Coexistence in Helminths of the Bank Vole Clethrionomys glareolus. I. Patterns of Co-Occurrence

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. British Ecological Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Animal Ecology. Summary 1. We describe the patterns of co-occurrence in gastrointestinal helminths of the bank vole Clethrionomys glareolus at two localities in Finland, Pallasjarvi in western Lapland and Lammi in southern Finland. 2. Four of 12 pairs of helminth species showed significant, but often inconsistent, positive co-occurrence patterns (presence-absence data). Similarly, the significant pairwise correlations in helminth abundance were rare (three of 10 pairs) and inconsistent. 3. The rarity of significant overall associations among helminth species in the presence-absence data (two positive associations in seven data sets) and total absence in the density data support the idea of independent co-occurrence. 4. Most helminth populations were independently aggregated in the host population, which is likely to promote their coexistence. 5. The patterns of co-occurrence suggest that evolution of competitive ability is favoured, especially in rare species whose populations are largely restricted to hosts with concomitant infections by the common species.

Interspecific competition among macroparasites in a density-dependent host population

“…The possibility that interactive or non-interactive processes may shape community structure has been continually debated in ecology (Schoener, 1986). Empirical studies present evidence for both synergistic and antagonistic interactions among parasite species (Lotz and Font, 1991;Haukisalmi and Hentonnen, 1993). Yet, a simulation study by Janovy et al (1990) shows that positive and negative interactions may actually play little role in shaping a natural community of parasites.…”

A model of co-occurrence: segregation and aggregation patterns in the mycoflora of the crayfish Procambarus clarkii in Lake Trasimeno (central Italy)

“…Using presence-absence data provides less uncertainty in measuring occurrence rather than in measuring abundance, and does not mask non-random community patterns (see Haukisalmi, and Henttonen 1993).…”

Pathogen Interactions, Population Cycles, and Phase Shifts

“…This debate continues despite the fact that the importance of pathogen interactions is becoming increasingly obvious in clinical settings [17][18][19][20][21]. One possible explanation for the apparent lack of interactions between pathogen species in wild host systems is that the pathogens may be temporally asynchronous within their hosts, resulting in a form of niche segregation and reducing the likelihood of direct interaction [12,22].…”

“…Nevertheless, while most forms of interspecific interaction are well documented, unequivocal evidence of the existence of interspecific pathogen interactions under field conditions is rare. This has led to suggestions that interspecific interactions are of little importance in shaping pathogen communities under natural conditions [6][7][8][9][10][11][12][13][14][15][16]. This debate continues despite the fact that the importance of pathogen interactions is becoming increasingly obvious in clinical settings [17][18][19][20][21].…”