Time Budget ofCancer irroratus(Say) andCarcinus maenas(L.) Under Various Temperature and Prey Density Conditions During Conspecific and Heterospecific Challenges

Abstract

ABSTRACT The green crab (Carduus maenas L.) is an exotic species in many parts of the world. It successfully invaded, at the end of the 1990s, the coast of Prince Edward Island, Canada, where rock crabs (Cancer irroratus Say) are commonly found. The relationship between these 2 species is still not well documented. The short-term time budget of both species was studied in autumn 2006 and spring 2007 under different experimental conditions to assess the effect of the green crab on the behavior of the rock crab. Crabs were observed in 3 competition treatments (1 crab, 2 conspecifics, or 2 heterospecifics) using 3 temperatures (5, 12, or 20°C) and 2 prey densities (4 or 30 mussels). The time spent foraging and in agonistic interactions by both species generally increased in high-temperature challenges, whereas the time spent inactive decreased, regardless of the season. Both crab species responded differently when facing a conspecific. Time spent foraging increased in certain cases whereas it decreased in ot...