Preferred thermal regime of the estuarine crabs Uca uruguayensis and Chasmagnathus granulata (Decapoda, Brachyura)

DEZI, R.E.; RODRÍGUEZ, E.M.; LUQUET, C.M.; CERVINO, C.O.; HAUT, G.E.

Comparative Physiology and Ecology

Premier Publications

Año: 1993 vol. 18 p. 149 - 155

0379-0436

1.- A horizontal and continuous temperature gradient frame was designed for determinantion of temperature preferences of the intertidal crabs Uca uruguayensis and Chasmagnathus granulata. These species were sample from the same community, located at the mouth of Rio de la Plata estuary, Argentina. Temperature and salinity acclimation were 20 +/-1ºC and 12 ppt respectivelly.2- Assays carried out with single animals, showed a similar mean preferred temperature between species (22-33ºC). C. granulata evidenced a wider thermopreferendum amplitude, wich correlattes with both its broader geographic distribution and with its habits of living in more thermically variable environments.3- In asssays with groups of crabs, the preferred thermal regime of U. uruguayensis as much wider that that revealed in single-specimen expereriments, in accordance with territoriality of the genus: enlargement of thermopreferendum toward hot temperatures could be related to the subtropical distribution of that species. On the contrary, groups of individuals of C. granulata showed a relative narrower preferred thermal regime than  the single ones, according to the individual aggregation observed under both natural and laboratory conditions.