Ecology

T. cymodoce are obligate symbionts of branching corals from the Family Pocilloporidae (Patton, 1974, Austin et al., 1980, Abele and Patton, 1976). As such, they can be found living within Pocillopora colonies throughout the reef flat and lagoon, including areas that are exposed at low tide (Patton, 1974, Austin et al., 1980). They are one of the dominant species of fauna associated with Pocillopora colonies within the Heron Island reef and are the most commonly encountered Trapezia species when observing communities living on Pocillopora colonies (Austin et al., 1980).  T.cymodoce are typically found in heterosexual pairs, with each inhabited Pocillopora colony housing only a single pair of adults at a time, although smaller adults and juveniles often co-occur with adult pairs (Patton, 1974). 

The crabs are able to hold on firmly to the coral using their walking legs while they use their claws to fend of intruders.Their body morphology is well suited to the Pocillopora colonies and they are able to move quickly thru the tight passages between coral branches.  

For more info relating to Pocillopora corals, see the page on this website on the Pocillopora species Stylophora pistillata.

 

Image: A pair of T. cymodoce individuals within the branches of a Pocillopora colony