Two stem-boring moths, the yellow stemborer (YSB) Scirpophaga incertulas (Walker), and the striped stemborer (SSB), Chilo suppressalis (Walker), damage rice in Asia. YSB is the dominant species in much of tropical Asia. Both species are oligophagous on domesticated and wild rice. We investigated the roles of host plant preferences and larval performance in determining the larval densities of both species in rice plots. In screenhouse experiments, YSB showed significant preference–performance coupling. Adults preferred high-tillering rice varieties during early vegetative growth. In contrast, SSB did not demonstrate oviposition preferences under the same screenhouse conditions, but did oviposit less on the wild rice Oryza rufipogon Griff. than on domesticated rice varieties during a choice experiment. Despite differences in preference–performance coupling, larval survival and biomass across 10 varieties were correlated between the two species. YSB and SSB larvae occurred in relatively high numbers on rice varieties with large tillers (IR70, IR68, and T16) in wet and dry season field experiments. However, whereas YSB was the dominant species on IR68 and IR70, it was relatively less abundant on T16, where SSB dominated. Results suggest that YSB preferentially attacked fast-growing rice varieties with high tiller numbers early in the crop cycle. Meanwhile SSB, which has weak preference–performance coupling, occurred in rice plants with large tillers that were relatively free of YSB later in the crop cycle. These factors may allow the species to coexist. We discuss the implications of proximate and ultimate factors influencing stemborer co-occurrence for the sustainable production of rice in tropical Asia.

中文翻译：

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两种水稻茎秆（鳞翅目：Pyralidae，Crambidae）偏好强度-性能耦合强度的差异促进了田间地块尺度的共存

两种蛀茎蛾，黄色茎蛀虫 (YSB) Scirpophaga incertulas (Walker) 和条纹茎蛀虫 (SSB) Chilo suppressalis (Walker) 在亚洲危害水稻。YSB 是亚洲大部分热带地区的优势种。这两个物种在驯化和野生稻上都是寡食的。我们研究了寄主植​​物偏好和幼虫性能在确定水稻地块中两种物种的幼虫密度方面的作用。在筛选室实验中，YSB 表现出显着的偏好-性能耦合。在早期营养生长期间，成年人更喜欢高分蘖水稻品种。相比之下，SSB 在相同的筛选条件下没有表现出产卵偏好，但在野生稻 Oryza rufipogon Griff 上的产卵量较少。比在选择实验中的驯化水稻品种。尽管偏好-性能耦合存在差异，但 10 个品种的幼虫存活率和生物量在两个物种之间是相关的。在雨季和旱季田间试验中，大分蘖水稻品种（IR70、IR68 和 T16）上的 YSB 和 SSB 幼虫数量相对较多。然而，虽然 YSB 是 IR68 和 IR70 上的优势物种，但它在 SSB 占主导地位的 T16 上相对较少。结果表明，YSB 在作物周期早期优先攻击具有高分蘖数的速生水稻品种。同时，偏好-性能耦合较弱的 SSB 发生在具有大分蘖的水稻植株中，这些植株在作物周期后期相对不含 YSB。这些因素可能使物种共存。