Effects of <I>Rag1</I> on the Preference and Performance of Soybean Defoliators

Abstract

The Rag1 gene confers antibiotic resistance to soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), and in 2010, varieties expressing Rag1 were released for commercial use in the United States. We do not know how Rag1 varieties will influence the broader community of defoliating insects that inhabit soybean fields. In 2010 and 2011, the preference and performance of pest insects that defoliate soybeans [Glycines max (L.) Merr] were tested using Rag1 and aphidsusceptible varieties. Three coleopterans and four lepidopterans were used: northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae); southern corn rootworm, Diabrotica undecimpunctata howardi Barber (Coleoptera: Chrysomelidae); bean leaf beetle, Ceratoma trifurcata Förster (Coleoptera: Chrysomelidae); fall armyworm, Spodoptera frugiperda ( J. E. Smith) (Lepidoptera: Noctuidae); corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae); soybean looper, Chrysodeix includens (Walker) (Lepidoptera: Noctuidae); and velvetbean caterpillar,Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae). The preference of insects was evaluated in choice and no-choice tests using Rag1 and susceptible soybeans. Lepidopterans also were evaluated on Rag1 leaves using four nutritional indices: relative growth rate, approximate digestibility, and efficiency of conversion of ingested material. In the majority of preference tests, no effect of Rag1 was detected, and in cases where preferences were found, there was no consistent pattern of preference for Rag1 vs. susceptible leaf tissue. Helicoverpa zea demonstrated a preference for resistant leaf tissue, but this was dependent on the genetic background of the variety. Evaluations of nutritional indices indicated that three species of Lepidoptera, S. frugiperda, H. zea, and A. gemmatalis, displayed reduced conversion efficiency for Rag1 soybeans, suggesting effects of antibiosis. RightsThis article is the copyright property of the Entomological Society of America and may not be used for any commercial or other private purpose without specific permission of the Entomological Society of America.This article is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/ent_pubs/178BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Effects of Rag1 on the Preference and Performance of Soybean DefoliatorsAuthor (s) ABSTRACT The Rag1 gene confers antibiotic resistance to soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), and in 2010, varieties expressing Rag1 were released for commercial use in the United States. We do not know how Rag1 varieties will inßuence the broader community of defoliating insects that inhabit soybean Þelds. In 2010 and 2011, the preference and performance of pest insects that defoliate soybeans [Glycines max (L.) Merr] were t...

Beyond Focal Pests: Impact of a Neonicotinoid Seed Treatment and Resistant Soybean Lines on a Non-Target Arthropod

“…The amino acid composition of leaf tissue from soybean lines with Rag1 genes is different than that of related plants lacking these genes [53]. Even so, consuming plant tissue from soybean lines with Rag genes did not alter fitness of western corn rootworm larvae ( Diabrotica virgifera virgifera LeConte) [54], and other studies [22,55] concluded that the presence of Rag1 genes had little impact on feeding (preference or defoliation) of several soybean pests within the Coleoptera and Lepidoptera, although in the latter study the authors documented reduced caterpillar growth rates. In contrast, Rich and Koch [23] found that brown marmorated stink bugs [ Halyomorpha halys (Stål)] preferred soybeans with Rag1 , and had lower levels of mortality when reared on pods from Rag1 plants.…”

“…Because soybean aphid biotypes have been found that can successfully colonize and develop on soybeans with Rag genes [17,18], researchers have been investigating pyramided resistance, in which multiple Rag genes are present within the same plant [19,20,21]. There is some information that the presence of Rag genes can impact the behavior and biology of other herbivores associated with soybean [22,23]. …”

Effects of Rag1 aphid‐resistant soybean on mortality, development, and preference of brown marmorated stink bug

“…Bruner et al. () showed that three species of Lepidoptera – Anticarsia gemmatalis Hübner, Helicoverpa zea (Boddie), and Spodoptera frugiperda (JE Smith) – had decreased weight gain when fed Rag1 aphid‐resistant soybeans, but one other species of Lepidoptera, Chrysodeixis includens (Walker), and three species of Coleoptera – Cerotoma trifurcata Föster, Diabrotica barberi Smith & Lawrence, and Diabrotica undecimpunctata howardi Barber – were unaffected by Rag1 aphid resistance. A separate study found that Rag1 aphid‐resistant soybean had no effect on survival of western corn rootworm, Diabrotica virgifera virgifera Leconte (Dunbar & Gassman, ).…”

“…() demonstrated that leaf tissue from Rag1 aphid‐resistant soybean retains resistance to A. glycines after detachment from plants. Furthermore, studies evaluating the effect of aphid‐resistant soybean on other insects have relied on detached plant tissue (Lundgren et al., ; Chandrasena et al., ; Dunbar & Gassman, ; Bruner et al., ). IA3027 and IA3027RA1 soybean were grown in 2014, using standard agronomic practices (Bennett et al., ; Kandel, ) and without insecticide application at the University of Minnesota Experiment Station (Saint Paul, MN, USA).…”

“…Defoliating pests (i.e., Coleoptera and Lepidoptera) of soybean have shown a variety of responses in terms of preference and performance when subjected to aphid‐resistant soybean (Chandrasena et al., ; Dunbar & Gassman, ; Bruner et al., ). The response of H. halys or other North American species of stink bugs to aphid‐resistant soybean has not been reported.…”