A Natural Experiment Untangling the Roles of Geography and Diet on Seed Beetle Speciation
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Description
Half of the world’s multicellular diversity is found within plant-insect interactions. One possible explanation for this diversity is that certain insect and plant lineages are driven by intricate coevolutionary relationships. This evolutionary ‘arms race’ often leads to specialization and subsequent speciation within many insect taxa. Seed beetles impose a particularly intense selective pressure on plants by directly consuming plant offspring, contributing to widespread specialization between seed beetle species and specific host plants. Thus, it is highly unusual to come across seed beetles that are considered relative generalists. The Great Plains seed beetle, Acanthoscelides fraterculus, presents a mystery as it has been reared from host plants across diverse genera. To determine whether A. fraterculus is a true generalist or is actually composed of many specialist populations (or even species), I conducted a natural experiment to untangle the geographic and coevolutionary influences that drive specialization. I compared the phenotypic and genotypic variation across A. fraterculus populations to resolve whether its population structure is defined by locality or host-associated coevolution. Results from this experiment will provide insights into the mechanisms driving the coevolution of phytophagous insects, which can contribute to understanding large scale community structuring and the formation of life’s diversity.
A Natural Experiment Untangling the Roles of Geography and Diet on Seed Beetle Speciation
Half of the world’s multicellular diversity is found within plant-insect interactions. One possible explanation for this diversity is that certain insect and plant lineages are driven by intricate coevolutionary relationships. This evolutionary ‘arms race’ often leads to specialization and subsequent speciation within many insect taxa. Seed beetles impose a particularly intense selective pressure on plants by directly consuming plant offspring, contributing to widespread specialization between seed beetle species and specific host plants. Thus, it is highly unusual to come across seed beetles that are considered relative generalists. The Great Plains seed beetle, Acanthoscelides fraterculus, presents a mystery as it has been reared from host plants across diverse genera. To determine whether A. fraterculus is a true generalist or is actually composed of many specialist populations (or even species), I conducted a natural experiment to untangle the geographic and coevolutionary influences that drive specialization. I compared the phenotypic and genotypic variation across A. fraterculus populations to resolve whether its population structure is defined by locality or host-associated coevolution. Results from this experiment will provide insights into the mechanisms driving the coevolution of phytophagous insects, which can contribute to understanding large scale community structuring and the formation of life’s diversity.