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1. Social foraging in vampire bats is predicted by long-term cooperative relationships

   https://doi.org/10.1371/journal.pbio.3001366  

   Ripperger, Simon P.; Carter, Gerald G. (September 2021, PLOS Biology)

   Hobaiter, Catherine (Ed.)

   Stable social bonds in group-living animals can provide greater access to food. A striking example is that female vampire bats often regurgitate blood to socially bonded kin and nonkin that failed in their nightly hunt. Food-sharing relationships form via preferred associations and social grooming within roosts. However, it remains unclear whether these cooperative relationships extend beyond the roost. To evaluate if long-term cooperative relationships in vampire bats play a role in foraging, we tested if foraging encounters measured by proximity sensors could be explained by wild roosting proximity, kinship, or rates of co-feeding, social grooming, and food sharing during 21 months in captivity. We assessed evidence for 6 hypothetical scenarios of social foraging, ranging from individual to collective hunting. We found that closely bonded female vampire bats departed their roost separately, but often reunited far outside the roost. Repeating foraging encounters were predicted by within-roost association and histories of cooperation in captivity, even when accounting for kinship. Foraging bats demonstrated both affiliative and competitive interactions with different social calls linked to each interaction type. We suggest that social foraging could have implications for social evolution if “local” within-roost cooperation and “global” outside-roost competition enhances fitness interdependence between frequent roostmates. 

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2. Do bats use scent cues from guano and urine to find roosts?

   https://doi.org/10.26451/abc.09.01.09.2022  

   Brown, Bridget; Carter, Gerald (February 2022, Animal Behavior and Cognition)

   Selection of habitat is a key determinant of reproductive success, and the process of finding and choosing these sites is often influenced by the presence of conspecifics. Many bats frequently switch roosts, and some bats repeatedly find new roosts. To find roosts with conspecifics or group members, bats can use social cues. However, most research on how bats use social cues for roost-finding has focused on acoustic cues. Here, we review and discuss the evidence for bat roost selection using scent cues from guano and urine stains, which are present at most bat roosts. We outline reasons why bats might, or might not, use scent in roost detection and selection, and we review evidence on the possible use of guano and urine in roost-finding from eight studies with 12 bat species (across four families). Overall, the sparse evidence that exists indicates that scent cues from guano and urine are not a strong and consistent lure in the species and situations that were tested. Most studies had unclear results or found no effect. Two of the eight studies found weak experimental evidence for bats using guano or urine to select a roosting site. Even if guano and urine can indicate the presence of bats at a roost, it is possible that the resulting olfactory cues do not contain sufficient social information to be used in roost selection, in contrast to olfactory cues from scent marking. Studies of how bats use sensory cues beyond sound could contribute to a better understanding of bat social behavior and roosting ecology. 

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3. Bumble bee workers adopt novel behavioral roles and reshape their social networks in the absence of a queen

   https://doi.org/10.1101/2025.01.07.630106  

   Ruttenberg, Dee M; Wolf, Scott W; Webb, Andrew E; Wyman, Eli S; White, Michelle L; Melo, Diogo; Traniello, Ian M; Kocher, Sarah D (January 2025, bioRxiv)

   Summary Dominant individuals often structure group organization, but less is known about how social networks differ in their absence or how variation among subordinates contributes to collective outcomes. Bumble bees (Bombus impatiens) provide an ideal system to study how individual behavior shapes colony organization: queens typically monopolize reproduction, but in some contexts individual workers can adopt queen-like social roles. We asked how this process shapes the collective phenotype. Using multi-animal pose tracking to quantify social behaviors, we compared matched queenright and queenless partitions from the same source colonies. Queenless colonies were more interactive and contained a subset of behaviorally extreme queen-like workers with higher movement, spatial centrality, and reproductive potential. Such variation, absent in queenright colonies, coincided with a shift to decentralized, efficient network structures. These results demonstrate how social context shapes the expression of individual phenotypes, revealing a mechanism by which seemingly hierarchical societies can retain latent social flexibility and underscoring the link between individual variation and collective organization. 

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4. Disparate social structures are underpinned by distinct social rules across a primate radiation

   https://doi.org/10.1101/2025.07.31.667759  

   Feder, Jacob A; Alberts, Susan C; Archie, Elizabeth A; Arlet, Małgorzata E; Baniel, Alice; Beehner, Jacinta C; Bergman, Thore J; Carter, Alecia J; Charpentier, Marie_J E; Chiou, Kenneth L; et al (July 2025, bioRxiv)

   ABSTRACT Over six decades of research on wild baboons and their close relatives (collectively, the African papionins) has uncovered substantial variation in their behavior and social organization. While most papionins form discrete social groups (single-level societies), a few others form small social units nested within larger aggregations (multi-level societies). To understand the social processes that shape this variation, a more systematic, comparative analysis of social structure is needed. Here, we constructed a database of behavioral and demographic records spanning 135 group-years across 13 long-term papionin field studies to (i) quantify variation in grooming network structure, and (ii) identify the factors (e.g., sex, kinship, and social status effects) that underlie these differences. We detected considerable variation in grooming network structure across the papionins, even within the classic single-level societies. The papionins could be best divided into three broad categories: single-levelcohesive, single-levelcliquish, andmulti-level. The cohesive single-level societies formed networks that were dense, moderately kin-biased, and weakly rank-structured, while the cliquish single-level societies formed networks that were relatively modular, highly kin-biased, and more strongly rank-structured. As expected, multi-level networks were highly modular and shaped by females’ ties to specific dominant males but varied in their kin biases. Taken together, these data suggest that: (i) discrete typologies obscure variation in social structure; and (ii) similarities in social structure are sometimes, but not always, shaped by similar social processes. SIGNIFICANCE STATEMENTDo all primate groups fit the same social mold? While factors like kinship and dominance shape the social lives of many of our close relatives, it remains unclear how their effects differ across species. Using a new database representing decades of field research, we found that baboons and their close relatives fell into one of three general patterns: one in which groups were cohesive and only somewhat nepotistic (i.e., kin- and rank-biased), another in which groups were more cliquish and nepotistic, and a final pattern in which groups were divided into clusters centered on dominant males. Distinct primate societies may thus reflect differences in the strength of females’ social biases towards kin and the degree of males’ social influence. 

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5. The Ecology of Nipah Virus in Bangladesh: A Nexus of Land-Use Change and Opportunistic Feeding Behavior in Bats

   https://doi.org/10.3390/v13020169  

   McKee, Clifton D.; Islam, Ausraful; Luby, Stephen P.; Salje, Henrik; Hudson, Peter J.; Plowright, Raina K.; Gurley, Emily S. (February 2021, Viruses)

   null (Ed.)

   Nipah virus is a bat-borne paramyxovirus that produces yearly outbreaks of fatal encephalitis in Bangladesh. Understanding the ecological conditions that lead to spillover from bats to humans can assist in designing effective interventions. To investigate the current and historical processes that drive Nipah spillover in Bangladesh, we analyzed the relationship among spillover events and climatic conditions, the spatial distribution and size of Pteropus medius roosts, and patterns of land-use change in Bangladesh over the last 300 years. We found that 53% of annual variation in winter spillovers is explained by winter temperature, which may affect bat behavior, physiology, and human risk behaviors. We infer from changes in forest cover that a progressive shift in bat roosting behavior occurred over hundreds of years, producing the current system where a majority of P. medius populations are small (median of 150 bats), occupy roost sites for 10 years or more, live in areas of high human population density, and opportunistically feed on cultivated food resources—conditions that promote viral spillover. Without interventions, continuing anthropogenic pressure on bat populations similar to what has occurred in Bangladesh could result in more regular spillovers of other bat viruses, including Hendra and Ebola viruses. 

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