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Culbert BM, Barnett JB, Ligocki IY, Salena MG, Wong MYL, Hamilton IM, Balshine S. Colorful facial markings are associated with foraging rates and affiliative relationships in a wild group-living cichlid fish. Curr Zool 2024; 70:70-78. [PMID: 38476131 PMCID: PMC10926260 DOI: 10.1093/cz/zoac100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 12/11/2022] [Indexed: 03/14/2024] Open
Abstract
Many animals use color to signal their quality and/or behavioral motivations. Colorful signals have been well studied in the contexts of competition and mate choice; however, the role of these signals in nonsexual, affiliative relationships is not as well understood. Here, we used wild social groups of the cichlid fish Neolamprologus pulcher to investigate whether the size of a brightly colored facial patch was related to 1) individual quality, 2) social dominance, and/or 3) affiliative relationships. Individuals with larger patches spent more time foraging and tended to perform more aggressive acts against conspecific territory intruders. We did not find any evidence that the size of these yellow patches was related to social rank or body size, but dominant males tended to have larger patches than dominant females. Additionally, patch size had a rank-specific relationship with the number of affiliative interactions that individuals engaged in. Dominant males with large patches received fewer affiliative acts from their groupmates compared to dominant males with small patches. However, subordinates with large patches tended to receive more affiliative acts from their groupmates while performing fewer affiliative acts themselves. Taken together, our results suggest that patch size reflects interindividual variation in foraging effort in this cichlid fish and offer some of the first evidence that colorful signals may shape affiliative relationships within wild social groups.
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Affiliation(s)
- Brett M Culbert
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - James B Barnett
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Isaac Y Ligocki
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA
- Department of Biology, Millersville University, Millersville, PA, USA
| | - Matthew G Salena
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Marian Y L Wong
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Ian M Hamilton
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA
- Department of Mathematics, The Ohio State University, Columbus, OH, USA
| | - Sigal Balshine
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
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Culbert BM, Ligocki IY, Salena MG, Wong MYL, Hamilton IM, Aubin-Horth N, Bernier NJ, Balshine S. Rank- and sex-specific differences in the neuroendocrine regulation of glucocorticoids in a wild group-living fish. Horm Behav 2021; 136:105079. [PMID: 34717080 DOI: 10.1016/j.yhbeh.2021.105079] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/27/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022]
Abstract
Individuals that live in groups experience different challenges based on their social rank and sex. Glucocorticoids have a well-established role in coordinating responses to challenges and glucocorticoid levels often vary between ranks and sexes. However, the neuroendocrine mechanisms regulating glucocorticoid dynamics in wild groups are poorly understood, making it difficult to determine the functional consequences of differences in glucocorticoid levels. Therefore, we observed wild social groups of a cooperatively breeding fish (Neolamprologus pulcher) and evaluated how scale cortisol content (an emerging method to evaluate cortisol dynamics in fishes) and expression of glucocorticoid-related genes varied across group members. Scale cortisol was detectable in ~50% of dominant males (7/17) and females (7/15)-but not in any subordinates (0/16)-suggesting that glucocorticoid levels were higher in dominants. However, the apparent behavioural and neuroendocrine factors regulating cortisol levels varied between dominant sexes. In dominant females, higher cortisol was associated with greater rates of territory defense and increased expression of corticotropin-releasing factor in the preoptic and hypothalamic regions of the brain, but these patterns were not observed in dominant males. Additionally, transcriptional differences in the liver suggest that dominant sexes may use different mechanisms to cope with elevated cortisol levels. While dominant females appeared to reduce the relative sensitivity of their liver to cortisol (fewer corticosteroid receptor transcripts), dominant males appeared to increase hepatic cortisol breakdown (more catabolic enzyme transcripts). Overall, our results offer valuable insights on the mechanisms regulating rank- and sex-based glucocorticoid dynamics, as well as the potential functional outcomes of these differences.
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Affiliation(s)
- Brett M Culbert
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada.
| | - Isaac Y Ligocki
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA; Department of Biology, Millersville University, Millersville, PA, USA
| | - Matthew G Salena
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Marian Y L Wong
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Ian M Hamilton
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA; Department of Mathematics, The Ohio State University, Columbus, OH, USA
| | - Nadia Aubin-Horth
- Département de Biologie and Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Quebec, Canada
| | - Nicholas J Bernier
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Sigal Balshine
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
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