Spatial and Temporal Variations in the Trematode Component Community of the Mudsnail Hydrobia ventrosa in Relation to the Occurrence of Waterfowl as Definitive Hosts

Abstract

The component community of larval trematodes infecting the mudsnail Hydrobia ventrosa (Montagu) was examined in coastal lagoons of the southern Baltic Sea among different host subpopulations in relation to the structure of the waterfowl community. The 10 trematode species observed represent the families Notocotylidae (1), Echinostomatidae (1 or 2), Heterophyidae (2). Monorchidae (1). Microphallidae (3 or 4), Psilostomatidae (1), and Hemiuridae (1). Eight of these species infect waterfowl as adults. The structure of the trematode communities was similar between sampling sites. Seven trematode taxa were commonly found at all sampling sites. Prevalence values of the 6 most abundant taxa, which infect birds as final hosts, were significantly different between neither sampling sites nor across year. Overall trematode prevalence in H. ventrosa fluctuated seasonally. Prevalence usually peaked in summer between July and September or October. Low prevalences were observed in late winter and early spring. In contrast, the seasonal maximum in waterfowl numbers differed between areas because of significant spatial differences in the bird community structure. The species composition of the component trematode community of H. ventrosa in the coastal lagoons of the southern Baltic Sea is more or less independent of the species composition of the waterfowl community. This independence presumably results from the lack of host specificity in most of the observed trematode species. Otherwise, the low host specificity in combination with the enormous waterfowl diversity in the coastal lagoons might explain the stability of the prevalence pattern of the component trematode community.

Larval trematodes infecting the South-American intertidal mud snail Heleobia australis (Rissooidea: Cochliopidae)

“…This finding could be explained by the high abundance of grapsid crabs-the second-intermediate hosts of the microphallid species (Alda et al 2011a), except for M. simillimus-along with the high diversity of gulls (Petracci and Delhey 2005). Microphallids also prevail in the intertidal gastropods from the Patagonian coast in Argentina (Gilardoni et al 2011) and in the rissooids of the European coast (Deblock 1980, Kube et al 2002, Skirnisoon et al 2004, Thieltges et al 2009.…”

“…This kind of larval trematode assemblage-i. e. with most trematode species showing low prevalence except for one or two species with a high abundance-is in fact, common in larval trematode assemblages of the rissooids from Europe, Oceania, and America (Deblock 1980, Jokela and Lively 1995, Kube et al 2002, Skirnisoon et al 2004, Thieltges et al 2009, Merlo and Etchegoin 2010.…”

Can the studies at a spatial scale of 100s meters detect the spatiotemporal fluctuations of a parasite assemblage?

“…Spatial and temporal variability in prevalence of larval digenean communities has been related to the density of the snail hosts (Kube et al 2002;Faltýnkova et al 2008). According to our results, only a negative association between prevalence of larval digeneans and snail's density was detected during the autumn.…”

Impact of trematodes on host survival and population density in the intertidal gastropod Zeacumantus subcarinatus

“…In snail-trematode associations it is commonly observed that trematode prevalence increases with increasing snail age (Whitlatch 1974, Hughes & Roberts 1981, Hughes & Answer 1982, Curtis & Hurd 1983, Sokolova 1995, Kube et al 2002. The simplest explanation is that older snails have been exposed to trematode infections for a longer period of time and therefore have a greater probability of being infected.…”