Dome-shaped functional response induced by nutrient imbalance of the prey
Dome-shaped functional response induced by nutrient imbalance of the prey
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DOI：
10.1098/rsbl.2011.0103
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发表时间：
2011-08-23
期刊：
影响因子：
3.3
通讯作者：
Toft, Soren
中科院分区：
文献类型：
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作者：
Bressendorff, Berith B.;Toft, Soren
营养生态学理论预测，捕食者应该根据猎物的营养成分调整捕获和消耗速度。这将影响捕食者的功能性反应，至少在高猎物密度时，即接近捕食者饱食时。在培养皿中使用简单的果蝇-狼蛛实验室系统，我们发现在7天的时间内，功能反应每天都在变化。在进食1 ~ 2天后，以营养不均衡的猎物为食的蜘蛛出现了圆顶状的功能反应（即在最高猎物密度时捕食减少），而以营养接近最佳的猎物为食的蜘蛛则出现了稳定增加或渐进的功能反应。之后（第5-7天），由于两种治疗方法的功能反应水平降低，差异消失。对春季的成年雌性蜘蛛和秋季的亚成虫蜘蛛进行的实验揭示了相反的模式：对于繁殖期的雌性蜘蛛来说，高脂质的猎物是最理想的，而对于冬季前的亚成虫来说，高蛋白的猎物是一个圆顶状（或简单地减少）的反应，高脂的苍蝇是最理想的猎物。我们的研究结果对捕食理论和生物控制模型有启示，到目前为止，忽视了营养方面；特别是，应纳入捕食者的动态营养状态。
Nutritional ecological theory predicts that predators should adjust prey capture and consumption rates depending on the prey's nutritional composition. This would affect the predator's functional response, at least at high prey densities, i.e. near predator satiation. Using a simple fruit-fly-wolf spider laboratory system in Petri dishes, we found that functional responses changed from day to day over a 7 day period. After 1 to 2 days of feeding, dome-shaped functional responses (i.e. reduced predation at highest prey densities) appeared in spiders fed nutritionally imbalanced prey, compared with steadily increasing or asymptotic functional responses with nutritionally near-optimal prey. Later again (days 5-7), the difference disappeared as the level of the functional response was reduced in both treatments. Experiments with adult females in spring and subadult spiders in autumn revealed opposite patterns: a dome-shaped response with high-lipid prey for reproductive females, for which protein-rich prey are optimal, and a dome-shaped (or simply reduced) response with high-protein prey for pre-winter subadults, for which high-lipid flies are the optimal prey. Our results have implications for predation theory and models of biological control that have, so far, neglected nutritional aspects; in particular, the dynamic nutritional state of the predators should be incorporated.