Parthenogenesis as a life strategy among mites of the suborder Uropodina (Acari: Mesostigmata)

Abstract

This paper presents the results of observations concerning the phenomenon of parthenogenesis among European mites of the suborder Uropodina. An analysis of the sex ratios of 66 Polish species revealed that 18 of them (more than one fourth of the examined species) consisted only of females. The authors observed no significant relationship between geographical distribution and the lack of males in the population. Populations consisting entirely of females were observed among widely distributed species as well as among species characterized by narrow geographical ranges. Nonetheless, an increase in the number of parthenogenetic species, especially as a percentage of Middle European and Scandinavian fauna, was also discernible. Species that reproduced without males were associated with forest litter and soil, whereas bisexual species "eagerly" inhabited various relatively unstable and temporary micro environ ments (for instance, dead wood, birds' or small mammals' nests). The authors aim to define the biological role of occasionally appearing males for the species consisting almost entirely of females and discuss ecological and evolutionary aspects of parthenogenesis in mites of the suborder Uropodina.