Co-operative Group Predation in a Sit-and-wait Cheyletid Mite

The Cheyletidae is a family of trombidiform mites with more than 100 predatory and parasitic species. The cheyletid Hemicheyletia morii Ehara is a predatory species occurring on leaves of tropical trees. Observations on the life history and behaviour of this species revealed a new type of sit-and-wait predacious tactic and a sociality previously unknown in Acari. In addition, nest cleaning by a member of the colony was observed. Our results show that this species possesses subsociality. These results are remarkable as group living, co-operative hunting and feeding are rare phenomena in this subclass. Furthermore, the occurrence of thelytoky observed suggests the importance of kin selection.