Innate host habitat preference in the generalist parasitoid Diachasmimorpha longicaudata: functional significance and modifications through learning.

DF SEGURA; MARIANA M. VISCARRET; SERGIO M. OVRUSKI; CLADERA, J

Conferencia; 3rd International Conference of Entomophagous Insects; 2013

Generalist parasitoids can sometimes find its hosts in a variety of habitats. This is especially true for parasitoids the hosts of which are also generalists. In this scenario, chemical cues released by the host habitat (not related to the host) will represent poor indicators of host location. Therefore it is unlikely that naïve females show a strong response to host habitat cues. However, these cues can become important during host searching if the parasitoid is able to modify its behaviour through learning. We assessed the response of naïve females of a fruit fly parasitoid towards four host habitats (apple, fig, orange and peach) in a Y-tube olfactometer. Contrary to what was expected, naïve females showed a perfectly hierarchic pattern of preference (fig>peach>orange>apple). We then evaluated if the pattern of preference was related to fitness gain by the choosing females, in accordance with the foraging theory. We found that the parasitism rate achieved on these fruit species and the weight of the host larvae can explain, to some extent, the preference of the females, whereas host habitat preference did not correlate with survival and fecundity of the progeny. As expected for a generalist parasitoid, the preference for host habitat was found to be quite plastic. We found that the females can change their preference towards fruit of different species depending on their previous experience and also the degree of infestation (number of available hosts) of the fruit.