Feeding Behaviour of the Mite Blattisocius mali on Eggs of the Fruit Flies Drosophila melanogaster and D. hydei

Abstract

Many predatory mites use insects for dispersal; however, their possible negative effects on insect hosts during transportation and on insect offspring while preying in the hosts’ habitats are still poorly understood. A recent study has revealed that the predatory mite Blattisocius mali can not only spread by means of drosophilid fruit flies but also feed on their bodies during dispersal. The aim of this study was to examine the capability of B. mali to prey upon the eggs of their fruit fly hosts and determine the effect of the egg’s age on the voracity of this predator. Drosophila melanogaster oviposited on agar media for 1 h and D. hydei for 8 or 16 h. During 10-h experiments with fifteen fly eggs per cage, a single female predator totally consumed on average 3.62 ± 0.673 “1-h” D. melanogaster eggs and 3.00 ± 0.612 “8-h” eggs of D. hydei, while it partially consumed 2.75 ± 0.586 and 3.00 ± 0.612 eggs of each fly species. In the experiments involving D. hydei, the predator totally destroyed a similar number of “8-h” and “16-h” eggs, but it partially consumed significantly more younger eggs than older eggs. Ethological observations showed that mites returned to some partially fed eggs, usually from the side where the first puncture was made, and only then did they consume them whole.