Neven Lisa G, Wakie Tewodros, Yee Wee L
USDA-ARS, Temperate Tree Fruit and Vegetable Research Unit, 5230 Konnowac Pass Road, Wapato, WA.
Environ Entomol. 2020 Jun 13;49(3):660-666. doi: 10.1093/ee/nvaa044.
Western cherry fruit fly, Rhagoletis indifferens Curran, is a quarantine pest of sweet cherries in the Pacific Northwest of the United States that overwinters as diapausing pupae. Eclosion responses of R. indifferens puparia to different low temperature durations and postdiapause conditions affect the pest status of the fly. Here, we determined the effects of holding R. indifferens puparia at 3°C for 0, 1, 2, 5, 10, 15, and 20 wk on adult eclosion times and rates at two simulated temperate and two simulated tropical climate treatments over 40 wk. When puparia were chilled 0, 1, or 2 wk, adult eclosion across the four climate treatments displayed a bimodal distribution with low eclosion at 3 wk and high eclosion at 23-35 wk. When puparia were chilled ≤ 10 wk, there was a weaker bimodal distribution. However, when puparia were chilled 15-30 wk, eclosion was more synchronous and occurred at 5-7 wk across the four postchill climate treatments. Eclosion was greater at a postdiapause temperature of 26°C than 23°C. Timing to 50% eclosion was faster at longer photoperiod (16:8 L:D) than shorter (12:12 L:D). The bimodality of eclosion in respect to the duration of low temperature exposure may be indicative of univoltine insect species with obligate diapause that may span over two seasons.
西方樱桃实蝇（Rhagoletis indifferens Curran）是美国太平洋西北部甜樱桃的一种检疫性害虫，以滞育蛹越冬。西方樱桃实蝇蛹对不同低温持续时间和滞育后条件的羽化反应会影响该害虫的发生状况。在此，我们测定了将西方樱桃实蝇蛹在3℃下分别保存0、1、2、5、10、15和20周，对其在40周内两种模拟温带气候和两种模拟热带气候处理下成虫羽化时间和羽化率的影响。当蛹冷藏0、1或2周时，在四种气候处理下成虫羽化呈现双峰分布，在第3周羽化率低，在第23 - 35周羽化率高。当蛹冷藏≤10周时，双峰分布较弱。然而，当蛹冷藏15 - 30周时，羽化更加同步，且在四种冷藏后气候处理下均在第5 - 7周发生。滞育后温度为26℃时的羽化率高于23℃。在较长光周期（16:8光:暗）下达到50%羽化的时间比在较短光周期（12:12光:暗）下更快。关于低温暴露持续时间的羽化双峰性可能表明该单化性昆虫物种具有可能跨越两个季节的专性滞育。
