Use of the introduced bivalve, Musculista senhousia, by generalist parasites of native New Zealand bivalves

introduced species are often thought to do well because of an escape from natural enemies. however, once established, they can acquire a modest assemblage of enemies, including parasites, in their new range. Here we quantified prevalence and effects of infection with copepods (family Myicolidae) and pea crabs (Pinnotheres novaezelandiae), in three mussel species, the non-native Musculista senhousia, and two native mussels, Perna canaliculus and Xenostrobus pulex, at Bucklands Beach, Auckland, New Zealand. Copepod prevalence was highest in X. pulex (17.9%), whereas pea crab prevalence was highest in P. canaliculus (33.6%). Both parasites infected M. senhousia, but at a much lower prevalence. Dry tissue weight was significantly lower in P. canaliculus infected with pea crabs. in addition, we experimentally investigated host species selection by pea crabs. in an experimental apparatus, pea crabs showed a significant attraction to P. canaliculus, but not so for X. pulex or M. senhousia. When the mussels were presented in combination, pea crabs showed a weak attraction for X. pulex. Pea crab attraction to M. senhousia was not significant. It appears that the introduced M. senhousia largely escapes the detrimental effects of infection with either parasite species compared with native mussels occurring in sympatry.