Direct and indirect cues of predation risk influence behavior and reproduction of prey: a case for acarine interactions

Abstract

Little is known about the flow of chemical information from higher to lower levels within the animal food chain. However, this information may determine the behavior and distribution of many animals (e.g., that of potential prey) when exposed to direct and indirect cues of predation risk. We used herbivorous spider mites, Tetranychus urticae Koch (Tetranychidae) as a model to examine the foraging and oviposition decisions that prey make when exposed to these cues. We conducted laboratory tests to determine if the previous presence of predators (direct cues) on leaf discs or the presence of injured conspecifics (indirect cues) alters the distribution of adults and eggs of T. urticae. When given a choice, after 24 h, fewer adults and eggs were found on leaf discs that had previously contained specialist spider mite predators, Phytoseiulus persimilis Athias-Henriot (Phytoseiidae), than on discs unexposed to predators. Also, more T. urticae emigrated from predator-exposed discs than from unexposed discs or from those that had previously contained nonpredatory mites (Tyrophagus putrescentiae, Acaridae). Finally, fewer T. urticae foraged and laid eggs on predator-exposed discs or on those with artificially damaged conspecifics (eggs or dead adults) than on discs with intact conspecifics. Tetranychus urticae probably recognizes infochemicals (kairomones) from its predators or cues from injured spider mites and consequently avoids feeding or ovipositing in areas exposed to these cues. Recognition and avoidance of kairomones from specialist predators by this prey are likely to be hereditary, but avoidance of injured conspecifics may be an adaptation to avoid predators that are not inherently recognized. We discuss the behavioral and ecological implications of our findings.

Learned predation risk management by spider mites

“…These results suggest that experience changed information processing and altered the response of the spider mites to the predator cues over time. The observed anti-predator strategies of the spider mites are similar to those reported in previous studies (Grostal and Dicke, 1999;Skaloudová et al, 2007;Fernández-Ferrari and Schausberger, 2013) but differ in various details. Moreover, all previous studies concerned with spider mite responses to predators or their cues only investigated the behavior of predatornaïve individuals and are therefore only directly comparable to the behavior of naïve spider mites in our work.…”

“…Moreover, all previous studies concerned with spider mite responses to predators or their cues only investigated the behavior of predatornaïve individuals and are therefore only directly comparable to the behavior of naïve spider mites in our work. Grostal and Dicke (1999) of T. urticae. They placed single adult females on predatorexposed and -unexposed leaf discs but, after 24 h, did not find changes in oviposition.…”

“…The differences may be due to using different experimental set-ups. We released the spider mites immediately but Grostal and Dicke (1999) only 2 h after predator removal. In Grostal and Dicke (1999) the chemosensory predator cues may have partly vanished, thus not causing or weakening the response of the spider mites.…”

“…We released the spider mites immediately but Grostal and Dicke (1999) only 2 h after predator removal. In Grostal and Dicke (1999) the chemosensory predator cues may have partly vanished, thus not causing or weakening the response of the spider mites. Like the predatornaïve mites in our study, Skaloudová et al (2007) observed oviposition shifts in T. urticae when exposed to P. persimilis cues and detected that increasing risk correlated with decreasing oviposition.…”

A Novel Disease Affecting the Predatory Mite Phytoseiulus persimilis (Acari, Phytoseiidae): 2. Disease Transmission by Adult Females

“…Avoidance of dead conspecifics has been reported for the American cockroach Periplaneta americana, which is repelled by intact and ruptured corpses of conspecifics (Rollo et al 1995). Moreover, female T. urticae avoid places with artificially damaged conspecifics (eggs or dead adults) (Grostal and Dicke 1999).…”