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Abstract

The night monkeys (Aotus azarai) of Formosa, Argentina provide an opportunity to investigate the influences of ambient temperature and photoperiod on reproduction in a highly seasonal environment: the Chaco. Between 1997 and we collected data to evaluate the relationship between rainfall, ambient temperature, photoperiod and food availability and the annual distribution of mating behavior and births in 15 groups of monkeys in the forests of the Eastern Argentinean Chaco. Our data show that the area is highly seasonal, characterized by significant fluctuations in rainfall, temperature, photoperiod and food availability. There are two rain peaks in April and November and a dry season lasting from June to August. Monthly mean temperatures were on average 11 • C lower during winter months than they were during summer months. Temperatures <10 • C and >33 • C were also frequent through the year. Days are 3 h longer during the summer than during the winter months. Insect abundance and the percentage of tree species producing fruits, flowers or new leaves reached a low in the coldest winter months. Mating was infrequent, and we only observed it between May and September. Half the births (n = 13) occurred during a 2-week period in October. Infant survival during the first 6 mo of life was high (96%). Our findings suggest an environmental control of reproduction. Changes in photoperiod and temperature may promote reproductive activity in females that might conceive and begin

Inbreeding avoidance, competition and natal dispersal in a pair-living, genetically monogamous mammal, Azara’s owl monkey ( Aotus azarae )

“…The third set of analyses investigated the influence of resource competition on the seasonality of dispersal. To attempt disentangling the potential influences of group composition changes associated with the birth season [68] and resource abundance we defined seasonality in two ways and performed separate analyses on each. First, we constructed 15 candidate generalized linear models for which the outcome variable was whether a dispersal occurred during the 'birth season', with a dataset of 210 individuals.…”

A 24-Year Record of Female Reproductive Dynamics in Two Sympatric Mouse Lemur Species in Northwestern Madagascar

“…The main proximate trigger of seasonal reproduction is day length (i.e., photoperiod) (Perret & Aujard, 2001). Nonetheless, some reproductive variation can be explained by changes in environmental factors, such as climate (temperature, rainfall) or resource availability, or by internal factors such as body condition and age (Brockman & van Schaik, 2005;Ellis et al, 2021;Fernandez-Duque et al, 2002;Huang et al, 2012;Savini et al, 2008;Stone & Ruivo, 2020).…”

Intergroup encounters in pair‐living primates: Comparative analysis and a case study of pair‐living and monogamous owl monkeys (Aotus azarae) of Argentina

“…The Azara's owl monkeys (Aotus azarae) from Formosa, Argentina, are pair-living, sexually and genetically monogamous primates that, in contrast to other species of the genus which are strictly nocturnal, show cathemeral activity patterns (Fernandez-Duque & de la Iglesia, 2023;Fernandez-Duque, Juárez et al, 2023;Fernandez-Duque, Rotundo, et al, 2023;Ziegler et al, 2022). In the Argentina population they are seasonal breeders producing a single infant once a year, usually born between late September and December Fernandez-Duque et al, 2002). The species shows extensive levels of biparental care, with males carrying, grooming, and sharing food with infants more than females do (Fernandez-Duque et al, 2020;Garcia de la Chica et al, 2023;).…”