结合实验、动物追踪和死亡率调查，研究人员发现入侵的大头蚁（Pheidole megacephala）会降低狮子（Panthera leo）捕杀其主要猎物——平原斑马（Equus quagga）的效率。大头蚁破坏了本地蚂蚁（Crematogaster spp.）与主导的哨刺金合欢（Vachellia drepanolobium）之间的互生关系，使树木容易受到大象（Loxodonta africana）的啃食，并导致景观能见度更高。
虽然在能见度较高的入侵区域，斑马被杀死的几率明显降低，但狮子的数量自入侵开始后并没有减少，这很可能是因为猎物转向了非洲水牛（Syncerus caffer）。这项研究表明，通过控制整个地貌的生物物理结构，一个微小的入侵者重构了标志性物种之间捕食者-猎物的动态关系。
据了解，互惠关系往往决定着生态系统，但它们也容易受到人类活动的影响。
附：英文原文
Title: Disruption of an ant-plant mutualism shapes interactions between lions and their primary prey
Author: Douglas N. Kamaru, Todd M. Palmer, Corinna Riginos, Adam T. Ford, Jayne Belnap, Robert M. Chira, John M. Githaiga, Benard C. Gituku, Brandon R. Hays, Cyrus M. Kavwele, Alfred K. Kibungei, Clayton T. Lamb, Nelly J. Maiyo, Patrick D. Milligan, Samuel Mutisya, Caroline C. Ng’weno, Michael Ogutu, Alejandro G. Pietrek, Brendon T. Wildt, Jacob R. Goheen
Issue&Volume: 2024-01-26
Abstract: Mutualisms often define ecosystems, but they are susceptible to human activities. Combining experiments, animal tracking, and mortality investigations, we show that the invasive big-headed ant (Pheidole megacephala) makes lions (Panthera leo) less effective at killing their primary prey, plains zebra (Equus quagga). Big-headed ants disrupted the mutualism between native ants (Crematogaster spp.) and the dominant whistling-thorn tree (Vachellia drepanolobium), rendering trees vulnerable to elephant (Loxodonta africana) browsing and resulting in landscapes with higher visibility. Although zebra kills were significantly less likely to occur in higher-visibility, invaded areas, lion numbers did not decline since the onset of the invasion, likely because of prey-switching to African buffalo (Syncerus caffer). We show that by controlling biophysical structure across landscapes, a tiny invader reconfigured predator-prey dynamics among iconic species.
DOI: adg1464
Source: https://www.science.org/doi/10.1126/science.adg1464