Desiccation tolerance of two freshwater crabs of the Amazon: Dilocarcinus pagei and Sylviocarcinus pictus (Decapoda, Trichodactylidae)

Abstract

Abstract This study investigated the resistance to desiccation of two species of freshwater crabs, Dilocarcinus pagei and Sylviocarcinus pictus. Dilocarcinus pagei survived almost twice as long as S. pictus, 127 ± 82.4 h and 69 ± 17.5 h, respectively. The females of both species survived longer than the males and the females of D. pagei survived longer than the females of S. pictus. Water loss until death was on average 30.12 ± 11.79% for D. pagei and 42.59 ± 7.49% for S. pictus. Dilocarcinus pagei showed a lower water loss than S. pictus until death and large S. pictus females and small D. pagei females exhibited a higher water loss, with differences between species and sex. The results reveal how these two species of crabs behave in extreme droughts in the Amazon floodplain. The females of both species were more resistant, although females of D. pagei were more resistant to desiccation than females of S. pictus, showing a higher degree of terrestriality.