Sex-specific responses to GnRH challenge, but not food supply, in kittiwakes: Evidence for the “sensitivity to information” hypothesis

• Published in: Hormones and Behavior
• Main Authors: Whelan, Shannon, Benowitz-Fredericks, Z Morgan, Hatch, Scott, Parenteau, Charline, Chastel, Olivier, Elliott, Kyle
• Other Authors: McGill University = Université McGill Montréal, Canada, Bucknell University, Institute for Seabird Research and Conservation, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: GnRH challenge; HPG axis; Hypothalamic–pituitary–gonadal; Luteinising hormone releasing hormone; Phenology; Seabird; Testosterone; [SDE]Environmental Sciences; rissa tridactyla
• Online Access: https://hal.science/hal-04176692; https://doi.org/10.1016/j.yhbeh.2023.105389

International audience Seasonal timing of breeding is usually considered to be triggered by endogenous responses linked to predictive cues (e.g., photoperiod) and supplementary cues that vary annually (e.g., food supply), but social cues are also important. Females may be more sensitive to supplementary cues because of their greater role in reproductive timing decisions, while males may only require predictive cues. We tested this hypothesis by food-supplementing female and male colonial seabirds (black-legged kittiwakes, Rissa tridactyla) during the pre-breeding season. We measured colony attendance via GPS devices, quantified pituitary and gonadal responses to gonadotropin releasing hormone (GnRH) challenge, and observed subsequent laying phenology. Food supplementation advanced laying phenology and increased colony attendance. While female pituitary responses to GnRH were consistent across the pre-breeding season, males showed a peak in pituitary sensitivity at approximately the same time that most females were initiating follicle development. The late peak in male pituitary response to GnRH questions a common assumption that males primarily rely on predictive cues (e.g., photoperiod) while females also rely on supplementary cues (e.g., food availability). Instead, male kittiwakes may integrate synchronising cues from their social environment to adjust their reproductive timing to coincide with female timing.