Ants

Ants along with bees and wasps belong to the large insect order, Hymenoptera. The entire Order contains over 108,000 species named thus far. North America alone has over 20,000 species. What we call ‘ants’ are generally Hymenopterans in the family Formicidae.

Ants are some of the most abundant creatures on earth. If you were to lay down outside anywhere, chances are the first insect you’d come across is an ant. They make up far more biomass than all humans combined and in most ecosystems, more than all the other animals as well.

In our opinion, however, ants are particularly interesting because of their social behavior. The ant colony is composed of a wingless, sterile, cast of female clones and a reproductive cast of winged males and females. The entire colony is centered on the fertile queen ant. Only the queen and the reproductive class have a full set of chromosomes. All the other ants are haploid, meaning they have half the number of chromosomes of the queen. The queen can decide which ants to make part of the worker cast (sterile females), by simply not fertilizing particular eggs. Thus, she keeps from adding that extra set of chromosomes. In the ant world, this makes them female. It also makes all the workers sisters. And, because they are cloned, haploid sisters, they are more related to each other, than they are to the queen or any offspring they would produce. Thus, if you were an ant, it’d be better for you to save your sister than for you to survive and try to produce an offspring of your own

This brings up a very important topic -- ‘altruism’. Have you ever wondered why when you touched an ant nest that hundreds of ants came scurrying out to bite you. If we were living in a ‘survival of the fittest’ world, those ants that came out to sacrifice themselves wouldn’t do so well. They’d survive no more! It’d seem better to run quickly an hide. That is if you see each ant as a single individual. If you see the ant colony, however, as one individual, it makes more sense. People have often made sense of this “survival of the fittest” dilemma by looking at the ants as a some sort of superanimal. But, then again, this is really not how animals work. Just remember, that it does benefit each ant to protect its sister (but only for ants), because of their unique breeding cast system whereby the colony is mostly composed of those sterile, haploid, sister drones.

On our Mexican trip we encountered many ant species. The ones that stick out most in our minds are the leaf-cutter ants, Bullhorn-Acacia ants and the army ants, all of which we found in southern Veracruz.

Leaf-Cutter Ants

Army Ants

Bull-horn Acacia Ants