The osmotic pressure and concentration of major ions in the haemolymph and urine of Gecarcoidea natalis in the rainforest during the wet season (February 1997)
| . | Haemolymph . | . | Urine . | . | ||
|---|---|---|---|---|---|---|
| . | Free ranging . | Confined . | Free ranging . | Confined . | ||
| Osmotic pressure (mOsm) | 753.3±28.3 | 798.8±6.0 | 768.7±30.2 | 816.4±6.2 | ||
| Na (mmol l−1) | 338.3±23.4 | 331.3±6.7 | 302.8±14.4 | 269.6±9.6 | ||
| K (mmol l−1) | 6.1±0.4 | 5.9±0.9 | 5.9±0.7 | 6.3±0.8 | ||
| Mg (mmol l−1) | 6.6±0.5 | 5.7±1.2 | 5.6±0.6 | 5.9±1.4 | ||
| Cl (mmol l−1) | 315.5±11.7 | 316.3±4.7 | 299.3±10.7 | 386.0 *†±5.3 | ||
| Ca (mmol l−1) | 18.4±0.9 | 16.8±1.2 | 9.5 †±1.3 | 16.1 *±2.0 | ||
| . | Haemolymph . | . | Urine . | . | ||
|---|---|---|---|---|---|---|
| . | Free ranging . | Confined . | Free ranging . | Confined . | ||
| Osmotic pressure (mOsm) | 753.3±28.3 | 798.8±6.0 | 768.7±30.2 | 816.4±6.2 | ||
| Na (mmol l−1) | 338.3±23.4 | 331.3±6.7 | 302.8±14.4 | 269.6±9.6 | ||
| K (mmol l−1) | 6.1±0.4 | 5.9±0.9 | 5.9±0.7 | 6.3±0.8 | ||
| Mg (mmol l−1) | 6.6±0.5 | 5.7±1.2 | 5.6±0.6 | 5.9±1.4 | ||
| Cl (mmol l−1) | 315.5±11.7 | 316.3±4.7 | 299.3±10.7 | 386.0 *†±5.3 | ||
| Ca (mmol l−1) | 18.4±0.9 | 16.8±1.2 | 9.5 †±1.3 | 16.1 *±2.0 | ||
Crabs were either free ranging in the rainforest or held within open-topped enclosures that allowed rainfall to enter and contact with the forest floor. Values are means ± s.e.m. (N=8-12 in each group).
, significantly different to free-ranging crabs at P<0.05;
, urine significantly different to haemolymph at P<0.05.