Water loss of crabs from different habitats

1. 1. Evaporative water loss in eleven species of brachyuran crabs was related to habitat. Crabs from terrestrial environments lost the least water while species from aquatic conditions lost the most. 2. 2. Evaporative loss was a function of body weight in all species. Small crabs had higher rates of loss per g than did large. Exponential equations depiciting the relationship were developed. 3. 3. Evaporative loss increased at higher temperature. 4. 4. Indirect evidence indicates that most water loss of crabs is through the integument exclusive of the gill chamber. 5. 5. Water loss of hermit crabs increased three times when their protective mollusk shell is removed. 6. 6. Water loss in the most terrestrial species of crabs was several times greater than terrestrial vertebrates, insects and arachnids.