Biology subjects

Gil, M. A.

Publications and source records attributed to Gil, M. A..

5 recordsLinked to original sources

bioRxiv2026

Collective behavior drives diversification across the tree of ray-finned fishes

Trait evolution and lineage diversification are thought to be driven by selection on the phenotypes of individuals. However, many important phenotypes are only manifested when individuals interact. Collective behavior is one such phenotype. During collective behavior, interactions among individuals lead to emergent group-level phenotypes that can govern individual fitness. Yet, whether collective behaviors exhibit similar patterns of trait evolution to individual traits and whether these group phenotypes have influenced macroevolutionary diversification is unknown. In ray-finned fishes, the most species-rich of all vertebrate classes, many species exhibit striking displays of collective behavior in the form of collective movement. Here, we use state-of-the-art machine learning methods for text and image analysis to quantify collective movement phenotypes for 2,839 Actinopterygian fishes, comprising nearly 10% of all extant species. We find that collective movement is highly evolutionarily stable in some clades and extremely labile in others, exhibiting over 300 evolutionary transitions. Consistent with theoretical predictions, collective movement is associated with more patchy diets and higher predation pressure. Finally, we find that the evolution of collective movement coincides with an increase in net macroevolutionary diversification rate. Our analyses reveal that collective behavior is deeply intertwined with ecological and evolutionary dynamics across a vast phylogenetic scale, unlocking new questions about the role of collective phenotypes in shaping the diversity of life on Earth. SignificanceCollective behavior is thought to contribute to the fitness of individuals that live in groups, but we still do not understand why some species exhibit collective behavior and others do not. We developed machine learning methods to quantify collective phenotypes for thousands of species spanning the phylogeny of ray-finned fishes and found collective behavior to be widespread and consistently correlated with experiencing higher predation pressure and foraging for grouping prey. Lineages that evolve collective movement show a higher net diversification rate. Our results illustrate that collective behavior is foundational to the broad-scale patterns of evolution and diversification in the largest vertebrate class.

evolutionary biology↗

bioRxiv2026

Collective learning and manifold behaviors in predator groups

Collective foraging in animal groups often relies on behavioral diversity, with individuals adopting different, sometimes complementary roles during shared tasks. However, most theoretical models predict that individuals responding to similar information cues in a shared environment should converge on a single optimal behavioral strategy. Using a spatially explicit multi-agent deep reinforcement learning model embedded in a three-species food chain, we show that stable behavioral diversity can emerge spontaneously among initially naive agents. Rather than converging on a single optimum, agents differentiate along a low-dimensional manifold of sensorimotor control, reflecting tradeoffs in speed regulation, spatial exploration, and deterministic turning rules. While multiple strategies yield comparable individual energetic returns, they are not interchangeable; group performance depends on how specific strategies combine to produce spatial resource partitioning and distributed directional influence. Replacing co-learned individuals with similarly competent agents trained in other groups disrupts these interaction structures and strongly reduces total energy acquisition. These results demonstrate that coordinated collective behavior and diverse, compatible strategies can arise endogenously from shared learning histories, but that this form of collective performance is path dependent and may be fragile to changes in group composition.

ecology↗

bioRxiv2024

Behavioral plasticity and the valence of indirect interactions

Behavioral plasticity in animals influences direct species interactions, but its effects can also spread unpredictably through ecological networks, creating indirect interactions that are difficult to anticipate. We use coarse-grained models to investigate how changes in species behavior shape these indirect interactions and influence the broader dynamics of ecological networks. As an illustrative example, we examine predators that feed on two types of prey, each of which temporarily reduces activity after evading an attack, thereby lowering vulnerability at the expense of growth. We demonstrate that this routine behavior can shift the indirect interaction between prey species from apparent competition to mutualism or parasitism. These shifts occur when predator capture efficiency drops below a critical threshold, causing frequent hunting failures. As a result, one prey species indirectly promotes the growth of the other by relaxing its density dependence through a cascade of network effects, paradoxically increasing predator biomass despite decreased hunting success. Empirical capture probabilities often fall within the range where such dynamics are predicted. We characterize these shifts in the qualitative nature of species interactions as changes in interaction valence, highlighting how routine animal behaviors reshape community structure through cascading changes within ecological networks.

ecology↗

bioRxiv2022

Wild animals suppress the spread of socially-transmitted misinformation

Understanding the mechanisms by which information and misinformation spread through groups of individual actors is essential to the prediction of phenomena ranging from coordinated group behaviours [1-3] to global misinformation epidemics [4-7]. Transmission of information through groups depends on the decision-making strategies individuals use to transform the perceived actions of others into their own behavioural actions [8-10]. Because it is often not possible to directly infer these strategies in situ, most studies of behavioural spread in groups assume individuals make decisions by pooling [7, 8, 10, 11] or averaging [8, 9] the actions or behavioural states of neighbours. Whether individuals adopt more sophisticated strategies that exploit socially-transmitted information, while remaining robust to misinformation exposure, is unknown. Here we uncover the impacts of individual decision-making on misinformation spread in natural groups of wild coral reef fish, where misinformation occurs in the form of false alarms that can spread contagiously. Using automated tracking and visual field reconstruction, we infer the precise sequences of socially-transmitted stimuli perceived by each individual during decision-making. Our analysis reveals a novel feature of decision-making essential for controlling misinformation spread: dynamic adjustments in sensitivity to socially-transmitted cues. We find that this property can be achieved by a simple and biologically widespread decision-making circuit. This form of dynamic gain control makes individual behaviour robust to natural fluctuations in misinformation exposure, and radically alters misinformation spread relative to predictions of widely-used models of social contagion.

ecology↗

bioRxiv2019

Social information drives ecological outcomes among competing species

Through its behavior, an organism intentionally or unintentionally produces information. Use of this social information by surrounding conspecifics or heterospecifics is a ubiquitous phenomenon that can drive strong correlations in fitness-associated behaviors, such as predator avoidance, enhancing survival within and among competing species. By eliciting indirect positive interactions between competing individuals or species, social information might alter overall competitive outcomes. To test this potential, we present new theory that quantifies the effect of social information, modeled as predator avoidance signals/cues, on the outcomes from intraspecific and interspecific competition. Our analytical and numerical results reveal that social information can rescue populations from extinction and can shift the long-term outcome of competitive interactions from mutual exclusion to coexistence, or vice versa, depending on the relative strengths of intraspecific and interspecific social information and competition. Our findings highlight the importance of social information in determining ecological outcomes.

ecology↗