Entomology

2. Learning In Parasitoid Wasp
(Hyssopus pallidus)
Group members
Muhammad Zeeshan Rana
Hafiz Muhammad
Sidra Naaz
Ashir waseem

3. Introduction
• Codling moth(Cydia pomonella ) is the major
pest of apple fruits.
 Hyssopus pallidus (parasitoid) used as
biocontrol of codling moth

4. • Parastoid wasp can find the moth through its
frass
• Its searching ability depends upon the traces
of frass

5. • This response have both genetic and learned
component
• Swiss scientist Silvia Dorne with its other
fellows did an experiment

6. • Reared the 30 generation on wheat germ diet
• 31st generation reared on apple fruit cues
• Original level was restored
Conclusion
Chemical component of moth frass is detected
innately but learning was required to
recognize it

7. Q. Did parasitoid need to learn fruit related chemicals from
caterpillars and their feces or exposure to fruit itself was
sufficient?
Moth caterpillar
(1st instar)
Feed on Apple
Extract the worm
(5th instar)

8. Continue…
worm
Wheat
germ
Apple
extract
Apple
Piece
Treated
filter
paper

9. • They introduced the mated female in the plastic
boxes
• The 2nd generation is transferred to the new
cages they were never exposed to the apple cues
• Introduced the mated female parasitoid and
compared the groups
• Conclusion
– Parastoid showed greater adult response to the host
frass or chemicals then the parsitoid reared without
them

10. Did a high response requires both the
taste and the smell???
• Reared 2 groups
– 1st group fed with apple supplement
– 2nd only exposed to the odor of apple
– Both showed same response
• Conclusion
– Smell was more important then the taste this
– In other insect case taste was more imporatnt the
smell

11. Was their a learning stage in the life of
parasitoid…????
• They reared the caterpillar on the plain
artificial diet
– 1st group was exposed to the apple extract at
different development stages
– 2nd group(control group) never exposed at all
• The new generation emerges they were
transferred into different new cages

12. Continue…
• When the 2nd generation caterpillar was 4 days
old they introduced the mated female parasitoid
• They observed their searching time to the apple
extract prepared from the natural frass of codling
moth
• Conclusion
– Adult shows no significant response
– Those exposed to host frass to their entire life shows
the same effect as those exposed to the host frass in
early stage only

13. Continue….
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Entire life Early stage Adult never exposed
Response
Stages exposed to the odour of apple extract

14. Did parasitoid respond to apple cues
or menthol…?????
• 1st group of parasitoid was reared on the
apple solvent extract
• 2nd group was reared with menthol
• Group 2nd was repelled by menthol
• 1st group shows greater response to the
solvent extract
• Conclusion
– Parasitoid only respond to the apple cues only

15. So we can conclude that….
• Parasitic wasp Hyssopus pallidus learns to locate
its hidden host by its frass and this recognition is
two stage process.
• Host-derived chemicals in frass innately.
• Apple derived chemicals learned only through
exposure in early life cycle not early adulthood,
but from egg to larva