Agriculture as a Co-Evolutionary Process
Richard Gawne, 2017 - 2018, Fellow Postdoctoral
It can be easy to forget that agriculture isn’t a uniquely human accomplishment. Various species of ants, bees, beetles, and termites maintain fungus gardens that are used as a primary food source. This means that in order to develop a truly general hypothesis about the origins or consequences of agriculture, we need to take human and insect systems into account. A review of the published literature from both of these fields reveals that research on the evolution of agricultural arrangements has been conducted almost exclusively from the perspective of the farmers, who are simply assumed to be ‘in charge’ of things. Accordingly, many have asked how the process of domestication affects the organisms being tended, but few have attempted to determine how partnering with a plant, animal, or fungus affects the evolutionary trajectory of the farmers. The driving rationale of the proposed project is that agriculture should be studied as a co-evolutionary process that elicits significant changes in both farmers and cultivars. It is well known that the brain sizes of human-domesticated animals tend to be reduced, compared to their wild progenitors. My first objective is to measure the ways in which entering into an agricultural relationship with fungi has impacted the brains of insect farmers. Normalizing for factors such as colony size, physical caste differentiation, and number, the prediction is that fungus-farming attine ants will show overall or region-specific reductions in brain size, compared to closely related hunter-gatherer species. On a more general level, the proposed project aims to shed new light on the origin of obligate multicellularity, castebased eusociality, and the other major transitions in evolution. Like some agricultural arrangements, transitional events involve an obligate dependence between formerly independent entities, driven by functional trait losses. I plan to use data on domestication to construct a predictive mathematical model that will allow us to make sense of the causes and consequences of trait losses, and identify the ‘point of no return’ that makes the formerly facultative partnership obligate.