Hot or Not: The Effects of Exogenous Testosterone on Female Attractiveness to Male Conspecifics in the Budgerigar

Abstract

An increasing number of studies indicate that not only females but also males can be selective when choosing a mate. In species exhibiting male or mutual mate choice, females may benefit from being attractive. While male attractiveness is often positively influenced by higher plasma levels of the androgenic hormone testosterone, it has been shown that testosterone can masculinise female behavior and morphology in several bird species, potentially rendering them less attractive. In this study, we investigated whether female budgerigars, Melopsittacus undulatus , suffer from increased plasma testosterone levels through a negative effect on their attractiveness to males. We experimentally increased plasma testosterone levels in testosterone-treated females (T-females) compared to controls (C-females) and allowed males to choose between a T- and a C-female in a two-way choice situation. Although testosterone treatment significantly affected female behavioral and morphological characteristics, males did not show a significant difference in preference between T- and C-females. These results suggest that experimentally increasing testosterone levels in females does not appear to influence male preference during initial mate choice. Our findings indicate that selection for higher levels of testosterone in male budgerigars is probably not constrained by a correlated response to selection causing negative effects on female attractiveness during initial mate choice. Evaluating whether or not a potential constraint may arise from negative testosterone-induced effects on other fitness related traits in females requires further work.

Testosterone activates sexual dimorphism including male-typical carotenoid but not melanin plumage pigmentation in a female bird

“…Evidence from a comparative analysis of sexual dimorphism in the Maluridae family suggests that the evolution of female bill coloration is a product of selection on females themselves (Karubian, 2013), rather than simply a byproduct of selection on the male phenotype (Lande, 1980). Female bill coloration is important in socio-sexual signaling in other avian species (Burley and Coopersmith, 1987;Murphy et al, 2009), as well as in male red-backed fairy-wrens (Karubian et al, 2011;Lindsay et al, 2009), and can be modulated by T in females (Lahaye et al, 2013;McGraw, 2006;Pham et al, 2014). Thus, androgens circulating in females at physiological rather than pharmacological levels (as induced by T implantation) can act on trait expression and may be the target of selection for mediating functionally significant variation in female ornamentation (Goymann and Wingfield, 2014).…”

“…Although exogenous T stimulates expression of some male-typical traits in females across taxa (Ketterson et al, 2005;Lahaye et al, 2013;Staub and De Beer, 1997), often only a portion of the sex-limited phenotype is produced. For example, T can increase song activity without inducing male-typical song rate (De Ridder et al, 2002), stimulate production of male-typical bill color at a lower than maletypical color intensity (Lahaye et al, 2013;McGraw, 2006), and stimulate production of male-typical feather structure without inducing male-like feather color (Peters, 2007). Therefore, although generally accepted as a primary mechanism for regulating many dimorphic characters, sex-specific T production may not be the only mechanism functioning, and the effects of T on various components of the dimorphic phenotype may be more or less sex specific.…”

Determinants of making success in female Tree Swallows (Tachycineta Bicolor)

“…T has been shown to have masculinizing effects on female traits in a variety of taxa, although whether such changes reduce their attractiveness to potential mates is unclear (Ketterson et al, 2005;Lahaye et al, 2013). Given that exogenous T increases aggressive behaviour in female tree swallows (Rosvall, 2013), in my study T-treated female tree swallows likely spent more time involved in aggressive interactions and territory defence, as previously suggested for spotless starlings (García-Vigón et al, 2008), rather than seeking extra-pair copulations.…”

Context‐dependent female preference for multiple ornaments in the bearded reedling

“…After that period, the opaque separators were removed and the position of the female was recorded every 1 sec for 30 min (Hoi and Griggio , ; Lahaye et al. ). All trials were video‐recorded and then analyzed.…”

“…At the beginning of a trial, choosing females and stimulus males were placed in their experimental chambers and allowed at least 30 min to acclimatize before the trial began. After that period, the opaque separators were removed and the position of the female was recorded every 1 sec for 30 min Griggio 2011, 2012;Lahaye et al 2013). All trials were video-recorded and then analyzed.…”