Every year, ants are at or near the top of service numbers for PMPs across the US. Pest species vary, from Argentine ants in the coastal states, to odorous house ants (OHA) in the Midwest (really all over the US, but I digress).
Polygyne in Ant Colonies: Primary and Secondary
It is common knowledge that ants are social, but it may come as a surprise to some that how colonies are organized is the most important factor governing the pest status of many ants. Many pest ants, including Argentine, odorous house ants (OHA), pharaoh, ghost, tawny crazy, and black crazy ants, are what entomologists refer to as “polygyne”, meaning there are multiple queens present in the same colony.
To further complicate the picture, ants can be either primarily or secondarily polygyne. Primary polygyny is less frequent and occurs when multiple queens found a colony without the help of workers. Queens in these species often fight with one another to suppress egg laying in less-dominant queens, especially if resources are scarce.
More common is secondary polygyny, where single-queen colonies accept additional queens or fuse with other colonies. These include the perennially pestiferous Argentine, odorous house, and crazy ants (tawny and black for our purposes).
Polygyne Colonies are Highly Mobile
So why do polygyne species pose such a problem? The answer lies in their nesting habits. Species like OHA, ghost ants, pharaoh ants, and black crazy ants are opportunistic nesters and have multiple nesting sites. They exploit short-lived nest sites, like clumps of leaves or tufts of dead grass that are available for a few days or weeks.
One study found that OHA colony fragments moved every 13 days. By tolerating multiple queens in a colony they are able to quickly exploit these sites and extend their invasion front, akin to the island hopping strategy employed by the Allies in the Pacific during WWII. Because these fragments will inevitably lose contact with one another, sometimes forever, having enough reproductive females to provide offspring to the many subunits means polygyne colonies are better at exploiting rapidly fluctuating environments.
Ant Control for Polygyne Species
For example, a bad Argentine ant infestation may have tens of millions of ants. At 17 queens for every 1,000 workers, we’re looking at hundreds of thousands of queens, and even more if the house happens to be on an invasion front.
Good luck killing all 170,000 queens with a single treatment. Even if you did, workers can rear new queens from existing eggs and first instar larvae. The goal for many polygyne species is to eliminate as many individuals as possible, which is generally accomplished using non-repellent products that don’t kill too quickly and transfer between nestmates. Baits, especially exterior baiting, should be considered as well.
To summarize, polygyne ants have multiple queens, exploit short-lived habitats, and don’t fall under the “kill the queen, kill the colony” paradigm. They exhibit some of the most complex social behavior in the animal kingdom and by understanding their behavior and colony structure it is possible to set appropriate expectations and provide superior control for customers.
More Resources
- Learn more about ants and get tips for ant control in MGK’s latest PMP Pulse Newsletter.
- MGK’s newest ant control solution, Sumari® Insecticide, can help you kill and control several polygyne ant species.
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