April 22, 2008

All About Ants!

By Michael Pettay, Horticulturist, University of Florida/IFAS
Pinellas County Extension Educator

This is the time of year when we start to receive calls about swarms of flying ants. This makes some curious to know more about them, although most just want to know that they’re not termites! For those latter folks I say look for their little waists. Ants have them. Termites don’t. This article is actually a general information piece about ants. diagram of termite and ant

Now, generalizing about ants is problematic. There are trillions of ants crawling around out there; somewhere around 8,000 species, and life does try everything once! But, here’s the usual case: typically, everyone in the colony is female. The queen is the only fertile, egg layer in the colony. The other females are sterile, and are either workers or soldiers.

The number of males in a colony varies. Consider, for example, the carpenter ants: a common ant found in palms, fallen logs and, occasionally, your attic. A few fertile, winged males and females are born in the spring, and soon swarm out of the colony to mate in flight. antThis seems to happen when extra resources are available. The males die shortly afterwards, but not because of heart failure from all those matings. Males just have short but happy lives. So, in the springtime, until the actual flight, the colony has a small number of males.

Each female tries to found a new colony. Not all succeed. Let’s follow one queen. She seeks moist, dead wood and lays up to 20 eggs. All of the eggs hatch as sterile female workers. The queen continues laying eggs until, after a few years, thousands of sterile workers fill the colony.

Having packed the house, the queen starts new colonies. From the time the young queen founded the colony until now, no males existed. In the spring, she lays eggs that develop into winged males and winged fertile females. The new kings and queens swarm out of the colony and the cycle repeats. ant

So, you ask, how does a queen ant do that? How does she make queens, kings, and workers? Well, the queen controls egg gender mostly through the manipulation of sperm. During that wild, mating party in her youth, she acquired a supply of sperm that lasts her lifetime. She selects suitable partners and mates with several, so her internal sperm bank contains a variety of good genetic material.

A queen controls an egg’s sex by fertilizing or not fertilizing the eggs. Females come from fertilized eggs and males from unfertilized eggs. The males can mate and therefore get to be kings, for a few short days.

Females come in three, types: sterile workers/soldiers and fertile queens. A queen controls which female type emerges through the genes she passes along. Actually, she doesn’t have absolute control over this process and can’t or sterile workers would cease to exist in a few generations. The genes for sterility are expressed conditionally: they may or may not cause a female to be sterile. Genes don’t dictate what happens. Instead, genes have to be turned on and, in the case of queen ants, it's thought that food plays a major role.

The idea is that when the larvae get enough food the larva hormone levels increase and this starts sex-organ development for the adult. A queen emerges.

By the way, the genes of the father ant determine whether a worker becomes a small worker or one large enough (twice the small worker size) to be a warrior or heavy-duty worker.

For more information about ants from the University of Florida, IFAS Extension:

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