Male chemical cues mediate the female preference for egg deposition site in Rhynchophorus ferrugineus
- Bulletin of Insectology 期刊
- The choice of a suitable oviposition site is critical for the reproductive success of many animals. In insects, oviposition site choice is often driven by chemicals: oviposition-deterring pheromones are well known for many insects, whereas oviposition-stimulating pheromones have only been reported for a few species. Here, we investigate which cues trigger the choice of a deposition site in the Red Palm Weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera Dryophthoridae), the worst palm pest. Our experiments clearly showed that females prefer to lay eggs in a substrate already used for the same purpose. To provide evidence for cues mediating this preference, we carried out a series of bioassays following a binary-choice test paradigm. Our results showed that neither the presence of eggs nor the polar or apolar compounds extracted from the egg surface affected female preference. Moreover, experiments in which the body of adults was rubbed on the substrate allowed us to exclude that body surface compounds are involved in this process. Bioassays preventing male-substrate contact suggested a role of the male in determining the female’s choice of the oviposition site. Our results suggest the male aggregation pheromone as the best candidate to mediate such female preference. Further studies will be necessary to clarify whether female preference represents a simple by-product of the aggregation pheromone effect or is due to a specific compound of the pheromone that triggers the female behaviour.