Limited genetic evidence for host plant-related differentiation in the Western cherry fruit fly Rhagoletis indifferens (Diptera: Tephritidae)

The shift of the fruit fly Rhagoletis pomonella (Walsh) in the mid-1800s from downy hawthorn, Crataegus mollis (Torrey & Asa Gray) Scheele, to introduced domesticated apple, Malus domestica (Borkhausen), in the eastern USA is a model for ecological divergence with gene flow. A similar system may exist in the northwestern USA and British Columbia, Canada, where Rhagoletis indifferens Curran (Diptera: Tephritidae) attacks the native bitter cherry Prunus emarginata (Douglas ex Hooker) Eaton (Rosaceae). Populations of R. indifferens have shifted and became economic pests on domesticated sweet cherry, Prunus avium (L.) L., shortly after sweet cherries were introduced to the region in the mid-1800s. The fruiting phenologies of the two cherries differ in a similar manner as apples and hawthorns, with domesticated sweet cherries typically ripening in June and July, and bitter cherries in July and August. Here we report, however, little evidence for genetic differentiation between bitter vs....19世纪中期，美国东部的苹果实蝇（Rhagoletis pomonella (Walsh)）从柔毛山楂（Crataegus mollis (Torrey & Asa Gray) Scheele）转向引种栽培苹果（Malus domestica (Borkhausen)）的寄主转换事件，是伴随基因流的生态分化研究的经典模型。类似的演化系统或存在于美国西北部与加拿大不列颠哥伦比亚省：当地的无饰实蝇（Rhagoletis indifferens Curran，双翅目：实蝇科（Diptera: Tephritidae））原本以本土苦樱桃Prunus emarginata (Douglas ex Hooker) Eaton（蔷薇科（Rosaceae））为寄主。在19世纪中期欧洲甜樱桃（Prunus avium (L.) L.）被引入该区域后不久，无饰实蝇种群便发生寄主转换，成为危害栽培甜樱桃的经济害虫。两种樱桃的结实物候与苹果和山楂的情况类似：栽培甜樱桃通常于6月至7月成熟，而苦樱桃则在7月至8月结果。然而，本研究未发现苦樱桃寄主种群与……之间存在遗传分化的显著证据。