Population Regulation in Rabbit Nematodes

Abstract

COMPARATIVELY little information is available on the factors governing the size of nematode infestations in wild mammals. Elton et al.¹ showed that infestations of Nematospiroides dubius in field-mice (Apodemus) tended to become larger as the host increased in weight, and Evans² demonstrated a similar tendency for Graphidium strigosum in wild rabbits (Oryctolagus); but for Passalurus arnbiguus he found that, after rabbits reached a weight of 3½ lb., infestations declined with further increase in host-weight. The authors interpreted their results as indicating the effects of increasing age of host. Recent work on the parasites of the wild rabbit (Oryctolagus cuniculus L.) in New Zealand gives confirmation of Evans's results for G. strigosum, and provides the first adequate picture of population-size in Trichostrongylus retortaeformis, a picture which differs markedly from those of the other nematodes mentioned above and forms the subject of the present communication.