Behavioural responses of females of the eriophyoid mite, Aculops allotrichus, to the presence of injured conspecifics

Abstract

ABSTRACT In many animal taxa, the presence of injured conspecifics triggers escape or freezing behaviour. We examined these anti-predatory responses in the eriophyoid mite Aculops allotrichus from Robinia pseudoacacia. The mite was tested on leaflets in cages with two leaf chambers connected by a tunnel, on compound leaves, on which only two opposite leaflets remained, and on leaf discs placed on glass. We released females onto a site with freshly pierced individuals and allowed them to move to a “safe” place. Females did not escape from dangerous patches in any of our tests. They did not refrain from oviposition or become motionless in the presence of damaged conspecifics, either. On the contrary, in the test with old leaf discs, females prolonged their stay on “risky” patches. Additionally, after five hours the proportion of females in chambers with pierced conspecifics was significantly higher than in the control, and only after 24 hours were there no differences between the two combinations. It indicates that the presence of injured conspecifics is not a cue of predation risk for A. allotrichus. In contrast, the eriophyoid can be arrested on “dangerous” leaves, and possible factors underlying this phenomenon are discussed.