Predator-experienced individuals often change their predation avoidance response when they re-encounter the same predators or their cues. Recent reports show that behavioural change sometimes occurs even before the re-encounter. To function as an adaptive strategy in the wild, such prospective experience-induced behaviour should change flexibly in response to changing situations. We assessed flexibility of experience-induced oviposition site shift in two closely related species of spider mites, Tetranychus kanzawai and T. urticae, from the viewpoint of reducing future predation risk on their eggs. We found that: (i) individuals of T. kanzawai shifted oviposition site depending on the presence of conspecific eggs; (ii) after experiencing predation threat T. kanzawai females shifted oviposition site even in the absence of any current predation threat; (iii) this experience-induced shift of oviposition site was weakened in the presence of conspecific males; and (iv) experience-induced behaviour was retained for a shorter period in T. urticae than in T. kanzawai, possibly because the demand for learning may differ with regard to biological conditions encountered in the wild.

As recent studies have revealed, previous exposure to a predator can change prey behavior even in the absence of current threat. We hypothesized that experiencing a predator increases prey avoidance of lower-quality resources even in the absence of a predator, which in turn influences the prey’s spatial distribution. We examined these hypotheses using the herbivorous spider mite Tetranychus kanzawai and the specialist predatory mite Neoseiulus womersleyi. We used Phaseolus vulgaris as a high-quality host plant and Hydrangea macrophylla as a low-quality host plant. First we examined whether T. kanzawai females that were previously exposed to predators preferred P. vulgaris to H. macrophylla under no current threat more than those without predator experience. Second, we tested the effect of predator experience on dispersal by T. kanzawai females on P. vulgaris or on H. macrophylla. Our results show that: (1) predator-experienced T. kanzawai females expressed stronger avoidance of the low-quality plant H. macrophylla than those without predator experiences; and (2) T. kanzawai females transferred to H. macrophylla traveled farther than those on P. vulgaris, especially females with previous predator experience. These findings reveal neglected aspects of the evolutionary interaction between predators and the habitat choices of their prey.

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