Status signalling, metabolic rate and body mass in the siskin: the cost of being a subordinate

• Published in: Animal behaviour Vol. 59; no. 1; pp. 103 - 110
• Main Authors: Senar, Juan Carlos, Polo, Vicente, Uribe, Francesc, Camerino, Montse
• Format: Journal Article
• Language: English
• Published: Kent Elsevier Ltd 01.01.2000; Elsevier; Harcourt Brace Jovanovich Ltd
• Subjects: Age; Animal behavior; Animal ethology; Aves; Biological and medical sciences; Carduelis spinus; Fundamental and applied biological sciences. Psychology; Insects; Metabolism; Psychology. Psychoanalysis. Psychiatry; Status; Vertebrata; Laboratory study; Animal communication; Costs; Intraspecific relation; Body weight; Metabolism; Social status; Vertebrata; Social dominance; Social interaction; Individual recognition; Aves; Visual signal
• ISSN: 0003-3472; 1095-8282
• DOI: 10.1006/anbe.1999.1281

The higher metabolic rate of dominant individuals, found in different species, has been interpreted as the cost that prevents subordinates from cheating by adopting large badges of status. However, an alternative prediction for status-signalling species, in which subordinates may recognize dominants, is that subordinates have the higher metabolic rate because of the greater stress of locating and actively avoiding aggressive interactions with them. In this study, the size of the black bib of the siskin, Carduelis spinus, which is a badge of dominance, was negatively correlated with metabolic rate in daylight, even when controlling for the bird's activity level in the respirometer chamber and its body mass. The size of the black bib, however, was not correlated with metabolic rate in darkness. This suggests that the difference between dominance classes is not related to intrinsic physiological differences, but that subordinates are more susceptible to stressful conditions. When controlling for metabolic rate, a positive correlation appeared between dominance status and body mass. This stresses the importance of knowing the effects of social status on energy requirements for understanding the relationship between body mass and dominance. We conclude that maintaining a high social status may be more stressful to subordinates than to dominant birds.