Meeting Abstract
5.4 Tuesday, Jan. 4 Linking habitat and intraspecific variation in the stress physiology of a coral reef fish, Stegastes partitus SCHRANDT, M.N.*; LEMA, S.C.; Univ. of North Carolina Wilmington; Univ. of North Carolina Wilmington mschrandt@disl.org
Geographic variation in behavior related to spatial variation in environmental conditions has been observed in many species, but the physiological bases for such behavioral variation have rarely been explored. Given the importance of hormones in regulating animals’ responses to environmental conditions, endocrine signaling is likely to act in mediating habitat-associated variation in behavior. Here, we examined stress-associated hormonal correlates of behavior in bicolor damselfish inhabiting different areas of a coral reef: dead coral rubble and live coral colonies. Damselfish behavior varied between the two habitats; fish from rubble showed more frequent aggression, shelter use, and courtship. In response to acute capture stress, plasma cortisol levels increased, regardless of habitat origin or sex. Fish sampled from these two habitats at either <2.5 min (‘baseline’) or 20 min (‘stressed’) after collection also showed differences in neural levels of mRNAs encoding the neuropeptides corticotrophin-releasing hormone (CRH) and urotensin 1, CRH binding protein (CRH-BP), and CRH receptors 1 (CRH-R1) and 2 (CRH-R2). Acute stress altered neural CRH and CRH-BP mRNA levels, although females showed habitat-specific patterns of transcript changes. Neural CRH-R2 mRNA levels increased in males from both habitats following acute stress, but overall were greater in males inhabiting rubble areas. Urotensin 1 transcript abundance varied with habitat origin and stress condition among females, but not males. Our results demonstrate sex-specific variation in transcriptional responses of bicolor damselfish to acute stress, and provide the first evidence that environmental conditions of the local coral reef habitat can influence a fish’s physiological response to stress.
