CSZ 2026

Les grillons régulent le volume de l’hémolymphe et l’équilibre ionique pendant la dessiccation

Desiccation is a prevalent stress for small insects and desiccation risk is expected to increase with increasing aridity under climate change. To survive in low humidity, insects must resist or tolerate water loss, but our understanding of how they do this remains incomplete. Here, we tested the hypothesis that crickets progressively lose haemolymph water volume which disrupts sodium and potassium balance during desiccation. We further tested that crickets restore extracellular ion balance if provided water for rehydration. We found that crickets strongly regulate haemolymph potassium concentration in the extracellular space during up to 18 h of desiccation, and sodium concentration increased somewhat during desiccation, but crickets were able to restore sodium concentrations to baseline levels after rehydration. Crickets lost 9.5% ± 0.4 of their initial mass (mean ± s.e.) during desiccation. Losses of over 35% of wet mass increased the risk of mortality and crickets were able to restore 90% of their initial mass after rehydration on average. Both sexes maintained haemolymph volume for up to 6 h of desiccation, after which haemolymph volume of females decreased after 18 h and recovered slightly after rehydration, whereas males maintained haemolymph volume throughout desiccation. Our results suggest that crickets are susceptible to desiccation and have limited tolerance for water loss, but can actively regulate ion concentration and haemolymph volume to avoid desiccation-induced hyperkalaemia. These mechanisms may serve as adaptive responses to increasing aridity under climate change.