The Effect of Maternal State on the Steroid and Macronutrient Content of Lesser Black-Backed Gull Eggs

Abstract

It has been proposed that female birds can influence the phenotype of their offspring by provisioning eggs with variable amounts of nutrients and maternal hormones. Egg quality is strongly influenced by maternal body reserves and the amount of food available at the time of egg formation. This study investigated the effects of maternal state and food availability on the capacity of female lesser black-backed gulls Larus fuscus to provision their eggs with macronutrients and steroid hormones. Maternal state was reduced by increasing egg-production effort, whereas extra food was provided to reverse this effect. Compared with eggs of first clutches, eggs of experimentally induced replacement clutches exhibited a lower yolk/albumen ratio and contained more yolk testosterone. During one of the three years in which the study was performed, replacement eggs also contained more 17β-estradiol. Food provisioning during the relaying interval did not affect changes in yolk/albumen ratio or steroid concentrations, but fed females produced bigger eggs in their replacement clutch. This study demonstrates significant within-female consistency in egg size, macronutrient content, and yolk steroid concentration, and it shows that these egg characteristics are influenced by maternal state, food availability, and the timing of breeding.

Experimental manipulation of food availability leads to short‐term intra‐clutch adjustment in egg mass but not in yolk androgen or thyroid hormones

“…One could also speculate that the sampling was too soon after the change in treatment to detect a response in yolk hormones – however manipulation of male quality using similar timescales was found to affect yolk androgen levels (Kingma et al ). Our results add to the equivocal set of results from studies on the relation between yolk androgens and food availability: food supplementation before and during laying decreased yolk androgen levels in gulls and kittiwakes (Verboven et al , Gasparini et al ), but had no effect in two other studies on the same species (Verboven et al , Benowitz‐Fredericks et al ). In zebra finches under poor quality diet pre‐laying, yolk androgen levels decreased over laying sequence whereas there was a flat pattern under high quality diet (Sandell et al ).…”

“…Importantly, the effect of yolk androgens on offspring may be dependent on environmental conditions (Groothuis et al , Müller et al , Tschirren et al ): females are expected to adjust deposition of maternal hormones in their eggs depending on prevailing environmental conditions or their own condition when these conditions are predictive for the conditions during offspring development, in order to adjust offspring phenotype to these conditions (predictive adaptive response, Lack ). Indeed, food supplementation before and during laying can affect yolk androgen levels but again the results are mixed, with some studies finding lower yolk androgen levels and/or an effect on the within clutch pattern (Verboven et al , Gasparini et al , Sandell et al , Vergauwen et al ), and others no effect (Verboven et al , Benowitz‐Fredericks et al ). Lower yolk androgen levels under good rearing conditions have been interpreted as to enable the chick to better bear the potential costs of androgens such as higher immunosuppression and oxidative damage whereas the stimulating effect of the hormone on begging behavior would be less important under such conditions (Verboven et al , Groothuis et al ).…”

Maternal effects mediated by egg quality in the Yellow-legged Gull Larus michahellis in relation to laying order and embryo sex

“…Thus, large eggs contained less estradiol than small eggs, both in terms of per unit yolk volume and in absolute terms. This negative relationship may depend in part on differences in nutritional status of females [78], which may concomitantly affect egg estradiol deposition and egg mass in opposite ways.…”

Lipids in maternal diet influence yolk hormone levels and post‐hatch neophobia in the domestic chick

“…In the lesser black-backed gull (Larus fuscus), pied flycatcher (Ficedula hypoleuca), and black-legged kittiwake (Rissa tridactyla) food supplementation prior to, and during oviposition affected androgen quantity in the yolk (Verboven et al, 2003;Verboven, Monaghan, Nager, & Evans, 2010). In the lesser black-backed gull (Larus fuscus), pied flycatcher (Ficedula hypoleuca), and black-legged kittiwake (Rissa tridactyla) food supplementation prior to, and during oviposition affected androgen quantity in the yolk (Verboven et al, 2003;Verboven, Monaghan, Nager, & Evans, 2010).…”