Certain organism-substrate relationships affecting the distribution of Uca minax (Crustacea: Decapoda)
The involvement of substrate in the ecology of the fiddler crab Uca minax was investigated by means of both field and laboratory studies. These included determination of the oxygen-holding capacities of five types of substrates on which this organism lives, as well as experiments to determine if there is substrate selection. The effect of population density on burrowing was also studied to determine the optimum number of individuals needed in the selection experiments, and to delineate the mechanisms these organisms use for avoiding dispersion onto less favorable substrates. Results indicate that Uca minax prefers substrates with high organic content, although these were shown to contain the lowest substrate oxygen. This evidence suggests that Uca minax prefers substrates of high energy value, and explains the significance of this species' adaptation in withstanding low oxygen tensions. Population density experiments indicate that at high population densities these crabs reduce intraspecific encounter and competition by burrowing and subsequently covering their burrows. Seasonal monitoring of burrow temperatures indicate the stability of this microenvironment as compared with the surrounding air temperature. These data also demonstrate the significance of the adjacent water in the habitat ecology of Uca minax.
- 1 - sciences appliquees, technologies et medecines
- 2 - sciences biologiques et medicales
- 3 - sciences biologiques fondamentales et appliquees. psychologie