Life begins when the sea lion is ashore: microhabitat use by a louse living on a diving mammal host

M.S. LEONARDI; E.A. CRESPO; D.G. VALES; M. FEIJOO; J.A. RAGA; F.J. AZNAR

BULLETIN OF ENTOMOLOGICAL RESEARCH

CAMBRIDGE UNIV PRESS

Año: 2012 vol. 102 p. 444 - 452

0007-4853

Among Anoplura, the Family Echinophthiriidae includes species infesting pinnipeds and otters. Previous evidence obtained from echinophthiriids infesting pinnipeds from seals indicates that flippers are the preferred infestation site while lice from fur seals select areas in function of the kind of the pelage. We studied habitat selection of Antarctophthirus microchir on South American sea lion pups, (Otaria flavescens Shaw, 1800) from Patagonia Argentina, during the austral summer of 2009. We found a clear pattern of habitat selection: eggs are laid on the dorsal surface, first instar nymphs hatch there and then migrate to the belly, where they develop into adults and copulate. Subsequently ovigerous females return to the dorsal surface. the first instar nymphs are characterized by their low locomotory ability, hence the fact that they migrate soon after hatching suggests a clear pressure leading to microhabitat restriction. It appears that A. microchir would prefer the host ventral area for development and copulation, and the dorsal area for oviposition.The reasons for this pattern are not clear and many factors could be involved. Sea lion pups periodically soak at high tides, and that prolonged immersion and very high humidity are known to be lethal for louse eggs. Selecting the dorsal area would be advantageous for oviposition because it dries more rapidly. Once the nymphs migrate to the ventral surface, the wet conditions would prevent desiccation of the nymphs in the arid environment where O. flavescens breeds