Ectoparasites of Antarctic Seals and Birds

The arthropod fauna decreases from the Subantarctic to the Antarctic, and many of the known species are ectoparasites of seals and birds. These comprise ticks, fleas, feather mites, respiratory mites and lice, both Mallophaga and Anoplura. Fleas and ticks are represented by species confined to the various Subantarctic islands south of South America or New Zealand, and by circumpolar species. One species of flea is probably circumpolar on Antarctica where it is found in the nests of silver grey fulmars and snow petrels. Most of the ecological studies have been confined to the fleas and ticks which infest penguins. Penguins can be heavily infested with the flea Parapsyllus magellanicus heardi and the tick Ixodes uriae on Macquarie Island. The severity of the infestations of each species of penguin is largely determined by their breeding and moulting behaviour. Most of the birds possess more than one species of louse, and penguins are no exception. The feathers of penguins trap an air blanket around the bird when it is swimming, so their lice can multiply whether the penguin is on land or in the sea. Consequently the ecology of penguin lice is probably not unlike that of other bird lice. The lice of seals differ greatly from other mammalian lice, and the lice of the elephant and weddell seal have been shown to multiply only when the seals are ashore. These lice are confined to the tail and flippers of the seal, parts of the body which are associated with thermoregulation. The fluctuations in blood supply and skin temperature of these regions afford more opportunities for the lice to breed when the seal is ashore, and to feed when the seal is at sea