Nematode parasites of free-living rabbits, Oryctolagus cuniculus (L.) in eastern Australia II. Variations in the numbers of Graphidium strigosum (Dujardin) Railliet & Henry

Abstract

Numbers of the stomach worm Graphidium strigosum were estimated in the stomachs of about 2500 rabbits collected from four sites in eastern Australia extending over 1-3 yr of regular sampling. At two of these sites - in the semi-arid far north-west of New South Wales and in subtropical south-central Queensland - G. strigosum was not found. At a third site in the riverine plain region of southern New South Wales G. strigosum was found in 15% of the 470 rabbits examined but it was never found in high numbers in any rabbit. At a subalpine site in south-eastern New South Wales G. strigosum probably infected all rabbits during their life and was often found in high numbers. Numbers of adult stomach worms tended to increase during the first year of the rabbit's life. During each breeding period (which is of 4-6 months duration at this site) female rabbits carried more Graphidium than did male rabbits, although this situation is only of quite short duration and might have been overlooked except by frequent sampling. It is thought that this pattern would be repeated each breeding period throughout the life of the rabbit and is probably of considerable ecological significance for the parasite.