Effect of seasonal changes on hormonal concentrations in the albumen gland of Archachatina marginata (Swainson, 1821) in Abeokuta, Ogun State, Nigeria

The commercially important giant land snail Archachatina marginata has a pattern of life-history and activity that is affected by seasonal changes in temperature and rainfall. Changes in the climatic conditions of our region of Nigeria have been recently observed and there is need to understand the influence of these changes on the reproductive physiology of these snails. Thus, this study examined the seasonal variation in five hormonal concentrations in the albumen gland to create a baseline to inform efforts to improve reproductive output. 240 A. marginata were obtained from the Department of Forestry and wildlife management of Federal University of Agriculture, Abeokuta (FUNAAB), Ogun State, Nigeria. The snails were acclimatised for three weeks and reared in the snail-rearing unit of the Department of Pure and Applied Zoology (FUNAAB). Twenty (20) snails were dissected every month for twelve months and the albumen gland separated. Samples collected were analysed in the laboratory (3 subsets of snails for each month), using standard chemical methods. The results show considerable variation from month to month, not all related to season or environmental variables. While all but FSH (Follicle Stimulating Hormone) showed peaks at the beginning of the wet season (April or May), there were significant changes within seasons that complicate analysis. It is notable that three hormones (luteinising hormone, oestrogen and progesterone) vary in parallel, while testosterone and FSH vary independently of these and each other.