Socioecological predictors of immune defences in wild spotted hyenas
Flies, AS and Mansfield, LS and Flies, EJ and Grant, CK and Holekamp, KE, Socioecological predictors of immune defences in wild spotted hyenas, Functional Ecology, 30, (9) pp. 1549-1557. ISSN 0269-8463 (2016) [Refereed Article]
Copyright 2016 The Authors. Functional Ecology Copyright 2016 British Ecological Society
1. Social rank can profoundly affect many aspects of mammalian reproduction and stress
physiology, but little is known about how immune function is affected by rank and other
socioecological factors in free-living animals.
2. In this study, we examine the effects of sex, social rank and reproductive status on immune
function in long-lived carnivores that are routinely exposed to a plethora of pathogens, yet
rarely show signs of disease.
3. Here, we show that two types of immune defences, complement-mediated bacterial killing
capacity (BKC) and total IgM, are positively correlated with social rank in wild hyenas, but
that a third type, total IgG, does not vary with rank.
4. Female spotted hyenas, which are socially dominant to males in this species, have higher
BKC, and higher IgG and IgM concentrations, than do males.
5. Immune defences are lower in lactating than pregnant females, suggesting the immune
defences may be energetically costly.
6. Serum cortisol and testosterone concentrations are not reliable predictors of basic immune
defences in wild female spotted hyenas.
7. These results suggest that immune defences are costly and multiple socioecological variables
are important determinants of basic immune defences among wild hyenas. The effects of these
variables should be accounted for when attempting to understand disease ecology and immune