This composite image is comprised of one image reflected and rotated to create eight. The unit image is the terminal component of the sting apparatus of Pogonomyrmex badius, the Harvester Ant.
Only female wasps, bees, and ants can sting. The sting apparatus is a highly modified ovipositor, the structure that in “non-stinging” wasps is used to lay eggs. In bees, wasps, and ants, the egg passes through a different opening. The sting is structurally and functionally very complex and composed of several highly modified parts. The stinger is also a bilaterally symmetrical organ; when in use, the paired harpoon-like shafts (lancets) separate from the dorsal cover (stylet) and are stabbed into prey or potential predator. Vibration of the abdomen causes the lancets to “saw,” in a reciprocating pattern, more deeply. At the base of the sting in the abdomen, glandular tissue secretes a cocktail of chemicals that are stored for later use in hunting prey or defense. A channel between the paired lancets and the stylet allows venom to enter the wound. In this species, venom injection works by a “valve-pump” mechanism, in which air is pumped out of a specialized bulb, which causes venom from the poison sac to be drawn into the bulb. Further protraction of the sting forces venom into the sting channel. Harvester ants have a very potent sting; experiments have shown that the venom of this species is one of the most toxic of all known insect venoms. The image was created using a JEOL 5300 scanning electron microscope -- 750X magnification.
Electron microscopy time provided by the Jordan Hall Imaging Facility; Darryl Krueger, Director.