Observations on the biology of Winterschmidtia hamadryas (Vitzthum) (Acari: Astigmata: Winterschmidtiidae) associated with the almond bark beetle, Scolytus amygdali Guerin-Meneville (Coleoptera: Scolytidae) in Iran

During 2001-2002 survey of mites and insects associated with the almond bark beetle, Scolytus amygdali GUERIN-MENEVILLE, 1847, in Iran (Tehran Province), all developmental stages of the mite species, Winterschmidtia hamadryas (VITZTHUM, 1923), were collected. The adults, nymphs and larvae of the mite were observed in great numbers in the scolytid galleries, and its deutonymphs were found phoretic on the adult beetles. Of 917 almond bark beetles collected from infested trees, 17.3% had at least one deutonymph of W. hamadryas. The attachment sites were the ventral surface of the abdomen, abdominal pleurites, femora, ventral and pleural thorax, between coxae II and III, and rarely on the dorsal body, elytra and on both sides of the head. Most of the deutonymphs (60.3%) were attached to the abdominal pleurites. The greatest number of these mites on a single beetle was 15. This species is one of the most abundant mite species which were found in the beetle galleries. Deutonyrnphs of this mite probably influence beetle activities or prevent their flight or shorten their dispersal distance