Biology subjects

Perkes, A.

Publications and source records attributed to Perkes, A..

4 recordsLinked to original sources

bioRxiv2026

Group-level phenotypes are idiosyncratic yet unpredictable over development in a clonal fish

Behavioral differences among groups can have profound impacts on individual fitness, yet how group-level phenotypes arise and change during development is poorly understood. Group-level differences may originate from genetic differences or subtle variation among individuals, but they can also emerge over time through social feedback mechanisms within and between groups, potentially producing dramatically different group-level behavior. Disentangling these drivers of group phenotypes is challenging because groups are typically studied after they are already well established. Using the naturally clonal Amazon molly, we establish replicate groups of genetically identical individuals and continuously track group-level behavior from birth throughout the first 55 days of life. This design allows us to control for genetic and environmental sources of variance, thereby establishing a null baseline for group-level differences. Furthermore, by recording over an extended period beginning from day 1 of life, we test whether group phenotypes follow predictable trajectories driven by individual differences or instead diverge due to social feedback during development. We find that average behavioral changes across groups follow predictable patterns during this early developmental phase. In contrast, differences among groups are highly unstable over longer timescales: although groups differ from very early in life, it appears that the rank-order of group-level phenotypes undergoes a shuffling mid-development, around 4-5 weeks of age. These results suggest that distinct processes generate group-level variation across ontogeny, with early differences largely reflecting consistent individual variation; then as individuals mature and become more socially responsive, social feedbacks push groups along divergent, less predictable behavioral trajectories.

animal behavior and cognition↗

bioRxiv2023

Bayesian updating for self-assessment explains social dominance and the winner effect

In animal contests, winners of previous contests often keep winning and losers keep losing. This coupling of previous experiences to future success, referred to as the winner-loser effect, plays a key role in stabilizing the resulting dominance hierarchies. Despite their importance, the cognitive mechanisms through which these effects occur are unknown. Identifying the mechanisms behind winner-loser effects requires identifying plausible models and generating predictions that can be used to test these alternative hypotheses. Winner-loser effects are often accompanied by a change in the aggressiveness of experienced individuals, which suggests individuals may be adjusting their self-assessment of their abilities after each contest. This updating of a prior estimate can be effectively described by Bayesian updating, and here we implement an agent-based model with continuous Bayesian updating to explore whether this is a plausible explanation of winner-loser effects. We first show that Bayesian updating reproduces known empirical results of typical dominance interactions. We then provide a series of testable predictions that can be used in future empirical work to distinguish Bayesian updating from simpler mechanisms. Our work demonstrates the utility of Bayesian updating as a mechanism to explain and ultimately predict changes in behaviour after salient social experiences.

animal behavior and cognition↗

bioRxiv2021

Cohesion in male singing behavior predicts group reproductive output in a social songbird

All social groups require organization to function optimally. Group organization is often shaped by social rules, which function to manage conflict, discourage cheating, or promote cooperation1-5. If social rules promote effective social living, then the ability to learn and follow these rules may be expected to influence individual and group-level fitness. However, such links can rarely be tested, due to the complexity of the factors mediating social systems and the difficulty of gathering data across multiple groups. Songbirds offer an opportunity to investigate the link between social rules and reproductive output because most of their social interactions are mediated by song, a well-studied and readily quantifiable behavior6,7. Using observations from 19 groups of brown-headed cowbirds (Molothrus ater) studied across 15 years, we find evidence for a previously undocumented social rule: cohesive group transitions between dominance- and courtship-related singing. Comparing across groups, the degree of cohesion in male singing behavior predicts the reproductive output of their group. Experimental manipulation of group structure via the introduction of juvenile males to captive flocks reduced group cohesion and adult male reproductive success. Taken together, these results demonstrate that cohesion in group behavioral states can affect both individual and group-level reproductive success, suggesting that selection can act not only on individual-level traits, but also on an individuals ability and opportunity to participate effectively in organized social interactions. Social cohesion could therefore be an unappreciated force affecting social evolution in many diverse systems.

evolutionary biology↗

bioRxiv2021

Variation in female songbird state determines signal state needed to evoke copulation

Female preferences for male signals largely determine courtship success. In most songbirds, females control reproduction via the copulation solicitation display (CSD), an innate, stereotyped posture produced in direct response to male displays. In some species, CSD can be elicited under controlled experimental conditions, allowing CSD production to be used as a bioassay for the underlying mechanics of courtship, however historically our ability to measure variability in CSD was limited. Using computer vision approaches to precisely quantify the trajectory of CSD in female brown-headed cowbirds (Molothrus ater), we show that song potency (how often a song elicits CSD) and female responsivity (how likely a female is to produce CSD) each predict whether a female produces CSD in response to a given presentation. Within elicited CSD, potency and responsivity also predict the duration and onset latency of the displays. By modeling and testing two alternative hypotheses of preference formation, we show that changes in response rates are consistent with a shifting receiver response threshold, suggesting that the song quality required to evoke the copulatory posture in a particular female will vary over time. These results establish a novel framework for exploring CSD and emphasize the importance of the internal state of receivers in determining behavioral responses and suggest that female responsivity acts in conjunction with male signal strength to determine the efficacy of male courtship signaling.

animal behavior and cognition↗