Tuesday, October 16, 2012

Ants, the Unlikely Pollinators

© Beatriz Moisset

Ants are seen visiting flowers with great frequency. People often ask me: Do ants pollinate? I answer with another question: What do you think? Are ants capable of pollinating flowers? Do they have what it takes to carry pollen from one flower to another, preferably of another plant?

Ants stealing nectar from the spur of a jewelweed. © Beatriz Moisset
Most pollinators can fly from plant to plant. Ants, lacking wings, don't go very far. Moreover, ants may be coated in some sort of antibiotics which may be detrimental to pollen. In some cases ants steal nectar from flowers, causing damage and reducing the likelihood of later pollinators' visits. Some plants resort to extrafloral nectaries, nectar-producing glands located in other plant parts, to keep the ants and other nectar robbers away from the valuable treasure reserved for legitimate pollinators.

Ants pollinating wood spurge. © Beatriz Moisset
Despite all these drawbacks, there are instances in which ants are pollinators. One case is that of spurge, or Euphorbia. This plant grows very low near the ground and tends to intertwine its runners with those of nearby plants. This increases the chances of ants going from the flowers of one plant to those of another without the need to fly. Perhaps the pollen of spurge is more resistant to the chemicals on an ant's body. So, ants pollinate spurge; although, there are also small bees that perform this job just as well.

A few other plants, also low-growing, are pollinated by ants. Finally, there are some interesting cases of orchids pollinated by ants in Australia in a highly specialized way. So, yes, ants join the ranks of pollinators. They may even be the pollinators of choice for some plants in harsh, dry climates.

Ant on Queen-Anne-lace. © Beatriz Moisset

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© Beatriz Moisset. 2012