A comparison of naive and conditioned responses of three generalist endoparasitoids of lepidopteran larvae to host-induced plant odours
Cristina Tamo, Ingrid Ricard, Matthias Held, Anthony C Davison & Ted Turlings
| Résumé |
Many parasitic wasps that exploit herbivores as their hosts make use
of herbivore-induced plant odours to locate their victims and these
wasps often exhibit an ability to learn to associate specific
plant-produced odours with the presence of hosts. This associative
learning is expected to allow generalist parasitoids to focus on
cues that are most reliably associated with current host presence,
but evidence Supporting this hypothesis is ambiguous. Using a
six-arm olfactometer we compared the responses of three generalist
larval endoparasitoids. Cotesia inarginiventris (Hymenoptera:
Braconidae), Microplitis rufiventris (Hymenoptera: Braconidae) and
Campoletis sonorensis (Hymenoptera: lchneunionidae). to the induced
odours of three plant species: maize (Zea mays), cowpea (Vigna
unguiculata). and cotton (Gossypium hirsutum). We tested the
responses of naive females as well as of females that were first
conditioned by parasitising host larvae feeding on one of the plant
species. Despite similarities in biology and host range the three
wasp species responded entirely differently. Naive C.
marginiventris and C. sonorensis chose equally among the induced
odours of the three plants. whereas naivc M. rufiventris. which may
have a somewhat more restricted host range, tended to prefer the
odour of maize. After conditioning, most C. marginiventris females
chose the odour of the plant species that they had experienced, but
conditioned M. rufiventris showed an even stronger preference for
maize odours. independently of the plant they had experienced.
Cotesia sonorensis did not show any change in its preference after
conditioning. We speculate that its extremely broad host range
allows C. sonorensis females to use fixed responses to cues
commonly associated with plants damaged by Lepidoptera. These
results imply that different generalist parasitoids may employ
different foraging strategies and that associative learning is not
necessarily part of it. |
| Mots-clés |
associative learning, herbivore-induced plant odours, host findings, parasitoids, MICROPLITIS-RUFIVENTRIS KOK, MARGINIVENTRIS CRESSON HYMENOPTERA, PARASITOID COTESIA-MARGINIVENTRIS, SPODOPTERA-LITTORALIS BOISD, INDUCED, VOLATILE EMISSIONS, CAMPOLETIS-SONORENSIS, AIRBORNE SEMIOCHEMICALS, CROCEIPES CRESSON, FORAGING BEHAVIOR, INFOCHEMICAL USE |
| Citation | Tamo, C., Ricard, I., Held, M., Davison, A. C., & Turlings, T. (2006). A comparison of naive and conditioned responses of three generalist endoparasitoids of lepidopteran larvae to host-induced plant odours. Animal Biology, 56(2), 205-220. |
| Type | Article de périodique (Anglais) |
| Date de publication | 2006 |
| Nom du périodique | Animal Biology |
| Volume | 56 |
| Numéro | 2 |
| Pages | 205-220 |