Why haven't we seen many fire ant mounds this spring?

April 28, 2006

Question Why haven’t we seen many fire ant mounds this spring?

Answer All gardeners know how hard it can be to dig in dry soil. Imagine how hard it would be to dig if the soil was dry and you were only a quarter of an inch long. Fire ants, like many insects, will wait until it rains before they begin any tunneling action.

Fire ants also live in colonies which produce new queens in the spring and fall. These new queens don’t wait to inherit the “queendom”. They have to start their own empire somewhere else. Over the years, these ants have learned to synchronize the release of the new queens with the rain.

Actually, there is a series of events that takes place in the colony when the rain comes in the spring and fall. First, the new queens and males are released from each colony. This release will typically take place around midday when the temperature is about 74˚F. Both the males and new queens have wings. After a sip of Red Bull (not really), they fly to a height between 300 and 900 feet. Mating takes place in the air. The males die shortly after falling back to earth. The queens will fall to the earth and rake their legs forward to snap off their wings. Evidently, mating in the air at a high altitude isn’t as exciting as it sounds.

In the South, as many as 97,000 queens may be produced per acre of infested land per year. Windy conditions during the mating process can spread the new queens over miles of terrain. Luckily, only 1% survive after they mate. Predators get most of them.

The surviving queens will produce 10 to 20 eggs per day for a few weeks. Within six to twelve months, a queen is capable of producing approximately 800 eggs per day. The average lifespan of a fire ant queen is six years. A mature colony will average 400,000 worker ants.

This spring, the fire ants have been waiting for rain. Even though the temperatures this winter and spring have been relatively mild, the rain clouds have refused to gather over North Carolina. Since the rain has arrived, the population explosion is on the horizon. Brace for impact.

If you have any questions about fire ant management, then visit this website http://fireant.tamu.edu/ If you don’t have internet access, then call the Cooperative Extension Office at 893-7533, write us at PO Box 1089, Lillington, NC 27546, or email me at gary_pierce@ncsu.edu The take home message for fire ant migration is “when it rains in the spring and fall, it also rains fire ants.”