2020 Volume 29 Issue 2 Pages 59-70
Several species of spider mites construct silk nests on leaf surfaces wherein they develop and reproduce (web-nesting species). Nesting patterns and behaviour of spider mites are related to predator avoidance, but the study of their influence on predatory fauna has been limited to species of a few genera. The present study investigates the occurrence of predators of Schizotetranychus brevisetosus, which make web nests and attack some predators, on evergreen oak in Kochi Prefecture, Japan. Of the total individual predators observed (n = 129), the highest proportion (38%) consisted of rove beetles Holobus spp. (Coleoptera: Staphylinidae), which are nest intruders and prey on mites at all stages of development. The second most abundant predators (26%) were Anystis spp. (Acari: Anystidae), which capture mites outside the nest. The common predators Phytoseiidae spp. (Acari) accounted for only 15% and were mostly found in hibernation. Other predators were rare, except for egg-eating Agistemus spp. (Acari: Stigmaeidae) (13%). The findings suggest that web nests and anti-predatory behaviours may bias the predatory fauna toward species that can cope with these anti-predatory strategies.
