On Importants

Are ants really that important? Clearly, readers of The Daily Ant ought to be settled on this question. But for the unantlightened, what strong evidence exists in the scientific literature to support the unique importance of ants in, say, tropical ecosystems? A skeptic could make the argument that such a view is only tentatively supported by qualitative assessments, back-of-the-envelope calculations, and inferences from rigorous but highly localized ecological tests. That is, until now!

Enter our team of Hymenopteran heroes: Hannah Griffiths, Louise Ashton, Alice Walker, Fevziye Hasan, Theodore Evans, Paul Eggleton, and Catherine Parr.

An antrepid crew! Alice Walker image unavailable.

The fellowship of the wingless researchers set out to quantify the relative role of foraging worker ants on resource removal across a large ecological area, explicitly comparing the impact of the ant community to other invertebrates as well as vertebrates. Working in a tropical rainforest in Malaysia, this band of biologists set up different types of plots – one set excluded ants using an ant-targeting bait-based chemical treatment, another set excluded vertebrates, and the third set excluded both ants and vertebrates. Then, they placed a variety of baits in each plot, and assessed resource removal rate. Thus, the relative role of ants, non-ant invertebrates, and vertebrates could each be assessed, and the hypothesis of ant dominance tested. [Note: The authors explain that bearded pigs destroyed many of their bait stations, which were removed from analyses, but that “the likelihood of a station being attacked by pigs was not significantly affected by plot treatment, cage treatment or bait type.” Per usual, vertebrates try to meddle in the affairs of inverts, but to no avail!]

What did the group of gregarious myrmecologists discover? Well, as reported in the Journal of Animal Ecology, they found ants to be of remarkable, irreplaceable importance. Specifically, ants contributed to no less than 52% of total bait removal, a percentage that the authors note is surely an underestimate, given that it was only possible to remove about 90% of ants in the ant removal treatment plot. Furthermore, this foraging impact was not compensated for when ants were excluded – that is, non-ant invertebrates were not up to the task of matching the rate of resource removal in absantia.

An ant doing her best to remove a resource. Photo: Alex Wild

Although such an exciting documentation of ant dominance relative to other organisms was unnecessary for those who are already formicid-forward in their thinking, this rigorous work by Hannah Griffiths and colleagues provides a novel type of results that support the view, often held with certainty, that ants are the most functionally important group of macroscopic organisms in the tropics – and, indeed, the world!