For pathogens that infect multiple species the distinction between reservoir hosts and spillover hosts is often difficult. In Alaska, three variants of the arctic rabies virus exist with distinct spatial distributions. We test the hypothesis that rabies virus variant distribution corresponds to the population structure of the primary rabies hosts in Alaska, arctic foxes (Vulpes lagopus) and red foxes (V. vulpes) in order to possibly distinguish reservoir and spill over hosts. We used mitochondrial DNA (mtDNA) sequence and nine microsatellites to assess population structure in those two species. mtDNA structure did not correspond to rabies virus variant structure in either species. Microsatellite analyses gave varying results. Bayesian clustering found 2 groups of arctic foxes in the coastal tundra region, but for red foxes it identified tundra and boreal types. Spatial Bayesian clustering and spatial principal components analysis identified 3 and 4 groups of arctic foxes, respectively, closely matching the distribution of rabies virus variants in the state. Red foxes, conversely, showed eight clusters comprising 2 regions (boreal and tundra) with much admixture. These results run contrary to previous beliefs that arctic fox show no fine-scale spatial population structure. While we cannot rule out that the red fox is part of the maintenance host community for rabies in Alaska, the distribution of virus variants appears to be driven primarily by the artic fox Therefore we show that host population genetics can be utilized to distinguish between maintenance and spillover hosts when used in conjunction with other approaches.

Milk is inhabited by a community of bacteria and is one of the first postnatal sources of microbial exposure for mammalian young. Bacteria in breast milk may enhance immune development, improve intestinal health, and stimulate the gut-brain axis for infants. Variation in milk microbiome structure (e.g., operational taxonomic unit[OTU] diversity, community composition) may lead to different infant developmental outcomes. Milk microbiome structure may depend on evolutionary processes acting at the host species level and ecological processes occurring over lactation time, among others. We quantified milk microbiomes using 16S rRNA high-throughput sequencing for nine primate species and for six primate mothers sampled over lactation. Our data set included humans (Homo sapiens, Philippines and USA) and eight nonhuman primate species living in captivity (bonobo [Pan paniscus], chimpanzee [Pan troglodytes], western lowland gorilla [Gorilla gorilla gorilla], Bornean orangutan [Pongo pygmaeus], Sumatran orangutan [Pongo abelii], rhesus macaque [Macaca mulatta], owl monkey [Aotus nancymaae]) and in the wild (mantled howler monkey [Alouatta palliata]). For a subset of the data, we paired microbiome data with nutrient and hormone assay results to quantify the effect of milk chemistry on milk microbiomes.We detected a core primate milk microbiome of seven bacterial OTUs indicating a robust relationship between these bacteria and primate species. Milk microbiomes differed among primate species with rhesus macaques, humans and mantled howler monkeys having notably distinct milk microbiomes. Gross energy in milk from protein and fat explained some of the variations in microbiome composition among species.Microbiome composition changed in a predictable manner for three primate mothers over lactation time, suggesting that different bacterial communities may be selected for as the infant ages. Our results contribute to understanding ecological and evolutionary relationships between bacteria and primate hosts, which can have applied benefits for humans and endangered primates in our care. K E Y W O R D Sbacteria, breast milk, infant, lactation, mammals, microbiota, symbiosis

Hand‐rearing and assisted‐rearing aardvarks in captivity has become commonplace and has led to success in breeding the species. However, the macronutrient content of aardvark milk past 1 month of age is unknown. A better understanding of aardvark milk composition would enhance captive management efforts. Here, we assayed milk samples from two captive individuals from 2 to 114 days postpartum (N = 21) for dry matter, fat, crude protein, total sugar, ash (total minerals), calcium (Ca), phosphorus (P), and gross energy. The body weight of one calf was measured from birth to weaning. Milk macronutrient composition was compared to that of other Afrotherian species and Xenarthra species with similar diets. Average protein, fat, and sugar concentrations of aardvark milk across lactation were 12.3%, 13.6%, and 2.5%, respectively. Ash averaged 1.9%, with Ca (0.50%) and P (0.35%) accounting for about 45% of total minerals. All measured nutrients increased over lactation except sugar, which decreased. Aardvark milk is high in energy (2.12 kcal/g) mostly derived from fat and protein and little energy from sugar. Calf growth was linear (r2 = 0.995) with a mean gain of 159 g/day, achieving almost 30% of adult weight at weaning. Within Afrotheria, aardvark milk is higher in fat and protein and lower in sugar than elephant milk and more closely resembles the milk of its fellow insectivore, the elephant shrew. Aardvark milk is also similar in composition to milk of insectivorous Xenarthra species (nine‐banded armadillo and giant anteater). Aardvark milk composition is consistent with the species’ high‐protein diet, fast growth, and nursing pattern.

Evidence suggests that exposure to nature and natural stimuli benefits individual and community-level mental health, leading to new efforts to incorporate mental health benefits into land conservation design, policy, and programming. This article summarizes the existing evidence about nature exposure and mental health and presents findings from a six-month knowledge-generation exercise conducted through the Yale School of the Environment to identify best practices and potential programmatic activities for the parks and land management sector to support youth mental health through nature-based, outdoor programming. Key recommendations include details on: (1) starting conversations about mental health and nature within the community, (2) recognizing organizational limitations and pursuing partnerships, (3) engaging communities in program development, (4) providing welcoming spaces to build participant comfort, and (5) creating programming that is flexible and adaptable, and becomes more challenging over time. Potential nature-based pilot activities include: (1) low-input ideas for short-term programming, one-off events, or reconfiguration of messaging materials, staff training, and the composition of the organization's board of directors; (2) medium-input ideas for partnering with outside organizations to connect existing user groups to preserved lands and expand activity offerings; and (3) high-input ideas for generating new programs, typically with organizational partners. The land conservation and parks stewardship sector has a unique opportunity to provide mental health benefits to the communities in which it operates, potentially raising the profile of conserved lands as important and beneficial for society.