Social context during ontogeny affects cannibalism and kin recognition of the predatory mite Amblyseius herbicolus at different life stages.

Abstract

Cannibalism is commonly found among phytoseiids at almost all mobile life stages. The avoidance of kin cannibalism in the presence of non-kin has been observed in a limited number of phytoseiid species. However, studies examining kin recognition by individuals at different life stages are limited. Early experience with conspecifics can alter individuals' social behaviour at later stages. In this study, we examined the influence of ontogenetic isolation on cannibalism and kin recognition by the predatory mite Amblyseius herbicolus (Chant) (Acari: Phytoseiidae) at different life stages. In a choice test, A. herbicolus protonymphs, deutonymphs, pre-ovipositional adults, and ovipositional adults were used as predators, and larvae (siblings vs. non-siblings) were given as prey. Two rearing treatments were applied to the predators to generate different social experience during ontogeny: reared in isolation or in pairs with ad libitum mixed stages of Carpoglyphus lactis (Acari: Carpoglyphidae). Social experience with siblings during ontogeny significantly reduced the cannibalism rate. Despite the social experience during ontogeny, protonymphs, deutonymphs, and pre-ovipositional adults did not discriminate siblings from non-siblings during cannibalism. The discrimination behaviour between siblings and non-siblings of A. herbicolus occurred after adults became ovipositional. We hypothesize that A. herbicolus adults could learn the characteristics of their larvae through the contact with and assessment of their eggs during oviposition. The result of this study shows that kin discrimination could be phase-specific. Future studies can investigate if contact with non-kin (or non-sibling) eggs and subsequently hatching larvae can influence the discrimination ability of ovipositional adults.