Data from: Temporal variation in the abundance and richness of foliage-dwelling ants mediated by extrafloral nectar

Plants bearing extrafloral nectaries (EFNs) are common in the Brazilian cerrado savanna, where climatic conditions having marked seasonality influence arboreal ant fauna organization. These ant-plant interactions have rarely been studied at community level. Here, we tested whether: 1) EFN-bearing plants are more visited by ants than EFN-lacking plants; 2) ant visitation is higher in the rainy season than in dry season; 3) plants producing young leaves are more visited than those lacking young leaves in the rainy season; 4) during the dry season, plants with old leaves and flowers are more visited than plants with young leaves and bare of leaves or flowers; 5) the composition of visiting ant fauna differs between plants with and without EFNs. Field work was done in a cerrado reserve near Uberlândia, MG State, Brazil, along ten transects (total area 3,000 m2), in the rainy (October-January) and dry seasons (April-July) of 2010-2011. Plants (72 species; 762 individuals) were checked three times per season for ant presence. Results showed that 21 species (29%) and 266 individuals (35%) possessed EFNs. These plants attracted 38 ant species (36 in rainy, 26 in dry season). In the rainy season, plants with EFNs had higher ant abundance/richness than plants without EFNs, but in the dry season, EFN presence did not influence ant visitation. Plant phenology affected ant richness and abundance in different ways: plants with young leaves possessed higher ant richness in the rainy season, but in the dry season ant abundance was higher on plants possessing old leaves or flowers. The species composition of plant-associated ant communities, however, did not differ between plants with and without EFNs in either season. These findings suggest that the effect of EFN presence on a community of plant-visiting ants is context dependent, being conditioned to seasonal variation.

具有花外蜜腺（extrafloral nectaries, EFNs）的植物在巴西塞拉多稀树草原中颇为常见，该区域显著的季节性气候条件对树栖蚂蚁类群的群落结构具有重要影响。这类蚁植交互作用在群落尺度上的研究却较为匮乏。本研究旨在检验以下假说：1）相较于无花外蜜腺的植物，具花外蜜腺的植物会吸引更多蚂蚁造访；2）雨季的蚂蚁造访频次高于旱季；3）雨季中，萌发新叶的植物比未萌发新叶的植物更易被蚂蚁造访；4）旱季时，保留老叶与花朵的植物，相比长出新叶或无叶无花的植物，会吸引更多蚂蚁；5）具与无花外蜜腺的植物，其造访蚂蚁的类群组成存在差异。本研究野外工作于2010-2011年的雨季（10月至次年1月）与旱季（4月至7月），在巴西米纳斯吉拉斯州乌贝兰迪亚附近的塞拉多保护区内开展，沿10条样带设置调查样地（总面积3000平方米）。研究者对72种共762株植物进行了监测：每个季节统计3次蚂蚁的造访情况。监测结果显示，其中21个物种（占比29%）、266株个体（占比35%）具有花外蜜腺。这些植物共吸引了38种蚂蚁（雨季36种，旱季26种）。雨季中，具花外蜜腺的植物的蚂蚁丰度与物种丰富度均显著高于无花外蜜腺的植物；但在旱季，花外蜜腺的有无并未对蚂蚁造访情况产生影响。植物物候对蚂蚁丰富度与丰度的影响存在差异：雨季中新叶植株的蚂蚁丰富度更高，而旱季中保留老叶或花朵的植株蚂蚁丰度更高。不过，无论在雨季还是旱季，具与无花外蜜腺的植物的伴生蚂蚁类群组成均无显著差异。本研究结果表明，花外蜜腺的存在对植物造访蚂蚁群落的影响具有情境依赖性，其效应受季节变化调控。