Assessing Differences in Desiccation Tolerance in Two Species of Hawaiian Swordtail Cricket

Abstract

Two species of Hawaiian swordtail cricket, L. orientalis and L. makaio, inhabit different locations on the island of Maui in the Hawaiian archipelago, generally with L. orientalis residing in a region of higher, and L. makaio inhabiting a region of lower, rainfall. This difference in habitation exposes the two species to different levels of humidity, with L. orientalis being subjected to greater levels of moisture than L. makaio, when controlling for elevation. It may be possible that these species’ distinct habitats are a result of different humidity preferences. These distributions in turn may be influenced by the different compositions of cuticular hydrocarbons (CHCs) that coat the surface of their bodies and prevent desiccation. To test whether such differences in desiccation resistance may exist, individuals from each species were subjected to a series of desiccation tolerance experiments, which measured the length of time in which each species could survive arid conditions. Additionally, the CHC profiles of each species were analyzed by extracting the CHCs from individuals of each species and running them through gas chromatography. The results of these experiments do not reveal a statistically significant difference in the survivability of L. orientalis and L. makaio in arid environments, though a difference in CHC profiles has been observed.