Diapause incidence in the two-spotted spider mite increases due to predator presence, not due to selective predation.
We recently reported evidence for increased diapause incidence in the spider mite Tetranychus urticae in presence of the predatory mite Typhlodromus pyri. This effect may arise from (1) selective predation on non-diapause spider mites, (2) predator-induced diapause in spider mites, or (3) both. Using a different strain of T. urticae, we first recovered increased diapause incidence in association with predators. Then, we tested for selective feeding in two-choice experiments with equal numbers of non-diapause and diapause spider mites. We found that the predatory mite had a significant preference for the latter. This indicates that increased diapause incidence in association with predatory mites is not due to selective predation. Therefore, predator-mediated physiological induction of diapause seems a more likely explanation. The cues leading to induction appear to relate to the predators, not their effects, since predation simulated by spider-mite removal or puncturing did not significantly affect diapause incidence. Why spider mites benefit from this response, remains an open question.
Kroon
Annemarie
A
Institute for Biodiversity and Ecosystem Dynamics, Section Population Biology, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
Veenendaal
René L
RL
Egas
Martijn
M
Bruin
Jan
J
Sabelis
Maurice W
MW
D000222:Adaptation, Physiological; D000818:Animals; D003080:Cold Temperature; D005247:Feeding Behavior; D005260:Female; D008925:Mites / Q000502:physiology*; D017440:Photoperiod; D011235:Predatory Behavior; D040102:Tetranychidae / Q000502:physiology*