Are we pre-selecting for new global pest ants?

Tapinoma sessile, the odorous house ant

A new report by Buczkowski & Krushelnyky of Tapinoma sessile spreading in Hawaii (pdf) raises a rather chilling prospect:

Because the odorous house ant ranges as far north as southern Canada and occurs at elevations over 4000 m in North America, there is serious cause for concern that, unlike most invasive ant species in Hawaii, it will be capable of invading high elevation habitats.

Hawaii has no native ants, and the tropical ants introduced to the archipelago are causing serious ecological problems at lower elevations. Now higher elevations may be vulnerable to ants as well. This is not good news.

Tapinoma sessile has always been a home-grown pest in North America, and although the species shows a suite of behaviors common to globally important invaders it had never established elsewhere. Until Hawaii.

What I find particularly interesting about Tapinoma sessile is how its pestiness has apparently increased over time. It is as though proximity to human landscapes has selected for larger colonies of more disturbance-tolerant ants and converted a previously minor nuisance into a more serious concern. This possibility, that some native ants may evolve into global pests simply through extended interactions with our own species, is troubling. New pests might be able to emerge from a much larger and less predictable pool of species that I had imagined.


source: Buczkowski, G., Krushelnycky, P. 2011. The odorous house ant, Tapinoma sessile (Hymenoptera: Formicidae), as a new temperate-origin invader. Myrmecol. News 16: 61-66; published Online Earlier 30 September 2011.

9 thoughts on “Are we pre-selecting for new global pest ants?”

  1. i don’t know if “pre-selecting” is the right phrase, but if you like it, go nuts. any time you have quick population turnover (viruses, bacteria, and yeah, even insects) you will have things thriving when humans remove the natural barriers to success. they will evolve around whatever controls are imposed on them. as long as MNCs make money by selling ever-increasing controls (antibiotics, pesticides, GMOs), you will never see a real attempt to change the process.

  2. I agree, it’s hard to say per-selected is the right word when active volcanoes creating new land are a factor. Hawaii is something of a breeding ground for invasive species already. I think something like 95% of the fauna growing there is comprised of composite ecosystems consisting of nonnative plants.

  3. As a note, in British Columbia, T. sessile is common up to Prince George (54 deg N). No one has sampled for ants above this latitude in BC so it is uncertain where it might disappear. Interestingly, I’ve done a lot of sampling to the west of Prince George near Houston and Smithers and have never encountered it in natural habitats there (clear-cut forests of varying seral age). I did not sample in urban areas though.

    As you move west from Prince George to Houston/Smithers area, it gets cooler and wetter. I’ve always wanted to sample along that route to see where they fall out of the system but have always been travelling with other project demands that necessitate ignoring “just curious” questions.

  4. All species respond to changes in their physical and trophic space. I think that simple adaptation or evolution in action is a more appropriate description of how species respond to the simplification of ecosystems that humans create.

    The ants have more food available and less competition, predation and therefore numbers / biomass increase. Opportunist species who have the flexibility to respond often do well in (human) disturbed environments.

    1. Tim – All species of the subfamilies Dolichoderinae, Myrmicinae and Pseudomyrmeciiniae universally lack cocoons. A number of genera or species in the remaining families also lack cocooons, facultatively or obligatorily.

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