Domatia and its effects on cannibalism and settling behavior of the predatory mites Phytoseiulus persimilis and Amblyseius swirskii

Cannibalism, killing and consuming conspecific individuals is a widespread phenomenon that happens in many species. In this study we have investigated the effect of domatia on the cannibalism behavior of the Phytoseiid predatory mites, Phytoseiulus persimilis and Amblyseius swirskii, on sweet pepper leaves with and without domatia. The without-domatia leaves were prepared by banning the domatium with glue. To avoid the unwanted effect of glue, we put the same glue drops next to each domatium. The experiment about the effect of domatia on the cannibalism rate of predatory mites on detached leaf disks showed that for P. persimilis, the presence of domatia significantly reduced the cannibalism rate (P < 0.05). In contrast, when we changed the predator species to A. swirskii, no significant effect was recorded (P > 0.05). To investigate the effect of domatia on the establishment rate of the predator, we used the pair of detached leaves with and without domatia connected through a plastic bridge. The predators were released in the middle of the bridge. The results showed that in both predator species, the presence rate of female predators on patches with domatia was significantly higher in comparison with those without domatia (P < 0.05). The probable reasons for the difference in predator behavior are discussed.