Pheromones have also been shown to play an important role in inter-sex behaviours in the Gryllidae family. \cite{TREGENZA_1997} was the first major study to prove the existence of cuticular pheromones in the Gryllus, by displaying the recognition of female pheromones on a live cricket and subsequent courting behaviour, and following alcohol wash of the female, a lack of courtship behaviour. This research was further expanded upon in \cite{Nagamoto_2005}, which explored the role of antennae and maxillary palpi in pheromone identification and subsequent behaviours, as well as emphasising the role age plays in pheromone secretion (Younger female crickets secreted a greater concentration of pheromones and elicited increased frequency of courtship behaviour in males).
From these previous studies, we predicted that the frequency agonistic displays would increase between sex-segregated male crickets, regardless of size difference under the presence of female scents.

Methods

Three 0.283mcircular sheets of filter paper were placed in enclosures of sex-segregated female crickets (n=28; n=16; n=34) over the weekend. The control sheets were placed in a cricket enclosure without any crickets over the weekend.
The sections were on the day of experimentation split cut into 1/12 sections (0.0236m2). Male crickets were selected randomly from male segregated enclosures, and their pronotum were measured with digital callipers with an error margin of 0.01cm. The measured crickets were then placed in individual tubes to recover for a minimum of one hour. A pair of crickets were then placed into opposite sides of a plexiglass arena (pictured in figure. 1), and the larger male was marked with a white spot of correction fluid for subsequent identification. The control filter paper or experimental filter paper placed in the middle section, and the crickets were allowed 5 minutes to acclimatise before the barriers were removed. Levels of cricket aggression were measured using the linearly scaled ethogram from \cite{Stevenson2012} . The crickets were observed for 10 minutes, at the end of which the crickets were replaced into a large enclosure with other crickets and observations ended. The enclosures were cleaned with isopropyl alcohol between trials to eliminate residual male pheromones from previous experiments. The experiment and control tests were repeated a total of 36 times.

WELFARE

All treatments of the experimental animals (Gryllus bimaculatus) complied with the Animals (Scientific Procedures) Act 1986, as well as Directive 2010/63/EU on the protection of animals for scientific purposes.