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In neither cultivar panel did market class or cultivar alone demonstrate as clear a significant divide between subspecies as did evaluating all the cultivars together. No-choice bioassays with cultivars representing the extremes of preference between subspecies were conducted to determine whether C. These no-choice bioassays were also designed to understand the agricultural relevance of the non-preference phenotype, and its applicability in plant breeding: for instance, if non-preference could be introgressed into all C. Accordingly, A. Leaf defoliation progress in field no-choice plots.

As one limitation of the field no-choice experiment is that the beetles could not be contained, the field results were verified in a controlled greenhouse setting. There was no significant difference in the mean damage total leaf defoliation between cultivars in the greenhouse no-choice bioassay Table 3 , indicating that C. However, the greenhouse no-choice bioassay revealed a substructure in the pattern and degree of beetle feeding Table 3.

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We have elucidated a significant factor affecting the structure of striped cucumber beetle A. Our cultivar panels represented the range of the cultivated crop within each subspecies, 34 and are consistent with reports on the genomic differentiation of these subspecies. In all, these results strongly implicated subspecies as a decisive driver of A.

Previous work examined differential cucumber beetle preference within a variety of cucurbit crops. However, applying this phylogenetic framework to previous studies demonstrates that subspecies is predictive of beetle damage in a variety of experimental designs and cultivar selections.

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Ferguson et al. This is also true of trial results for feeding damage published by McGrath, 6 where 10 C. In addition, when Hoffmann et al. In all of these field trials, authors relied on natural populations of beetles for damage, and reported the presence of multiple beetle species of the tribe Luperini.

Wiseman et al. The plant metabolic processes driving beetle preference in C. Broadly within the Cucurbitaceae family, cucurbitacins have been classically described as the key biomolecules dictating herbivore behavior. Generalist herbivores tend to perform poorly on cucurbitacin-rich plants; for instance, two-spotted mites Tetranuchys urticae Koch.

In contrast, over the course of a long co-evolutionary history, specialist herbivores of the Cucurbitaceae, like A. Cucurbitacins B, D and E have been detected in C. Unlike production of cucurbitacin C in C.

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In addition, the foundation of most knowledge of the role of cucurbitacins in influencing the behavior of diabroticite beetles is known from Luperini beetle species other than A. For instance, A. The preference of A. In addition, these cucurbitacins are neither a prerequisite, nor even augment, A. Although cucurbitacins are certainly the most studied specialized defensive metabolite from cucurbit crops, there is evidence that other classes of non-volatile and volatile biomolecules may explain the disparities in herbivore preference between subspecies.

Differences in non-volatile nutritive compounds like cotyledon sugar content, 24 and root nitrogen, 20 have been reported. Contrasts in both floral 25—27 and non-floral 3 plant volatiles have also been shown to elicit differential beetle preference. Other yet unknown factors may exist as well that drive the extreme difference in preference considering that these two C. Although efforts will be directed at achieving a more complete understanding of the biochemical and genetic framework that underlie preference, this knowledge of A.

Trap-cropping strategies already take advantage of highly preferred cucurbits to pull beetles away from the market crop. Our results both identify C. Specifically, how would A.

Curcurbita pepo subspecies delineates striped cucumber beetle (Acalymma vittatum) preference

Our results from both field and greenhouse trials indicate that, although non-preference does not equate to resistance per se , it exploits a nuance in striped cucumber beetle feeding patterns, which leads to the non-preferred cultivar sustaining significantly less damage, even when a preferred cultivar is not locally available. In addition, in the greenhouse, concentrated damage on only a few plants of the non-preferred cultivar, were also observed, inviting the question of the role of host plant resistance in non-preference.

This result, A. Although these no-choice tests only made use of two of the many available cultivars, by employing the structural framework for organizing A. Overall, the no-choice component of this study has provided new insights into striped cucumber beetle preference and the effectiveness in field deployment, and informs the breeding of C.


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This study was the first to consider subspecies as a driver of beetle preference within C. By basing this work in a biological context, this contrast provides an accessible structural framework for understanding variation in preference within C. This structure immediately allows plant breeders and entomologists to augment pest control options, and also promotes future work to understand the biochemical and genetic foundation of A.

Any opinions, findings, conclusions or recommendations expressed in the publication are those of the author s and do not necessarily reflect the view of the United States Department of Agriculture USDA. National Center for Biotechnology Information , U. Journal List Hortic Res v. Hortic Res. Published online Jun Author information Article notes Copyright and License information Disclaimer. This work is licensed under a Creative Commons Attribution 4. Abstract The striped cucumber beetle Acalymma vittatum F.

Introduction The damage inflicted upon plants of the Cucurbitaceae family by the striped cucumber beetle, Acalymma vittatum F. Materials and methods Plant material A panel of 29 cultivars from six C. Table 1 Striped cucumber beetle damage in field and greenhouse GH trials of early-harvest C.

Open in a separate window. Table 2 Striped cucumber beetle damage in field and greenhouse GH trials of mixed-harvest C. Insects All adult striped cucumber beetles A. Field cultivar bioassays Field bioassays of both cultivar panels were conducted at Freeville Organic Research Farm over two consecutive years — Greenhouse cultivar bioassays To complement the field bioassays, both cultivar panels were grown and evaluated in controlled conditions using enclosure cages at the Guterman Greenhouse.

Field no-choice bioassay In addition to understanding the effect of subspecies on beetle preference given choice among a range of cultivars, the differences in herbivory elicited by subspecies when A.


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    5. Greenhouse no-choice bioassay To control for field variability, and the ability of A. Results Field cultivar bioassays Early-harvest and mixed-harvest panels were evaluated at the Organic Research Farm to test A.

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    Figure 1. Greenhouse cultivar bioassays To control for field variation, both panels were also exposed to field-collected striped cucumber beetles in a restricted greenhouse setting. Field no-choice bioassay No-choice bioassays with cultivars representing the extremes of preference between subspecies were conducted to determine whether C. Figure 2. Greenhouse no-choice bioassay As one limitation of the field no-choice experiment is that the beetles could not be contained, the field results were verified in a controlled greenhouse setting.

    Table 3 Distribution of striped cucumber beetle damage to leaves in greenhouse no-choice bioassay. Abbreviation: NS, not significant. Discussion We have elucidated a significant factor affecting the structure of striped cucumber beetle A. Notes The authors declare no conflict of interest. Resistance in cucumber, Cucumis sativus L. Hort Sci ; 6 : — Insect Pests of Farm, Garden, and Orchard , 8th edn.

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    Kairomonal attractants for Acalymma vittatum Coleoptera: Chrysomelidae. Environ Entomol ; 19 : 8— Diabroticite rootworm beetles. Plant Kairomones in Insect Ecology and Control. Defoliation and infestation of Cucurbita pepo genotypes by Diabroticite beetles. Hort Sci ; 31 : — Attractiveness to cucumber beetles and susceptibility to bacterial wilt varies among cucurbit crop types and varieties. In: Maynard DN ed. Effect of striped cucumber beetle Coleoptera: Chrysomelidae foliar feeding on pumpkin yield.

    J Entomol Sci ; 38 : — Influence of leaf herbivory, root herbivory, and pollination on plant performance in Cucurbita moschata.