MISCHOCYTTARUS

Primitively Eusocial Wasps

Like most primitively eusocial insects, primitively eusocial wasps have an annual colony life cycle, with new colonies founded in the spring. Queens maintain their dominance over the workers in the colony by aggression, and physical encounters between queens and workers can become quite violent. All primitively eusocial wasps are paper wasps; the nest is constructed of chewed plant material and consists of a series of cells, arranged like a honeycomb.

In some instances primitively eusocial wasp colonies are founded by more than one wasp. The evolutionary dynamics underlying this pattern of multiple founding are complex and have been the center of considerable scientific controversy. Generally all the foundresses are related, the daughters of a queen from the previous season. One view holds that the non-queen foundresses are "ladies-in-waiting", occupying the nest but not working, waiting to take over if the queen dies or if a chance to usurp the queen presents itself. Another view is that the non-queen foundresses are a kind of "insurance policy" placed by the mother against the death of her daughter, the new queen. Finally, multiple founding could be an adaptation to pressure from predators and parasites; in habitats where the risk of predation or parasitism is high, queens protect themselves by grouping together, gaining more from mutual protection than they lose from lost reproductive potential.

The best-known paper wasps are Polistes, which is found through much of the world, Mischocyttarus, which lives in the new world tropics (with a few species making their way into North America), and Ropalidia, from India and Southeast Asia.

Mischocyttarus is an excellent, but somewhat unusual, example of a paper wasp. The queen lays her eggs in the cells and the developing larvae are fed insect prey by the queen (or by workers, once they emerge). Most species in this genus are tropical, but in the United States, we have three different species of Mischocyttarus wasps, one along the West Coast, one in the foothills of the Rocky Mountains as far north as Wyoming, and the other in Florida. They look much like Polistes, but they are distinguished by having a long, narrow petiole between the thorax and abdomen. Mischocyttarus nests are usually better hidden than Polistes, often between walls or, in nature, in cracks in rocks.. Polistes' lifestyle is quite similar to that of Mischocyttarus.