Cross-modal effect of natal habitat experience increases receptivity to non-natal habitat cues in generalist parasitic wasps

Exposure to natal habitats induces preferences in individual organism for foraging cues that originate from their developmental habitat. However, the natal experience of habitat generalists may play a different role in their habitat selection, since they use a broad range of foraging cues in a non-natal habitat. In this study, the effects of natal habitat experiences on the responses of females of the generalist parasitoid Aphidius gifuensis Ashmead to cues from natal or non-natal habitats were investigated. The landing rates on plant-host complexes (PHCs) and undamaged plants (UDPs) of natal (wheat) and non-natal (broad bean) plant systems in a wind tunnel increased after encounters with host aphids on the wheat-PHCs when the wasps had previously been exposed to wheat-UDPs. However, without the previous exposure to wheat-UDPs, the landing rate on the broad bean-PHCs was not increased. Similar increase found in responses to green paper disc dummies suggested involvement of visual stimuli in the reinforcement. In olfactometer tests, preferences for broad bean-UDPs over broad bean-PHCs were found but wasps with previous exposure to wheat-UDPs and host encounter on wheat-PHCs did not show the preference. These results suggest that the early exposure to natal habitat plants modified later learning and response to visual cues from potential non-natal habitat plants, and olfactory learning might be involved in the modification. This cross-modal effect of early natal experience would compensate for the loss of host-searching efficiency due to uncertain information of potential non-natal habitats.