Creature Feature

Odorous House Ants

Odorous house ants (OHAs) belong to a subfamily of ants that use strong odors from anal glands as a chemical defense—there is no stinger. The odor isn’t unique to them, but comes in handy when identifying them against similar-looking pest ants. Although historically described as “rotten coconut”, pest management professionals (PMPs) didn’t always agree about what the odor smelled like. A study in 2015 clarified the source of the odor as an organic compound also associated with bleu cheese and rotten coconut. Penicillium molds that turn coconuts rotten are also used to make bleu cheese, so PMPs that smell either are both correct. 

Most PMPs have probably dealt with OHAs since these ants are native to the 48 contiguous United States. Their broad native range indicates that they are adaptable to a variety of environments. In natural habitats, OHAs form small, single-queen colonies that are subdominant to other ant species. However, in urban settings, they adapt so well to man-made environments that they can form supercolonies with multiple queens and nests that are dominant over other ant species.

Since OHAs are opportunistic nesters that can create multiple connected nests, non-repellent products are ideal for managing them. Most of the year, indoor ant complaints are often caused by outdoor colonies. It’s important to inspect building exteriors for ant trails that lead to nests, both of which can be treated with non-repellent liquid residuals. OHAs often nest in wall voids, which can be treated with a non-repellent dust or ant baits.