Abstract Diapause induction in multivoltine insects is an ecophysiological event that is generally triggered by seasonal cues such as photoperiod and temperature. The rice leaf bug, Trigonotylus caelestialium (Kirkaldy), feeds on various Poaceae grasses and produces several generations a year. Previous studies have shown that adults produce diapause and nondiapause eggs under short-day and long-day conditions, respectively. However, there is a distinct midsummer peak in diapause incidence before an autumnal increase in diapause incidence in the field, which cannot be explained by the laboratory results.The present study was performed to examine the environmental factors affecting the diapause incidence in mid-summer and the adaptive significance of this phenomenon. Seasonal trends in diapause incidence differed significantly among three sites located 150–400 m apart from each other and with different host plants. The suitability of host plants differs depending on species and seasonally. Therefore, the microhabitat difference in diapause trend is believed to be due to the difference in host plants. When field-collected female adults laying diapause eggs in late June were fed a seasonally deteriorating host (the orange foxtail, Alopecurus aequalis Sobol. [Poales: Poaceae]), they kept laying diapause eggs, whereas when fed a suitable host (the wheat, Triticum aestivum L. [Poales: Poaceae]) for 5 d, they changed oviposition mode to lay nondiapause eggs.These results indicate that host-plant suitability affects the oviposition mode of T. caelestialium. Diapause-egg oviposition in mid-summer in T. caelestialium has adaptive significance as a bet-hedging strategy against unpredictable dietary conditions.

中文翻译：

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当地种群夏季卵滞育发生率的微生境变化：适应于 Trigonotylus caelestialium (Hemiptera: Miridae) 寄主植物适宜性下降

摘要 多生昆虫滞育诱导是一种生态生理事件，通常由光周期和温度等季节性因素触发。稻叶虫 Trigonotylus caelestialium (Kirkaldy) 以各种禾本科草为食，一年繁殖几代。先前的研究表明，成虫分别在短日照和长日照条件下产生滞育和非滞育卵。然而，在田间滞育发生率秋季增加之前，滞育发生率有一个明显的仲夏高峰，这无法用实验室结果来解释。本研究旨在考察影响仲夏和田间滞育发生率的环境因素。这种现象的适应性意义。滞育发生率的季节性趋势在彼此相距 150-400 m 且寄主植物不同的三个地点之间存在显着差异。寄主植物的适宜性因物种和季节而异。因此，滞育趋势的微生境差异被认为是由于寄主植物的差异造成的。当田间采集的在 6 月下旬产下滞育卵的雌性成虫喂食季节性恶化的寄主（橙色狐尾草，Alopecurus aequalis Sobol。[Poales：禾本科]）时，它们继续产下滞育卵，而当喂食合适的寄主（小麦、 Triticum aestivum L. [Poales: Poaceae]) 5 d，它们改变产卵模式为非滞育卵。这些结果表明寄主植物适宜性影响T. caelestialium 的产卵模式。在 T 的仲夏滞育卵产卵。