Temporal variation in genetic composition of migratory Helicoverpa zea in peripheral populations

Authors: Perera, Omaththage; FESCEMYER, HOWARD - PENNSYLVANIA STATE UNIVERSITY; FLEISCHER, SHELBY - PENNSYLVANIA STATE UNIVERSITY; Abel, Craig

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2020
Publication Date: 7/23/2020
Citation: Perera, O.P., Fescemyer, H.W., Fleischer, S.J., Abel, C.A. 2020. Temporal variation in genetic composition of migratory Helicoverpa zea in peripheral populations. Insects. 2020(11):463. https://doi.org/10.3390/insects11080463.
DOI: https://doi.org/10.3390/insects11080463

Interpretive Summary: Genetic composition of migrant populations of bollworm (Helicoverpa zea (Boddie)) captured using pheromone traps during 2002, 2005, 2016, and 2018 from Landisville and Rocksprings in Pennsylvania, USA were studied using markers. A total of 702 insects were divided into 16 putative populations based on collection time and site. Statistical genetic analysis of indicated high genetic diversity and low genetic divergence was found in 2002 and 2005 populations. Although high genetic divergence was observed in 2018 populations between two sites, no evidence for divergence was detected in comparisons among collection sites. The shift in genetic composition of H. zea population in 2018 may be influenced by factors including migration patterns, gene flow, environment, and host plant availability. Further assessment of peripheral populations of H. zea will be needed to assess the impacts of genetic changes on resistance management tactics.

Technical Abstract: Migrant populations of Helicoverpa zea (Boddie) captured during 2002, 2005, 2016, and 2018 from Landisville and Rock Springs in Pennsylvania, USA were genotyped using 85 single nucleotide polymorphism (SNP) markers. Samples (n = 702) genotyped were divided into 16 putative populations based on collection time and site. Fixation indices (F-statistics), analysis of molecular variance, and discriminant analysis of principal components were used to examine within and among population genetic variation. The observed and expected heterozygosity in putative populations ranged from 0.317–0.418 and 0.320–0.359, respectively. Broad range of FST (0.0–0.2742) and FIS (0.0–0.2330) values indicated different genotype frequencies between and within the populations, respectively. High genetic diversity within and low genetic differentiation between populations was found in 2002 and 2005. Interestingly, high genetic differentiation between populations from two collection sites observed in 2018 populations was not evident in within-site comparisons of putative populations collected on different dates during the season. The shift of H. zea population genetic makeup in 2018 may be influenced by multiple biotic and abiotic factors including tropical storms. Continued assessment of these peripheral populations of H. zea will be needed to assess the impacts of genetic changes on pest control and resistance management tactics.