Tarantulas are a relatively unstudied category of invertebrate which are popular with hobbyists and increasingly used in laboratory research. As their presence in the veterinary setting is limited, very little is known about the biochemistry of their haemolymph as obtained by in house sampling and analysis. A handful of studies have been performed to attempt to establish a normal range for certain parameters in healthy members of a few particular species, but that is the extent of the current research. In this study, 12 tarantulas of the Nhandu chromatus species purchased as immature siblings and kept under standardised conditions for 2.5 years were anaesthetised with isoflurane and had 0.2 ml of haemolymph sampled and analysed for: total protein, glucose, calcium, phosphorous and uric acid. As well as having kept a diary of their daily feed intake and recorded dates of ecdysis, the exposure time to anaesthetic and perceived effectiveness were recorded. The variables originally proposed for this investigation are based on 2 separate feeding regimes, differing in terms of feed quantity and the effect on the aforementioned biochemical parameters. Upon receipt of the biochemical results from the first sampling, it became apparent that unexpected correlations could be made between the stage of ecdysis, susceptibility to anaesthesia and the total protein levels in the haemolymph. Those that were due to shed imminently, indicated by cessation in feeding, had recognisably and significantly higher total protein levels and reached a better level of anaesthesia in less time. Additional samplings are planned in the future to specify more definitive parameters. The observations made inadvertently so far could constitute novel information and be practically useful to tarantula enthusiasts and anaesthetists, and therefore, potentially of high clinical significance.
