AN IN-SITU CORING TECHNIQUE FOR ESTIMATING THE POPULATION-SIZE OF HOUSE-DUST MITES IN THEIR NATURAL HABITAT

An in situ core sampling method was used to obtain absolute population density estimates for the mite, Dermatophagoides pteronyssinus Troues sart (Acari : Pyroglyphidae) in the mattress habitat. At the 95% fiduc ial limit the numbers of D. pteronyssinus in the top 1.5 cm of substra ta were 8,200-26,800 mites m(-2). Mite densities that were calculated from vacuum samples of the same habitat underestimated the abundance o f D. pteronyssinus by more than three orders of magnitude. Vacuuming d id not detect all mite species inhabiting the mattress, and eggs and i mmature mites were under-represented in vacuum samples. The importance of absolute population estimates versus relative estimates of abundan ce and population density indices is discussed, and a number of ways i n which the core sampling approach may contribute to future house dust mite research are suggested.