The gut microbiome has the potential to buffer temporal variations in resource availability and consumption, which may play a key role in the ability of animals to adapt to a broad range of habitats. We investigated the temporal composition and function of the gut microbiomes of wild common marmosets (Callithrix jacchus) exploiting a hot, dry environment-Caatinga-in northeastern Brazil. We collected fecal samples during two time periods (July-August and February-March) for 2 years from marmosets belonging to eight social groups. We used 16S rRNA gene amplicon sequencing, metagenomic sequencing, and butyrate RT-qPCR to assess changes in the composition and potential function of their gut microbiomes. Additionally, we identified the plant, invertebrate, and vertebrate components of the marmosets\' diet via DNA metabarcoding. Invertebrate, but not plant or vertebrate, consumption varied across the year. However, gut microbiome composition and potential function did not markedly vary across study periods or as a function of diet composition. Instead, the gut microbiome differed markedly in both composition and potential function across marmosets residing in different social groups. We highlight the likely role of factors, such as behavior, residence, and environmental heterogeneity, in modulating the structure of the gut microbiome.
OBJECTIVE: In a highly socially cohesive and cooperative primate, group membership more strongly predicts gut microbiome composition and function than diet.

Understanding how animal collectives and societies form and function is a fundamental goal in animal biology. To date, research examining fish shoaling behavior has focused mostly on the general principles and ecological relevance of the phenomeon, while the ways in which physiological state (e.g., nutrition) affects collective behavior remain overlooked. Here, we investigated the shoaling behavior of common minnows (Phoxinus phoxinus) with three different nutritional states (control treatment: fasting for 24 h, fasting treatment: fasting for 7 days, and digestion treatment: 1 h after satiation feeding) across two ecological contexts (i.e., without and with food). No effects of either nutritional state or context were found on swimming speed, but the acceleration was greater in the digestion group than in the control group, with that in the fasting group being intermediate. Similar to change tendency in group length and group width of shoals, both interindividual distance and nearest neighbor distance were also greater in the fasting group than in the digestion group, suggesting that fasting and digestion may exert opposite driving forces on group cohesion. However, neither nutritional state nor context influenced the group area, group speed, group percent time moving, or group polarization. Both the foraging efficiency and the percentage of food items consumed by the fish shoals were greater in the fasting and control groups than in the digestion group. Our study suggested that one week of hunger and the energetically demanding stage of food digestion tend to have opposite influences on group shape, while the social foraging context does not influence the individual and group behavior of fish.

The social system of animals involves a complex interplay between physiology, natural history, and the environment. Long relied upon discrete categorizations of \"social\" and \"solitary\" inhibit our capacity to understand species and their interactions with the world around them. Here, we use a globally distributed camera trapping dataset to test the drivers of aggregating into groups in a species complex (martens and relatives, family Mustelidae, Order Carnivora) assumed to be obligately solitary. We use a simple quantification, the probability of being detected in a group, that was applied across our globally derived camera trap dataset. Using a series of binomial generalized mixed-effects models applied to a dataset of 16,483 independent detections across 17 countries on four continents we test explicit hypotheses about potential drivers of group formation. We observe a wide range of probabilities of being detected in groups within the solitary model system, with the probability of aggregating in groups varying by more than an order of magnitude. We demonstrate that a species\' context-dependent proclivity toward aggregating in groups is underpinned by a range of resource-related factors, primarily the distribution of resources, with increasing patchiness of resources facilitating group formation, as well as interactions between environmental conditions (resource constancy/winter severity) and physiology (energy storage capabilities). The wide variation in propensities to aggregate with conspecifics observed here highlights how continued failure to recognize complexities in the social behaviors of apparently solitary species limits our understanding not only of the individual species but also the causes and consequences of group formation.

Primate social organizations, or grouping patterns, vary significantly across species. Behavioral strategies that allow for flexibility in grouping patterns offer a means to reduce the costs of group living. Chimpanzees (Pan troglodytes) have a fission-fusion social system in which temporary subgroups (\"parties\") change in composition because of local socio-ecological conditions. Notably, western chimpanzees (P. t. verus) are described as showing a higher degree of bisexual bonding and association than eastern chimpanzees, and eastern female chimpanzees (P. t. schweinfurthii) are thought to be more solitary than western female chimpanzees. However, reported comparisons in sociality currently depend on a small number of study groups, particularly in western chimpanzees, and variation in methods. The inclusion of additional communities and direct comparison using the same methods are essential to assess whether reported subspecies differences in sociality hold in this behaviorally heterogeneous species. We explored whether sociality differs between two communities of chimpanzees using the same motion-triggered camera technology and definitions of social measures. We compare party size and composition (party type, sex ratio) between the western Gahtoy community in the Nimba Mountains (Guinea) and the eastern Waibira community in the Budongo Forest (Uganda). Once potential competition for resources such as food and mating opportunities were controlled for, subspecies did not substantially influence the number of individuals in a party. We found a higher sex-ratio, indicating more males in a party, in Waibira; this pattern was driven by a greater likelihood in Gahtoy to be in all-female parties. This finding is the opposite of what was expected for eastern chimpanzees, where female-only parties are predicted to be more common. Our results highlight the flexibility in chimpanzee sociality, and caution against subspecies level generalizations.

UNASSIGNED: Food sociality refers to the exploration of food production, exchange, distribution, and consumption and influences on cultural communication and social meaning. This study aimed to investigate food sociality in three provinces of South China to provide theoretical and practical evidence of food sociality in the region and to revise nutrition policies.
UNASSIGNED: We conducted a qualitative study comprising 25 experts in the fields of nutrition, sociology, food science, and agriculture from Hainan, Guangdong, and Guangxi Province by using a semi-structured in-depth interview, which included 28 pre-determined questions covering six topics. The interviews were conducted between November 2020 and March 2021. Verbatim transcripts were analyzed thematically using NVivo 11.0.
UNASSIGNED: Of the 25 experts, the mean age was 50.6 (SD = 8.4) years, 15 (60%) were male, and 22 (88%) held a master\'s degree or above. The analysis showed that food sociality in three provinces of South China mainly comprises social functions of food and dietary behavior. Regarding social functions of food, the experts expressed that food represents local culture (72%, 18 experts), presents social status and economic power (40%, 10 experts), and is central to special occasions, traditional customs, and etiquette activities (60%, 15 experts). In terms of social functions of dietary behaviors, the majority of experts indicated that food is a social communication tool (72% experts), has geographical characteristics (80% experts), and, to some extent, is used as a proxy for reward or punishment. Furthermore, festivals are one of the core elements of food sociality in the region, although food safety is a major concern. Some dietary behaviors, such as overindulgence in afternoon tea and encouraging drinking, may increase the risk of chronic diseases.
UNASSIGNED: Food sociality in three provinces of South China is mainly related to the social function of food and dietary behavior. It is a combination of local culture, social status and economic power, traditional customs, rewards and punishments, geographical food preference, and social communication tools. The authors recommend increasing food safety at festivals and promoting healthy eating behaviors in order to improve the overall health of the population in this region.

The Himalayan marmot Marmota himalayana is widely distributed across the Qinghai-Tibetan Plateau and lives in social groups, yet the mating system of this highly social marmot species is unknown. In this study, the genetic mating system of Himalayan marmots was investigated using microsatellite markers to determine which mating strategies individuals employ. Results revealed that both monogamous and polygamous mating relationships occur in our study population, indicating that the genetic mating system of this marmot species is promiscuity. This study presents the first genetic evidence on the mating system for Himalayan marmots, yet indicates that further studies employing both a genetic and behavioral framework are needed to better understand the social structure and reproductive biology of this marmot species.

Mixed-species groups of birds, fishes and mammals have traditionally been described in taxa-specific journals. However, mixed-species systems are actually more widely found when one includes aggregative (non-moving) systems, such as those common in amphibians and invertebrates. The objective of this special issue is to dispel the idea that mixed-species phenomena are a \'niche topic\' to ecology and instead explore how taking a mixed-species perspective can change our conception of important ecological patterns and processes. A mixed-species perspective starts by understanding the relative abundance and positioning of individuals of different species and their behavioural synchrony; it is enriched by understanding differences between species in their vulnerability/attractiveness to predators, their potential for competing with other group participants and their use as a source of public information. Contributions to the special issue show how the mixed-species perspective can change our ideas about invasion ecology, island biogeography, keystone species, mimicry, predator eavesdropping and more. Rather than seeking synthesis, the special issue celebrates the taxonomic and conceptual breadth of the field of mixed-species groups, with detailed descriptions of many distinctive systems. This article is part of the theme issue \'Mixed-species groups and aggregations: shaping ecological and behavioural patterns and processes\'.

Aculeate hymenopterans use their venom for a variety of different purposes. The venom of solitary aculeates paralyze and preserve prey without killing it, whereas social aculeates utilize their venom in defence of their colony. These distinct applications of venom suggest that its components and their functions are also likely to differ. This study investigates a range of solitary and social species across Aculeata. We combined electrophoretic, mass spectrometric, and transcriptomic techniques to characterize the compositions of venoms from an incredibly diverse taxon. In addition, in vitro assays shed light on their biological activities. Although there were many common components identified in the venoms of species with different social behavior, there were also significant variations in the presence and activity of enzymes such as phospholipase A2s and serine proteases and the cytotoxicity of the venoms. Social aculeate venom showed higher presence of peptides that cause damage and pain in victims. The venom-gland transcriptome from the European honeybee (Apis mellifera) contained highly conserved toxins which match those identified by previous investigations. In contrast, venoms from less-studied taxa returned limited results from our proteomic databases, suggesting that they contain unique toxins.

Host symbionts are often considered an essential part of the host phenotype, influencing host growth and development. Bumble bee is an ideal model for investigating the relationship between microbiota and phenotypes. Variations in life history across bumble bees may influence the community composition of gut microbiota, which in turn influences phenotypes. In this study, we explored gut microbiota from four development stages (early-instar larvae, 1st instar; mid-instar larvae, 5th instar; late-instar larvae, 9th instar; and adults) of workers and queens in the bumble bee Bombus terrestris using the full-length 16S rRNA sequencing technology. The results showed that morphological indices (weight and head capsule) were significantly different between workers and queens from 5th instar larvae (p < 0.01). The alpha and beta diversities of gut microbiota were similar between workers and queens in two groups: early instar and mid instar larvae. However, the alpha diversity was significantly different in late instar larvae or adults. The relative abundance of three main phyla of bacteria (Cyanobacteria, Proteobacteria, and Firmicutes) and two genera (Snodgrassella and Lactobacillus) were significantly different (p < 0.01) between workers and queens in late instar larvae or adults. Also, we found that age significantly affected the microbial alpha diversity as the Shannon and ASVs indices differed significantly among the four development stages. Our study suggests that the 5th instar larval stage can be used to judge the morphology of workers or queens in bumble bees. The key microbes differing in phenotypes may be involved in regulating phenotypic variations.

The technology of long reads substantially improved the contingency of the genome assembly, particularly resolving contiguity of the repetitive regions. By integrating the interactive fragment using Hi-C, and the HiFi technique, a solid genome of the honeybee Apis mellifera carnica was assembled at the chromosomal level. A distinctive pattern of genes involved in social evolution was found by comparing it with social and solitary bees. A positive selection was identified in genes involved with cold tolerance, which likely underlies the adaptation of this European honeybee subspecies in the north hemisphere. The availability of this new high-quality genome will foster further studies and advances on genome variation during subspeciation, honeybee breeding and comparative genomics.