Population genomics and phylogeography of the boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), in the United States, northern Mexico, and Argentina

Authors: RASZICK, TYLER - Texas A&M University; DICKENS, MICHAEL - Texas A&M University; Perkin, Lindsey; TESSNOW, ASHLEY - Texas A&M University; Suh, Charles; RUIZ-ARCE, RAUL - Animal And Plant Health Inspection Services (APHIS), National Wildlife Center; BORATYNSKI, THEODORE - Animal And Plant Health Inspection Services (APHIS), National Wildlife Center; FALCO, MARCELO - Agricultural Education School No 13; JOHNSTON, J - Texas A&M University; SWORD, GREGORY - Texas A&M University

Submitted to: Molecular Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2021
Publication Date: 4/1/2021
Citation: Raszick, T.J., Dickens, M., Perkin, L.C., Tessnow, A., Suh, C.P., Ruiz-Arce, R., Boratynski, T.N., Falco, M.R., Johnston, J.S., Sword, G.A. 2021. Population genomics and phylogeography of the boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), in the United States, northern Mexico, and Argentina. Molecular Ecology. 14(7):1778-1793. https://doi.org/10.1111/eva.13238.
DOI: https://doi.org/10.1111/eva.13238

Interpretive Summary: Despite the success of the U.S. Boll Weevil Eradication Program, boll weevil populations remaining in southern Texas and northern Mexico, and to a lesser extent, in Central and South America, continue to pose a threat to previously eradicated areas in the U.S. If an area is re-infested with boll weevils, knowledge of the geographical origin of these weevils will be critical for developing sound regulatory and management policies to prevent or minimize future re-infestations. In collaboration with Texas A&M University and USDA-APHIS, we obtained boll weevil specimens from southern Texas, northern Mexico, and Argentina, and identified hundreds of genetic markers (single nucleotide polymorphisms) that could be used to differentiate boll weevil populations based on their geographic origin. This work brings us one step closer to developing a set of diagnostic tools to determine whether a weevil captured in a trap is a boll weevil or some other weevil species, and to identify the most likely geographical source of the captured boll weevils.

Technical Abstract: Despite the success of the United States (US) Boll Weevil Eradication Program, the boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), remains a threat to cotton production in the southern US and is arguably the most important cotton pest in Central and South America. Management of this species is complicated by the existence of morphologically similar variants and re-infestations of areas where eradication had been successful. To date, no study has applied a high-throughput sequencing approach to better understand the population genetic structure of the boll weevil. Furthermore, only a single study has investigated genetic relationships between populations in North and South America. Here, we used double digest restriction site-associated DNA sequencing (ddRADseq) to resolve the population genomic structure of the boll weevil in the southern US, northern Mexico, and Argentina, test the two-form and three-form hypotheses of boll weevil variation in North America using a phylogeographic approach, and determine the relationship of the South American populations to the North. Our results supported the two-form hypothesis of boll weevil variation in North America wherein there are two major genetic lineages – one consisting of populations found geographically west of the Sierra Madre Occidental mountain range and the second consisting of populations found to the east – both are highly sub-structured across space and time. Boll weevil populations from Argentina were more closely related to the eastern lineage, suggesting a range expansion by the eastern lineage, but additional sampling across Central and South America is needed to determine a probable origin.