Habitat preference of Cyclograpsus pumilio (Decapoda, Brachyura, Varunidae) inhabiting the upper intertidal limit of pebble shores

Abstract

For the varunid crab Cyclograpsus pumilio Hangai & Fukui, 2009, that inhabits the upper intertidal limit of pebble shores, habitat preference for tidal height and pebble size was investigated using field and laboratory experiments. Crabs transplanted to a level lower than the distribution range survived less than those within the distribution range. Crabs placed in cages containing differently sized pebbles showed no difference in their survival with respect to the pebble size. An experiment to determine the pebble size preference showed that the males preferred the smaller pebbles, whereas the females preferred the larger pebbles.