Life cycles and larval behavior of two species of Hydrachna (Acari, Hydrachnidae), parasitic upon Corixidae (Hemiptera–Heteroptera)

Abstract

The seasonal population fluctuations, population distributions, and pattern of attachment of the larvae of two species of Hydrachna parasitic upon Sigara solensis Abbott and Sigara modesta Hungerford were investigated in a permanent pond in Waterloo County, Ontario, throughout 1969. Seasonal fluctuations of parasitism occurred as a result of the fluctuations in the numbers of the free-living larvae and of the corixid hosts. Analysis of the intensity distribution of the larvae on their hosts fitted the data to a Poisson distribution. The parasitic larvae of the two mite species were evenly distributed over most of the potential attachment sites on their hosts. Absence, or reduced numbers, of larvae at any site has been explained in terms of nonavailability of the site to parasitism as a result of host behavior or physical unsuitability.