CLUSTERING REDUCES WATER-LOSS BY ADULT AMERICAN HOUSE-DUST MITES DERMATOPHAGOIDES-FARINAE (ACARI, PYROGLYPHIDAE)

We investigated male clustering behaviour in large bulk cultures of th e American house dust mite, Dermatophagoides farinae. Aggregation in t he colony was restricted to males only. The water loss rates for indiv idual males in isolation and as a group of six were determined. Males in a group of six retained water nearly twice as effectively (they had lower rates of net water loss) than individuals. Clustering is thus a n adaptive behaviour to help reduce water loss. Because the clustering response was observed exclusively by males, this behaviour may serve an additional purpose system that involves a pheromone system. (C) 199 8 Chapman & Hall Ltd.