Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 27. (Budapest, 1994)

The phenomenon "cannibalism" in Dermatophagoides farinae (Acari) populations Zsuzsa HALMAI Pathological Department of 'Szent Margit' Hospital, H1032 Budapest, Bécsi út 132. Hungary (Received 30 October, 1994) Abstract: In the course of the routine parasitological examination of housedust samples, nearly 65,000 mites have been isolated and identified since 1969. So far the beginning of the 1980's chitinous particles of other Dermatophagoides mites and those of other mite species have regularly been found in the bodies of house-dust mites, mostly D. farinae females. The possible significance and causes of the phenomenon "cannibalism" are discussed in this paper. Key words: house-dust mites, Dermatophagoides farinae, "cannibalism" INTRODUCTION "Cannibalism" in a strict sense means an extraordinary behaviour of animals eating or mutilating members of their own kind. This can occur as an abnormal individual incident, or may be the manifestation of an intraspecific population control mechanism when the density is high. Larvae and adults of weevils eat their own eggs besides their natural diet at an increasing population density. This can frequently be observed among harvest spiders and other genera behaving as predators. It has also been observed among predator mite Cheyletus eruditus that "many of the newly emerged larvae are eaten by the female if they are kept in a confined space" (Hughes, 1961). Concerning Acari, Pyroglyphidae we have some data about Dermatophagoides farinae (Brody et al. 1972) and D. pteronyssinus (Bronswijk 1973). Both species were cultured and then studied by light and electron microscopy. Most of D. farinae mites were reported to be "cannibalistic", as their mid- and hindgut contained some parts of the cuticle of ingested mites. Wharton's (1976) experience was similar. Before this study, no data had been available on the cannibalistic behaviour of house-dust mites in their natural habitat. This is why the present observations are reported MATERIAL AND METHODS A routine parasitological examination of house-dust samples collected in the homes of asthmatic children has been carried out since 1969. So far nearly 65, 000 mites have