Studies on the attaching behavior of the Lardoglyphus konoi (Acari, Lardoglyphidae) hypopus and its molting into the tritonymph

Abstract

Hypopi of the lardoglyphid mite, Lardoglyphus konoi (Sasa et Asanuma), reared individually did not molt into tritonymphs. Hypopi, which were mass-reared with adults of their own species, attached to the adults and molted into tritonymphs at a low rate. Molting of mass-reared hypopi occurred also when they were placed on yeast suspension, but no hypopi molted when they were placed on agar or starch. Molting of individually-reared hypopi was low on yeast suspension, and, likewise, none molted on agar or starch. Hypopi could also attach to larvae of the dermestid beetle, Attagenus unicolor japonicus Reitter, but they tended to leave from the larvae and further development did not occur. The hairs of the larvae of another beetle, Anthrenus verbasci L., prevented attachment of hypopi. Hypopi of L. konoi, on the contrary, attached very easily to larvae of the third dermestid beetle, Dermestes maculatus DeGeer. Transstadial migration of hypopi through developmental stages of the beetle from larvae to adults was also observed. Swollen hypopi of L. konoi successfully molted into tritonymphs at the highest rate after attachment to adult D. maculatus. Longevity of hypopi was shortest when they were reared individually. These results might indicate that attachment of hypopi of L. konoi to other organisms is the fundamental behavior for their longterm survival and molting into tritonymphs.