Site selection by parasitic helminths: interspecific interactions, site segregation, and their importance to the development of helminth communities

Abstract

That parasites actively select specific sites in their hosts is well known. Some parasites respond to changing conditions within the host by making diel or other short-term migrations, which may be modified by the presence of other parasites.Evidence is presented to support the hypothesis that continued interactions between parasites lead to niche diversification, and that site segregation, and consequently narrow site specificity, is an important part of niche specialization. The paucity of cases of interactive site segregation as compared with those of genetically stabilized selective site segregation suggests that parasite faunas are mature communities, the diversity of which has been established to an important extent through biotic interactions.

Implicações da agregação espacial de parasitas para a dinâmica populacional na interação hospedeiro-parasita

“…Dessa forma, interações competitivas entre diferentes espécies de parasitas influenciarão apenas pequenas proporções de cada população de parasitas presente em hospedeiros infectados concomitantemente 15,20 . A diversidade de espécies em comunidades de parasitas é resultado, entre outros fatores, de interações entre a história evolutiva e a ecologia dos hospedeiros 35 .…”

Distribution of helminths in the digestive tracts of New Zealand freshwater eels

“…Holmes (1973) mentioned only two studies (MacKenzie & Gibson 1970, Williams et al 1970 in his review of site selection of parasitic helminths, and Crompton (1973) added only one further study (Thomas 1964) in his review of the sites occupied by parasites in the vertebrate alimentary tract. The authors of many more general studies simply noted the position of the nematode in the host (Sogandares-Bernal 1955, Noble & King 1960, Kane 1966, Moravec 1966, Joy 1971, 1974, Stromberg & Crites 1975).…”

Helminths of the Lizard Salvator merianae (Squamata, Teiidae) in the Caatinga, Northeastern Brazil

“…The massive presence of species of nematodes infecting the lizard S. merianae, in contrast with the absence of other taxa of helminths (such as acanthocephalans, cestodes and trematodes), can be explained in the present observational study, through competitive exclusion (Holmes, 1973), where parasite competition for resources, would be the answer to infer why a taxon appears to be absent in the presence of others (Friggens and Brown, 2005).…”