Elevated temperature induces a decrease in intermolt period and growth per molt in the lesser blue crab Callinectes similis Williams, 1966 (Decapoda: Brachyura: Portunidae)

Temperature can impact many processes in ectotherms. With global temperatures rising due to climate change, many ectotherms may exhibit changes in growth rates and size at maturity, and these changes can have population-level effects. Predicting responses of species to climate change will require not only knowledge of thermal-tolerance limits, but also effects of temperature change on growth rates and other life-history parameters. For arthropods that exhibit discontinuous growth (i.e., molting), this includes both intermolt period and growth per molt. Previous laboratory and field experiments suggest that temperature affects both intermolt period (IMP) and growth per molt (GPM) in many crustaceans. We investigated the effect of temperature on the growth process in the lesser blue crab Callinectes similisWilliams, 1966 to examine differences in temperature sensitivity of growth rates. Crabs reared under elevated temperatures exhibited decreased intermolt period (IMP) and growth per molt (GPM), resulting in smaller sizes at each instar. If this pattern continued through the pubertal molt, elevated temperatures would result in smaller size at maturity.