Physiological state and associative learning determine response of predatory mite to food-related and oviposition-related volatiles

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F. Faraji, A. Janssen & M. W. Sabelis

University of Amsterdam, Institute for Biodiversity and Ecosystem, Section Population Biology, Kruislaan 320, 1098 SM, Amsterdam, The Netherlands

Females of the predatory mite Iphiseius degenerans visit flowers for feeding but oviposit on leaves. We conducted Y-tube experiments to test the hypothesis that preference for cues related to these feeding and oviposition sites (flower and leaf odours) depends on the physiological state (hungry or fed) and experience of individuals. Females collected from pepper plants were either starved in the absence of any stimulus or were allowed to feed by placing them in pepper flowers, where flower odours are associated with the presence of food (pollen). When tested in a Y-tube olfactometer, fed females, that had thus been conditioned to flower odours, strongly preferred the odours of pepper leaves over flower odours, whereas starved females preferred flower odours. Females with no experience on pepper plants, by contrast, showed a weak preference to only leaf odours either when fed or starved. Our results can be explained by the fact that fed females mainly search for oviposition sites on leaves, whereas starved females try to localise food. These results suggest that the foraging behaviour of I. degenerans is influenced by a combination of associative learning, innate response and the physiological state of individuals.

Index terms: Iphiseius degenerans, experience, flower and leaf volatiles, olfaction.

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