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Disruption of an ant-plant mutualism shapes interactions between lions and their primary prey

Published Article

Africa

Publication date: January 25, 2024

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Invasive big-headed ants disrupt ant–acacia mutualism, increasing elephant browsing and creating more open habitats. This reduces lions’ success hunting zebra, but populations persist by shifting prey to buffalo, showing how a small invader can reshape ecosystem structure and predator–prey dynamics.

Subject Tags

  • Biodiversity
  • Biodiversity offsetting
  • Wildlife

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.

Citation

Kamaru, D.N., Palmer, T.M., Riginos, C., Ford, A.T., Belnap, J., Chira, R.M., Githaiga, J.M., Gituku, B.C., Hays, B.R., Kavwele, C.M. and Kibungei, A.K., 2024. Disruption of an ant-plant mutualism shapes interactions between lions and their primary prey. Science, 383(6681), pp.433-438. https://doi.org/10.1126/science.adg1464 

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