The general life cycle of
Polistes can be divided into four phases: • Founding (or pre-emergence) phase • Worker phase • Reproductive phase • Intermediate phase
Founding (or pre-emergence) phase The founding stage begins in the spring when a solitary female (the "foundress") (or a small group of related females) initiates the construction of a nest. The wasps begin by fashioning a
petiole, a short stalk which will connect the new nest to a substrate (often the eave of a house or outbuilding), and building a single brood cell at the end of it. Further cells are added laterally in a hexagonal pattern, each cell surrounded by six others. Although nests can achieve impressive sizes, they almost always maintain a basic shape: petiolated (
stellocyttarous), single-combed, unprotected, and open (
gymnodomous). Eggs are laid by the foundress directly into the brood cells and are guarded by the foundress and the assisting females (if present). After the first larvae hatch, the foundress feeds them via progressive provisioning, bringing softened caterpillar flesh to the larvae multiple times throughout their development (as opposed to the one-time provisioning seen in some other hymenopteran groups). Each of this first seasonal brood of new paper wasps is exclusively female and destined to a subordinate worker position inside the nest; they do not found their own nests and instead assist their mother in the care and maintenance of future sisters. Some foundress wasps do not build their own nests, but rather attempt to usurp that of another female. These usurpation attempts may or may not be successful, but almost always result in impressive displays of aggression and violence. Females may also adopt a more peaceful alternative reproduction strategy by joining the nest of a close relative (usually a sister) and working as assisting females. In the latter case, such cofounding females are generally, but not exclusively, close relatives.
Worker phase The worker phase usually begins in the early summer, roughly two months after colony initiation, with the emergence of the first workers. These new females take up most of the colony's work duties, foraging, caring for brood, and maintaining the structure of the nest. Around this time, those females which assisted in nest foundation (if present) are driven from the nest by aggressive behavior on the part of the foundress, and leave either to start their own late-season nests or usurp another's.
Reproductive phase The reproductive phase of the colony begins when the first female reproductives (the
gynes) emerge from their brood cells. These reproductives differ from their worker sisters by having increased levels of fat stores and
cryoprotectant carbohydrate compounds (allowing them to survive the overwintering period). These reproductives contribute genes directly to the next generation, while their worker sisters normally pass along their genes indirectly.
Intermediate phase Once male reproductives emerge and both males and females disperse from the natal nest for mating flights, the so-called intermediate phase begins. Brood care and foraging behavior decline and worker numbers drop as dying individuals are no longer replaced by new ones. Intracolonial aggression increases and the social cohesion of the nest declines. In temperate
Polistes species, individuals (almost exclusively inseminated females) gather in groups of up to 50 individuals and seek a sheltered location (called a
hibernaculum) in which to overwinter. ==Behavior==