Molecular Diagnosis of Populational Variants of <I>Anthonomus grandis</I> (Coleoptera: Curculionidae) in North America

Abstract

The utility of the cytochrome oxidase I (COI) DNA sequence used for DNA barcoding and a Sequence Characterized Amplified Region for diagnosing boll weevil, Anthonomus grandis Boheman, variants was evaluated. Maximum likelihood analysis of COI DNA sequences from 154 weevils collected from the United States and Mexico supports previous evidence for limited gene flow between weevil populations on wild cotton and commercial cotton in northern Mexico and southern United States. The wild cotton populations represent a variant of the species called the thurberia weevil, which is not regarded as a significant pest. The 31 boll weevil COI haplotypes observed in the study form two distinct haplogroups (A and B) that are supported by five fixed nucleotide differences and a phylogenetic analysis. Although wild and commercial cotton populations are closely associated with specific haplogroups, there is not a fixed difference between the thurberia weevil variant and other populations. The Sequence Characterized Amplified Region marker generated a larger number of inconclusive results than the COI gene but also supported evidence of shared genotypes between wild and commercial cotton weevil populations. These methods provide additional markers that can assist in the identification of pest weevil populations but not definitively diagnose samples.

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

“…Managers in any growing region would be best served by a robust understanding of where genetic populations occur and what reservoirs exist that could possibly contribute to re‐infestations. Population genetic approaches have previously been effective for determining the sources of re‐infestations (Barr et al, 2013 ; Kim et al, 2006 , 2008 ). It is imperative that future studies consider the possibility that population structure can be influenced by yearly changes in habitat quality or by management and eradication programs themselves, and studies may need to be repeated to monitor for potential shifts in the population structure.…”

“…Though natural processes could certainly contribute to such temporal instability, it would be unwise to neglect the potential influence of management. (Barr et al, 2013;Kim et al, , 2008. It is imperative that future studies consider the possibility that population structure can be influenced by yearly changes in habitat quality or by management and eradication programs themselves, and studies may need to be repeated to monitor for potential shifts in the population structure.…”

“…Under this “three‐form” hypothesis, the southeastern boll weevil is described as having a geographic range stretching across the southeastern United States extending south into northern Mexico, east of the Sierra Madre Occidental mountain range, where it overlaps with the Mexican boll weevil variant; the Mexican boll weevil has a U‐shaped distribution throughout much of Mexico's lowlands, with only a slight overlap with the very limited range of the Thurberia weevil in southern Arizona and northern Sonora (Supporting Information A ). These subspecific denominations are based primarily on morphological characteristics that are notoriously unreliable and may be labile to diet (Barr et al, 2013 ; Roehrdanz, 2001 ). Combined with the overlapping ranges of the three forms, these inadequate morphological descriptions have led to inconsistent application of taxonomic status to boll weevil populations throughout the literature and can cause confusion for management.…”

Pest categorisation of Anthonomus grandis

“…The species A. grandis had previously been segregated on the basis of several adult characteristics (including morphological and behavioural traits) into three subspecies (Warner, ; Cross, ; Burke et al, ; Barr et al., ): The south‐eastern boll weevil ( Anthonomus grandis grandis ), feeding on commercial cotton, The Thurberia or Arizona wild cotton boll weevil ( Anthonomus grandis thurberiae ), feeding on Gossypium thurberi Todaro (wild cotton, also known as Gossypium thurberiae ), which could be found in southern Arizona and northern regions of Sonora, Mexico, and was not regarded as a significant pest of commercial cotton, and The Mexican boll weevil, an intermediate form found on Gossypium hirsutum and different wild hosts including Gossypium davidsonii Kell, Gossypium barbadense L., Hampea rovirosae Standley and also G. thurberi . …”

Estrategias de control del picudo del algodón ( Anthonomus grandis Boheman) en el Caribe Colombiano: Un modelo conceptual.

“…Tres subespecies o poblaciones de A. grandis son identificadas : grandis, thurberiae e intermedia . (Alvarado et al 2017;Barr et al 2013;Kuester et al 2012;Roehrdanz 2001;Warner 1966;Werner 1960) .…”