Owens D, Nuessly G S, Kendra P E, Colquhoun T A, Seal D R
Everglades Research and Education Center, University of Florida, 3200 E. Palm Beach Rd., Belle Glade, FL 33430.
USDA-ARS Subtropical Horticulture Research Station, 13601 Old Cutler Rd., Miami, FL 33158.
Environ Entomol. 2017 Aug 1;46(4):885-894. doi: 10.1093/ee/nvx096.
Fresh market sweet corn (Zea mays L., convar. saccharata var. rugosa, Poales: Poaceae) ears produced in Florida are damaged by the larvae of Euxesta stigmatias Loew, Euxesta eluta Loew, and Chaetopsis massyla Walker (Diptera: Ulidiidae) that renders ears unmarketable. No standard lure exists for monitoring these pests. Oviposition substrate and attractant bioassays were designed to identify attractive substrates for further semiochemical investigation. Frass from the fall armyworm, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae), was more attractive than other ovipositional substrates tested for E. eluta and C. massyla, and resulted in greater ovipositional output. Tassel-derived armyworm frass was more attractive than leaf-derived frass for oviposition. Frass also resulted in greater oviposition output by two species. In attraction bioassays, frass was generally preferred over the corresponding corn tissue, and only C. massyla demonstrated a preference for silk-frass over tassel-frass. The most promising substrates were then evaluated by electroantennography (EAG) to quantify olfactory responses. Frass volatiles also elicited greater antennal responses than corn volatiles. With tassel-frass, greater amplitude EAG responses were recorded from immature E. eluta female antennae, while mature female E. stigmatias exhibited greater responses. Equivalent antennal response to silk-frass was observed from E. eluta. Overall, silk-frass elicited the greatest EAG responses among all three fly species. Our results indicate that armyworm frass is an important resource in the chemical ecology of corn-infesting silk flies, and this substrate warrants further investigation for potential attractants that may facilitate development of novel management tools for these pests.
佛罗里达州生产的新鲜市场甜玉米（玉米属，糖质变种，皱缩变种，禾本目：禾本科）穗受到玉米穗蝇（Euxesta stigmatias Loew）、暗翅玉米穗蝇（Euxesta eluta Loew）和马氏斑翅蝇（Chaetopsis massyla Walker）（双翅目：突眼蝇科）幼虫的损害，导致玉米穗无法进入市场。目前尚无用于监测这些害虫的标准诱捕剂。设计了产卵基质和引诱剂生物测定法，以确定有吸引力的基质，用于进一步的化学生态学研究。草地贪夜蛾（Spodoptera frugiperda J.E. Smith）（鳞翅目：夜蛾科）的粪便比测试的其他产卵基质对暗翅玉米穗蝇和马氏斑翅蝇更具吸引力，并导致更高的产卵量。来自雄穗的草地贪夜蛾粪便比来自叶片的粪便对产卵更具吸引力。粪便也导致这两个物种的产卵量更高。在引诱生物测定中，粪便通常比相应的玉米组织更受青睐，只有马氏斑翅蝇表现出对花丝粪便比对雄穗粪便的偏好。然后通过触角电位图（EAG）评估最有前景的基质，以量化嗅觉反应。粪便挥发物也比玉米挥发物引起更大的触角反应。对于雄穗粪便，未成熟的暗翅玉米穗蝇雌虫触角记录到更大幅度的EAG反应，而成熟的玉米穗蝇雌虫表现出更大的反应。暗翅玉米穗蝇对花丝粪便的触角反应相同。总体而言，花丝粪便在所有三种蝇类中引起的EAG反应最大。我们的结果表明，草地贪夜蛾粪便在侵染玉米的穗蝇化学生态学中是一种重要资源，这种基质值得进一步研究，以寻找潜在的引诱剂，可能有助于开发针对这些害虫的新型管理工具。
