Crustacean hyperglycaemic hormone function, roles and importance in the diel and seasonal migration physiology of land crabs

红蟹（Gecarcoidea natalis）是印度洋圣诞岛（Christmas Island）特有的一种陆地蟹，其幼虫期为3周，每年必须进行一次年度繁殖迁徙，交配并将卵投入海中。在几个月的旱季之后，季风开始时，迁徙就开始了。在旱季，螃蟹活动少，很少有机会进食。因此，红蟹比其他螃蟹在运动生理和盐管理方面表现出明显的季节性差异，因为它们从旱季的低活动状态转变为雨季的繁殖迁徙。有实验室证据表明，肽激素；特别是甲壳类高血糖激素（CHH）在转换能量代谢和盐泵通过鳃中很重要。然而，没有确凿的证据表明在自然野外条件下有任何作用。CHH肽在x器官内靠近眼睛下方的神经组织中形成，并在眼柄的窦腺中运输储存。该项目将研究CHH作为调节季节性和昼夜节律代谢的信号。这将通过a)检查CHH基因表达和CHH的产生/释放，b)测量尿液和过隔离灌注鳃的盐重吸收，以及c)确定代谢和离子状态在CHH反馈中的作用来完成。有关环境和行为线索的工作将与澳大利亚公园合作。该项目汇集了布里斯托尔和班戈的实验室，工作范围从基因组、激素生理学到野外生态学。分子生物学将通过野外工作与自然环境和行为联系起来。这种螃蟹是一个岛上特有的，具有独特的保护价值。它们是热带雨林结构的主要决定因素，对岛屿采矿后的恢复及其经济至关重要。通过与国家公园的联系，这个项目将继续我们对这一进程的投入。

The red crab Gecarcoidea natalis is an endemic land crab on Christmas Island (Indian Ocean) which retains a 3 week larval stage and each year must make an annual breeding migration to mate and cast the eggs into the ocean. The migration begins at the onset of the monsoon after many months of dry season. During the dry season the crabs have low activity and little opportunity to feed. Thus red crabs, more so than other crabs, show marked seasonal differences in exercise physiology and salt management as they switch from a low activity state in the dry season to their breeding migration in the wet season. There is laboratory evidence that shows that peptide hormones; specifically the Crustacean Hyperglycaemic Hormone (CHH) is important in switching energy metabolism and in salt pumping across the gills. However, there is no conclusive evidence of any role under natural field conditions. The CHH peptides are formed in nervous tissue close beneath the eye within the X-organ and transported for storage in the sinus gland in the eyestalk. The project will examine CHH as a signal in regulating seasonal and circadian metabolism underlying this switch. This will be done by a) examining CHH gene expression and the production/release of CHH, b) measuring salt reabsorption from the urine and over isolated perfused gills, and c) determining the role of metabolic and ionic status in feed-back on CHH. The work on environmental and behavioural cues will be in association with Parks Australia. The project brings together laboratories at Bristol and Bangor and the work ranges from genomic, through hormone physiology to field ecology. The molecular biology will be related through field work to the natural circumstances and behaviour. The crabs are endemic to a single island and of unique conservation value. They are a primary determinant of rain forest structure and crucial in post-mining rehabilitation of the Island and its economy. Through liaison with National Parks this project will continue our input into this process.