Tracie M. Jenkins

Discovery and distribution of Megacopta cribraria (Hemiptera: Heteroptera: Plataspidae) in northeast Georgia

In October 2009, large aggregations of Megacopta cribraria (F.) (Heteroptera: Plataspidae) were discovered on outside, perimeter walls of houses in northeast Georgia, prompting homeowners to contact county Extension agents and pest management professionals to learn more about the insect and to rid the premises of the nuisance. The insect was flying from nearby patches of kudzu ( Pueraria spp .) onto houses, presumably in an attempt to locate overwintering sites. In its native Asia, one of its preferred hosts is kudzu, an invasive, leguminous vine that now grows throughout the southeastern U.S. Before discovery in Georgia, M. cribraria was unknown from the New World. In addition to its emergence as a nuisance pest, M. cribraria has been reported as a pest of numerous legume crops in Asia, including soybean, Glycine max Merrill . As of August 9, 2010, M. cribraria was known from 48 counties in northeast Georgia and 13 counties in northwest South Carolina. In late June and early July 2010, M. cribraria was found on soybeans in 20 of the 48 Georgia counties and five counties in South Carolina.

From Asian curiosity to eruptive American pest: Megacopta cribraria (Hemiptera: Plataspidae) and prospects for its biological control

The kudzu bug or bean plataspid, Megacopta cribraria (Fabricius), is native to Asia where it appears to be widely distributed (although the taxonomy is not entirely clear), but is infrequently a pest of legumes. This bug appeared in 2009 in the southeastern United States, where it is closely associated with kudzu, Pueraria montana Lour. [Merr.] variety lobata [Willd.] Maesen & S. Almeida. However, the insect has become a consistent economic pest of soybeans, Glycine max (L.) Merr., and some other leguminous crops in areas where large numbers can build in kudzu, in addition to being a considerable nuisance in urban landscapes where kudzu occurs. The insect has remarkable capacity for movement and has spread rapidly from nine Georgia counties in 2009 to seven states in 2012. Despite being a nuisance in urban areas and a crop pest, high populations of the bug also reduce the biomass of kudzu, which is itself a seriously problematic invasive weed, complicating the status of M. cribraria in its expanded range. Extant predators and a pathogen in the US have been observed attacking kudzu bugs in the laboratory and field, but no parasitism of eggs or nymphs has been observed to date. A single record of parasitism of an adult kudzu bug by a tachinid fly is known from the US, but no other adult parasitism has been observed in the US or elsewhere. Extant enemies may eventually significantly reduce the bug’s populations, but at present native enemies appear to be insufficient for the task, and exotic enemies from the kudzu bug’s native range may offer the best possibility for effective biological control in the US. Based on the available literature, the best option for an importation biological control program appears to be the platygastrid egg parasitoid Paratelenomus saccharalis (Dodd) because of its apparent host specificity, intimate biological linkages with M. cribraria, and wide geographic distribution in the Eastern Hemisphere. Other natural enemies may eventually emerge as good candidates for importation, but at present P. saccharalis appears to be the most promising.

Correlation of mitochondrial haplotypes with cuticular hydrocarbon phenotypes of sympatric Reticulitermes species from the southeastern United States.

Three sympatric Reticulitermes species have been identified in Georgia, USA, based on morphological characters from alates and soldiers: R. flavipes, R. virginicus, and R. hageni, but species identification at individual collection sites is often difficult because alate production is seasonal and soldiers comprise 1–3% of the colony. We therefore set up an experiment to determine if chemical phenotypes and mtDNA haplotypes can be used together to separate species of subterranean termites. Subterranean termites of the order Reticulitermes (Isoptera: Rhinotermitidae) were collected from 20 inspection ports across four soil provinces in Georgia. Each collection was identified to species using dichotomous keys. Two collections, HH11 and BH25, however, could not be unequivocally keyed to species and were classified as unknown. The mitochondrial cytochrome oxidase II (COII) gene was sequenced from individual members of each collection and the variation in cuticular hydrocarbon phenotypes from these same collections was characterized. The cuticular hydrocarbon and mtDNA phylogenetic analyses show agreement with both unknown collections falling out in a separate clade. Specimens from HH11 nad BH25 are different morphologically, chemically, and genetically from the three known sympatric species in Georgia. Our results suggest that these two collections may represent at least one new taxon in Reticulitermes. Furthermore, the association of cuticular hydrocarbon phenotypes and mtDNA haplotypes demonstrates that, when combined with morphological characters, they are useful in separating known species, determining new species, and understanding termite evolution.

Compensatory base changes illuminate morphologically difficult taxonomy

Compensatory base changes (CBCs) in the ribosomal RNA (rRNA) internal transcribed spacer 2 (ITS2) secondary structures have been used to successfully verify the taxonomy of closely related species. CBCs have never been used to distinguish morphologically indistinct species. Under the hypothesis that CBCs will differentiate species in higher eukaryotes, novel software for CBC analysis was applied to morphologically indistinguishable insect species in the genus Altica. The analysis was species-specific for sympatric Altica beetles collected across four ecoregions and concordant with scanning electron microscopy data. This research shows that mining for CBCs in ITS2 rRNA secondary structures is an effective method for eukaryotic taxon analysis.

DNA Technology, Interstate Commerce, and the Likely Origin of Formosan Subterranean Termite (Isoptera: Rhinotermitidae) Infestation in Atlanta, Georgia

Abstract This study was the first to use DNA sequencing data to infer the origin of a Formosan subterranean termite, Coptotermes formosanus Shiraki, infestation. Cytochrome oxidase II gene sequence was used to define eight specific maternal lineages from 14 geographic locations across the southeastern United States, Hawaii, and China. One maternal lineage, A, was unique to all the Atlanta collections and one New Orleans collection, which indicated that termites at these sites shared a common maternal ancestor. The impact of interstate commerce in terms of Formosan subterranean termite introductions is addressed as is the industry response needed to arrest the spread of these termites via commercial traffic in used railroad cross ties.

Discovering and verifying DNA polymorphisms in a mung bean [V. radiata (L.) R. Wilczek] collection by EcoTILLING and sequencing

BackgroundVigna radiata, which is classified in the family Fabaceae, is an important economic crop and a dietary staple in many developing countries. The species radiata can be further subdivided into varieties of which the variety sublobata is currently acknowledged as the putative progenitor of radiata. EcoTILLING was employed to identify single nucleotide polymorphisms (SNPs) and small insertions/deletions (INDELS) in a collection of Vigna radiata accessions.FindingsA total of 157 DNA polymorphisms in the collection were produced from ten primer sets when using V. radiata var. sublobata as the reference. The majority of polymorphisms detected were found in putative introns. The banding patterns varied from simple to complex as the number of DNA polymorphisms between two pooled samples increased. Numerous SNPs and INDELS ranging from 4–24 and 1–6, respectively, were detected in all fragments when pooling V. radiata var. sublobata with V. radiata var. radiata. On the other hand, when accessions of V. radiata var. radiata were mixed together and digested with CEL I relatively few SNPs and no INDELS were detected.ConclusionEcoTILLING was utilized to identify polymorphisms in a collection of mung bean, which previously showed limited molecular genetic diversity and limited morphological diversity in the flowers and pod descriptors. Overall, EcoTILLING proved to be a powerful genetic analysis tool providing the rapid identification of naturally occurring variation.

Population Genetic Baseline of the First Plataspid Stink Bug Symbiosis (Hemiptera: Heteroptera: Plataspidae) Reported in North America

The stink bug, Megacopta cribraria, has an obligate relationship with a bacterial endosymbiont which allows it to feed on legumes. The insect is a pest of soybeans in Asia and was first reported in the Western Hemisphere in October 2009 on kudzu vine, Pueraria montana, in North Georgia, USA. By October 2010 M. cribraria had been confirmed in 80 counties in Georgia actively feeding on kudzu vine and soybean plants. Since the symbiosis may support the bugs ecological expansions, a population genetic baseline for the symbiosis was developed from mitochondrial DNA (mtDNA) and nuclear DNA (nuDNA) gene sequence collected from each insect and its primary γ- proteobacterium and secondary α -proteobacterium endosymbionts. A single mitochondrial DNA haplotype was found in all insects sampled in Georgia and South Carolina identified as GA1. The GAI haplotype appears to be rapidly dispersing across Georgia and into contiguous states. Primary and secondary endosymbiont gene sequences from M. cribraria in Georgia were the same as those found in recently collected Megacopta samples from Japan. The implications of these data are discussed.

Preliminary Genetic Analysis of a Recently-Discovered Invasive True Bug (Hemiptera: Heteroptera: Plataspidae) and Its Bacterial Endosymbiont in Georgia, USA

A true bug (Hemiptera: Heteroptera: Plataspidae), previously known only in the Old World from India and Pakistan to China, Korea, Japan and Malaysia to Australia, was discovered in mid-October 2009 in several northeastern counties in Georgia (USA). Specimens of the stinkbug were submitted by professional pest control operators and county agents following homeowner complaints of the large number of insects migrating from kudzu killed by recent frosts. The insect was identifi ed using morphological characters as the bean plataspid, Megacopta cribraria (F.) (Hemiptera: Plataspidae), by J.E. Eger, Jr. (Dow AgroSciences, Tampa, FL). The identifi cation was confi rmed by entomologists at North Dakota State University and the USDA-ARS Systematics Laboratory (Washington, DC). Genomic DNA was extracted using methods of Jenkins et al. (2009, Ann. Entomol. Soc. Am. 102: 380 395) from 3 specimens collected in northeast Georgia. The cytochrome oxidase subunit I (COI) gene fragment was then a mplified and sequenced according to Jenkins et al. (2009). The COI s equences from all 3 specimens were identical, indicating a single female line age. When these sequences were subjected to a GenBank Blast search (Altschul et al.1990. J. Mol. Evol. 215: 403 410), M. cribraria (GenBank # AY627332) was the closest match (11 base differences out of 789 total bases or 98.6% identity). A γ-Proteobacterium, Candidatus Ishikawaella capsulata (Hosokawa et al. 2006. PLOS Biol. 4: e337. DOI: 10.1371/journal.pbio.0040337), reportedly lives in the posterior midgut of plataspid stinkbugs and appears to be necessary for normal growth and development. It also has been implicated in increased fecundity (Fukatsu and H osokawa. 2002, Appl. Environ. Microbiol. 68: 389 396). The female bean plataspid,

Subterranean termites in the urban landscape: Understanding their social structure is the key to successfully implementing population management using bait technology

Subterranean termites will likely continue to be major economic insect pests in the urban environment. Public concerns about pesticide use will not abate but continue to drive development and implementation of environmentally more acceptable control strategies for subterranean termites. Termite baits are a promising alternative to soil termiticide treatments for protection of structures, but the correlation between killing termites in the landscape and protecting structures is tenuous given our current understanding of termite biology. We discuss the problems associated with defining the efficacy of termite bait products in regard to determining termite population parameters in the field. This discussion is in the form of six case histories involving measures of termite activity and relatedness taken over a three-year period. Our findings highlight the need to include control populations in studies of termite bait efficacy, the mobility of termite populations over time, the importance of defining the techniques used to describe termite colony associations, and the need to use a multidisciplinary research approach in addressing the question of termite social structure.

Insights Into Flea Beetle (Coleoptera: Chrysomelidae: Galerucinae) Host Specificity From Concordant Mitochondrial and Nuclear DNA Phylogenies

ABSTRACT Flea beetles in the genus Altica are herbivorous, urban agricultural pests that are morphologically difficult to distinguish. Host plant associations, therefore, have been used as an important species character in field studies. Indigenous weeds in the Onagraceae, genus Oenothera, are known to serve as developmental hosts for the flea beetle Altica litigata Fall. Although host plant specificity in herbivorous beetles is labile and adult A. litigata have been reported to aggregately feed on plants in the nonindigenous Lythraceae, genus Lagerstroemia, there is no evidence that these ornamental trees serve as developmental hosts. Because adult A. litigata feed on host plants from species in two plant genera, this study was designed to test two hypotheses. The first hypothesis that was tested was whether adult flea beetles collected from primrose and crape myrtle plants across four ecoregions are phenotypically (morphology) and genotypically (genotype) A. litigata. The second hypothesis that was tested was whether two unlinked loci, cytochrome oxidase subunit I and internal transcribed spacer, are phylogenetically concordant for flea beetle species. If so, they could be used to determine the intraspecific geographic history of A. litigata collected from Oenothera and Lagerstroemia species. We discuss how these markers, in conjunction with morphology and host plant feeding behavior, can not only help to validate morphologically difficult taxa but also can illuminate herbivore-plant genetic structure through phylogeny analyses.