Genome size evolution in the beetle genus Diabrotica

Diabrocite corn rootworms are one of the most economically significant pests of maize in the United States and Europe and an emerging model for insect-plant interactions. Genome sizes of several species in the genus Diabrotica were estimated using flow cytometry along with that of Acalymma vittatum as an outgroup. Within the Diabrotica subgroups fucata and virgifera, genome sizes ranged between 1.59 - 1.68 gigabase pairs (Gb) and between 2.31- 2.65 Gb, respectively, and the Acalymma vittatum genome size was around 1.69 Gb. This result indicated that a substantial increase in genome size occurred in the ancestor of the virgifera group. Further analysis of fucata group and virgifera group genome sequencing reads indicated that the genome size difference between the Diabrotica subgroups could be attributed to a higher content of transposable elements, mostly miniature inverted-transposable elements (MITEs) and LTR gypsy-like elements.

Using Cucumis sativus, Acalymma vittatum, Celatoria setosa, and generalist pollinators as a case study for plant–insect interactions

Showcasing how semiochemicals are both multifunctional and can influence a community of organisms is a constant frontier shared by chemical ecologists and applied entomologists alike. As researchers in these fields continue to share broad and overlapping interests, converging on one system could allow for a better understanding of community interactions and the chemical substances that mediate them. Cucurbit systems are strategically positioned to study these types of interactions because they combine the elements of plant–herbivore, plant–predator, and plant pollinator into one model and are systems where researchers can pursue both basic and applied questions. In this review, we propose Cucumis sativus [cucumber], Acalymma vittatum [striped cucumber beetle], Celatoria setosa [a natural enemy], and generalist pollinators as a system for continued investigation into semiochemicals, their multifunctional roles, and their influence on both target and nontarget organisms. We believe this system is ripe for further exploration at the frontiers in chemical ecology and applied entomology.

Transcriptome Sequencing of the Striped Cucumber Beetle, Acalymma vittatum (F.), Reveals Numerous Sex-Specific Transcripts and Xenobiotic Detoxification Genes

Acalymma vittatum (F.), the striped cucumber beetle, is an important pest of cucurbit crops in the contintental United States, damaging plants through both direct feeding and vectoring of a bacterial wilt pathogen. Besides providing basic biological knowledge, biosequence data for A. vittatum would be useful towards the development of molecular biopesticides to complement existing population control methods. However, no such datasets currently exist. In this study, three biological replicates apiece of male and female adult insects were sequenced and assembled into a set of 630,139 transcripts (of which 232,899 exhibited hits to one or more sequences in NCBI NR). Quantitative analyses identified 2898 genes differentially expressed across the male–female divide, and qualitative analyses characterized the insect’s resistome, comprising the glutathione S-transferase, carboxylesterase, and cytochrome P450 monooxygenase families of xenobiotic detoxification genes. In summary, these data provide useful insights into genes associated with sex differentiation and this beetle’s innate genetic capacity to develop resistance to synthetic pesticides; furthermore, these genes may serve as useful targets for potential use in molecular-based biocontrol technologies.

Striped Cucumber Beetle Acalymma vittatum F. (Insecta: Coleoptera: Chrysomelidae)

The striped cucumber beetle, Acalymma vittatum F. (Figure 1) is a serious agricultural pest of plants in the family Cucurbitaceae in eastern North America. Crops affected by larval and adult feeding include cucumber, Cucumis sativus L., cantaloupe, Cucumis melo L., pumpkin, Cucurbita pepo L., and other Cucurbita spp. (Dill and Kirby 2016). The striped cucumber beetle is a vector of the plant disease bacterial wilt (Eaton 2016). Though the striped cucumber beetle occurs throughout Florida, it is the least commonly reported among three chrysomelid species on cucurbit crops in the state. The spotted cucumber beetle, Diabrotica undecimpunctata howardi Barber, and banded cucumber beetle, Diabrotica balteata LeConte, are more common in Florida, causing damage symptoms that are similar to striped cucumber feeding damage (Webb 2010). Includes: Introduction - Distribution - Description and Life Cycle - Damage - Monitoring - Management - Selected References.https://edis.ifas.ufl.edu/in1215 Also published at http://entnemdept.ufl.edu/creatures/VEG/BEAN/striped_cucumber_beetle.html

Muskmelon Cultivar Attractiveness to Striped Cucumber Beetle and Susceptibility to Bacterial Wilt

Bacterial wilt of cucurbits, incited by Erwinia tracheiphila (E. F. Smith) and vectored by the striped cucumber beetle [Acalymma vittatum (F.)] (SCB), is a serious disease of muskmelon (Cucumis melo L.). Cultivars differ in attractiveness to SCB and susceptibility to bacterial wilt, but no cultivar resistant to bacterial wilt has been introduced. In 2015 and 2016, replicated field plots of eight cultivars were grown at Lafayette, Wanatah, and Vincennes, IN, to identify differences in attractiveness to SCB and susceptibility to bacterial wilt. ‘Savor’ had significantly more beetle activity than ‘Hales Best’, ‘Superstar’, and ‘Aphrodite’ in three of six site-years, and more than ‘Diplomat’, ‘Dream Dew’, ‘Athena’, and ‘Wrangler’ in two site-years. Beetle activity for ‘Athena’, ‘Superstar’, and ‘Wrangler’ did not differ significantly from ‘Aphrodite’ for any site-year. Bacterial wilt severity was significantly greater for ‘Diplomat’ and ‘Dream Dew’ than for other cultivars in four site-years. ‘Superstar’ had the least disease in five site-years, but significantly less than ‘Aphrodite’, ‘Athena’, and ‘Hales Best’ in only one site-year. At one site, additional plots of each cultivar were populated with five SCBs per plant, and rowcovers were applied to keep the SCBs near the plants for 3 weeks. This resulted in similar beetle activity on all cultivars, but most disease in ‘Dream Dew’ and least in ‘Superstar’ and ‘Athena’. Marketable yield was generally highest for ‘Aphrodite’, ‘Superstar’, and ‘Athena’ when plants were exposed to natural beetle populations. Overall, ‘Savor’ and ‘Diplomat’ were the most attractive to beetles, and ‘Diplomat’ and ‘Dream Dew’ were the most susceptible to bacterial wilt. ‘Aphrodite’, ‘Athena’, and ‘Superstar’ were less attractive to beetles and showed more tolerance to bacterial wilt in both 2015 and 2016.