Yolk testosterone levels and offspring phenotype correlate with parental age in a precocial bird

Genetic differences in yolk testosterone levels influence maternal hormone deposition in the second laying cycle in Japanese quails

“…Previous studies in altricial birds have demonstrated that the maternal deposition of yolk androgens declines between the eggs of the first and second clutches during one breeding season (Schwabl, 1997;Tobler et al, 2007). Similarly, a decline of yolk T levels was found from the early to the latest stages of the first laying cycle in Japanese quails (Okuliarova et al, 2009;Guibert et al, 2012). Moreover, both egg laying intensity and egg quality gradually decrease after the first year of age (Woodard et al, 1973;Joyner et al, 1987) and this damping of reproductive functions is associated with reduced plasma gonadotropin levels and pituitary responsiveness to GnRH in ageing hens (Sharp et al, 1992;Ciccone et al, 2005).…”

“…In particular, altricial birds can produce a distinct pattern of yolk androgen concentrations within a single clutch (Schwabl, 1993;Eising et al, 2001) as well as between successively laid clutches (Schwabl, 1997;Gil et al, 2006;Tobler et al, 2007). This between-clutch pattern of yolk androgen deposition was not investigated in free-living precocial birds yet but a decline of yolk testosterone (T) concentrations was found between the early and the latest stages of the first reproductive cycle in domestic species (Okuliarova et al, 2011a;Guibert et al, 2012). Regarding this intra-individual variability, limited studies deal with changes of maternal hormone deposition across the longer period of the reproductive lifespan and in association with age-specific reproductive success that can be important from both the evolutionary and ecological perspectives.…”

Long-life partners or sex friends? Impact of parental pair bond on offspring personality

“…Researchers have reported similar influences of maternal age for birds: egg yolk hormonal modulations are related to maternal characteristics (AdkinsRegan et al, 2013;Gil, 2008;Groothuis and Schwabl, 2008;Groothuis et al, 2005). For instance, chicks of older Japanese quail (Coturnix c. japonica Linnaeus) parents were heavier at hatching, their sexual development occurred sooner, and their emotional reactivity was lower in the presence of novelty but higher following social separation (Guibert et al, 2012). These results could be related to the lower levels of yolk testosterone in older females' eggs (Guibert et al, 2012;Okuliarová et al, 2009).…”

“…For instance, chicks of older Japanese quail (Coturnix c. japonica Linnaeus) parents were heavier at hatching, their sexual development occurred sooner, and their emotional reactivity was lower in the presence of novelty but higher following social separation (Guibert et al, 2012). These results could be related to the lower levels of yolk testosterone in older females' eggs (Guibert et al, 2012;Okuliarová et al, 2009).…”

“…Indeed, many factors can influence yolk composition, such as females' intrinsic characteristics [e.g. maternal age (Guibert et al, 2012)] and social environment [e.g. social instability (Guibert et al, 2010;Mazuc et al, 2003), breeding density (Reed and Vleck, 2001;Schwabl, 1997;Pilz and Smith, 2004), aggression by conspecifics (Whittingham and Schwabl, 2002)].…”