Studies on the ectoparasites of seals and penguins. 2. The ecology of the louse Antarctophthirus ogmorhini enderlein on the weddell seal, Leptonychotes weddelli lesson.

Abstract

The Weddell seal, Leptonychotes weddelli, which lives around the shores of Antarctica, is infested with the blood-sucking louse Antarctophthirus ogmorhini. Infestations spread solely from female seals to their pups by the transference of adult lice, and are frequent and heaviest on yearling and immature seals but are less frequent and lightest on mature seals. Few mature bulls are infested. Lice are usually restricted to the tail, ankle, hip, and hind flipper, but the margins of the anal and penile orifices of males may be infested, and occasionally the axilla of the fore flipper. The skin temperature of these sites of infestation varies with the thermoregulatory requirements of the seal, thus providing more opportunities than elsewhere on the body for lice to reproduce when the seal is ashore, and to feed when the seal is at sea. The number of lice is largely determined by the behaviour of the Weddell seal, and numbers are greatest on those age groups which haul out of the sea most frequently throughout the year. The principal physiological adaptation of A. ogmorhini for survival on the Weddell seal is the ability to become active and to reproduce at 5-15°C. Eggs can develop and hatch at constant temperatures as low as 0-4°C.