Studies on the Transmission of Cotton Rat Filariasis

The infection of the gulls Larus argentatus Pont., L. fuscus L. and L. marinus L. with Cestoda on the coast of Wales

An account is given of the incidence and intensity of infection of the gulls Larus argentatus Pont., L. fuscus L., and L. marinus L. with Cestoda on the coast of Wales. Eleven species of cestodes were found in the three species of gulls, nine in L. argentatus, eight in L. fuscus and six in L. marinus. Nine new host records and two new British records are listed.

The presence of the cestode parasites did not appear to be harmful to the birds.

Ecological and systematic notes are given on each of the cestode species. The basic cestode fauna of L. argentatus, L. fuscus and L. marinus on the coast of Wales comprised three species, namely Tetrabothrius cylindraceus (Rud.), T. erostris (voennberg) and Anomotaenia micracantha (Krabbe).

The factors influencing the intensity and incidence of infection are considered and it is concluded that infection is determined mainly by the food and feeding habits of the host. It is shown that the number of cestodes per bird may be represented by a negative binomial distribution. There is some evidence to suggest that high intensities of infection were associated with high incidences. Three main stages in the development of the helminth-fauna of gulls are described and are related to the age and activity of the bird.

It is a pleasure to record our personal thanks to those to whom we are indebted, namely the Nature Conservancy and the West Wales Naturalists' Trust for permission to work on Skomer Island, to Mr D. R. Saunders, Warden of Skomer Island, for help in the collection of some of the Great Black-backed Gulls, to Mr P. Hope Jones who collected the gulls from Malltraeth, and to Professor J. G. Baer, Departement de Zoologie, Université de Neuchâtel, Professor W. E. Kershaw, Department of Parasitology and Entomology, University of Liverpool, and Mr Stephen Prudhoe, British Museum (Natural History), for the loan of specimens, and to Mr M. D. B. Burt, Department of Natural History, University of St Andrews, for identifying the specimens of Paricterotaenia paradoxa.

The participation of one of us (M. P. H.) in this work was made possible through the generous assistance of a D.S.I.R. research studentship, which is gratefully acknowledged.

Feeding behaviour of pathogen-infected vectors

Evidence from many sources indicates that, in several parasite–vector systems, flight ability, fecundity or gonotrophic concordance of vectors, are affected by parasites (including bacteria, rickettsia and viruses) and in some cases parasites cause well-documented pathogenic effects (see reviews, for example, by Lavoipierre (1958a) and Hawking & Worms (1961) on filaria; Molyneux (1977, 1983) for trypanosomatids; Killick-Kendrick (1979) for Leishmania).