The biology of the Alpine Accentor Prunella collaris. III. The coevolution of Alpine Accentors and lice (Phthiraptera)

The species Philopterus emiliae is more abundant in the bodies of accentors than Ricinus subpallidus. Of the 100 inspected accentors, 36 were insected by Ph.emiliae, and 10 by R. subpallidus. There is probably no evidence of competition between the two lice. Two birds only harboured both species of lice. Seasonal change is probably important determinant of population size and sex ratio of lice Ph. emiliae. Females of lice are probably capable of adaptive selection of females of accentors for the purposes of vertical transmission and lice dispersal. Species Ph. emiliae is also capable of adaptive sex ratio manipulation. Presuming a female bias in the lice departing from large late winter subpopulations to colonize on new hosts (from late May to early August) could explain the female bias of the summer subpopulations. Male bias of louse subpopulation occurred in autumn and early winter.