Food supply is one of the major drivers of animal behavior,and the gut microbiome is an important mediator be-tween food supply and its effects on physiology.However,predicting the outcome of diet change on microbiome and consequences for the animal has proven extremely challenging.We propose this reflects processes occurring at different scales.Inadequate accounting for the multi-level complexity of nutrition(nutrients,foods,diets)obscures the diet influence on microbiome and subsequently animal.Here,we present a detailed year-round,multi-level analysis of diet and microbiome changes in a wild population of a temperate primate,the rhesus macaque(Macaca mulatta).Total daily food and nutrient intake of 6 male and 6 female macaques was monitored in each of the 4 sea-sons(total 120 days observations).For each individual,we found significant variation in the microbiome between all 4 seasons.This response was more strongly correlated with changes in macronutrient intake than with food items and much of the response could be explained at the level of 6 ecological guilds—sets of taxa sharing similar responses to nutrient intake.We conclude that study of diet,microbiome,and animal performance in ecology will more effectively identify patterns if diet is recorded at the level of nutrient intake.Although microbiome response to diet does show variation in species-level taxa in response to food items,there is greater commonality in response at the level of guilds.A goal for microbiome researchers should be to identify genes encoding microbial attributes that can define such guilds.
Sex allocation theory predicts the optimal investment to male and female offspring.However,a biased sex ratio requires explanations as to why the deviation occurs.Rhesus macaque(Macaca mulatta)is the most widely distributed nonhuman primate species and the Taihangshan macaque(Macaca mulatta tcheliensis)occupies the northern limit of all rhesus macaque natural populations worldwide.We observed one macaque troop(Wangwu-1[WW-1])inhabiting Taihangshan Macaque National Nature Reserve and recorded all birth events and the sex of newborn macaques from 2004 to 2013.Our aim was to apply the Trivers–Willard hypothesis to this free-ranging rhesus macaque troop,and to understand the relationship between climatic parameters(precipitation and temperature)and birth sex ratio.We found that the total newborn macaques showed a female-biased sex ratio at birth in the WW-1 troop,but there were no significant biased birth sex ratios in all matriarchs and in high-ranking and middle-ranking matrilineal units.However,the low-ranking macaque matrilineal unit was significantly female-biased.Moreover,we found that the annual precipitation of the previous year was positively associated with the birth sex ratio,and there was an interactive effect of troop size and current winter temperature on the birth sex ratio.The underlying mechanisms for the effects of social and climatic factors on birth sex ratio could be complex,and we discuss several plausible explanations.
Jundong TIANBaishi WANGZhenlong WANGJindong LIUJiqi LU
