Mate locating and access behaviour of the parasitic pea crab,Nepinnotheres novaezelandiae, an important parasite of the musselPerna canaliculus

Abstract

Pea crabs are globally ubiquitous symbionts in the marine environment that cause serious economic impact in the aquaculture production of several major bivalve species. However, little is known about their host-parasite interactions, especially the mating behaviour of these parasites that could prove useful for controlling their infestation in aquaculture. In this study, the mate location behaviour of male New Zealand pea crabs, Nepinnotheres novaezelandiae (Filhol, 1885), was observed when dwelling in its preferred host, the commercially important green-lipped mussel, Perna canaliculus. Given the cryptic behaviour of the male crabs, a novel trapping system was developed to determine whether male crabs would exit their mussel hosts in response to an upstream female crab. The presence of receptive female crabs placed upstream successfully attracted 60% of male crabs from their host over 24 h. Observations of the nocturnal mate-finding behaviour of male crabs were made in darkness using infrared video recordings. Males spent on average 49 min on empty hosts and never left a mussel containing a female conspecific once found, spending 200 min on average to gain entry to the mussel. Male crabs were often observed stroking the mantle edge of the mussel whilst attempting to gain entry, successfully increasing mussel valve gape during entry from 3.7 to 5.5 mm. A pheromone-based mate location system is likely used by this crab to greatly reduce the risks associated with the location of females.

Parasites and coral‐associated invertebrates that impact coral health

“…Cheng and Dai (2009) suggest that these copepods use a chemical cue to facilitate this relaxation, but there is currently no evidence to support this hypothesis. Other parasitic crustaceans have been shown to ‘tickle’ bivalve hosts to gain entry (Trottier & Jeffs 2015). Cheng and Dai (2010) observed that Xarifia fissilis (Humes, 1985) consumed Symbiodiniaceae within their Pocillopora damicornis (Linnaeus, 1758) hosts, which remained photosynthetically viable in the gut of these copepods after two weeks.…”

Life Cycle and Life History Strategies of Parasitic Crustacea

“…Many of these relationships are not well studied, and some may be parasitic. They retard the growth of some commercial molluscs by 30% causing serious problems and millions of dollars in losses in aquaculture (Trottier and Jeffs 2015).…”

“…This is because hosts are more active and sensitive during the day and can squash males. Trottier and Jeffs (2015) observed males being crushed. Additionally, they are subject to predation less in the dark, than in the light of day.…”

New host record of pea crab Arcotheres purpureus (Alcock, 1900) (Crustacea: Decapoda: Pinnotheridae) with first description of male

“…Most of these species live inside bivalve molluscs or in the tubes or burrows of polychaetes and other marine organisms (McDermott, 2009). As globally ubiquitous symbionts of the marine environment, these pea crabs cause serious economic impact in the aquaculture production of several major bivalve species (Trottier and Jeffs, 2015).…”