Testing the Role of Cuticular Hydrocarbons in Male Mate Recognition and Interspecific Mating Barriers in the Hawaiian Cricket Laupala

Hawaiian swordtail crickets of the genus Laupala are the fastest speciating arthropods currently known. Species of Laupala are morphologically and ecologically cryptic but demonstrate variable sexual behaviors. Thus, we hypothesize that the mystery behind Laupala’s rapid speciation lies within their sexual behavior and processes of mate recognition. In Laupala, male mate recognition is hypothesized to be heavily influenced by cuticular hydrocarbon (CHC) signals, thereby mediating reproductive barriers between species through sexual isolation. Here, we test this hypothesis by manipulating the identity of CHCs present on female antennae. To manipulate CHCs, we use a novel painting technique, involving the application of conspecific CHCs to the antennae of heterospecific females. Through gas chromatography and a principal component analysis, we present evidence that validates this painting technique. We then contrast the results of male behavior in mating trials involving heterospecific pairs with unmanipulated versus manipulated female antennae, thereby testing the hypothesis that CHCs play a role in male mate recognition and sexual isolation between species of Laupala. These results support a central role of CHCs as a mating barrier within the elaborate mating behavior of Laupala.