Resolving the drivers of variation in cooperative social groups along environmental gradients

Environmental variation is thought to affect the evolution of cooperative social groups in nature, but it is not always clear why. Social groups may help individuals buffer the effects of environmental challenges in some species, while other groups may form because benign environments allow individuals to tolerate each other when there are enough resources to go around.

This project makes use of within-species variation in social groups of Australian birds across environmental gradients to better understand the relationship between environment and social groups, and how differences between species in these relationships relate to their underlying cooperative social behavior. By integrating theory, citizen science, and detailed field experiments, this project will reveal how and why some species confront environmental challenges by helping each other in groups, while other species confront the same challenges by breaking those groups apart.

The project will use social media platforms to engage participants, addressing their questions and sharing research outcomes. This will allow participants to be directly involved in the direction of future research, a key way to link the experience of participating in citizen science projects with learning. Further, the data generated from this study will be used in K-12 classrooms to help students understand topics both related to and beyond biology by linking trait variation to the environment and geographic space through a partnership with Galactic Polymath Education Studio.

This project develops an ecogeographic approach to understand the processes that generate within- and across-species variation in structure of cooperative social groups across environmental gradients. Such an integration of ecogeographic patterns across two levels of biological organization will provide new information about how cooperative groups evolve.

This approach can simultaneously address whether social systems respond to environmental gradients and why species may respond differently from one another. This will be accomplished through three aims: 1) developing a theoretical framework for understanding how environmental effects on social dynamics may generate variation in group structure across environmental gradients, 2) examining ecogeographic patterns in social groups size across several species through the use a cross-continental citizen science dataset on Australian fairywrens (Aves, Maluridae), and 3) explicitly linking disparate patterns of variation to changes in fitness and behavior through observational and experimental studies in two specific species .

This work will extend social evolution theory on group conflict to predict the consequences for group size and behavior along environmental gradients. Additionally, use of citizen science data on within-species variation in social systems will address how interacting factors, such as temperature, rainfall, or land use might decouple patterns of environment-group size variation.

Finally planned field experiments will allow the testing of the role of social conflict in generating such patterns. This proposed method of integrating intraspecific and interspecific patterns will contribute to further development of ecogeographic theory generally.

This project is jointly funded by the Behavioral Systems Cluster (BSC) and the Established Program to Stimulate Competitive Research (EPSCoR).

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.