Wolfe Ashleigh K, Bateman Philip W, Fleming Patricia A
Department of Environment and Agriculture, Curtin University, Perth, Bentley, WA, 6102, Australia.
School of Veterinary and Life Sciences, Murdoch University, Perth, Murdoch, WA, 6150, Australia.
Curr Zool. 2018 Jun;64(3):311-318. doi: 10.1093/cz/zox039. Epub 2017 Jun 27.
Urbanization facilitates synanthropic species such as rodents, which benefit the diets of many predators in cities. We investigated how urbanization affects the feeding ecology of dugites , a common elapid snake in south-west Western Australia. We predicted that urban snakes: 1) more frequently contain prey and eat larger meals, 2) eat proportionally more non-native prey, 3) eat a lower diversity of prey species, and 4) are relatively heavier, than non-urban dugites. We analyzed the diet of 453 specimens obtained from the Western Australian Museum and opportunistic road-kill collections. Correcting for size, sex, season, and temporal biases, we tested whether location influenced diet for our 4 predictions. Body size was a strong predictor of diet (larger snakes had larger prey present, a greater number of prey items, and a greater diversity of prey). We identified potential collection biases: urban dugites were relatively smaller (snout-vent length) than non-urban specimens, and females were relatively lighter than males. Accounting for these effects, urban snakes were less likely to have prey present in their stomachs and were relatively lighter than non-urban snakes. Other urban-adapted carnivores appear to benefit from urbanization through increased food supplementation, but we found the opposite of this: urban dugites were less likely to contain a meal, and their meals were smaller, indicating they did not make greater use of synanthropic species than was evident for non-urban snakes. In contrast to other carnivores, snakes do not appear to fit a consistent directional pattern for size differences between urban and non-urban populations.
城市化促进了啮齿动物等伴人动物的生存，而这些动物为城市中许多食肉动物提供了食物来源。我们研究了城市化如何影响杜吉特蛇（一种在澳大利亚西南部常见的眼镜蛇科蛇类）的觅食生态。我们预测，与非城市环境中的杜吉特蛇相比，城市中的蛇类：1）更频繁地捕食且食量更大；2）所捕食的外来猎物比例更高；3）捕食的猎物种类多样性更低；4）相对更重。我们分析了从西澳大利亚博物馆以及通过机会性收集的道路死亡样本中获取的453个标本的饮食情况。在对体型、性别、季节和时间偏差进行校正后，我们针对上述4个预测检验了地点是否会影响饮食。体型是饮食的一个重要预测指标（体型较大的蛇捕食的猎物更大、猎物数量更多且猎物种类多样性更高）。我们识别出了潜在的收集偏差：城市中的杜吉特蛇（吻肛长度）相对非城市样本更小，且雌性相对雄性更轻。考虑到这些影响因素后，城市中的蛇胃中含有猎物的可能性更低，且相对非城市中的蛇更轻。其他适应城市环境的食肉动物似乎通过增加食物补充而从城市化中受益，但我们发现情况恰恰相反：城市中的杜吉特蛇进食的可能性更低，且食量更小，这表明它们并未比非城市中的蛇更多地利用伴人动物。与其他食肉动物不同，蛇类在城市和非城市种群之间的体型差异似乎并不呈现一致的方向性模式。
