Population dynamics are shaped by species interactions with resources, competitors, enemies, and environmental fluctuations that alter the strength of these interactions. We used a food web approach to investigate the population dynamics of an abundant Arctic mosquito species, Aedes nigripes (Diptera: Culicidae). Specifically, we evaluated the importance of bottom-up variation in aquatic biofilms (food) and top-down predation from diving beetles (Colymbetes dolabratus, Coleoptera: Dytiscidae) on mosquito population performance. In spring 2018, we tracked mosquito and predator populations across eight ponds in western Greenland, measured biofilm productivity with standardized samplers, and estimated grazing-pressure by invertebrate consumers with an in-situ exclosure experiment. We also assessed the quality of biofilms as nutrition for mosquito larvae and evaluated pond attributes that might influence biofilm productivity and food quality. Our results indicated that mosquito population dynamics were more related to resource quality and intraspecific competition than to the density of predaceous diving beetles. Ponds with better quality biofilm tended to have more hatching larvae and those populations experienced higher per capita mortality. This aggregation of larvae in what would otherwise be the best mosquito ponds was enough to produce relatively low fitness. Thus, the landscape would support more mosquitoes if they instead distributed themselves to match predictions of the ideal free distribution. Although mortality rates were highest in ponds with the highest initial densities, the increased mortality was not generally enough to compensate for initial abundance, and 78% of the variation in the density of mosquitoes emerging from ponds was explained by the initial number of larvae in a pond. Resource quality was a strong predictor of consumer abundance, yet there was no evidence that biofilm grazing pressure was greater in ponds where mosquito density was higher. Collectively, our results suggest that mosquito ponds in western Greenland are a mosaic of source and pseudo-sink populations structured by oviposition tendencies, biofilm resource quality, and density dependent larval mortality.

中文翻译：

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北极池塘的消费者资源动态

种群动态是由物种与资源、竞争者、敌人和环境波动的相互作用形成的，这些相互作用改变了这些相互作用的强度。我们使用食物网方法研究了丰富的北极蚊种黑纹伊蚊（双翅目：蚊科）的种群动态。具体来说，我们评估了水生生物膜（食物）的自下而上的变化和潜水甲虫（Colymbetes dolabratus，鞘翅目：Dytiscidae）自上而下的捕食对蚊子种群表现的重要性。2018 年春季，我们跟踪了格陵兰西部八个池塘的蚊子和捕食者种群，使用标准化采样器测量了生物膜生产力，并通过原位封闭实验估计了无脊椎动物消费者的放牧压力。我们还评估了作为蚊子幼虫营养的生物膜的质量，并评估了可能影响生物膜生产力和食品质量的池塘属性。我们的研究结果表明，与捕食性潜水甲虫的密度相比，蚊子种群动态与资源质量和种内竞争更相关。生物膜质量更好的池塘往往有更多的孵化幼虫，这些种群的人均死亡率更高。这种幼虫聚集在原本最好的蚊子池塘中，足以产生相对较低的适应度。因此，如果蚊子自己分布以匹配理想自由分布的预测，则景观将支持更多的蚊子。尽管初始密度最高的池塘死亡率最高，死亡率的增加通常不足以弥补最初的丰度，从池塘中出现的蚊子密度变化的 78% 是由池塘中最初的幼虫数量来解释的。资源质量是消费者丰度的有力预测因素，但没有证据表明蚊子密度较高的池塘中生物膜放牧压力更大。总的来说，我们的研究结果表明，格陵兰西部的蚊子池塘是由产卵趋势、生物膜资源质量和密度依赖的幼虫死亡率构成的源和伪汇种群的马赛克。资源质量是消费者丰度的有力预测因素，但没有证据表明蚊子密度较高的池塘中生物膜放牧压力更大。总的来说，我们的研究结果表明，格陵兰西部的蚊子池塘是由产卵趋势、生物膜资源质量和密度依赖的幼虫死亡率构成的源和伪汇种群的马赛克。资源质量是消费者丰度的有力预测因素，但没有证据表明蚊子密度较高的池塘中生物膜放牧压力更大。总的来说，我们的研究结果表明，格陵兰西部的蚊子池塘是由产卵趋势、生物膜资源质量和密度依赖的幼虫死亡率构成的源和伪汇种群的马赛克。