Molecular data confirms the rediscovery of the greater chestnut weevil (Curculio caryatrypes) in Pennsylvania and Virginia

Monday, November 11, 2024

8:36 AM – 8:48 AM MST

Location: Phoenix Convention Center, 224 B, PCC

Presenting Author(s)

MC

Michael Alexander Charles (he/him/his)

PhD Candidate
University of Memphis
Collierville, Tennessee

Co-Author(s)

DM

Duane D. McKenna

Professor
University of Memphis
Memphis, Tennessee

The introduction of invasive fungal pathogens led to the 20^th-century functional extinction of the American chestnut (Castanea dentata) and the decline or extinction of several of it specialized insect associates. Last collected in 1997, the greater chestnut weevil (Curculio caryatrypes), the largest species of acorn weevil in North America, and a host-specialist on American chestnut, has been presumed extinct for nearly 3 decades. However, photos posted on social media in 2022 and 2023 suggested the persistence of the weevil in at least two localities. Because the photos came to our attention during the winter of 2023-24, at which time adults were no longer present, larvae were collected from nuts found underneath hybrid chestnut trees at both locations for rearing and two larvae from each site were used for DNA sequencing. The larval DNA sequences were compared to 11 other Curculio species, including two pinned adult specimens of the greater chestnut weevil, and two other Curculionini. In the resulting phylogeny, the four larvae of purported greater chestnut weevil formed a single clade along with historical (museum) specimens of this species with maximal bootstrap support.