A Laboratory Study of the Effect of Temperature on the Embryonic Diapause of the Hermit Crab Pagurus proximus Komai, 2000 (Decapoda: Paguridae) from Peter the Great Bay, Sea of Japan

Under laboratory conditions, the effect of temperature on the reversible arrest in embryo development, which occurs as a result of winter spawning, was studied in the hermit crab Pagurus proximus , Komai, 2000 from Amurskiy Bay (Peter the Great Bay, Sea of Japan). In clutches of females that spawned under natural conditions at a water temperature of 5°C and below, an increase in water temperature to 14–16°C led to the termination of embryonic diapause and the synchronous resumption of egg development, regardless of whether the temperature conditions changed at the beginning or at the end of the winter breeding season. No embryonic diapause was observed in clutches of females of P. proximus that were captured in December–April and spawned in the laboratory at a water temperature of 14–16°С. From this it follows that the primary signal for diapause initiation and termination in P. proximus is temperature, which directly affects the embryo. The data we obtained confirm that embryonic diapause of the hermit crab P. proximus is not obligate but is induced by habitat conditions, primarily by ambient temperature. The possibility of using P. proximus as a model object for studying the mechanisms of embryonic diapause in decapods is considered.