Living near the limits: Effects of interannual variation in food availability on diet and reproduction in a temperate primate, the Taihangshan macaque (Macaca mulatta tcheliensis). Issue 1 (19th December 2019)

• Record Type: Journal Article
• Authors: Cui, Zhenwei; Wang, Zhenlong; Zhang, Shiqiang; Wang, Baishi; Lu, Jiqi; Raubenheimer, David
• Is Part Of: American journal of primatology. Volume 82:Issue 1(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-12-19
• Subjects: geometric framework of nutrition -- lactation -- Macaca mulatta tcheliensis -- nutrient balance -- Pregnancy; Primates -- Periodicals; Primates -- Périodiques; 599.8
• DOI: 10.1002/ajp.23080
• Languages: English
• ISSNs: 0275-2565

Abstract

Abstract: Nutrient intake of animals is influenced by an interplay of external and internal factors, such as food availability and reproductive state, respectively. We used the nutritional geometry framework to analyze individual‐based data on energy and nutrient intake in relation to reproductive state in a population of rhesus macaques ( Macaca mulatta tcheliensis ), which live in a harsh high‐latitude habitat, the Taihangshan mountains of China, and exhibit strong reproductive seasonality. We combined data over a 3‐year period on food availability, diets, reproductive output, and components of maternal investment to understand how Taihangshan macaques respond to variation in food availability and nutrition in reproduction. Our results show there was high interannual variation in availability of an important staple source of fat and carbohydrates (nonprotein energy), seeds of oak ( Quercus spp). Despite this variability in seed availability skewing the dietary macronutrient ratios considerably (from 12.96% to 30.12% dietary energy from protein), total metabolizable energy intake was maintained across years during pregnancy. Lactating females had higher mean daily energy intakes than pregnant females. As in pregnant females, energy intake was maintained constant across years, but only when seed availability enabled the contribution of available protein to energy intake to be maintained between 15.32% (2013) and 17.97% (2015). In 2014, when seeds were scarce, lactating females had a shortfall in energy intake compared with 2013 and 2015. This corresponded with a reduction in the number of females giving birth (11 out of 23), but there was no interannual difference in survival rates. Compared to 2013 and 2015, in 2014 females had greater weight loss (drew on body reserves), moved less, and spent more time nursing their offspring. We discuss implications of these results for range limitation in Taihangshan macaques. Abstract : Research Highlights: 1. We have previously shown that the Taihangshan macaques respond to this interannual variation in dietary balance by ingesting constant energy regardless of its macronutritional composition (Cui et al., 2018, Behav Ecol, 29(4), 804–813). Our study thus suggests that flexible macronutrient handling is a key capacity that enables Taihangshan macaques to inhabit an extreme temperate environment characterized by both seasonal and interannual macronutrient variation. Here we extend this study, to test whether the edge‐of‐range status of the Taihangshan population of macaques might be accounted for by limits to the capacity for flexible macronutrient handling. We focused on reproduction, which is both a common, if not the most common, demographic explanation for range limits, and the most energetically demanding phase of the life cycle. 2. Our results, together with our previous study (Cui et al., 2018, Behav Ecol, 29(4), 804–813), show that Taihangshan rhesus macaques are remarkably tolerant of interannual dietary variability. Nonetheless, they are likely living close to the limits of their tolerance, as evidenced by the fact that in years with low seed availability they are incapable of matching energy intakes of better years, and reproduction is reduced despite the investment of additional maternal effort. 3. Our paper not only will make a contribution to the theory of ecological generalism, but will also contribute to understanding how nutrition contributes to range limitation in primates.