Metabolic and behavioural effects of hermit crab shell removal techniques: Is heating less invasive than cracking?

Abstract Hermit crabs (Paguroidea; Latreille 1802) offer great opportunities to study animal behaviour and physiology. However, the animals’ size sex cannot be determined when they are inside their shell; information crucial many experimental designs. Here, we tested effects of two most common procedures used make leave shells: heating shell apex cracking with a bench press. We compared each on metabolic rate, hiding time, duration recovery time relative unmanipulated hermit crabs. The forced abandon through increased respiratory rate shortly after manipulation (1 h) recovered in less than 24 h, as occurs individuals suddenly exposed high temperatures upper-intertidal zone. removed from shells via spent more new shells; this effect was evident immediately lasted similar responses exhibited life-threatening predator attack. Both methods expected stressful, harmful, or fear-inducing; however, temperature required force is below critical thermal maxima inhabitants tropical tide pools. wide windows intertidal crustaceans shorter consequences suggest harmful procedure for removing shells.