When checked, Shutterstock's safe search screens restricted content and excludes it from your search results. Male mandrills have bright red and blue coloration on the face, leading Darwin to write that "no other member in the whole class of mammals is coloured in so extraordinary a manner as the adult male mandrills" (Darwin, 1871). The hypothesised relationships between MHC, immune function, pathology, endocrinology, bright colour and mate choice have influenced our own studies in mandrills.
This work has been undertaken in collaboration with Dr E Jean Wickings at CIRMF (Gabon), Dr Joanna Setchell, Durham University and Dr Tessa Smith, University of Chester. More than 130 years after Darwin published his theory, our research has examined why males vary in colour and why females choose to mate with brighter males.
Research on birds suggested that elaborate ornaments are the product of an evolutionary arms race between pathogens and their hosts.


Knapp (2006)Life history in male mandrills (Mandrillus sphinx): Physical development, dominance rank and group association.
Knapp (2006) High levels of diversity characterise mandrill (Mandrillus sphinx) Mhc-DRB sequences.
Knapp (2006)Signal content of red facial coloration in female mandrills (Mandrillus sphinx). If only healthy males can afford to produce bright colour, females can choose to reproduce with brightly coloured males possessing 'good genes' for pathogen resistance, which will be passed on to their offspring. Heritable and differential pathogen resistance has been attributed to the Major Histocompatibility Complex (MHC) genes.
Knapp (in press) Parasite prevalence, diversity and parasite load in a semi-free-ranging colony of mandrills.


Knapp (2006) Secondary sexual characters and female quality in primates Behavioral Ecology and Sociobiology, 61(2):305-315. However, the 'immunocompetence hypothesis' posits a trade-off between the costs and benefits of a high level of testosterone.
This results in females choosing males with showy traits, and therefore choosing mates with an immune system that can still function despite such depression.



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