The Behavior of Ants
Taxonomy
The classification of ants is as follows:
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Genus: Approximately 290 known genera
Species: Approximately 8800 known species
Morphology
Ants have three major body parts: head, thorax, and gastor (abdomen).
The thorax can be broken down into two major parts: the alitrunk which
contains the legs and wings, and the petiole which is found directly anterior
to the gastor and is found only in ants. Ants have mandibles (jaws) which
are of varied structures. These varied structures provide for a plethora
of functions ranging from grasping, tearing, cutting and other special
tasks. Most ants have a stinger at the end of the gastor. Some ants can
release this stinger in a similar fashion to honeybees. The stinger is
only found in female ants and is a modified ovipositor (egg laying organ).
Ants have compound eyes which have not been shown to effect their behavior,
although some ants seem to be able to detect movement. They have very
sensitive antennae that are used for a wide array of communication.
Nearly all ants have a unique gland found on the petiole called the metapleural
gland. Most importantly, this gland has been shown to contain antibacterial
and antifungal chemicals which are essential for survival in the humid,
dark nests in the ground or rotting vegetation. This gland secretes an
antiseptic substance that at times acts as a repellent to attacking organisms.
It is also thought that the metapleural gland releases pheromones for
communication.
Origins
The oldest fossil remains of modern ants is preserved in amber and has
been dated by radioactive isotopes to be approximately 80 million years
old. It has many of the characteristics of modern ants while also presenting
many characteristics of the ant's distant relative, the nonsocial aculeate
wasp. Like modern ants, the fossil contains the metapleural gland, petiole
turning down towards the gastor, and a relatively small thorax without
wings.
The fossil contains the following wasp like characteristics: short mandibles
with only two teeth, stinger that can be extruded, unconstricted gastor,
and double tibial spurs. The fossil antennae have a short first segment
and a long flexible segmented structure for the rest of the antennae.
This antennae combines both wasp and ant features. An early Cretaceous
fossil that may be an ant has been discovered. Unfortunately, the gastor
has been folded back over the thorax, thereby restricting the view of
the petiole. It is a less well preserved specimen, and, therefore, scientists
are uncertain as to its' morphology.