Invasion of ecosystems by alien species is a global concern. Robinia pseudoacacia L. (Fabaceae) is one such species which impacts on native diversity and ecosystem functioning. We assessed how R. pseudoacacia affects flower visitation by arthropods in commercial apple orchards in eastern Free State, South Africa. We used paired observations to compare the abundance and diversity of flower visitors and their interactions with the two plant species. Our results showed that R. pseudoacacia flowers attract African honey bees (Apis mellifera) more than apple flowers. However, flower visitation by Diptera, particularly March flies (Bibionidae) was higher in apple flowers. Arthropods of other orders appeared to be minor visitors for both plants as they were recorded in small numbers. Flower visitation rates by A. mellifera did not vary significantly between the two plant species, though it was marginally higher in R. pseudoacacia. The interaction network for the two plant species and their flower visitors showed high nestedness indicating that they are drawing from the same pool of pollinators. Therefore, there is competition for flower visitors between R. pseudoacacia and apples based on the number of shared partners, an interaction which may potentially affect apple pollination and ultimately compromise fruit quality and yields. These findings further support the need to sustainably manage R. pseudoacacia in all invaded habitats including agro-ecosystems.

外来物种对生态系统的入侵是一个全球性的问题。Robinia pseudoacacia L.（豆科）就是这样一种影响本地多样性和生态系统功能的物种。我们评估了刺槐如何影响南非自由州东部商业苹果园中节肢动物对花卉的访问。我们使用配对观察来比较花卉访客的丰度和多样性以及他们与两种植物物种的相互作用。我们的结果表明，刺槐花吸引了非洲蜜蜂（Apis mellifera) 比苹果花多。然而，双翅目，特别是三月蝇（Bibion​​idae）对苹果花的访问量较高。其他目的节肢动物似乎是这两种植物的次要访客，因为它们的数量很少。A. mellifera 的花卉访问率在两种植物之间没有显着差异，尽管R. pseudoacacia略高。两种植物物种及其花卉访客的交互网络显示出高度嵌套，表明它们来自同一个传粉媒介。因此，刺槐之间存在着对花客的竞争。和苹果基于共享伙伴的数量，这种相互作用可能会影响苹果授粉并最终影响水果质量和产量。这些发现进一步支持在包括农业生态系统在内的所有入侵栖息地中可持续管理R. pseudoacacia的必要性。