Sexual coloration and sperm performance in the Australian painted dragon lizard, Ctenophorus pictus

Abstract

Theory predicts trade-offs between pre- and post-copulatory sexually selected traits. This relationship may be mediated by the degree to which males are able to monopolize access to females, as this will place an upper limit on the strength of post-copulatory selection. Furthermore, traits that aid in mate monopolization may be costly to maintain and may limit investment in post-copulatory traits, such as sperm performance. Australian painted dragons are polymorphic for the presence or absence of a yellow gular patch ('bibs'), which may aid them to monopolize access to females. Previous work has shown that there are physiological costs of carrying this bib (greater loss of body condition in the wild). Here, we show that male painted dragons use this bright yellow bib as both an inter- and intrasexual signal, and we assess whether this signal is traded off against sperm performance within the same individuals. We found no relationship between aspects of bib colour and sperm swimming velocity or percentage of motile sperm and suggest that the bib polymorphism may be maintained by complex interactions between physiological or life-history traits including other sperm or ejaculate traits and environmental influences.

Long‐term effects of superoxide and DNA repair on lizard telomeres

“…As expected, superoxide covaries with mitochondrial content, but how this is related to among‐morph differences in mitochondrial content and superoxide is incompletely understood. We know that: (a) red males are more aggressive and have higher testosterone levels; (b) yellow males are more subdued but have higher success in sperm competition; (c) there are confirmed differences in metabolic rate among morphs, and (d) the orange morph has been described as some intermediate between the red and yellow (Friesen, Wilson et al., ; McDiarmid, Friesen, Ballen, & Olsson, ; Olsson, Healey, & Astheimer, ; Olsson, Healey et al., ; Olsson, Healey, Wapstra et al., ; Olsson, Healey, Wapstra, & Uller, ; Olsson, Schwartz, Uller, & Healey, ; Olsson, Wilson et al., ). Lastly, recently a “blueish” morph was described that is behaviourally uncharacterized and does not quite fit into the “biochemical continuum” along the yellow‐red morphs, perhaps due to lack of carotenoids or other “red/yellow” integumental pigments (Friesen, Wilson et al., ).…”

Morph‐specific metabolic rate and the timing of reproductive senescence in a color polymorphic dragon

“…Male painted dragons are polymorphic for two distinct color traits: head color (red, orange, yellow, and blue; Friesen et al., , Olsson et al., , Rollings et al., ) and the presence or absence of a yellow gular patch or bib (henceforth bibbed or non‐bibbed; McDiarmid, Friesen, Ballen, & Olsson, , Olsson et al., ). Males with red head‐coloration tend to be more aggressive, have higher testosterone, and beat yellow‐headed males in staged competitions (Healey et al., , Olsson, Healey, & Astheimer, ).…”

“…Males of any head‐color may also exhibit a bib. Bibbed males are more likely to attract females in staged preference trials and to win male–male competition trials when they compete against non‐bibbed rivals (McDiarmid et al., ). As bibbed and non‐bibbed males do not differ in sperm performance (McDiarmid et al., ), it is likely that these advantages in pre‐copulatory sexual selection explain why bibbed males are less likely than non‐bibbed males to lose paternity to neighboring males in the wild (Olsson et al., ).…”

“…Bibbed males are more likely to attract females in staged preference trials and to win male–male competition trials when they compete against non‐bibbed rivals (McDiarmid et al., ). As bibbed and non‐bibbed males do not differ in sperm performance (McDiarmid et al., ), it is likely that these advantages in pre‐copulatory sexual selection explain why bibbed males are less likely than non‐bibbed males to lose paternity to neighboring males in the wild (Olsson et al., ). However, while beneficial in a reproductive context, the aggressiveness of bibbed males may come with costs as is known to be the case for other species (Andersson, , Marler & Moore, , Marler, Walsberg, White, Moore, & Marler, , Olson & Owens, , Thompson & Georgiev, ).…”

The relationship of body condition, superoxide dismutase and superoxide with sperm performance

“…Indeed, bibbed males are more attractive to females in staged preference trials and more likely to 155 win male-male competition trials when pitted against non-bibbed rivals indicating there is a 156 precopulatory mating advantage for bibbed males (McDiarmid et al, 2017b). Bibbed males are less 157 likely than non-bibbed males to lose paternity to neighbouring males in the wild ( and 36 non-bibbed males).…”