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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. Bidirectional interactions between host social behaviour and parasites arise through ecological and evolutionary processes

   https://doi.org/10.1017/S0031182020002048  

   Hawley, Dana M.; Gibson, Amanda K.; Townsend, Andrea K.; Craft, Meggan E.; Stephenson, Jessica F. (March 2021, Parasitology)

   null (Ed.)

   Abstract An animal's social behaviour both influences and changes in response to its parasites. Here we consider these bidirectional links between host social behaviours and parasite infection, both those that occur from ecological vs evolutionary processes. First, we review how social behaviours of individuals and groups influence ecological patterns of parasite transmission. We then discuss how parasite infection, in turn, can alter host social interactions by changing the behaviour of both infected and uninfected individuals. Together, these ecological feedbacks between social behaviour and parasite infection can result in important epidemiological consequences. Next, we consider the ways in which host social behaviours evolve in response to parasites, highlighting constraints that arise from the need for hosts to maintain benefits of sociality while minimizing fitness costs of parasites. Finally, we consider how host social behaviours shape the population genetic structure of parasites and the evolution of key parasite traits, such as virulence. Overall, these bidirectional relationships between host social behaviours and parasites are an important yet often underappreciated component of population-level disease dynamics and host–parasite coevolution. 

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3. Analyzing the Engagement of Social Relationships during Life Event Shocks in Social Media

   https://doi.org/10.1609/icwsm.v17i1.22134  

   Choi, Minje; Jurgens, David; Romero, Daniel M. (June 2023, Proceedings of the International AAAI Conference on Web and Social Media)

   Individuals experiencing unexpected distressing events, shocks, often rely on their social network for support. While prior work has shown how social networks respond to shocks, these studies usually treat all ties equally, despite differences in the support provided by different social relationships. Here, we conduct a computational analysis on Twitter that examines how responses to online shocks differ by the relationship type of a user dyad. We introduce a new dataset of over 13K instances of individuals' self-reporting shock events on Twitter and construct networks of relationship-labeled dyadic interactions around these events. By examining behaviors across 110K replies to shocked users in a pseudo-causal analysis, we demonstrate relationship-specific patterns in response levels and topic shifts. We also show that while well-established social dimensions of closeness such as tie strength and structural embeddedness contribute to shock responsiveness, the degree of impact is highly dependent on relationship and shock types. Our findings indicate that social relationships contain highly distinctive characteristics in network interactions, and that relationship-specific behaviors in online shock responses are unique from those of offline settings. 

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4. Gaps in Information Access in Social Networks

   https://doi.org/10.1145/3308558.3313680  

   Fish, Benjamin; Bashardoust, Ashkan; Boyd, Danah; Friedler, Sorelle; Scheidegger, Carlos; Venkatasubramanian, Suresh (January 2019, The Web Conference (WWW))

   The study of influence maximization in social networks has largely ignored disparate effects these algorithms might have on the individuals contained in the social network. Individuals may place a high value on receiving information, e.g. job openings or advertisements for loans. While well-connected individuals at the center of the network are likely to receive the information that is being distributed through the network, poorly connected individuals are systematically less likely to receive the information, producing a gap in access to the information between individuals. In this work, we study how best to spread information in a social network while minimizing this access gap. We propose to use the maximin social welfare function as an objective function, where we maximize the minimum probability of receiving the information under an intervention. We prove that in this setting this welfare function constrains the access gap whereas maximizing the expected number of nodes reached does not. We also investigate the difficulties of using the maximin, and present hardness results and analysis for standard greedy strategies. Finally, we investigate practical ways of optimizing for the maximin, and give empirical evidence that a simple greedy-based strategy works well in practice. 

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5. Exploring the Factors Underlying Adaptive Social Plasticity in Foragers Using an Agent-Based Model

   https://doi.org/10.1093/icb/icaf126  

   Prasher, Sanjay; Hobson, Elizabeth_A (July 2025, Integrative And Comparative Biology)

   Synopsis Recent studies in group-living species suggest that being a valuable group member (a source of information or other resources) should increase social connectedness. This is because individuals may recognize and associate more with valuable individuals to increase the chances of benefiting from their activity, a process we refer to here as adaptive social plasticity. However, it is still unclear what minimum cognitive abilities are required for animals to alter their social interactions based on the value provided by different group members. We varied the cognitive skills of individuals in an agent-based model and evaluated changes in how access to a food resource impacts an informed agent's social connectedness. We modeled a social foraging scenario in an arena with one food patch, which only one informed individual (i.e., producer) can make accessible. Agents’ movement decisions were driven by three cognitive-based parameters: attention (probability of perceiving successful foragers), preference (probability of following successful foragers), and memory (number of time steps a successful forager was remembered). To understand what combination of these parameters may facilitate adaptive social plasticity, we compared the producer's strength (number of interactions) in a proximity network and the foraging success of non-producers between simulations with different combinations of parameter values. We found that non-zero values of each of our parameters are necessary for increases in producer strength and non-producer foraging success to occur. The largest increases in producer strength were seen at intermediate memory values and high values of attention and preference. Unless foragers were programmed to be able to move directly to the food patch when it was accessible to them, a non-zero value of memory was needed for them to experience an increase in foraging success. Furthermore, relationships between attention, memory, and foraging success were influenced by preference values, with the highest foraging success achieved at low to intermediate values of preference. Our results highlight the necessity of certain cognitive skills for animals to take advantage of the foraging success of their group mates, and scenarios in which rigid following behavior may lead to less beneficial results for foragers. This model lays the groundwork for further investigations into the cognitive and environmental factors expected to influence a feedback process between social connections and the value provided and received by group members. 

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