An experimental investigation of a direct life-cycle inReighardia sternae(Diesing, 1864), a pentastomid parasite of the herring gull (Larus argentatus)

Abstract

A direct life-cycle inReighardia sternae, a cephalobaenid pentastomid of gulls was investigated: the work was prompted by a report of eggs and larvae recovered from the stomach and intestine of a naturally infected gull.Infective pentastomid eggs were obtained by surgically transplanting maturing femaleReighardia, taken from freshly shot wild gulls, into captive recipients. Faecal material from birds thus artificially infected was collected daily and examined for eggs. Eggs were force fed to 33 hand-reared (from eggs or nestlings) juvenile gulls which were selected at random and sacrificed at intervals thereafter and examined for pentastomids.One hour after infection, primary larvae appear in the body cavity where they moult immediately. They grow steadily and by 27–35 days are sexually differentiated, and by 66 days have copulated. Fertilized females take a further 116 days to produce eggs by which time they are 7·6 cm long.The complex migrations undertaken by developing larvae in the gull, and the problems of the mechanism of direct transmission, are discussed.