Meeting Abstract
Territorial aggression can vary based on species or the identity of the competitor. Some species exhibit ‘dear enemy’ recognition; where lower levels of aggression are directed toward neighboring, territorial individuals. Cyprinodon variegatus has been shown to outcompete closely related species due to high levels of aggression and territorial males exhibit dear enemy recognition. Recently, C. variegatus has been introduced into the home range of Cyprinodon rubrofluviatilis, leading to hybridization. We examined territorial establishment and maintenance between heterospecific neighbors and evaluated if heterospecific neighbors express dear enemy recognition. We also tested the hypothesis that territorial males of each species differ in their expression of dear enemy recognition. We found that territorial male C. rubrofluviatilis and C. variegatus in conspecific and heterospecific groups do show more aggression towards non-territorial males. Change in aggressive behaviors over time depends upon the behavior, the identity of the individual, and community structure. Energetically expensive aggressive acts towards territorial neighbors decreased after territory establishment while aggression towards non-territorials did not change. Less energetically expensive behaviors increased towards territorial males while no displays were directed towards non-territorials. C. rubrofluviatilis established territories faster, more often and reduced aggression more over time when compared to C. variegatus. When aggression is decreased towards invasive species, hybridization may increase, leading to introgression. This is the first study to show heterospecific dear enemy recognition between vertebrate species and to compare the expression of dear enemy recognition between closely related species.
