The spotted wing drosophila (SWD) is supposed to show only two distinct seasonal phenotypes: the dark, diapausing winter morph (WM) and the light, reproductively active summer morph (SM). It is unclear if these phenotypes result from a true developmental switch or from the expression of extreme phenotypes of continuous thermal reaction norms. This study aims to investigate this question by examining traits across a range of temperatures. Using 12 developmental temperatures (8 to 30 °C), we assessed traits including viability, growth, morphology, cold tolerance, metabolic rate, and ovarian maturation. Gradual increases in temperature induced gradual changes in all these traits, indicating classical nonlinear thermal reaction norms. Low temperatures (14 °C and below) produced flies with extended development, dark color, larger size, increased cold tolerance, reduced metabolism, and delayed oogenesis, characteristic of the WM. Given the months required for emergence and egg maturation at cold, distinct generations of SWD may develop in discrete environments resulting in an apparent biphenism. What appears to be distinct phenotypes (WM and SM) may actually result from continuous thermal reaction norms. This implies the need for precise terminology in SWD. We recommend using terms like ‘winter-acclimated’ or ‘winter phenotype’ rather than ‘winter morph’. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

中文翻译：

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果蝇 （Drosophila suzukii） 中明显的季节性双相实际上源于连续反应规范


斑翅果蝇 （SWD） 应该只显示两种不同的季节性表型：深色、滞育的冬季形态 （WM） 和浅色、生殖活跃的夏季形态 （SM）。目前尚不清楚这些表型是来自真正的发育转变还是来自连续热反应规范的极端表型的表达。本研究旨在通过检查温度范围的性状来研究这个问题。使用 12 种发育温度 （8 至 30 °C），我们评估了包括活力、生长、形态、耐寒性、代谢率和卵巢成熟度在内的性状。温度的逐渐升高导致所有这些特性的逐渐变化，表明经典的非线性热反应模。低温（14 °C 及以下）产生的果蝇发育时间长、颜色深、体型较大、耐寒性增强、新陈代谢减少和卵子发生延迟，这是 WM 的特征。考虑到在寒冷时出现和卵子成熟所需的月数，不同世代的 SWD 可能会在离散的环境中发展，从而导致明显的双语。看似不同的表型（WM 和 SM）实际上可能是连续热反应规范的结果。这意味着 SWD 需要精确的术语。我们建议使用 “冬季适应 ”或 “冬季表型” 等术语，而不是 “冬季形态”。© 2024 作者。由John Wiley & Sons Ltd代表化学工业协会出版的《害虫管理科学》。