Primate mating systems and the evolution of immune response

Area of Science:

• Primate immunology
• Evolutionary biology
• Comparative physiology

Background:

• White blood cell (WBC) and red blood cell (RBC) counts are common hematological indicators.
• Variations in these counts can reflect health status and physiological adaptations.
• Mating systems and reproductive strategies can influence various biological traits.

Purpose of the Study:

• To investigate the relationship between WBC and RBC counts and health status in captive non-human primates.
• To explore correlations between basal WBC counts, mating systems, and relative testis size.
• To determine if RBC counts are similarly affected by health or mating systems.

Main Methods:

• Hematological analysis of 762 specimens from 25 primate genera and 38 species.
• Comparison of WBC and RBC counts between healthy and ill animals.
• Statistical analysis, including comparative analysis of independent contrasts (CAIC), to assess correlations with mating systems and relative testis size.

Main Results:

• Ill primates exhibited significantly higher WBC counts than healthy ones.
• Basal WBC counts in healthy primates positively correlated with multiple partner mating, a finding robust to phylogenetic control.
• WBC counts also positively correlated with relative testis size, an independent index of mating system.
• RBC counts showed no significant association with health status or mating systems.

Conclusions:

• A significant correlation exists between WBC counts and primate mating systems, as well as relative testis size.
• These findings suggest a potential link between immune function and reproductive strategies in primates.
• Further research is needed to establish the evolutionary causation of basal WBC counts in primates.