Close Encounters

Bromeliads offer ants a summer residence in Costa Rica

Myrmecophobes might want to avoid studying bromeliads in the forests of Costa Rica during the summer. There are plenty of plants, but they seem to attract fire ants.
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Beatrice Rost-Komiya and colleagues working in Costa Rica have studied how bromeliads alter what ant species you find on orange trees. The results, published in PLOS One, could help develop natural defences against pests.

A Solenopsis ant. Image: Canva.

Rost-Komiya and colleagues found that orange trees with bromeliads had a different mix of ant species on them compared with orange trees that had no bromeliads. In particular, trees with bromeliads hosted Solenopsis ants, known as fire ants. While the study showed that the fire ants don’t need the bromeliads to live on a tree, they are more likely to inhabit a tree with bromeliads.

The authors refer to previous work that bromeliads can be keystone species for a habitat. They can provide shelter for ants who, in return, provide nutrients from the food they digest. Getting the right ants onto a tree could help orange farmers, as some ants act as bodyguards against herbivores and pathogens.

The ecologists tracked how the bromeliads affected the ant community by visiting two orange groves located around Santa Cecilia, in Costa Rica. The groves hadn’t had a history of pesticide use, so the insects on the trees would have been affected only by changes made in the experiment.

“In each of two study sites, we identified 20 trees naturally with and 20 trees naturally without bromeliads. Of these 20 trees with bromeliads, 10 trees would continue to bear bromeliads (“with-with”) whereas the other 10 trees would eventually have their bromeliads removed (“with-removal”).” write Rost-Komiya and colleagues.

While the bromeliads affected the ant populations, removing them had no noticeable effect. The authors believe this result might be due to the removal coinciding with the move from the dry to the wet season.  


Rost-Komiya, B., Smith, M.A., Rogy, P. and Srivastava, D.S. (2022) “Do bromeliads affect the arboreal ant communities on orange trees in northwestern Costa Rica?,” PLOS One, 17(7),

Translations by Google Translate.

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