Effects ofPlagiorhynchus cylindraceus(Acanthocephala) on the energy metabolism of adult starlings,sturnus vulgaris

Abstract

Although the relationship between intestinal parasitism, the ingestion and use of energy, and host survival is expected, little work has been done to outline the effect of such organisms upon their host's nutritional requirements in an ecological context. This study is the first to demonstrate that an intestinal helminth previously reported to be of little or no histopathological consequence, Plagiorhynchus cylindraceus, has a significant detrimental impact upon the flow of food energy through a definitive host, the European starling, Sturnus vulgaris. Within both male and female adult European starlings reductions in standard metabolic rates occurred as the result of initial infection, indicating that the host's basal metabolism/thermal regulatory abilities were altered. Moreover, initially infected male starlings, but not females, had an increased consumption and excretion of energy and maintained lower average daily body weights versus controls when temperature stressed. These results appear to be due to either a parasite-mediated alteration in host activity and/or to the disruption of host-digestive abilities. Additionally, these data indicate that, overall, male and female S. vulgaris respond differently to infection and that intestinal helminths normally thought to be of little or no pathological consequence to the host are factors that should be addressed in future studies regarding animal energetics, ecology, and behaviour.

Physiological responses of insular wild black rat (Rattus rattus) to natural infection by the digenean trematode Fasciola hepatica

“…Several studies reported the effect on body mass and physiology of sub-lethal helminth parasites on vertebrate hosts (Connors and Nickol 1991;Hammond 2000, 2001). These parasites can reside in their host for weeks, months or years causing a chronic infection.…”

Population variation in the metabolic response of deer mice to infection with <i>Capillaria</i> <i>hepatica</i> (Nematoda)

“…Parasitic infections can impair hosts' metabolic capacities, and these effects may be exaggerated in stressful conditions (for example, see Schall et al 1982;de Lope et al 1993). To date, there have been relatively few studies of the consequences of parasitic infection on the metabolic capacities of wild vertebrates (fish, Walkey and Meakins 1970;Lester 1971;Lemly and Esch 1984;Coleman 1993;amphibians, Goater et al 1993;lizards, Schall et al 1982;Christian and Bedford 1995;Oppliger et al 1996;and birds, Hayworth et al 1987;Connors and Nickol 1991;Booth et al 1993;Chappell et al 1996) and only a single study of wild mammals (Munger and Karasov 1989).…”

Sex discriminatory effect of the AcanthocephalanAcanthocephaloides propinquuson a gobiid fishGobius Bucchichii

“…However, it might be difficult in field studies to detect patholo gical impact, as affected individuals should be rapidly eliminated by predation (Holmes, 1983). Moreover, the effect of the parasite (if there is one) may not be obvious on the biological indices studied at the level of the population even if it has been previously demons trated that host energy metabolism could be affected by acanthocephalans (Connors & Nickol, 1991). On the one hand, sex hormone secretion for gonad maturation in females after maturity can play an influential role in the regulation of the immune res ponse and therefore favor parasitism (Alexander & Stimson, 1988;M0ller, 1993).…”