The red crabs of Christmas Island, roles of crustacean hyperglycaemic hormone in diel and seasonal migration physiology

Gecarcoidea_natalisThe annual migration of red crabs, which are endemic to Christmas Island in the Indian Ocean has rightly been called one of the great spectacles of the natural world. Each year, at the start of the wet season, on full moon, mature male and female red crabs (Gecarcoidea natalis) migrate to the shores of the island to interact, mate and spawn. This migration involves significant energy demands on the crabs, but during the dry season, crabs are relatively inactive. Furthermore, since these crabs are entirely terrestrial, there are opposing burdens placed upon their osmoregulatory mechanisms during the year. Evidence is now accumulating suggesting that a key adaptive hormone, which influences energy mobilisation and osmoregulatory capacity in red crabs is the well-known crustacean hyperglycaemic hormone (CHH). Since this crab shows extreme adaptation to seasonal xeric/wet conditions and undergoes long, energy demanding migrations, we are now in the enviable position of being able to further define the roles of this hormone in theses processes, by careful measurement of CHH titres and corresponding gene expression profiles from samples collected in the field during diel and seasonal cycles. In a parallel project, we seek to understand the analogous processes in the blue crab, Discoplax celeste (Turner et al., 2013; Morris et al., 2010).
Please note: This project wass funded to, and coordinated by, the principal investigator, Professor Steve Morris, Bristol University) who sadly, passed away in 2010 , to whom enquiries should be made.

Funded by NERC.
Researchers: Prof. S. Morris (deceased), Dr U. Postel, Dr Lucy Turner (MBA, Plymouth), Dr. S.G. Webster (Bangor)