Schuh Marissa K, Bahlai Christie A, Malmstrom Carolyn M, Landis Douglas A
Department of Entomology, Michigan State University, East Lansing, MI, USA.
Department of Biological Sciences, Kent State University, Kent, OH, USA.
J Econ Entomol. 2019 Feb 12;112(1):440-449. doi: 10.1093/jee/toy292.
As interest in production of second-generation biofuels increases, dedicated biomass crops are likely to be called upon to help meet feedstock demands. Switchgrass (Panicum virgatum L.) is a North American native perennial grass that as a candidate biomass crop, combines high biomass yields with other desirable ecosystem services. At present, switchgrass is produced on limited acres in the United States and experiences relatively minor insect pest problems. However, as switchgrass undergoes breeding to increase biomass yield and quality, and is grown on more acres, insect pest pressure will probably increase. To investigate how currently available switchgrass ecotypes and cultivars may influence herbivory by generalist insect herbivores, we performed feeding trials using neonate and late-instar fall armyworm [Spodoptera frugiperda JE Smith (Lepidoptera: Noctuidae)]. No-choice feeding experiments were used to explore how switchgrass varieties influence larval establishment, consumption levels, and life-history traits in contrast to a preferred host, corn (Zea mays L.). Neonate S. frugiperda consumed greater amounts of corn than switchgrass and increased amounts of upland versus lowland ecotypes. Late-instar larvae, which do the majority of the larval feeding, exhibited lower consumption of lowland ecotypes, which led to increased development time and reduced pupal weights. The exception to these trends was the upland cultivar 'Trailblazer', which unexpectedly performed similarly to lowland cultivars. These results suggest that both switchgrass ecotype and cultivar can influence feeding damage by a common generalist herbivore. These findings can be used to help inform current switchgrass planting decisions as well as future breeding efforts.
随着对第二代生物燃料生产的兴趣增加，专用生物质作物可能会被要求来帮助满足原料需求。柳枝稷（Panicum virgatum L.）是一种北美本土多年生草本植物，作为候选生物质作物，它兼具高生物量产量和其他理想的生态系统服务功能。目前，柳枝稷在美国的种植面积有限，且遭受的虫害问题相对较小。然而，随着柳枝稷通过育种来提高生物量产量和质量，以及种植面积的扩大，虫害压力可能会增加。为了研究当前可用的柳枝稷生态型和品种如何影响多食性昆虫食草动物的取食情况，我们使用初孵幼虫和大龄秋粘虫[Spodoptera frugiperda JE Smith（鳞翅目：夜蛾科）]进行了取食试验。采用无选择取食实验来探究柳枝稷品种与首选寄主玉米（Zea mays L.）相比如何影响幼虫的定殖、取食量和生活史特征。初孵秋粘虫取食玉米的量多于柳枝稷，取食高地生态型柳枝稷的量多于低地生态型。进行大部分幼虫取食的大龄幼虫取食低地生态型柳枝稷的量较少，这导致发育时间延长和蛹重减轻。这些趋势的例外是高地品种‘开拓者’，它意外地表现得与低地品种相似。这些结果表明，柳枝稷的生态型和品种都能影响常见多食性食草动物造成的取食损害。这些发现可用于为当前柳枝稷的种植决策以及未来的育种工作提供参考。
