Dados do Trabalho

Título

Sex allocation in Alouatta palliata: mothers care more for their sons than for their daughters

Resumo

The Trivers-Willard hypothesis (TWH) predicts that maternal care should vary according to offspring sex depending on maternal physical condition and on the impact of maternal investment on offspring reproductive success. Mantled howler monkeys (Alouatta palliata) meet the assumptions of the TWH: sons are energetically more expensive and have a greater variance in fitness than daughters. Our aim was to determine if there were differences in maternal care in relation to offspring sex and maternal physical condition in mantled howler monkeys living at the Los Tuxtlas region (Veracruz, Mexico). We recorded mother-infant interactions in 23 dyads, performed genetic analysis to determine offspring sex, and measured C-peptide in urine samples of mothers to determine their physical condition. Offspring sex was a good predictor of maternal care. On average, sons spent more time in ventro-ventral and generic contact with their mothers than daughters, a result that supports the TWH. There was a positive relationship between the physical condition of the mother and the time of generic contact and proximity with the offspring. These results converge with predictions of sex allocation theory and indicate that maternal care is influenced by the sex of the offspring and the physical condition of the mother.

Financiamento

Universidad Veracruzana; CONACyT (beca 866671, SEP-CONACyT 254217)

Palavras-chave

C-peptide, maternal investment, rearing