Desiccation resistance and mating behavior in laboratory populations of Drosophila simulans originating from the opposing slopes of Lower Nahal Oren (Israel)

Lower Nahal Oren in Northern Israel, often referred to as \"Evolution Canyon\", has been proposed as a microscale model site for ecological evolution. However, conflicting mating assay and stress-resistance contribute to controversy over the Nahal Oren model. In this study we further tested the Nahal Oren model, while extending its focus from Drosophila melanogaster to its sister species, D. simulans. Using fly populations derived from the opposing canyon slopes and acclimated to laboratory conditions for 11-22 generations we did not find a significant slope effect on desiccation resistance (p=0.96) or body metabolic fuel content (p>0.43) which would indicate a genetic basis for adaptation to local resource limitation. Multiple-choice mating assays (47-48% homotypic couples in two replicate populations) did not indicate divergence from a random mating pattern between north and south-facing slope flies. In conclusion, our findings do not support divergence of D. simulans populations acr...

以色列北部下纳哈尔奥伦（Lower Nahal Oren）常被称为“进化峡谷（Evolution Canyon）”，已被提议作为生态演化研究的微尺度模型位点。然而，相互矛盾的交配试验（mating assay）与抗逆性（stress-resistance）研究结果，使得纳哈尔奥伦模型存在诸多争议。本研究进一步验证了纳哈尔奥伦模型，并将研究对象从黑腹果蝇（Drosophila melanogaster）扩展至其近缘物种拟暗果蝇（Drosophila simulans）。本研究使用来自峡谷对立坡向、且在实验室条件下驯化11~22代的果蝇种群开展实验，未发现坡向对果蝇抗干燥能力（p=0.96）或体内代谢底物含量（p>0.43）存在显著影响——而这类影响本应体现出果蝇适应本地资源限制的遗传基础。多选交配试验结果（两个重复种群中同型交配配对占比为47%~48%）未显示北向坡与南向坡果蝇种群间存在偏离随机交配模式的分化。综上，本研究结果并不支持拟暗果蝇种群存在acr...