The influence of aphid polyphenism on life histories and oviposition decisions of (hyper)parasitoids
(2018)
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- Authors
- Supervisors
- Hance, Thierry
- Abstract
- Aphids are attacked by a broad range of natural enemies, notably parasitoids. These insects lay their egg inside aphids and the larva feed on aphid haemolymph and tissues. Female parasitoids have to make decisions in order to maximize their offspring success, which mainly depends on the host quality. Winged aphids are produced in the colony when environmental conditions are detrimental. This thesis is interested in the nutritional value of winged and wingless aphids and the oviposition choices made by parasitoids and hyperparasitoids (parasitoids that parasitize primary parasitoids). Winged aphids are usually considered as low-quality hosts for parasitoids, because nutrients are required for the production of wings and subsequent flight. We demonstrated that winged aphids of the species Myzus persicae were heavier than wingless aphids and contained more free sugars, lipids and proteins. They are, in our case, hosts of higher quality compared to wingless aphids. Consequently, parasitoids of the species Aphidius colemani and hyperparasitoids of the species Asaphes vulgaris that developed in immature winged aphids were fatter. We were unable, however, to identify a choice between immature winged and wingless hosts as parasitism rates were similar on different morphs in the laboratory. We did, however, show that winged aphids displayed fewer defensive behaviours against parasitoids compared to wingless aphids. In the field, we showed that parasitism rates on winged aphids were far lower than on wingless aphids. Winged aphids contain more nutrients and are less defensive; hence we could expect that winged aphids constitute a risk for parasitoids if they disperse.
- Affiliations
Citations
Pirotte, J. (2018). The influence of aphid polyphenism on life histories and oviposition decisions of (hyper)parasitoids. https://hdl.handle.net/2078.5/102433