The crustacean hyperglycemic hormone (CHH) is a multifunctional neuropeptide involved in various biological processes, including glucose recognition, lipid mobilisation, osmoregulation, ionoregulation, and ecdysteroid synthesis. This study aimed to determine the effects of different environmental conditions on the release levels of CHH in green shore crabs, Carcinus maenas, within a 10 minute period, CHH release being an indicator that a stress response has occurred. The crabs were exposed to various conditions simulating their natural habitat, such as heat shock, cold shock, salinity, and hypoxia. It was found that CHH release in crabs varies depending on environmental conditions with heat shock, cold shock and hypoxia causing significant changes in CHH levels. Notably, significant increases in CHH levels were observed at the 5 min mark for temperatures of 30oC, 25oC, 5oC and for the hypoxia condition. No significant changes were seen in response to low salinity, possibly due to the osmoregulatory response taking longer than the 10 min measurement period. Additionally, red shore crabs exhibited higher CHH levels under hypoxia compared to green crabs, suggesting that red crabs are less able to adapt to the stress of hypoxia. Further research could potentially compare temperature and salinity conditions on red crabs against that of green crabs.
Understanding CHH release within 10 minutes of a crab being exposed to environmental stressors can advance our knowledge of the neuropeptide’s role in stress response and help determine how quickly shore crabs can mobilise the hormone. This research also provides insights into the function of similar hormones in insects and other invertebrates, due to the similarities between neuropeptides in these species.