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Abstract

abstract

The house mouse Mus musculus at Marion Island are predominantly insectivorous but opportunistically omnivorous in their foraging strategy. Pringleophaga marioni larvae predominated in their diet, and these as well as adult weevils, their larvae and pupae (Ectemnorrhinus similis) and arachnids were preyed upon more intensely during winter. The main constituents of plant food types were Agrostis magellanica and Poa cookii seeds, the greater amount of plant material being taken during summer. Diet diversity and variety were moreover lower during winter as mice are apparently finding and consuming a wider variety of food during summer. Mice are therefore entering the ecosystem at the second (invertebrate herbivores) and third (invertebrate carnivores) trophic levels and have successfully adapted to cope with the high latitude insular terrestrial environment.