Explaining variation in extreme selfish behavior: Untangling the co-evolutionary relationship of cannibalism, dispersal and kin discrimination.

Selfish behavior can provide significant advantages in nature, allowing individuals to increase their survival and reproductive success at the expense of others. One of the most extreme forms of selfishness is cannibalism, where individuals consume members of their own species. While it seems highly beneficial, cannibalistic behavior varies within and across species.

This project investigates this conundrum to reveal what factors restrict cannibalism and how it co-evolves with other social behaviors. Scientists predict that behaviors like kin recognition and movement patterns may evolve alongside cannibalism to reduce its negative effects. This study will test this idea using flour beetles, a well-established model organism in evolutionary biology.

Researchers will first study natural beetle populations to measure differences in cannibalism. Then, they will conduct experiments in controlled environments to see how cannibalism, kin recognition, and movement behaviors evolve under different conditions, such as limited food availability and restricted movement. The results will provide new insights into how social behaviors evolve and why individuals within a species differ in their level of selfishness.

This project is committed to expanding opportunities for students to engage in scientific research. Undergraduate students will take part in hands-on research experiences, developing essential skills for careers in science. Additionally, the project will create educational resources for K-12 teachers, enabling students to explore evolution and behavior through interactive experiments with flour beetles.

These efforts will help introduce a wide range of students to scientific inquiry, spark interest in research, and encourage future careers in STEM fields.

This project investigates how selfish behaviors, such as cannibalism, evolve alongside kin discrimination and dispersal. Theoretical models suggest that these traits should co-evolve to mitigate the costs of extreme selfishness, yet empirical tests are limited. This study will use Tribolium confusum, a widely distributed pest species where cannibalism strongly limits population size, to combine field surveys and experimental evolution in testing key predictions about the evolution of social behaviors.

First, researchers will quantify natural variation in cannibalistic behavior within and among populations to identify the extend of natural behavioral diversity. Next, controlled experiments will manipulate dispersal constraints and genotype diversity to test how limited movement affects the co-evolution of cannibalism and kin discrimination. A second experiment will manipulate food availability to examine how environmental stress influences the evolution of selfishness and its interaction with kin recognition and dispersal.

By initiating experiments with beetle populations that vary in their natural levels of cannibalism, this study will reveal the range of evolutionary trajectories that can emerge under different ecological conditions. This research will address major gaps in understanding how selfishness and cooperation evolve by providing a direct empirical test of theoretical models.

Because the study examines fundamental evolutionary principles, its findings will be broadly relevant to other species, including those in agriculture and pest management. The results will contribute to longstanding debates in behavioral biology and significantly advance our knowledge of how complex social behaviors evolve across different environmental contexts.

This project is jointly funded by the Behavioral Systems Cluster in the Division of Integrative and Organismal Systems and the Evolutionary Processes Cluster in the Division of Environmental Biology.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.