Biology of House Finch feather mites, Proctophyllodes pinnatus (Acari: Proctophyllodidae), parallels variation in preen gland secretions

Abstract

ABSTRACT Except for Dubinin's classic works in the 1950s, there is very little information on the natural history or population dynamics of feather mites (Astigmata: Acariformes, Pterolichoidea). We studied variation in numbers of the different life stages of the feather mite Proctophyllodes pinnatus (Nitzsch) (Analgoidea: Proctophyllodidae) on captive House Finches Carpodacus mexicanus (Müller) (Passeriformes: Fringillidae) from December 2003 to November 2004. Simultaneously, we also studied how preen gland secretion varied in those birds. We monitored 20 House Finches (10 individuals of each sex) for the presence of mites on their wing feathers. There was seasonal variation in the abundance and prevalence of mites on different individual birds. Most birds did not show any mites from December to April. Mite numbers started to increase in July and peaked in August–September. In September, we observed more mites of early stages than in any other months. We also observed higher proportions of adults in August and October and fewer adults than expected in September, suggesting that more than one generation was involved. By November, very few mites were present on the wing feathers. The variation in mite numbers paralleled variation in the composition and quantity of preen gland secretions produced by the host House Finches. In most of the captive birds, secretion peaked in the month following peak mite-abundance. During the period when mite abundance was highest, secretions contained a higher diversity of chemicals. Prevalence of mites on wild House Finches showed similar trends to those observed in captive birds. Relative abundances of life stages on wild birds collected in July were similar to those observed for captive House Finches in the same month.