3. The Wings
A butterfly wing is made of a
thin membrane webbed with
veins. Colourful scales cover the
membrane. They strengthen and
stabilize the wings.
A butterfly cannot regenerate
lost scales. If a butterfly loses a
lot of scales, the underlying
membrane may become more
prone to tears, and that could
affect its ability to fly.
4. Scales
• Scales - pigmented with melanins that give them blacks and browns.
• Blues, greens, reds and iridescence are created by the microstructure of the scale.
• Scales that comprised them contain photonic crystals whose atoms are spaced so
precisely that only certain wavelengths of light can pass through.
• The crystals are also saturated with fluorescent pigments that help them create specific
wavelengths of light, visible to us as bright colours.
• Tiny, mirror like structures known as distributed Bragg reflectors reflect this fluorescent
light as well as all the other light the photonic crystal allows to pass through. The result:
butterfly wings that transform ordinary sunlight into brilliant greens and blues incredibly
efficiently.
• The scales cling somewhat loosely to the wing and come off easily without harming the
butterfly.
5. A patch of wing Scales close up
A single scale Microstructure of a scale
6. Polymorphism
• Many species have developed deceptive appearances to fool would-be predators by
taking on the look of other unpalatable species.
• The researchers found that at least 18 genes in a tight area on one chromosome combine
to create a so-called “supergene” that functions as a single switch to control wing pattern
mimicking and create as many as seven different appearances.
• These butterflies are the ‘transformers’ of the insect world, but instead of being able to
turn from a car into a robot with the flick of a switch, a single genetic switch allows these
insects to morph into several different mimetic forms.
• Evolutionary strategy - mechanism for rapidly adaptable change.
8. Structure
• Butterflies are flying insects with two pairs
of scaly wings and two segmented, clubbed
antennae.
• A three-part body (head, thorax and
abdomen), 3 pairs of jointed legs,
compound eyes, and a segmented
exoskeleton.
12. Eggs
Shape : spherical or ovate
Butterfly eggs are fixed to a leaf with a special
glue (whose nature is unknown) which
hardens rapidly. Each species of butterfly has
its own host plant range.
The same glue is produced by a pupa to secure
the setae of the cremaster.
This glue is so hard that the silk pad, to which
the setae are glued, cannot be separated.
The egg stage lasts a few weeks in most
butterflies but eggs laid close to winter go
through a diapause (resting) stage, and the
hatching may take place only in spring.
13. Larvae & Caterpillars
Almost all of them are herbivorous
and some insect eating.
They mature through a series of
stages called instars.
At the end of each instar, the larva
moults the old cuticle, and the new
cuticle expands, before rapidly
hardening and developing pigment.
Development of butterfly wing
patterns begins by the last larval
instar.
Anatomy: three pairs of true legs
from the thoracic segments and up to
6 pairs of prolegs arising from the
abdominal segments. These prolegs
have rings of tiny hooks called
crochets that help them grip the
substrate.
14. Dangerous
defenses
Some caterpillars have hairs and bristly
structures that provide protection while others
are gregarious and form dense aggregations.
Some species also form associations with ants
and gain their protection.
15. Pupa
• The larva transforms into a pupa (or chrysalis) by anchoring itself to a
substrate and moulting for the last time.
• They make chrysalis make by secreting silk from 2 glands that are located
inside of them. This thread will stick together and grow hard when fresh air
touches them. Is often camouflaged so that predators cannot see them.
• Pupal transformation into a butterfly through metamorphosis inside the
cocoon : pupal wings undergo rapid mitosis and absorb a great deal of
nutrients. In the pupa, the wing forms a structure that becomes compressed
from top to bottom and pleated from proximal to distal ends as it grows, so
that it can rapidly be unfolded to its full adult size.
16. The pupa may be covered in silk and
attached to many different types of
debris or may not be covered at all.
The pupa stays attached to the leaf by
silk spun by the caterpillar before it
spins the silk for the full pupa.
17. Wing development
• Tiny developing wing disks can be found
when larvae are dissected
• Increase dramatically in size during the
last larval instar and begin to develop
patterns associated with several landmarks
of the wing.
• Near pupation, the wings are forced
outside the epidermis under pressure.
Initially quite flexible and fragile, by the
time the pupa breaks free of the larval
cuticle they have adhered tightly to the
outer cuticle of the pupa.
• Within hours, the wings form a cuticle so
hard and well-joined to the body that
pupae can be picked up and handled
without damage to the wings. Last instar wing disk
18. Prepare for take-off
After it emerges from its pupal stage, a butterfly
cannot fly until the wings are unfolded. A newly
emerged butterfly needs to spend some time inflating
its wings with blood and letting them dry, during
which time it is extremely vulnerable to predators.
Drying takes one to three hours.
19. Adult or Imago
The adult, sexually mature,
stage of the insect.
The fore and hind wings are
not hooked together.
They have six legs.
20. Flight
• Flight is driven primarily by action of the forewings.
• Hind wings are thought to allow them to take swift, tight turns to evade
predators.
• In hotter climates butterflies can easily overheat, so they are usually active only
during the cooler parts of the day, early morning, late afternoon or early
evening. s to direct sunlight, which rapidly warms their flight muscles.
• They rely on a variety of techniques, often employed in successive strokes, over
the course of a flight.
• These creatures use a number of "unconventional aerodynamic mechanisms” to
generate force.
• The butterflies appear to switch effortlessly among these mechanisms from
stroke to stroke.
21. In preparation for flight, these cold blooded
aerial acrobats expose their wings to direct
sunlight, which rapidly warms their flight
muscles.
22. Killer colours
Host plants often have toxic
substances in them and caterpillars
are able to sequester these substances
and retain them into the adult stage.
This helps making them unpalatable
to birds and other predators. Such
unpalatibility is advertised using
bright red, orange, black or white
warning colours. This signal may be
mimicked by other butterflies
(coevolution of insects and their host
plants – evolutionary arms race).
23. Blending Options…
Camouflage is also important
defence strategies, which involves
the use of coloration shape to
blend into the surrounding
environment.
25. Deception
Wing markings called eyespots are
present in some species.
It may have an auto-mimicry role –
causing ambush predators such as
spiders to approach from the wrong
end and allow for early visual
detection.
In others, the function may be intra-
species communication, such as
mate attraction.
Or may be an evolutionary anomaly.
26. Just another leaf…
Basking is an activity which is
more common in the cooler
hours of the morning. Many
species will orient themselves to
gather heat from the sun.
27. A sweet foot
A butterfly's sense of taste,
200 times stronger than
humans is coordinated by
chemoreceptors on feet,
which work only on
contact, and are used to
determine whether an egg-
laying insect's offspring will
be able to feed on a leaf
before eggs are laid on it.
28. Small Wonders
The exact size, length and weight
of a butterfly generally keeps
differing, but the average size of a
butterfly is anywhere between 0.5
to 1 inches, their length is usually
between 8 to 12 inches and weight
approximately 0.0001 ounce.