publications

2024

1. The evolution of democratic peace in animal societies

   K. L. Hunt, M. Patel, D. P. Croft, and 6 more authors

   Nature Communications, Aug 2024

   Publisher: Nature Publishing Group

   Abs DOI

   A major goal in evolutionary biology is to elucidate common principles that drive human and other animal societies to adopt either a warlike or peaceful nature. One proposed explanation for the variation in aggression between human societies is the democratic peace hypothesis. According to this theory, autocracies are more warlike than democracies because autocratic leaders can pursue fights for private gain. However, autocratic and democratic decision-making processes are not unique to humans and are widely observed across a diverse range of non-human animal societies. We use evolutionary game theory to evaluate whether the logic of democratic peace may apply across taxa; specifically adapting the classic Hawk-Dove model to consider conflict decisions made by groups rather than individuals. We find support for the democratic peace hypothesis without mechanisms involving complex human institutions and discuss how these findings might be relevant to non-human animal societies. We suggest that the degree to which collective decisions are shared may explain variation in the intensity of intergroup conflict in nature.

2. Calculating Relatedness: A Pedigree of Definitions

   Matishalin Patel, and J. Arvid Ågren

   Cold Spring Harbor Perspectives in Biology, Oct 2024

   Publisher: Cold Spring Harbor Lab

2023

1. Animal-AI 3: What’s New & Why You Should Care

   Konstantinos Voudouris, Ibrahim Alhas, Wout Schellaert, and 9 more authors

   Dec 2023

   arXiv:2312.11414 [cs]

   Abs DOI

   The Animal-AI Environment is a unique game-based research platform designed to serve both the artificial intelligence and cognitive science research communities. In this paper, we present Animal-AI 3, the latest version of the environment, outlining several major new features that make the game more engaging for humans and more complex for AI systems. New features include interactive buttons, reward dispensers, and player notifications, as well as an overhaul of the environment’s graphics and processing for significant increases in agent training time and quality of the human player experience. We provide detailed guidance on how to build computational and behavioural experiments with Animal-AI 3. We present results from a series of agents, including the state-of-the-art Deep Reinforcement Learning agent (dreamer-v3), on newly designed tests and the Animal-AI Testbed of 900 tasks inspired by research in comparative psychology. Animal-AI 3 is designed to facilitate collaboration between the cognitive sciences and artificial intelligence. This paper serves as a stand-alone document that motivates, describes, and demonstrates Animal-AI 3 for the end user.

2022

1. Microbial warfare and the evolution of symbiosis

   Matishalin Patel, and Stuart West

   Biology Letters, Dec 2022

   Publisher: Royal Society

   Abs DOI

   Cooperative symbionts enable their hosts to exploit a diversity of environments. A low genetic diversity (high relatedness) between the symbionts within a host is thought to favour cooperation by reducing conflict within the host. However, hosts will not be favoured to transmit their symbionts (or commensals) in costly ways that increase relatedness, unless this also provides an immediate fitness benefit to the host. We suggest that conditionally expressed costly competitive traits, such as antimicrobial warfare with bacteriocins, could provide a relatively universal reason for why hosts would gain an immediate benefit from increasing the relatedness between symbionts. We theoretically test this hypothesis with a simple illustrative model that examines whether hosts should manipulate relatedness, and an individual-based simulation, where host control evolves in a structured population. We find that hosts can be favoured to manipulate relatedness, to reduce conflict between commensals via this immediate reduction in warfare. Furthermore, this manipulation evolves to extremes of high or low vertical transmission and only in a narrow range is partly vertical transmission stable.

2021

1. Teleost fish use optic flow to estimate distance travelled

   C. Karlsson, J. K. Willis, M. Patel, and 1 more author

   Communications Biology, Dec 2021

   Publisher: Springer Nature

2020

1. Kin discrimination, negative relatedness, and how to distinguish between selfishness and spite

   Matishalin Patel, Stuart A. West, and Jay M. Biernaskie

   Evolution Letters, Feb 2020

   DOI

2019

1. Uncovering the rules of microbial community invasions

   Jean C. C. Vila, Matt L. Jones, Matishalin Patel, and 2 more authors

   Nature Ecology & Evolution, Aug 2019

   Abs DOI

   Model simulations incorporating ecological and evolutionary processes uncover five general rules that describe invasions in microbial communities.

2. Crystal toxins and the volunteer’s dilemma in bacteria

   Matishalin Patel, Ben Raymond, Michael B. Bonsall, and 1 more author

   Journal of Evolutionary Biology, Aug 2019

   tex.ids= patelCrystalToxins2019a, patelCrystalToxinsVolunteer

   Abs DOI

   The growth and virulence of the bacteria Bacillus thuringiensis depend on the production of Cry toxins, which are used to perforate the gut of its host. Successful invasion of the host relies on producing a threshold amount of toxin, after which there is no benefit from producing more toxin. Consequently, the production of Cry toxin appears to be a different type of social problem compared with the public goods scenarios that bacteria usually encounter. We show that selection for toxin production is a volunteer’s dilemma. We make specific predictions that (a) selection for toxin production depends upon an interplay between the number of bacterial cells that each host ingests and the genetic relatedness between those cells; (b) cheats that do not produce toxin gain an advantage when at low frequencies, and at high bacterial density, allowing them to be maintained in a population alongside toxin-producing cells. More generally, our results emphasize the diversity of the social games that bacteria play.