Temperature-driven changes in the neuroendocrine axis of the blue crab Callinectes sapidus during the molt cycle

[Display omitted] •Premolt blue crabs exhibited a larger response (reduction) in ecdysteroid concentrations at 19 °C than the intermolt animals;•The premolt Y-organ showed an expressive reduction of the ecdysteroid receptor CasGC-YO1 transcripts compared to the intermolt animals at 19 °C;•The XO-SG displayed higher ecdysteroid receptor expression at all three temperatures in the intermolt animals compared to premolt crabs, whereas in the hepatopancreas there was an increase in the receptor transcripts only at 19 °C.•Both heat shock proteins show increased gene expression in the Y-organ of premolt crabs subjected to 19 °C.•In the XO/SG, CasMIH transcripts were not affected by molt stage or temperature while CasCHH expression increased in the XO/SG of intermolt animals subjected to the warmer temperature compared to 19 °C and to premolt crabs at the same temperature. Environmental cues such as temperature induce macroscopic changes in the molting cycle of crustaceans, however, the physiological mechanisms behind these changes remain unclearWe aimed to investigate the regulatory mechanisms in the intermolt and premolt stages of the Callinectes sapidus molt cycle in response to thermal stimuli. The concentration of ecdysteroids and lipids in the hemolymph, and the expression of heat shock proteins (HSPs) and molt key genes were assessed at 19 °C, 24 °C and 29 °C. The premolt animals exhibited a much larger response to the colder temperature than intermolt animals. Ecdysteroids decreased drastically in premolt animals, whereas the expression of their hepatopancreas receptor (CasEcR) increased, possibly compensating for the low hemolymphatic levels at 19 °C. This decrease might be due to increased HSPs and inhibited ecdysteroidogenesis in the Y-organ. In addition, the molting-inhibiting hormone expression in the X-organ/sinus gland (XO/SG) remained constant between temperatures and stages, suggesting it is constitutive in this species. Lipid concentration in the hemolymph, and the expression of CasEcR and CasHSP90 in the XO/SG were influenced by the molting stage, not temperature. On the other hand, the expression of HSPs in the hepatopancreas is the result of the interaction between the two factors evaluated in the study. Our results demonstrated that temperature is an effective modulator of responses related to the molting cycle at the endocrine level and that temperature below the control condition caused a greater effect on the evaluated responses compared t