Testing early life effects frameworks: developmental constraints and adaptive response hypotheses do not explain fertility outcomes in wild female baboons.

In evolutionary ecology, two classes of explanations are frequently invoked to explain early life effects on adult outcomes. Developmental constraints (DC) explanations contend that the costs of early adversity arise from limitations adversity places on optimal development. Adaptive response (AR) hypotheses propose that later life outcomes will be worse when early and adult environments are poorly 'matched'.

Eukaryotic composition across seasons and social groups in the gut microbiota of wild baboons.

Background: Animals coexist with complex microbiota, including bacteria, viruses, and eukaryotes (e.g., fungi, protists, and helminths).

Application of microbiome feedback theory to animals: Can parasites drive coexistence in ungulate communities?

Parasites can have large impacts on host populations, but the extent to which parasite dynamics impact or respond to multi-species community structure remains uncertain. Empirical and theoretical studies within the host-microbiome feedback framework (often called plant-soil feedback) has provided strong evidence of the importance of soil pathogens to plant community structure and function. We adapt this framework to herd animals by extending the mathematics of host-microbiome feedback theory to accommodate increased likelihood of exposure to microbiomes from conspecific hosts rather than heterospecific hosts.

Reevaluating the relationship between female sociality and infant survival in wild baboons.

Over the past few decades, studies have provided strong evidence that the robust links between the social environment, health, and survival found in humans also extend to nonhuman social animals. A number of these studies emphasize the early life origins of these effects. For example, in several social mammals, more socially engaged mothers have infants with higher rates of survival compared to less socially engaged mothers, suggesting that positive maternal social relationships causally improve offspring survival.

Social and environmental predictors of gut microbiome age in wild baboons.

Mammalian gut microbiomes are highly dynamic communities that shape and are shaped by host aging, including age-related changes to host immunity, metabolism, and behavior. As such, gut microbial composition may provide valuable information on host biological age. Here, we test this idea by creating a microbiome-based age predictor using 13,563 gut microbial profiles from 479 wild baboons collected over 14 years.

Shared environments complicate the use of strain-resolved metagenomics to infer microbiome transmission.

Background: In humans and other social animals, social partners have more similar microbiomes than expected by chance, suggesting that social contact transfers microorganisms. Yet, social microbiome transmission can be difficult to identify based on compositional data alone. To overcome this challenge, recent studies have used information about microbial strain sharing (i.

Early-life paternal relationships predict adult female survival in wild baboons.

Parent-offspring relationships can have profound effects on offspring behavior, health, and fitness in adulthood. These effects are strong when parents make heavy investments in offspring care. However, in some mammals, including several species of carnivores, rodents, and primates, fathers live and socialize with offspring, but paternal care is subtle or indirect.

Energetic costs of social dominance in wild male baboons.

In vertebrates, glucocorticoids can be upregulated in response to both psychosocial and energetic stressors, making it difficult to identify the cause of elevated glucocorticoid concentrations when both types of stressors are present. This problem has been particularly challenging in studies of social dominance rank in wild animals. In contrast to glucocorticoids, thyroid hormone concentrations are largely unaffected by psychosocial stressors and therefore offer a better estimate of energetic challenges.

Eukaryotic composition across seasons and social groups in the gut microbiota of wild baboons.

Background: Animals coexist with complex microbiota, including bacteria, viruses, and eukaryotes (e.g., fungi, protists, and helminths).

Re-evaluating the relationship between female social bonds and infant survival in wild baboons.

Over the past few decades studies have provided strong evidence that the robust links between the social environment, health, and survival found in humans also extend to non-human social animals. A number of these studies emphasize the early life origins of these effects. For example, in several social mammals, more socially engaged mothers have infants with higher rates of survival compared to less socially engaged mothers, suggesting that positive maternal social relationships causally improve offspring survival.

Social and environmental predictors of gut microbiome age in wild baboons.

Mammalian gut microbiomes are highly dynamic communities that shape and are shaped by host aging, including age-related changes to host immunity, metabolism, and behavior. As such, gut microbial composition may provide valuable information on host biological age. Here we test this idea by creating a microbiome-based age predictor using 13,563 gut microbial profiles from 479 wild baboons collected over 14 years.

Shared environments complicate the use of strain-resolved metagenomics to infer microbiome transmission.

In humans and other social animals, social partners have more similar microbiomes than expected by chance, suggesting that social contact transfers microorganisms. Yet, social microbiome transmission can be difficult to identify based on compositional data alone. To overcome this challenge, recent studies have used information about microbial strain sharing (i.

Testing frameworks for early life effects: the developmental constraints and adaptive response hypotheses do not explain key fertility outcomes in wild female baboons.

In evolutionary ecology, two classes of explanations are frequently invoked to explain "early life effects" on adult outcomes. Developmental constraints (DC) explanations contend that costs of early adversity arise from limitations adversity places on optimal development. Adaptive response (AR) hypotheses propose that later life outcomes will be worse when early and adult environments are poorly "matched.

Infant spatial relationships with adult males in a wild primate: males as mitigators or magnifiers of intergenerational effects of early adversity?

Adult male mammals can provide infants with protection and enhance their access to resources. They can also pose a risk to infants, either directly through infanticide or other aggression, or indirectly by placing infants at increased risk of conspecific or heterospecific conflict. Both benefits and costs may be especially important for offspring born to mothers in poor condition.

Using non-invasive behavioral and physiological data to measure biological age in wild baboons.

Biological aging is near-ubiquitous in the animal kingdom, but its timing and pace vary between individuals and over lifespans. Prospective, individual-based studies of wild animals-especially non-human primates-help identify the social and environmental drivers of this variation by indicating the conditions and exposure windows that affect aging processes. However, measuring individual biological age in wild primates is challenging because several of the most promising methods require invasive sampling.

Ecology and age, but not genetic ancestry, predict fetal loss in a wild baboon hybrid zone.

Objectives: Pregnancy failure represents a major fitness cost for any mammal, particularly those with slow life histories such as primates. Here, we quantified the risk of fetal loss in wild hybrid baboons, including genetic, ecological, and demographic sources of variance. We were particularly interested in testing the hypothesis that hybridization increases fetal loss rates.

DNA methylation signatures of early-life adversity are exposure-dependent in wild baboons.

The early-life environment can profoundly shape the trajectory of an animal's life, even years or decades later. One mechanism proposed to contribute to these early-life effects is DNA methylation. However, the frequency and functional importance of DNA methylation in shaping early-life effects on adult outcomes is poorly understood, especially in natural populations.

Thyroid hormone concentrations in female baboons: Metabolic consequences of living in a highly seasonal environment.

How female mammals adapt metabolically in response to environmental variation remains understudied in the wild, because direct measures of metabolic activity are difficult to obtain in wild populations. However, recent advances in the non-invasive measurement of fecal thyroid hormones, triiodothyronine (T3), an important regulator of metabolism, provide an opportunity to understand how female baboons living in the harsh Amboseli ecosystem in southern Kenya adapt to environmental variability and escape strict reproductive seasonality. Specifically, we assessed how a female's activity budget, diet, and concentrations of fecal T3 metabolites (mT3) changed over the course of the year and between years.

Microbial transmission in the social microbiome and host health and disease.

Although social interactions are known to drive pathogen transmission, the contributions of socially transmissible host-associated mutualists and commensals to host health and disease remain poorly explored. We use the concept of the social microbiome-the microbial metacommunity of a social network of hosts-to analyze the implications of social microbial transmission for host health and disease. We investigate the contributions of socially transmissible microbes to both eco-evolutionary microbiome community processes (colonization resistance, the evolution of virulence, and reactions to ecological disturbance) and microbial transmission-based processes (transmission of microbes with metabolic and immune effects, inter-specific transmission, transmission of antibiotic-resistant microbes, and transmission of viruses).

Ecology and evolution of the social microbiome.

Animals with close social relationships often have similar microbiomes. These socially structured microbiomes can arise through multiple mechanisms that are often difficult to disentangle, including transmission between social partners or via socially structured, shared environments. Here, we review evidence for socially structured microbiomes and propose methods to differentiate the mechanisms that given rise to them.

Environmental, sex-specific and genetic determinants of infant social behaviour in a wild primate.

Affiliative social bonds are linked to fitness components in many social mammals. However, despite their importance, little is known about how the tendency to form social bonds develops in young animals, or if the timing of development is heritable and thus can evolve. Using four decades of longitudinal observational data from a wild baboon population, we assessed the environmental determinants of an important social developmental milestone in baboons-the age at which a young animal first grooms a conspecific-and we assessed how the rates at which offspring groom their mothers develops during the juvenile period.

Five Decades of Data Yield No Support for Adaptive Biasing of Offspring Sex Ratio in Wild Baboons ().

AbstractOver the past 50 years, a wealth of testable, often conflicting hypotheses have been generated about the evolution of offspring sex ratio manipulation by mothers. Several of these hypotheses have received support in studies of invertebrates and some vertebrate taxa. However, their success in explaining sex ratios in mammalian taxa-especially in primates-has been mixed.

Early life drought predicts components of adult body size in wild female baboons.

Objectives: In many taxa, adverse early-life environments are associated with reduced growth and smaller body size in adulthood. However, in wild primates, we know very little about whether, where, and to what degree trajectories are influenced by early adversity, or which types of early adversity matter most. Here, we use parallel-laser photogrammetry to assess inter-individual predictors of three measures of body size (leg length, forearm length, and shoulder-rump length) in a population of wild female baboons studied since birth.