Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

A transmission study of two sympatric digeneans: spatial constraints and solutions.

Abstract

The distributions of infected molluscan hosts of Maritrema misenensis, a parasite of charadriid birds, and Lepocreadium pegorchis, a parasite of sparid fishes, were examined along a transect spanning the mediolittoral and upper infralittoral zones at the edge of a protected small bay (Baie du Brusc) in southeastern France in July 1991. For both parasites, the first intermediate host (Cerithium mediterraneum and Amyclina corniculum, respectively) occurs in an area separated spatially from the definitive host: in each case, only a small fraction of the potential first intermediate hosts, those nearest the source of eggs, are infected. In both cases, 2nd intermediate hosts (Orchestia mediterranea, and Venerupis aurea, Venus verrucosa and Cerastoderma glaucum, respectively) overlap in distribution only slightly (or not at all) with the first intermediate hosts (and, in the case of L. pegorchis, with the definitive hosts). The strategies evolved to overcome these spatial constraints on transmission are discussed.