Ant foraging strategies vary along a natural resource gradient

Food selection by foragers is sensitive to the availability of resources, which may vary along geographical gradients. Hence, selectivity of food types by foragers is expected to track these resource gradients. Here we addressed this hypothesis and asked if foraging decisions of seed-eating ants differ along a geographic gradient of habitat productivity. The study was carried out for two years at five sites along a natural climatic gradient, ranging from arid to Mediterranean, where plant productivity varies 6-fold across a short geographic distance of 250 km. We found that in ant colonies of the genus Messor, collective foraging decisions differed along the gradient. Specifically, at the high-productivity sites, a stronger association was found between plant seed availability and selectivity, suggesting that colonies respond more accurately to within-patch variation in food amounts. In contrast, colonies in low-productivity sites foraged in patches with higher concentration of seeds, s...

觅食者的食物选择会随资源可获得性发生变化，而资源可获得性可能随地理梯度产生波动。因此，觅食者对食物类型的选择性理应追踪这些资源梯度的变化。本研究针对这一假说展开探讨，旨在明确食籽蚂蚁的觅食决策是否会随栖息地生产力的地理梯度产生差异。
本研究在一条覆盖从干旱到地中海气候的自然气候梯度上的5个样地开展了为期两年的野外调查：该梯度在250公里的短地理距离内，植物生产力差异可达6倍。
研究结果显示，收获蚁属（Messor）蚁群的集体觅食决策确实随该地理梯度发生了变化。具体而言，在高生产力样地中，植物种子可获得性与觅食选择性之间的相关性更强，这表明蚁群能更精准地响应斑块内部的食物量差异。与之相反，低生产力样地中的蚁群会优先选择种子浓度更高的觅食斑块，s...