EXTRAORDINARY SEX-ROLES IN THE EURASIAN DOTTEREL - FEMALE MATING ARENAS, FEMALE-FEMALE COMPETITION, AND FEMALE MATE CHOICE

The mating system of the Eurasian dotterel, Charadrius morinellus, is compared with what would be expected in sex-role-reversed lekking (i.e ., female-female competition and mate choice by males). Female dottere l are potentially polyandrous and, in this study, compete for access t o males on mating arenas. Males provide all parental care. Intrasexual plumage variation is prominent in both sexes. Bright females win more of their fights than do dull females because bright females are more likely to initiate fights, and all females are unlikely to attack fema les brighter than themselves. Also, compared with dull females, bright females do more courting, pair earlier in the season, and are more li kely to pair with a bright male. Since bright males are apparently in better physical condition than dull males, we suggest that females pre fer males that will be good parents. Thus, as no evidence was found of any active mate choice by males, it seems that females are the more a ctive sex in mate choice. Hence, although competition among females on the mating arenas of the dotterel resembles competition among males o n leks, the direction of mate choice does not appear to match the anal ogy of sex-role-reversed lekking. This observation suggests that compe tition and mate choice are not simply opposite sex roles-individuals o f one sex can both compete for mates and exert mate choice.