Ectoparasites of house sparrows ( Passer domesticus ): an experimental test of the immunocompetence handicap hypothesis and a new model

2000 ◽  
Vol 47 (4) ◽  
pp. 230-242 ◽  
Author(s):  
A. Poiani ◽  
A. R. Goldsmith ◽  
M. R. Evans
Keyword(s):  
Experimental Test ◽  
Passer Domesticus ◽  
House Sparrows ◽  
New Model ◽  
Immunocompetence Handicap Hypothesis ◽  
Handicap Hypothesis

scholarly journals Non-breeding feather concentrations of testosterone, corticosterone and cortisol are associated with subsequent survival in wild house sparrows

2011 ◽  
Vol 279 (1733) ◽  
pp. 1560-1566 ◽  
Author(s):  
Lee Koren ◽  
Shinichi Nakagawa ◽  
Terry Burke ◽  
Kiran K. Soma ◽  
Katherine E. Wynne-Edwards ◽  
...  
Keyword(s):  
Stress Hormones ◽  
Passer Domesticus ◽  
House Sparrows ◽  
Long Term Study ◽  
Darwinian Fitness ◽  
Liquid Chromatography Tandem Mass ◽  
In The Wild ◽  
The Subject ◽  
As Stress

Potential mechanistic mediators of Darwinian fitness, such as stress hormones or sex hormones, have been the focus of many studies. An inverse relationship between fitness and stress or sex hormone concentrations has been widely assumed, although empirical evidence is scarce. Feathers gradually accumulate hormones during their growth and provide a novel way to measure hormone concentrations integrated over time. Using liquid chromatography–tandem mass spectrometry, we measured testosterone, corticosterone and cortisol in the feathers of house sparrows ( Passer domesticus ) in a wild population which is the subject of a long-term study. Although corticosterone is considered the dominant avian glucocorticoid, we unambiguously identified cortisol in feathers. In addition, we found that feathers grown during the post-nuptial moult in autumn contained testosterone, corticosterone and cortisol levels that were significantly higher in birds that subsequently died over the following winter than in birds that survived. Thus, feather steroids are candidate prospective biomarkers to predict the future survival of individuals in the wild.

scholarly journals Social and endocrine correlates of immune function in meerkats: implications for the immunocompetence handicap hypothesis

2018 ◽  
Vol 5 (8) ◽  
pp. 180435 ◽  
Author(s):  
Kendra N. Smyth ◽  
Nicholas M. Caruso ◽  
Charli S. Davies ◽  
Tim H. Clutton-Brock ◽  
Christine M. Drea
Keyword(s):  
Immune Function ◽  
Social Status ◽  
Dominant Species ◽  
Reproductive Activity ◽  
Trade Offs ◽  
Endocrine Mechanism ◽  
Immunocompetence Handicap Hypothesis ◽  
Handicap Hypothesis ◽  
Serum Bacteria ◽  
Bacteria Killing

Social status can mediate effects on the immune system, with profound consequences for individual health; nevertheless, most investigators of status-related disparities in free-ranging animals have used faecal parasite burdens to proxy immune function in the males of male-dominant species. We instead use direct measures of innate immune function (complement and natural antibodies) to examine status-related immunocompetence in both sexes of a female-dominant species. The meerkat is a unique model for such a study because it is a cooperatively breeding species in which status-related differences are extreme, evident in reproductive skew, morphology, behaviour, communication and physiology, including that dominant females naturally express the greatest total androgen (androstenedione plus testosterone) concentrations. We found that, relative to subordinates, dominant animals had reduced serum bacteria-killing abilities; also, relative to subordinate females, dominant females had reduced haemolytic complement activities. Irrespective of an individual's sex or social status, androstenedione concentrations (but not body condition, age or reproductive activity) negatively predicted concurrent immunocompetence. Thus, dominant meerkats of both sexes are immunocompromised. Moreover, in female meerkats, androstenedione perhaps acting directly or via local conversion, may exert a double-edged effect of promoting dominance and reproductive success at the cost of increased parasitism and reduced immune function. Given the prominent signalling of dominance in female meerkats, these findings may relate to the immunocompetence handicap hypothesis (ICHH); however, our data would suggest that the endocrine mechanism underlying the ICHH need not be mediated solely by testosterone and might explain trade-offs in females, as well as in males.

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