How Sweet Rewards Shape Cooperation Between Ants and Desert Cacti

Hooded Oriole

24-10-2025

Zhuang breathes in the fresh air, feeling the Dao flow through his chest...
“Perhaps,” he whispers, “the fish I chase are not the river’s fish, but my own dream?”
“The fish I catch,” adds Kingfisher, “are gifts of the river—offered when I become this very river.”

In Kingfisherish Wandering [1]

© Wix

In the Mojave Desert, life thrives through unlikely partnerships. One such alliance unfolds between the silver cholla cactus (Cylindropuntia echinocarpa) and desert ants, bound by a sugary exchange. A new study by Braun and Lortie [2] published in the Journal of Ecology reveals how small shifts in nectar availability can reshape this delicate cooperation, determining which ants protect the cactus—and how well.

The silver cholla secretes nectar from tiny glands called extrafloral nectaries (EFNs), which attract ants that, in turn, defend the cactus from herbivores [3-5]. This mutualism is not static: ants differ in how effectively they protect plants, and they also compete for access to nectar [6,7]. Braun and Lortie [2] experimentally increased nectar resources on wild silver chollas to see how this affected ant communities and plant health.

Over two spring seasons, the researchers found that extra nectar increased ant abundance but changed who dominated. The competitive fire ant Solenopsis xyloni became more common on nectar-supplemented plants, replacing the less aggressive but more beneficial Crematogaster depilis. Only C. depilis significantly reduced herbivores—especially the cactus coreid bug (Chelinidea vittiger)—and increased seed production, confirming it as the cactus’s most effective protector.

The study shows that even well-intentioned increases in resources can disrupt ecological harmony. While more nectar drew more ants, it also intensified competition and shifted community composition, potentially reducing the cactus’s net benefit. The findings underscore that in mutualistic systems, the quality of partnership matters as much as the quantity of allies.

Through the lens of Nature Quotient (NQ), this study exemplifies how harmony in nature depends on nuanced cooperation rather than unrestrained abundance. The cactus does not thrive by offering unlimited sweetness—it prospers through balance, attracting allies who reciprocate [8]. Likewise, human societies can learn from this ecological metaphor: peace, whether ecological or social, emerges not from maximizing gain but from nurturing relationships that sustain mutual well-being [9,10]. Cultivating high NQ—awareness of interdependence and restraint—can help humanity emulate the adaptive intelligence of these desert ecosystems.

References

[1] Nguyen MH. (2025). Kingfisherish Wandering. https://www.amazon.com/dp/B0FVLLLXNW/

[2] Braun J, Lortie CJ. (2025). Experimental resource supplementation shifts ant-mediated defence on silver cholla. Journal of Ecology. https://doi.org/10.1111/1365-2745.70178

[3] Rico-Gray V, Oliveira PS. (2007). The ecology and evolution of ant-plant interactions. University of Chicago Press.

[4] Chamberlain SA, Holland JN. (2009). Quantitative synthesis of context dependency in ant–plant protection mutualisms. Ecology, 90, 2384-2392. https://doi.org/10.1890/08-1490.1

[5] Leal LC, Peixoto PE. (2017). Decreasing water availability across the globe improves the effectiveness of protective ant–plant mutualisms: A meta-analysis. Biological Reviews, 92, 1785-1794. https://doi.org/10.1111/brv.12307

[6] Fagundes R, et al. (2017). Differences among ant species in plant protection are related to production of extrafloral nectar and degree of leaf herbivory. Biological Journal of the Linnean Society, 122, 71-83. https://doi.org/10.1093/biolinnean/blx059

[7] Ness JH, Morris WF, Bronstein JL. (2009). For ant-protected plants, the best defense is a hungry offense. Ecology, 90, 2823-2831. https://doi.org/10.1890/08-1580.1

[8] Vuong QH, Nguyen MH. (2025). On Nature Quotient. Pacific Conservation Biology, 31, PC25028. https://doi.org/10.1071/PC25028

[9] Tran TT. (2025). Flying beyond didacticism: The creative environmental vision of ‘Wild Wise Weird’. Young Voices of Science. https://youngvoicesofscience.org/?p=1963

[10] Nguyen MH, Ho MT, La VP. (2025). On “An” (安): Inner peace through uncertainty, nature quotient, and harmony with Dao. http://books.google.com/books/about?id=NIKMEQAAQBAJ