title: Contrasting effects of increased yolk testosterone content on development and oxidative status in gull embryos.
abstract: Hormone-mediated maternal effects generate variation in offspring phenotype. In birds, maternal egg testosterone (T) exerts differential effects on offspring traits after hatching, suggesting that mothers experience a trade-off between contrasting T effects. However, there is very little information on T pre-natal effects. In the yellow-legged gull (Larus michahellis), we increased yolk T concentration within physiological limits and measured the effects on development and oxidative status of late-stage embryos. T-treated embryos had a larger body size but a smaller brain than controls. Males had a larger brain than females, controlling for overall size. T treatment differentially affected brain mass and total amount of pro-oxidants in the brain depending on laying order. T-treatment effects were not sex dependent. For the first time in the wild, we show contrasting T pre-natal effects on body mass and brain size. Hence, T may enforce trade-offs between different embryonic traits, but also within the same trait during different developmental periods.
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, Milan I-20133, Italy marco.parolini@unimi.it andrea.romano@unimi.it.
authors.forename: Marco
authors.identifier: 0000-0003-0226-1709
authors.initials: M
authors.lastname: Parolini
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, Milan I-20133, Italy marco.parolini@unimi.it andrea.romano@unimi.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Romano
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, Milan I-20133, Italy.
authors.forename: Cristina Daniela
authors.initials: CD
authors.lastname: Possenti
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, Milan I-20133, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Caprioli
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, Milan I-20133, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Rubolini
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, Milan I-20133, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Saino
mesh_terms: D000818:Animals; D001921:Brain / Q000196:embryology / Q000502:physiology; D046091:Charadriiformes / Q000196:embryology* / Q000502:physiology; D004530:Egg Yolk / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000196:embryology* / Q000502:physiology; D005260:Female; D008297:Male; D018384:Oxidative Stress; D012727:Sex Characteristics; D013739:Testosterone / Q000378:metabolism*
chemical_list: D013739:Testosterone
keywords: Brain mass; Embryo; Growth; Larus michahellis; Oxidative status; Sexual dimorphism; Testosterone