The Role of Wing Coloration in Sex Recognition and Competitor Recognition in Rubyspot Damselflies (Hetaerina spp.)

Abstract

The decision rules that animals use for distinguishing between conspecifics of different age and sex classes are relevant for understanding how closely related species interact in sympatry. In rubyspot damselflies (Hetaerina spp.), the red wing coloration of mature males is hypothesized to be a key trait for sex recognition and competitor recognition within species and the proximate trigger for interspecific male-male aggression. We tested this hypothesis by manipulating the wing coloration of tethered conspecific intruders and measuring the responses of territory holders of three species in the field. As predicted, covering the red spots of mature males with black ink nearly eliminated territorial responses, and in some cases, territorial holders clasped the blackened males as if they were females. Adding red spots to female wings triggered territorial responses and nearly eliminated sexual responses. Immature males with artificial red spots were attacked at the same rate as mature male intruders, and much more frequently than were immature male controls. The results varied somewhat by species. In H. titia, the only species of Hetaerina with substantial black wing pigmentation, the effects of blackening the red spots of intruders varied both geographically and seasonally. But even when blackening the red spots of male intruders did not reduce the aggressive response of H. titia territory holders, adding artificial red spots to female wings elicited aggressive responses and nearly eliminated sexual responses. The results of this study further strengthen the evidence that interspecific aggression in Hetaerina results from overlap in territorial signals and that the derived black wing pigmentation of H. titia reduces interspecific aggression.

Seasonal polyphenism in wing coloration affects species recognition in rubyspot damselflies (Hetaerina spp.)

“…The early‐season phenotype of H. titia more closely resembles sympatric congeners and is remarkably distinct from the late‐season phenotype, leading early researchers to classify light and dark variants of H. titia as separate species (Appendix S1). Previous studies on sympatric Hetaerina species have linked species differences in male wing coloration to interspecific fighting (Anderson & Grether, , ; Drury & Grether, ; Grether et al ., ) and species differences in female wing coloration to reproductive interference (i.e. heterospecific clasping; Drury et al ., ).…”

Why are female color polymorphisms rare in territorial damselflies?

“…Males have reddish‐brown body coloration and red wing patches (Figure a), while females have greenish‐brown body coloration and amber wing patches (Figure b). Previous research on a similar species, Hetaerina americana, showed that putting artificial red patches on female wings reduced sexual responses and triggered aggressive responses from territorial males (Grether, Drury, Berlin, & Anderson, ), as predicted by the misdirected aggression hypothesis. This might explain the absence of andromorphic females in Hetaerina , but does not help account for the absence of multiple heteromorphs.…”

“…The difference in how males responded to females with red and green bands suggests that body coloration plays a role in sex recognition in Hetaerina , as it does in other odonates (reviewed in Xu, Cerreta, Schultz, & Fincke, ), although aggressive responses to red‐banded females were much less consistent and intense than responses to male intruders (Drury et al., ). By contrast, putting red wing patches on female H. americana eliminated sexual responses and caused the females to be attacked almost as aggressively as male intruders (Grether et al., ). In combination, these studies indicate that any fitness benefits of andromorphic coloration through reduced male mating harassment would likely be offset by costs of misdirected aggression in Hetaerina .…”

Colour pattern divergence in reef fish species is rapid and driven by both range overlap and symmetry

“…Firstly, fine‐scale patterns may play a key role (Grether et al . ). For example, the spot on the caudal peduncle that differentiates C. ocellicaudus from C. melannotus (Fig.…”