Maternal investment of female mallards is influenced by male carotenoid-based coloration

Abstract

The differential allocation hypothesis predicts that females modify their investment in a breeding attempt according to its reproductive value. One prediction of this hypothesis is that females will increase reproductive investment when mated to high-quality males. In birds, it was shown that females can modulate pre-hatch reproductive investment by manipulating egg and clutch sizes and/or the concentrations of egg internal compounds according to paternal attractiveness. However, the differential allocation of immune factors has seldom been considered, particularly with an experimental approach. The carotenoid-based ornaments can function as reliable signals of quality, indicating better immunity or ability to resist parasites. Thus, numerous studies show that females use the expression of carotenoid-based colour when choosing mates; but the influence of this paternal coloration on maternal investment decisions has seldom been considered and has only been experimentally studied with artificial manipulation of male coloration. Here, we used dietary carotenoid provisioning to manipulate male mallard (Anas platyrhynchos) bill coloration, a sexually selected trait, and followed female investment. We show that an increase of male bill coloration positively influenced egg mass and albumen lysozyme concentration. By contrast, yolk carotenoid concentration was not affected by paternal ornamentation. Maternal decisions highlighted in this study may influence chick survival and compel males to maintain carotenoid-based coloration from the mate-choice period until egg-laying has been finished.

Adjustment of female reproductive investment according to male carotenoid-based ornamentation in a gallinaceous bird

“…In contrast with direct colour manipulations, Giraudeau et al (2011) have recently intensified the colour of the bill of male mallards by increasing carotenoid levels in their diet, which led females to lay larger eggs and also eggs with larger antibacterial content (i.e. lysozyme).…”

“…Nevertheless, examples for carotenoid-based ornaments are limited to few bird species, including the zebra finch (Taeniopygia guttata: e.g. Burley 1986;Gil et al 1999), two seabirds (Sula nebouxii: Velando et al 2006; Larus michahellis: Morales et al 2009), and more recently, the mallard (Anas platyrhynchos: Giraudeau et al 2011).…”

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

“…While it has been found that females may use bare-part coloration of their mate as a cue to continuously adjust reproductive investment after paring (e.g. [77–79]), the function of female bare-part color on male reproductive decisions has been largely neglected. Research has shown that male blue-footed boobies, Sula nebouxii , use female dynamic foot coloration as a cue to modify parental effort and to adjust their frequency of intra-pair courtship and extra-pair behavior [80,81].…”

Microbiome affects egg carotenoid investment, nestling development and adult oxidative costs of reproduction in Great tits

“…; Giraudeau et al . ). It is thus surprising that females do not appear to adjust egg ovotransferrin and lysozyme according to their exposure to micro‐organisms, thus pointing out the need for further studies investigating the role of these substances regarding to embryo and nestling microbial exposure and the factors determining their allocation in eggs.…”