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1. Lévy movements and a slowly decaying memory allow efficient collective learning in groups of interacting foragers

   https://doi.org/10.1371/journal.pcbi.1011528  

   Falcón-Cortés, Andrea; Boyer, Denis; Aldana, Maximino; Ramos-Fernández, Gabriel (October 2023, PLOS Computational Biology)

   Martinez-Garcia, Ricardo (Ed.)

   Many animal species benefit from spatial learning to adapt their foraging movements to the distribution of resources. Learning involves the collection, storage and retrieval of information, and depends on both the random search strategies employed and the memory capacities of the individual. For animals living in social groups, spatial learning can be further enhanced by information transfer among group members. However, how individual behavior affects the emergence of collective states of learning is still poorly understood. Here, with the help of a spatially explicit agent-based model where individuals transfer information to their peers, we analyze the effects on the use of resources of varying memory capacities in combination with different exploration strategies, such as ordinary random walks and Lévy flights. We find that individual Lévy displacements associated with a slow memory decay lead to a very rapid collective response, a high group cohesion and to an optimal exploitation of the best resource patches in static but complex environments, even when the interaction rate among individuals is low. 

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2. Roadside Dining: The Collective Movement Behavior of Sulawesi Moor Macaques in a Provisioning Context

   https://doi.org/10.1002/ajp.23727  

   Trinidad, Joshua; Scharf, Henry R; Ngakan, Putu Oka; Riley, Erin P (January 2025, American Journal of Primatology)

   ABSTRACT How group‐living primates come to a consensus about navigating their environment is a result of their decision‐making processes. Although decision‐making has been examined in several primate taxa, it remains underexplored for primates living in anthropogenic landscapes. To shed light on consensus decision‐making and flexibility in this process, we examined collective movement behavior in a group of wild moor macaques (Macaca maura) experiencing a risk‐reward tradeoff as a result of roadside provisioning within Bantimurung Bulusaraung National Park in South Sulawesi, Indonesia. Our goal was to determine whether individual characteristics (e.g., sex, dominance rank, and/or social network centrality) predict the likelihood of initiating a collective movement and if the opportunity to receive food provisions along the road alters these patterns. Using the all‐occurrences method, we recorded the location, time, and identity of initiators and followers of each collective movement observed from April to June 2023 (N = 61). We used conditional logistic regression models to examine which individual characteristics predicted initiation overall and based on two destination categories: forest‐ and road‐directed collective movements. Initiation was distributed amongst most of the group, indicating a partially‐shared decision‐making style. Overall, adult males were more likely to initiate collective movements than adult females. However, for collective movements directed toward the risky roadside, dominance, rather than sex, was a better predictor of initiation, with higher ranked individuals being more likely to initiate collective movements. Examining the decision‐making processes in this species through collective movements can provide insight into how primates come to a consensus and the extent to which anthropogenic factors shape these processes. By shedding light on how moor macaques navigate the risk‐reward tradeoff at this site, our results can also inform the management of human‐macaque interfaces. 

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3. Social convergence of gut microbiomes in vampire bats

   https://doi.org/10.1098/rsbl.2021.0389  

   Yarlagadda, Karthik; Razik, Imran; Malhi, Ripan S.; Carter, Gerald G. (November 2021, Biology Letters)

   The ‘social microbiome’ can fundamentally shape the costs and benefits of group-living, but understanding social transmission of microbes in free-living animals is challenging due to confounding effects of kinship and shared environments (e.g. highly associated individuals often share the same spaces, food and water). Here, we report evidence for convergence towards a social microbiome among introduced common vampire bats, Desmodus rotundus , a highly social species in which adults feed only on blood, and engage in both mouth-to-body allogrooming and mouth-to-mouth regurgitated food sharing. Shotgun sequencing of samples from six zoos in the USA, 15 wild-caught bats from a colony in Belize and 31 bats from three colonies in Panama showed that faecal microbiomes were more similar within colonies than between colonies. To assess microbial transmission, we created an experimentally merged group of the Panama bats from the three distant sites by housing these bats together for four months. In this merged colony, we found evidence that dyadic gut microbiome similarity increased with both clustering and oral contact, leading to microbiome convergence among introduced bats. Our findings demonstrate that social interactions shape microbiome similarity even when controlling for past social history, kinship, environment and diet. 

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4. Habitat use and seed removal by invasive rats ( Rattus rattus ) in disturbed and undisturbed rain forest, Puerto Rico

   https://doi.org/10.1111/btp.12640  

   Shiels, Aaron B.; Ramírez de Arellano, Gabriela E. (March 2019, Biotropica)

   Abstract Despite frequent occurrences of invasive rats (Rattusspp.) on islands, their known effects on forests are limited. Where invasive rats have been studied, they generally have significant negative impacts on native plants, birds, and other animals. This study aimed to determine invasive rat distribution and effects on native plant populations via short‐term seed removal trials in tropical rain forest habitats in the Luquillo Experimental Forest, Puerto Rico. To address the first objective, we used tracking tunnels (inked and baited cards inside tunnels enabling animal visitors’ footprints to be identified) placed on the ground and in the lower canopy within disturbed (treefall gaps, hurricane plots, stream edges) and undisturbed (continuous forest) habitats. We found that rats are present in all habitats tested. Secondly, we compared seed removal of four native tree species (Guarea guidonia,Buchenavia capitata, Tetragastris balsamifera,andPrestoea acuminata) between vertebrate‐excluded and free‐access treatments in the same disturbed and undisturbed habitats. Trail cameras were used to identify animals responsible for seed contact and removal. Black rats (Rattus rattus) were responsible for 65.1% of the interactions with seeds, of which 28.6% were confirmed seed removals. Two plant species had significantly more seeds removed in disturbed (gaps) than undisturbed forest.Prestoea acuminatahad the lowest seed removal (9% in 10 days), whereas all other species had >30% removal. Black rats are likely influencing fates of seeds on the forest floor, and possibly forest community composition, through dispersal or predation. Further understanding of rat–plant interactions may be useful for formulating conservation strategies. 

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5. Evolutionary Transitions of Parasites between Freshwater and Marine Environments

   https://doi.org/10.1093/icb/icac050  

   Okamura, Beth; Gruhl, Alexander; De Baets, Kenneth (May 2022, Integrative and Comparative Biology)

   Abstract Evolutionary transitions of organisms between environments have long fascinated biologists, but attention has been focused almost exclusively on free-living organisms and challenges to achieve such transitions. This bias requires addressing because parasites are a major component of biodiversity. We address this imbalance by focusing on transitions of parasitic animals between marine and freshwater environments. We highlight parasite traits and processes that may influence transition likelihood (e.g., transmission mode, life cycle, host use), and consider mechanisms and directions of transitions. Evidence for transitions in deep time and at present are described, and transitions in our changing world are considered. We propose that environmental transitions may be facilitated for endoparasites because hosts reduce exposure to physiologically challenging environments and argue that adoption of an endoparasitic lifestyle entails an equivalent transitioning process as organisms switch from living in one environment (e.g., freshwater, seawater, or air) to living symbiotically within hosts. Environmental transitions of parasites have repeatedly resulted in novel forms and diversification, contributing to the tree of life. Recognizing the potential processes underlying present-day and future environmental transitions is crucial in view of our changing world and the current biodiversity crisis. 

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