de la Fuente Marie Ann S, Marquis Robert J
Department of Biology, University of Missouri-St. Louis, 8001 Natural Bridge Road, St. Louis, MO 63121-4499, USA, , , , , , US.
Oecologia. 1999 Feb;118(2):192-202. doi: 10.1007/s004420050718.
One possible function of extrafloral nectaries is to attract insects, particularly ants, which defend plants from herbivores. We determined whether ants visiting saplings of the tree Stryphnodendronmicrostachyum (Leguminosae) provide protection (decreased plant damage due to ant molestation or killing of herbivores) and benefit (increased plant growth and reproduction associated with ant presence) to the plant. We compared ant and herbivore abundance, herbivore damage and growth of ant-visited plants and ant-excluded plants grown in sun and shade microhabitats of a 6-ha plantation in Costa Rica over a 7-month period. Results show that ants provided protection to plants not by reducing herbivore numbers but by molesting herbivores. Ants also reduced the incidence of pathogen attack on leaves. Protection was greater in the shade than in the sun, probably due to lower herbivore attack in the sun. Protection was also variable within sun and shade habitats, and this variability appeared to be related to variable ant visitation. Results also indicate that ant presence benefits the plant: ant-visited plants grew significantly more in height than ant-excluded plants. The cultivation of ants may serve as an important natural biological control in tropical forestry and agroforestry systems, where increased plant density can otherwise lead to increased herbivore attack.
花外蜜腺的一个可能功能是吸引昆虫，尤其是蚂蚁，这些蚂蚁会保护植物免受食草动物侵害。我们研究了拜访豆科植物小叶斯特里菲木树苗的蚂蚁是否能为植物提供保护（因蚂蚁骚扰或杀死食草动物而减少植物损伤）以及益处（与蚂蚁存在相关的植物生长和繁殖增加）。我们比较了哥斯达黎加一个6公顷种植园中，在阳光和阴凉微生境下，7个月内有蚂蚁拜访的植物和排除蚂蚁的植物上蚂蚁和食草动物的数量、食草动物造成的损伤以及植物的生长情况。结果表明，蚂蚁保护植物并非通过减少食草动物数量，而是通过骚扰食草动物。蚂蚁还降低了叶片受病原体攻击的发生率。阴凉处的保护作用比阳光下更强，可能是因为阳光下食草动物的攻击较少。在阳光和阴凉栖息地内，保护效果也存在差异，这种差异似乎与蚂蚁拜访的变化有关。结果还表明，蚂蚁的存在对植物有益：有蚂蚁拜访的植物在高度上比排除蚂蚁的植物生长得明显更多。在热带林业和农林复合系统中，蚂蚁的培育可能作为一种重要的自然生物控制手段，否则植物密度增加会导致食草动物攻击增加。
