Combat behaviors predictive of fight outcome in Gromphadorhina portentosa

In the winner effect, animals that have previously won an aggressive encounter gain an increased probability of winning subsequent aggressive interactions. This effect has been studied in males of various species, from crickets to humans. However, the effects are under-studied in Madagascar hissing cockroaches, <i>Gromphadorhina portentosa.</i> Here, we aimed to determine the influence of the winner effect in unfavorable conflicts. To test this, smaller winner-affected male <i>G. portentosa</i> were placed in combat trials against substantially larger males. We tested the limits of the winner effect, and identified behaviors that were predictive to winning a match regardless of treatment group.