Untitled

Abstract

From a series of experiments, the host finding behaviour of by Lipolexis oregmae are studied through perception of various stimuli, viz., olfactory, contact of host substrate, visual and gustatory. Olfactory and contact receptors in parasitoid are located in her antennae. Only when 5 segments of both the antennae are amputed or waxed, the parasitoid took significantly more time to make first contact with the host. Similarly, time taken between first contact with the host and oviposition only vary significantly when 5 antennal segments were nullified their function. Oviposition by blind parasitoid suggests that sight does play a part in host finding but has a greater role in the proper orientation of the parasitoid to hosts during oviposition. Normal females were found to spend more time (452 ± 156 s) on the infested (with hosts) leaf of host plant followed by on leaves from which the aphids were shortly removed (235 ± 125 s) and on uninfested leaves (fresh and healthy) (107 ± 31 s). The additional time was spent by the normal females in the licking of the honeydew. Licking of honeydew not only provides necessary nourishment to the parasitoids but also it assures them of the presence of their hosts. The presence of kairomones in the honeydew cannot be ruled out. Therefore, gustation (tasting honeydew) is partly helpful in host finding by reducing the host approaching period. The data presented herein demonstrated that the olfaction of chemical cues (kairomones) secreted by the aphid, vision and gustation of honeydew excreted by the aphid play major role in host finding by the parasitoid, Lipolexis oregmae and its antennae play major role in this process.