Association of Ereynetes tritonymphs (Acari: Ereynetidae) with the fungus gnat, Bradysia impatiens (Diptera: Sciaridae)

Abstract

Large numbers of tritonymphs of an Ereynetes (Ereynetes) species were found phoretic on the fungus gnat, Bradysia impatiens (Joh.), and in soilless growing media containing potato roots in a research greenhouse. The incidence of infestation of fungus gnats by mites was 98.9% and the mite load averaged 27, ranging from 0 to 85 mites per host. More mites were found on male than female hosts. Most mites were found on the thorax and anterior part of abdomen and about 60% of the mites were on the upper part of the body. Over 50% of the tested gnats showed some impairment of flying ability, apparently because the mite infestation affected the proper movement of the wings. Impaired flying ability increased with mite loads. Gnats infested with an average of 54 mites were unable to fly. This study comprises the first reported association of Ereynetes with Diptera and the first report on phoretic association of acarine tritonymphs with insects.