Investigating the effects of group size variation on social interactions and energy ... Social interactions: ⢠Degree. = number of grooming partners. ⢠Grooming.
Behavioural and physiological consequences of group size variation in Verreaux’s sifakas KATJA RUDOLPH1, CLAUDIA FICHTEL1, MICHAEL HEISTERMANN2 and PETER M. KAPPELER1 1Sociobiology
and Behavioural Ecology, German Primate Centre (DPZ), Göttingen, Germany 2Endocrinology Laboratory, German Primate Centre (DPZ), Göttingen, Germany
Introduction Larger groups offer more opportunities for social interactions but can negatively impact individual time and energy budgets. BUT - most studies on interspecific comparisons - no clear patterns founda e.g.: Group size Energy budgets: Elephants, Rhesus monkeys Group size Energy budgets: Sheep, Prairie voles Group size Energy budgets: Red colobus monkeys (How) Does intraspecific group size variation influence social behaviour and body condition?
Aims: Investigating the effects of group size variation on social interactions and energy budgets, indirectly measured via glucocorticoid concentrations (fGCM), in wild lemurs.
log (fGCM in µg/g)
log (Aggressive events/h)
Grooming rate (s/h)
log (Social Grooming Network Degree)
Results
Group size
Grooming rate (s/h)
Group size
Aggressive events/h
Summary Sifakas in larger groups invest more time in affiliative interactions. Energy budgets are not affected by sociality.
Conclusion Group size effects on social interactions & energy budgets vary across mammal species.
Methods ➢ Wild sifaka population in Kirindy Forest, Madagascar ➢ Behavioural observations (n >550h, Apr. – Oct.‘16): Social interactions: • Degree
= number of grooming partners
• Grooming
= total duration of grooming given and received
• Aggression
= all events of chases, bites, displacements, etc.
➢ Individual measures of fecal glucocorticoids (n = 630 samples) aMarkham, A. C., &
Gesquiere, L. R. (2017). Costs and benefits of group living in primates: an energetic perspective. Phil. Trans. R. Soc. B, 372(1727), 20160239
