Structure and evolution of host plant associations in Eustylini and Geonemini
Many broad-nosed weevils (Entiminae) are known to feed on a wide range of host plants. For instance, Diaprepes abbreviatus, a pest on citrus, are recorded to feed on >200 species of plants, making it arguably the most generalistic weevil species known to date. Knowledge of host plants of Entiminae is scattered, and when available, is not amenable to phylogenetic tests of evolutionary scenarios, due to the lack of phylogenies for most of the species in that group. Collecting information on host plant associations typically involves extended field work, not always afforded during regular collecting trips, especially those conducted abroad for a short duration (<20 days).
This project has taken a "molecular profiling" approach to investigate weevil-host plant associations, focused on species in the Geonemimini and Eustylini. Plant DNA preserved in weevil digestive tract was isolated by subjecting either a whole specimen or part of a specimen, typically the abdomen, to the process of DNA extraction. We have amplified and cloned two genes, rbcL and trnL, commonly used in molecular identification (aka DNA barcoding) of plants. More than 100 specimens representing at least 80 species have been processed as of Dec 2015 and data analyses are being performed. A weevil phylogeny based on these species is also available, by resampling and expanding data used in the Exophthalmus biogeography project.
I am specifically interested in answering these questions: (1) How many different plant species can a weevil feed on in a relatively short period of time (assuming <48 h)? (2) How are weevil host plants structure in a local community? How often do co-occurring weevils feed on the same host plant? (3) Have weevils coevolved with their host plant species? This scenario is unlikely, but little tested in a phylogenetic framework.
I am collaborating with two undergraduate student researchers on this project, Juyan Pourturk and Pavithra Paravastu.
Some preliminary results were reported in a poster (below) presented at the 2014 Annual Meeting of the Entomological Society of America.
This project has taken a "molecular profiling" approach to investigate weevil-host plant associations, focused on species in the Geonemimini and Eustylini. Plant DNA preserved in weevil digestive tract was isolated by subjecting either a whole specimen or part of a specimen, typically the abdomen, to the process of DNA extraction. We have amplified and cloned two genes, rbcL and trnL, commonly used in molecular identification (aka DNA barcoding) of plants. More than 100 specimens representing at least 80 species have been processed as of Dec 2015 and data analyses are being performed. A weevil phylogeny based on these species is also available, by resampling and expanding data used in the Exophthalmus biogeography project.
I am specifically interested in answering these questions: (1) How many different plant species can a weevil feed on in a relatively short period of time (assuming <48 h)? (2) How are weevil host plants structure in a local community? How often do co-occurring weevils feed on the same host plant? (3) Have weevils coevolved with their host plant species? This scenario is unlikely, but little tested in a phylogenetic framework.
I am collaborating with two undergraduate student researchers on this project, Juyan Pourturk and Pavithra Paravastu.
Some preliminary results were reported in a poster (below) presented at the 2014 Annual Meeting of the Entomological Society of America.