The cost of claw loss: The consequences of autotomy on burrowing in an ecosystem engineer, the Slender Crayfish, <i>Faxonius compressus</i>

Abstract Autotomy, the voluntary shedding or self‐amputation of a body part, is widespread across the animal kingdom and serves as a defense mechanism to evade predation and reduce non‐predatory entrapment. Although autotomy can enhance survival, it often comes at a cost, as animals with lost appendages may face reduced locomotive ability and impairment of other fitness‐relevant behaviors. In decapod crustaceans, including crayfishes, autotomy frequently involves the loss of one or both claws, structures that are essential for mating, foraging, defense, and burrowing. Moreover, given the critical role of crayfishes as ecosystem engineers, the ecological implications of autotomy in these species remain poorly understood. This study investigates the effects of claw autotomy on the burrowing behavior of the Slender Crayfish, Faxonius compressus , a stream‐dwelling species known for constructing intricate burrow networks in the hyporheic zone. We hypothesized that limb autotomy would reduce burrow creation and depth, thereby impacting burrow availability for other species. In controlled lab trials assessing burrowing behavior before and after autotomy, we found that F. compressus was able to construct burrows of similar depth before and after single claw autotomy, although before autotomy, males were less likely to create burrows than females. However, individuals with double claw autotomy dug significantly shallower burrows, reducing the average burrow depth by over 34 mm, with no differences between sexes. These findings suggest that single claw autotomy does not reduce burrow depth, while losing both claws reduces the depth of burrows in both sexes—potentially disrupting a key ecosystem function. This research highlights the broader ecological consequences of autotomy in ecosystem engineers like crayfish, since reduced burrow construction could impact shelter‐dependent species.