Pine moth (Rhycionella buolina) is Pimpla ruficollis
 Ovarian development due to the oil of the pine tree (Thorpe and
Caudle, 1938)
 Eurytoma curta under natural conditions attracted to the flower
heads of the knap weed after that opens its bracts for gall fly.
 Closely related species different host selection process
 Eg. Aphytis chrysomphali and Aphytis lingnanensis on Aoniedella
aurantii
Pine tree knap weed

14. 1. HOST HABITAT FINDING…
EncarsiaEncarsia formosaformosa prefers to lay eggs on white flies feeding onprefers to lay eggs on white flies feeding on
glabrous leaves.glabrous leaves.

15. 1. HOST HABITAT FINDING…
 Visual
 Tactile
 Acoustic
 Allelochemcals
 Pheromones
 Associative learning (conditioning).
Cues:
Attract stimuli

16. 2. HOST FINDING
 It is difficult to separate two process /salt ecological selection
 Location of the host in the habitat
 Arrestant stimuli
 Random and non random searching movement
 Host finding most by tactile and olfactory cues
 Many sharp turnings on the patch of the host eg. Nasonia sp.
 Finally contacts the host

17. 2. HOST FINDING……

19. 2. HOST FINDING……

20. 2. HOST ACCEPTANCE
 May not attack the host if there is no proper stimuli
 Determines the host specificity
 Truly host selection process and is clearly innate behaviour of the
parasitoid
 It is the salt’s psychological selection of the host
 Nasonia sp. with puparium of the Musca domestica no
marked attraction until it became 2-3 mm and climbed on the
puparium
 Move forward and downward projecting its antennae vertically
and tapping the surface known as drumming.
 The parasite stops drumming and flexes its body and tapping the
body with its ovipositor.
 In a such a way to drill the abdomen with its ovipositor.

21. 2. HOST ACCEPTANCE…….
 If the host is suitable the eggs are laid and feeding tube was
formed.
 At the end the host blood will be sucked and remove its ovipositor.
 Drumming not always leads to tapping
 Tapping definitely leads to the drilling
 Drumming will be changed to the different place of the puparium
 Again the tapping and drilling
 This process will be continued 2-3 times before complete insertion
of the ovipositor

22. 2. HOST ACCEPTANCE…….
 Insertion followed by oviposition and feeding tube formation
 Feeding tube formation occurs without the oviposition when there
is no ovaries
1. Finding host area,
2. Finding fly puparium,
3. Drumming and drilling response and
4. Oviposition and feeding response

23. Host habitat finding
Host finding
Host acceptance
Contact
Climbing on the puparium
Movement forward and down ward
Start of drumming mechanism
Tapping
Drilling
Venom injection
Repetition
Oviposition
Feeding tube formation
Suck the blood
Host marking
Left the host

24. Nasonia sp. climbing on the puparium of blow fly

26. MANNER AND PLACE OF OVIPOSITION
 Leads to the host specificity
 Oviposition habitat divides into the 3 categories
1. Oviposition apart from the host eg. Dipterans and
few hymenopterans
2. Oviposition on the host eg. Hymenopterans
3. Oviposition in the host eg. Hymenopterans

27. UTILIZATION OF THE OVIPOSITOR
 It is an power of parasite to utilize its ovipositor for effective
parasitization (Flanders, 1947)
 Power is measured by the
Strength
Length
Flexibility
Time
 The egg size is the major factor for changes in the ovipositor
 Small- easily flow
 Bigger- distortion of the ovipositor

29. PARALYSATION OF THE HOST
 First investigation on the Bracon hebetor by Beard in 1952
 Injection of the venom
 Bracon hebetor first paralyse all the hosts then go for the oviposition
 He concluded that 1/200 parts of the host blood-permanent paralysis
 It is not compulsory
 Site of action is neuromuscular junction

30. 4. HOST SUITABILITY
 It is an internal factor of the host
 Physiological in nature
 If the host found immune or unsuitable the host-parasitic
relationship may not established
 It is the final step in the host selection process
 Oviposition not a index of the host suitability
 According to the place of the host the suitability will vary
 Eg. Mesoleius tenthredinus x Larch sawfly, Pristiphora erichsonii
(Canada)
 Mesoleius tenthredinus x Larch sawfly, Pristiphora erichsonii
(Manitoba and Saskatchewan)

31. HOST DEFENCE MECHANISMHOST DEFENCE MECHANISM
 Enemy-free space,
 Concealment or physical counter-attack
 Uptake of the antibacterial and antifungal substances
Internal
External

32. HOST DEFENSE MECHANISMHOST DEFENSE MECHANISM
1.Cellular reactions
 The formation of a cyst by host cells around foreign objects.
 Encapsulation has been reported to occur in epidermal,
tracheal, gut, muscle and nervous tissue.
 Haemolymphic capsules are formed by the haemocytes
congregating and differentiating into two layers; and the cells of
the inner layer form connective tissue fibers
Encapsulation (Phagocytosis)

33. HOST DEFENCE MECHANISMHOST DEFENCE MECHANISM
 Melanization involves the deposition of pigment around
a parasitoid.
 Many authors feel that Melanization is associated with
encapsulation and is essentially a cellular phenomenon.
 The melanin formed is derived from tyrosine by way of
the phenolase reactions
Melanization

34. Pigmentation formation around the egg

35. HOST DEFENCE MECHANISMHOST DEFENCE MECHANISM
2.Humoral reactions2.Humoral reactions
 Body fluids or the cellular secretions on or inside the parasitoid
 Coccophagus gurneyi female larvae gradually disintegrate in the
body fluids of Pseudococcus longispinus without visible
reactions.
 Leptomastix dactylopii larvae in Phenacoccus solani
 Monoctonus paladum in the aphid Aulacorthrum circumflexum.

36. CONCLUSIO
N
PART III

37. CONCLUSION
“Biological control is an ecofriendly and naturally
acceptable method of pest management included in the
integrated pest management programmes. Biological control
involved with parasitoids and predators. A parasitoid can select
the host by a various steps like host habitat finding, host
finding, host acceptance and host suitability. Understanding of
the host selection process” host suitability in which the
parasitoid will dominate the defence mechanism and establish a
host parasitic relationship for continuous excavate the nutrients
for developing progeny. Understanding these complex steps will
enhances the sustainable biological control”

38. Please keep watch......
Host selection behaviour in parasitoid

39. TEXT BOOKS
Biological control of insect pests and weeds by Paul Debach
Introduction to Insect behaviiour.123-127p Atkin.
Introduction to general and applied entomology by Awasthi VB.
Insect pest predators YA. Sathe and TV. Bhosale
Insects as natural enemies a practical perspective by Mark A Jarvis
WEB SITES
www.wikipedia.com
www.cirrus.com
www.nature magnified.com
www.tolweb.org
www.tiptopbio.com
www.naturenorth.com
www.biobest.be
www.entnemdept.ufl.edu
www.britannica.com
www.nycaes cornell.com
REFERENCES

40. Thank You
Presented by
Sabhavat Srinivasnaik
ID.NO:2015800506
I Ph. D (Agrl. Entomology)