Department of Biology and the Whitney R. Harris World Ecology Center, University of Missouri-St. Louis, St. Louis, MO, 63121, USA.
Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil.
Oecologia. 2021 Jun;196(2):427-439. doi: 10.1007/s00442-021-04934-7. Epub 2021 May 10.
Wood-boring beetle larvae act as ecosystem engineers by creating stem cavities that are used secondarily as nests by many arboreal ant species. Understanding the heterogeneity and distribution of available cavities and their use by ants is therefore key to understanding arboreal ant community assembly and diversity. Our goals were to quantify the abundance and diversity of beetle-produced cavity resources in a tropical canopy, reveal how ants use these resources, and determine which characteristics of the cavity resource contribute to ant use. We dissected branches from six common tree species in the Brazilian Cerrado savanna, measuring cavity characteristics and identifying the occupants. We sampled 2310 individual cavities, 576 of which were used as nests by 25 arboreal ant species. We found significant differences among tree species in the proportion of stem length bored by beetles, the number of cavities per stem length, average entrance-hole size, and the distribution of cavity volumes. The likelihood that a cavity was occupied was greater for cavities with larger entrance-hole sizes and larger volumes. In particular, there was a strong positive correlation between mean head diameters of ant species and the mean entrance-hole diameter of the cavities occupied by those ant species. Wood-boring beetles contribute to the structuring of the Cerrado ant community by differentially attacking the available tree species. In so doing, the beetles provide a wide range of entrance-hole sizes which ant species partition based on their body size, and large volume cavities that ants appear to prefer.
蛀木甲虫幼虫通过在树干中形成腔室来充当生态系统工程师，这些腔室随后被许多树栖蚂蚁物种用作巢穴。因此，了解可用腔室的异质性和分布情况以及蚂蚁对它们的利用情况，是理解树栖蚂蚁群落组装和多样性的关键。我们的目标是量化热带树冠层中由甲虫产生的腔室资源的丰度和多样性，揭示蚂蚁如何利用这些资源，并确定腔室资源的哪些特征有助于蚂蚁的利用。我们从巴西塞拉多草原的六种常见树种中分离出树枝，测量腔室特征并确定腔室的居住者。我们共采集了 2310 个个体腔室，其中 576 个被 25 种树栖蚂蚁物种用作巢穴。我们发现，在被甲虫蛀蚀的树干长度比例、每段树干上的腔室数量、平均入口孔大小以及腔室体积分布等方面，不同树种之间存在显著差异。腔室具有较大的入口孔尺寸和较大的体积时，被占用的可能性更大。特别是，蚂蚁物种的平均头径与这些蚂蚁物种所占据的腔室的平均入口孔直径之间存在很强的正相关关系。蛀木甲虫通过有差异地攻击现有树种，对塞拉多蚁群的结构产生影响。这样一来，甲虫提供了广泛的入口孔尺寸，而蚂蚁物种则根据其体型进行划分，并且喜欢较大体积的腔室。
