The relationship between concealed ovulation and mating systems in anthropoid primates: a phylogenetic analysis

Area of Science:

• Primate evolutionary biology
• Behavioral ecology
• Reproductive strategies

Background:

• Concealed ovulation, the absence of visual cues for ovulation, is a debated adaptation in primates.
• Two hypotheses exist: promoting paternal care via paternity confidence or confusing paternity to improve male investment in offspring.

Purpose of the Study:

• To investigate the evolutionary pressures leading to the loss of ovulatory signs in primates.
• To determine whether concealed ovulation evolved to promote paternal care or paternity confusion.

Main Methods:

• Phylogenetic analysis of extant primate taxa.
• Mapping of mating systems and ovulatory signs onto independently derived phylogenetic trees.
• Inferring ancestral states and tracing the evolution of concealed ovulation and mating systems.

Main Results:

• Concealed ovulation and multimale mating systems were inferred as ancestral states for anthropoid primates.
• Loss of ovulatory signs occurred more frequently in non-monogamous contexts (8-11 times) than under monogamy (0-1 times).
• Monogamy evolved independently multiple times, often in the absence of ovulatory signs, suggesting concealed ovulation may precede monogamy.

Conclusions:

• The hypothesis that concealed ovulation evolved to confuse paternity receives stronger support.
• While linked, the absence of ovulatory signs appears more likely to promote monogamy than vice versa.
• The adaptive function of concealed ovulation may shift in lineages that evolve monogamy.