Rediscovering a small piece of New Harmony's heritage:

In 1836, Thomas Say published descriptions of dozens of new insect species that he had found in New Harmony, Indiana during the time that he lived and worked there. These descriptions were the partial result of more than a decade of work in New Harmony by a scientist who is now remembered as one of the great pioneers of biology and natural history in the exploration of the New World. One of the insects named and described by Say was a tiny yellow ant, about 2 mm or 1/8 th of an inch in length, named Solenopsis molesta. S. molesta, roughly traslated: the "bothersome scar-face", was well known to the Harmonists as the "little yellow ant" and was sometimes a real pain in the Harmonists' necks (or whatever body part the ant happened to crawl over). In his description, Say writes:

[The ant] is frequently found in houses in great numbers. They sometimes eat vegetable food, and some of my garden seeds have severely suffered from their attacks. They also devour grease, olive oil, &c. Their sting is like the puncture of a very fine needle. I placed a piece of meat on a window board frequented by these little depredators; it was soon absolutely covered by them, and thus enabled me to destroy thousands, every few hours that I returned to examine the bait, for several days, during which time their apparent numbers scarcely diminished.

Modern houses are usually safe from these ants, which cannot stray too far from moist dark conditions beneath the surface of the soil but the ants may still be found outdoors.

Like the vast majority of plants, animals, fungi, and protozoa in the world, this ant has happily spent the last 160 years since Say's orginal description going about it's business in obscurity, Say's description and naming notwithstanding. The ant has no problem knowing who it is. The same cannot be said of biologists, however. When scientists discover a new species and name it, they must designate an actual specimen or group of specimens as a "type". In this way anyone studying this species in the future has an absolute comparison that allows him or her to know that they are working with the correct creature. Type specimens are then, the only physical link between the ideas contained in species' names, species' descriptions, and the accumulated knowledge published in scientific paper on the biology of any given species. Unfortunately, many of Say's type specimens have been lost in the last century and a half, including S. molesta. So, the identity of S. molesta is currently a mystery.

To further complicate matters, the diversity in the genus Solenopis is poorly known; these ants are small and the different species often look very similar to each other. It is almost certain that there are some species that have been named more than once, some species names that encompas more than one species, and some species that are entirely new to science in this genus. Hence, my ant project is to collect and study Solenopsis species from the places where Thomas Say did the same thing in the scientific heyday of New Harmony more than 160 years ago. The object of this work is to rediscover Say's ant and bring some order to the portion of the genus Solenopsis that contains the species S. molesta and other species closely related to it. Some aspects of the ant's biology are helpful in this pursuit.

Biology of the Thief Ants

Thief ants are a group of ants within the genus Solenopsis that make their living by constructing a nest next to the nests of other ants. They then tunnel into the nest of the neighboring ants and make their way to the brood chambers where larvae, pupae, and eggs are kept. Once there, the thief ant foragers live up to their name by carrying off the eggs and brood of their hosts. The stolen brood becomes the food of the thief ants. Some thief ants (those in the S. molesta species group) may also occasionally become household pests, living in nests constructed in cracks, under floors, and behind baseboards from which they forage on greasy scraps that they find in the house. Thief ants are able to effectively steal the brood of their hosts and retreat to their own burrows for several reasons. First, they are extremely small. The tunnels that they use to infiltrate the host nests are small enough that the host defenders cannot persue them. Second, these ants are ferocious fighters with strong mandibles and a nasty sting. Finally, the venom of thief ants is, itself, a powerful ant repellent and the theif ants use it to make the portions of the host ant's nest that they invade noxious to the hosts. For a delightful and quaint summary of thief ant biology, click here.