Why are females ornamented? A test of the courtship stimulation and courtship rejection hypotheses

Abstract

Female ornamentation was initially thought to reflect genetic correlation with the more elaborate male trait. However, this cannot explain female-specific ornamentation, such as the conspicuous coloration displayed by females of many species during breeding. Females may exhibit distinctive, reproductive coloration to 1) advertise receptivity and stimulate male courtship or 2) advertise nonreceptivity when gravid to reduce male courtship, harassment, and potentially costly copulations. We tested both hypotheses in the Lake Eyre dragon lizard (Ctenophorus maculosus) by quantifying female coloration, using spectroradiometry and a model of lizard color perception, and male and female behavior across the female reproductive cycle. Females develop bright orange coloration on their throat and abdomen during the breeding season, whereas males remain cryptically colored. The onset of orange coloration was associated with enlarging follicles, acceptance of copulations, and escalation of male courtship. Rather than fading once females were no longer receptive, however, the intense orange coloration remained until oviposition. Furthermore, despite maximal coloration associated with nonreceptivity, males persisted with courtship and copulation attempts, and females increased rejection behaviors comprising lateral displays and flipping onto their backs (to prevent forced intromission), both of which emphasize the conspicuous ventrolateral coloration. These apparently costly rejection behaviors did not reduce male harassment but did decrease the frequency of potentially costly copulations. These results suggest that 1) males do not determine female receptivity based on coloration alone and 2) the potentially costly rejection behaviors may have evolved to reduce the direct costs of mating.

The evolution of female ornaments and weaponry: social selection, sexual selection and ecological competition

“…Holbrookia maculate [141]) are relatively dull when attracting males but bright after copulation. The mechanism driving these inverse patterns has not yet been identified, but it is thought that such post-copulatory signals may reduce costly harassment by advertising that the females are no longer fertilizable [142,143]. Sexual mimicry of males by females is thought to be adaptive for similar reasons, at least in polymorphic insects [144].…”

Unraveling the thread of nature’s tapestry: the genetics of diversity and convergence in animal pigmentation

“…Many reptiles use sexually dimorphic color patches during territorial or courtship interactions (Chan et al, 2009a;Cooper and Burns, 1987). Finally, reptile coloration is important for thermoregulation because color can influence heat acquisition for these ectotherms (Clusella Trullas et al, 2007;Forsman, 1995).…”

“…Specifically, color can be rapidly changed in response to local conditions (e.g., temperature, stress, predators; Castrucci, 1997;Rosenblum, 2005;Stuart-Fox and Moussalli, 2009). Second, many reptiles change color seasonallyfemales of many species obtain bright coloration during the breeding season to communicate information about breeding status (Chan et al, 2009a;Hager, 2001). Third, many reptiles change color ontogenetically; for example, conspicuous tail coloration is observed in juveniles of several species, but not in adults (Hawlena et al, 2006).…”

Ontogenetic colour change signals sexual maturity in a non‐territorial damselfly

“…Signalling sexual maturity through change in colour has been reported in many taxa including insects, amphibians, reptiles and birds (Bell & Zamudio, ; Chan, Stuart‐Fox, & Jessop, ; Corbet, ; Griggio, Devigili, Hoi, & Pilastro, ). Ischnura heterosticta , I. genei, I. elegans and I. senegalensis females change colour during ontogenesis; juvenile females carry fewer eggs and mate less frequently than adult females (Hinnekint, ; Huang & Reinhard, ; Sanmartín‐Villar & Cordero‐Rivera, ; Takahashi & Watanabe, ).…”