Personality and gonadal development as sources of individual variation in response to GnRH challenge in female great tits.

摘要: Seasonal timing of reproduction is a key life-history trait, but we know little about the mechanisms underlying individual variation in female endocrine profiles associated with reproduction. In birds, 17β-oestradiol reproductive hormone that links brain neuroendocrine mechanisms, involved information processing and decision-making, to downstream liver, where egg-yolk produced. Here, test, using simulated induction system through Gonadotropin-Releasing Hormone (GnRH) challenge, whether ovary pre-breeding great tits responds stimulation by increasing oestradiol. We also assess how this response modified individual-specific traits like age, ovarian follicle size, personality, females from lines artificially selected for divergent levels exploratory behaviour. show GnRH injection leads rapid increase circulating concentrations oestradiol, responses varied among individuals. Females more developed follicles showed stronger fast behaviour increases compared slow line, indicating heritable component. This study shows greatly varies individuals can be attributed several commonly measured traits, which sheds light on shaping phenotypes.