Dispersal is fundamental to life on our planet. Dispersal facilitates colonization of continents and islands. Dispersal mediates gene flow among populations, and influences the rate of spread of invasive species. Theory suggests that individuals consistently differ in dispersal propensity, however determining the relative contributions of environmental factors to individual and population-level dispersal, represent a major challenge to understand the spread of organisms. To address this, we conducted a field experiment using Drosophila melanogaster. As proxies for individuals with different dispersal propensities, we used wildtype strains of flies with natural variants of the foraging gene, known to influence dispersal in laboratory and field experiments. These included flies with for^s alleles known to be less dispersive, flies with the for^R alleles which are more dispersive flies as well as an outbred population established from field collected flies. We released approximately 6000 flies of each strain in an experimental arena (100 m x 100 m) in the field and our recaptures were used to determine dispersal of flies over time. To estimate environmental effects on dispersal, we measured temperature, wind direction and wind speed. Using partial-differential equations we combined ecological diffusion with advection to estimate dispersal rates and responses to wind. We found that temperature effects elicited a similar response in high and low dispersal lab strains with dispersal rate increasing with temperature most rapidly at temperatures above 18 ^oC. This was in contrast to outbred flies which remained unresponsive to temperature changes. We also detected a response to wind with advection rates increasing linearly with wind speed for all flies in general. Our results suggest that response to temperature and wind can minimize known differences in behavioural predispositions to disperse. Our results also suggest that the direction and magnitude of wind may play a key role in the colonization and distribution of fly populations. Our findings therefore have implications for forecasting the spread of pests and invasive species as well as pathogens and vectors of disease. Our findings further contribute to the understanding of how the environment can modify behavioural predispositions and to influence population-level dispersal in fly populations in particular and insect species in general.

中文翻译：

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扩大规模：了解从个体差异到人口水平分散的运动

分散是我们星球上生命的基础。分散有助于大陆和岛屿的殖民化。分散介导了种群之间的基因流动，并影响了入侵物种的扩散速度。理论表明，个人在传播倾向上始终存在差异，但是确定环境因素对个人和人群水平传播的相对贡献，是理解生物体传播的主要挑战。为了解决这个问题，我们使用果蝇（Drosophila melanogaster）进行了实地实验。作为具有不同分散倾向的个体的代理，我们使用了具有觅食基因天然变异体的苍蝇野生型菌株，该菌株在实验室和野外实验中会影响分散。这些包括苍蝇与对于^小号已知较少分散的等位基因，苍蝇与对^{- [R}等位基因这是更分散苍蝇以及从现场收集苍蝇建立了一个杂交种群。我们在野外的实验场所（100 mx 100 m）释放了每种菌株大约6000只果蝇，我们的捕获记录用于确定果蝇随时间的散布情况。为了估算环境对扩散的影响，我们测量了温度，风向和风速。使用偏微分方程，我们将生态扩散与对流相结合，以估计扩散速度和对风的响应。我们发现温度效应在高和低分散实验室菌株中引起相似的响应，在温度高于18时，分散速率随温度的增加最快。^ØC.与远亲果蝇相反，后者对温度变化无反应。我们还检测到了对所有风的平流率随风速线性增加的风响应。我们的结果表明，对温度和风的响应可以使行为倾向的已知差异最小化。我们的结果还表明，风的方向和强度可能在果蝇种群的定居和分布中起关键作用。因此，我们的发现对预测害虫和入侵物种以及病原体和病媒的传播具有重要意义。我们的发现进一步有助于理解环境如何改变行为易感性，并影响尤其是蝇类种群和一般昆虫物种的种群水平分布。