DISSERTATION RESEARCH: The phylogenetic consequences of mutualism and antagonism in the coevolution of palm flower weevils.

Harvard University, Cambridge MA

Investigators

Abstract

Palms are widely distributed throughout the tropics and subtropics, and many of them produce massive floral displays that attract dozens of insect species. These insects interact with the plants that they visit in different ways. Some are pollinators and beneficial to the plant, while others feed on seeds and flowers. Still other insects are visitors that have little impact on the survival and reproductive success of the plant. A very common group of visitors to palm flowers belong to a family of beetles known as weevils. Weevils are incredibly diverse, with around 60,000 species already described and many more still unknown to science. This project will test ideas about how different kinds of insect-plant interactions, beneficial, harmful or otherwise, may affect the evolution of these herbivore insects. A wealth of data will be generated on the diversity and natural history of weevils associated with the Queen palm genus, Syagrus, which includes the several palms widely used for landscaping in tropical and subtropical areas. Results from the research will be disseminated in technical articles, and also in formats broadly accessible to the general public. Finally, undergraduate and graduate students will be trained in diverse molecular techniques for studying insect evolution. The palm genus Syagrus has over 50 species distributed throughout South America. Following a comprehensive survey of weevils associated with nearly 70% of the species of Syagrus, this study will use target enrichment and high-throughput DNA sequencing methods to obtain dozens of molecular markers across ~300 weevil species and reliably estimate the phylogeny of the group. The resulting phylogeny will be used to infer when this group diversified and the influence of insect-host interactions on diversification. By combining information on weevil and plant phylogenetic histories, and mode of interaction between each species of weevil and its host plant, this study aims to address how palm weevils are related to each other, whether antagonistic weevils are more specialized than mutualistic one, and whether the phylogeny of mutualistic weevils matches the phylogeny of their hosts more closely than the phylogeny of antagonistic weevils.