Dispersion and abundance of Maritrema arenaria in Semibalanus balanoides in north-east Ireland

Abstract

Infection of the barnacle Semibalanus balanoides with the digenean trematode Maritrema arenaria was investigated at 17 sites along the Co. Down coastline. There was a low background level of infection. Abundance of M. arenaria, however, was substantially greater at sites close to fish factories and at a site close to a sewage works. Aggregation of M. arenaria in S. balanoides was least marked at low mean parasite burdens. The parasitic burden was related more closely to barnacle size at a site of heavy infection than at one with a low abundance. There was a significant association between height on the shore and number of encysted metacercariae in S. balanoides. This was independent of variation in host size. It is concluded that relationships that bring about overdispersion of digeneans, such as that between the size-structure of the host population and parasite infection, may be dependent on the overall abundance of the parasite.

Population biology of Meiogymnophallus minutus (Trematoda: Gymnophallidae) in cockles from the Exe Estuary

“…Bed 5, for example, where cockles had high intensities of infection (Table 2), has one of the highest concentrations of S. plana on the estuary, and also has relatively large numbers of oystercatchers selectively feeding on clams and cockles (Boates & Goss-Custard, 1989). The close association of all three hosts required in the life cycle may best explain such high intensity infections, as has been suggested for other marine host-parasite systems (Carrol et al, 1990;Copeland et al, 1987;Curtis & Hurd, 1983;Irwin & Irwin, 1980). An alternative (but not necessarily independent) explanation is that infection characteristics of trematode larvae on the estuary result from the strength and direction of tidal currents.…”

Parasitism can influence the intertidal zonation of non-host organisms

“…Parasitism may influence zonation in two basic ways: (1) directly through the impact on host abundance or behaviour, and (2) indirectly through parasitic mediation of the interspecific interactions in which host species are engaged. However, empirical evidence for either is still scarce: The trematode Maritrema arenaria may be partly responsible for sudden shoreward declines in the abundance of the encrusting barnacle Semibalanus balanoides (Carrol et al 1990). Trematode infections have also been shown to affect the zonation of periwinkles Littorina spp.…”

Occurrence of Maritrema arenaria (Digenea: Microphallidae) in the acorn barnacle, Balanus perforatus (Cirripedia: Balanidae) from south-west Wales

“…Mitchell & Dessi (1984) found higher incidences of infection in the larger specimens of Balanus (Semibalanus) balanoides. Similarly, Carrol et al (1990) found positive correlation between the size and the number of parasites in the heavily infected specimens.…”