Aggression and discrimination among closely versus distantly related species of Drosophila

Abstract

Fighting between different species is widespread in the animal kingdom, yet this phenomenon has been relatively understudied in the field of aggression research. Particularly lacking are studies that test the effect of genetic distance, or relatedness, on aggressive behaviour between species. Here we characterized male–male aggression within and between species of fruit flies across the Drosophila phylogeny. We show that male Drosophila discriminate between conspecifics and heterospecifics and show a bias for the target of aggression that depends on the genetic relatedness of opponent males. Specifically, males of closely related species treated conspecifics and heterospecifics equally, whereas males of distantly related species were overwhelmingly aggressive towards conspecifics. To our knowledge, this is the first study to quantify aggression between Drosophila species and to establish a behavioural bias for aggression against conspecifics versus heterospecifics. Our results suggest that future study of heterospecific aggression behaviour in Drosophila is warranted to investigate the degree to which these trends in aggression among species extend to broader behavioural, ecological and evolutionary contexts.

Melanic pigmentation and light preference within and between two Drosophila species

“…In contrast, Gupta et al. ( 2019 ) found that aggressive behavior tended to be lower toward heterospecifics than toward conspecifics, which would if anything tend to promote coexistence rather than spatial segregation of the two species.…”

“…The 2017, 2018, and 2019 datasets included cages populated with both D. americana and D. novamexicana , while the 2020 datasets featured only one type of fly per cage. Several species of male Drosophila have indeed been shown to demonstrate differential patterns of aggression toward conspecific versus heterospecific males (Gupta et al., 2019 ). However, this finding was primarily observed when the species involved were distantly related, whereas D. americana and D. novamexicana are sister species thought to have diverged less than 0.5 MYA (Caletka & McAllister, 2004 ).…”

Global meta-analysis reveals urban-associated behavioral differences among wild populations

“…Alternatively, since we independently assigned behaviors to categories, prior meta-analyses and individual studies may have conflated multiple different behaviors under the aggression label. For example, aggression is sometimes defined as agonistic interactions with conspecifics (Oyegbile and Marler, 2005), heterospecifics (Vullioud et al, 2013), or humans (Class et al, 2014), and these behaviors are not necessarily be equivalent (Gupta et al, 2019; Peiman and Robinson, 2010).…”