Belonogaster petiolata

Belonogaster petiolata is a species of primitively eusocial wasp that dwells in southern Africa, in temperate or subhumid climate zones. This wasp species has a strong presence in South Africa and has also been seen in northern Johannesburg. Many colonies can be found in caves. The Sterkfontein Caves in South Africa, for example, contain large populations of B. petiolata. This species primarily eats small insects, especially caterpillars, which are considered its 'solid food', while nectar is its liquid food. It also requires water for survival. Belonogaster petiolata belongs to the genus Belonogaster, of the subfamily Polistinae, and is closely related to B. juncea and B. grisea. Belonogaster wasps are part of the family Vespidae and the order Hymenoptera. Species in this family display a full range of social organization, from completely solitary to highly eusocial life cycles. Many of B. petiolata's characteristics are very similar to those of B. grisea. In both species, the production of smaller, unmated worker offspring reaches a maximum before the production of larger queens who leave the nest and mate. These wasps have a thorax (upper midsection area) and a longer striped gaster with a sting on the end. The peduncle is the first gastral segment. The legs are attached to the thorax. The queen B. petiolata has a large gaster and a smaller head, while the worker wasps have relatively large heads and smaller gasters. Also, queens, males and other members of the reproductive caste have larger fat reserves than the workers, allowing them to survive the winters. B. petiolata construct paper nests out of pulp that often hang in caves or under shelter. The wasps often get pulp from old cells or from larvae just before maturation. Before the larvae mature, the wasps chew the cells at the base to help the offspring emerge. This cell debris is used to build nests. The nest has combs in which the queen often dwells. Later on, however, the queen may move to the top of the nest to rest. B. petiolata can be found in southern Africa and they have a large presence in the country of South Africa. They prefer warm temperate or moist subhumid climates, with mean daily temperatures varying between a maximum of 25 °C (77 °F) and minimum of 14.9 °C (58.8 °F) in January and a maximum of 15.7 °C (60.3 °F) and minimum of 5.3 °C (41.5 °F) in June. This species primarily resides in sheltered caves. They build nests hanging from cave walls. This species is abundant in southern Africa, and it is not a threatened species. The annual nesting cycle of B. petiolata is similar to other Polistines that dwell in similar temperate climates. Colonies which are started by a single queen are usually only primitively eusocial and smaller in size, while colonies started by groups of queens are more eusocial and house more individuals. The annual nesting cycle in B. petiolata typically begins in August, where nests are created by overwintered foundress females. In a colony, there is a pre-emergence period. This occurs before the emergence of the first offspring, which are the worker wasps. Next, there is a post-emergence period, which is the whole duration of the colony cycle following the appearance of offspring wasps. There is also a pre-matrifilial phase, which is the first part of the post-emergence period when subordinate foundresses are still present in nests and interact with workers. Following this period is the matrifilial phase which follows the disappearance of all subordinates. Now, colonies consist only of the queen and her workers. Lastly, there is a reproductive phase where reproductive offspring (gynes and males) are born. Typically, gynes begin emerging from nests in early February, so any female collected in colonies up to the end of January of each season will most likely be workers. Nesting is annual with single, overwintered foundresses initiating new nests in spring. The overwintering period is about 4.5 months. Later, in roughly half of the cases, one or more additional females come to form multiple foundress colonies and join these initial foundresses. Foundress associations of up to 16 foundresses can be formed. A dominance hierarchy then forms with the dominant female becoming the queen and the others becoming subordinates. The queen helps build and initiate the nest at first, during the pre and post emergence periods, but then becomes lethargic. She stops foraging for pulp and ceases her aid in the nest construction. At the end of the season, the female queen leaves the nest for the winter and returns the following year to create a new colony. Several factors appear to contribute to brood decline and the end of the colony cycle in B. petiolata. These include: cessation of the supply of solid food to colonies and larvae during the reproductive phase, a decrease in the worker/larva ratio during the latter phase due to the slow loss of workers, increasing the number of gynes and males, and an adult priority over food reception from foragers. The brood gets aborted to feed hungry adults. Eventually, the brood declines and the adults leave the nest. Usually, some cell demolition is done by the queen in post emergence colonies.