Taxonomy and phylogeny
''Belonogaster petiolata'' belongs to theDescription and identification
These wasps have aDistribution and habitat
''B. petiolata'' can be found in southern Africa and they have a large presence in the country ofColony cycle
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 (Mortality and decline of a colony
Several factors appear to contribute toBehavior
Dominance hierarchy
The workers carry out nearly all the basic work, like creating and fixing damage to the nest, getting food, and feeding the larvae. The queen's primary job is to lay eggs. When there is an active queen, workers often have undeveloped ovaries. However, when the queen is removed, 11% of workers develop mature ovaries. This is reproductive suppression under the power of the queen. If there are any eggs found that are not laid by the queen, she eats them (Dominant interactions and communication
The queen creates a dominance hierarchy by initiating dominant interactions. These include biting, hooking, and soliciting. In hooking, females grasp subordinates and hang from them in a hook like formation while receiving regurgitate. The queen often displays these behaviors to assert her dominant status to the other wasps. In soliciting, the dominant female approaches the other female with her antennae outstretched and antennates her head, especially her mouthparts. The other females respond by ignoring the soliciting, remaining immobile in a submissive way until the other wasp leaves, or by soliciting back. Sometimes the queens initially exhibit dominance behaviors, but then move to the top of the nest and become more inactive towards the end of the colony cycle. Other times, the queens are always dominant throughout the whole cycle. Females usually direct their dominance behaviors at the females directly below them in the dominance hierarchy. The queens are the most aggressive females in the nest, so receive fewer threats.Oophagy and oviposition behaviors
Sometimes, a queen or another female will eat eggs laid in her own colony. The majority of the time she eats the eggs of her subordinates, however, a female may occasionally eat her own eggs. Queens also undertake egg inspections to see if the eggs in the nest are their own or if they were laid by a subordinate. The majority of oophagies are committed by the queen (87.5%). Oviposition is the laying of eggs. Queens lay 83.3% of the eggs in pre-emergence colonies, which is a significantly higher rate of oviposition than that of subordinates. Workers were never observed eating or laying eggs.Trophallaxis
The larval saliva of ''B. petiolata'' contains manyKin selection
Caste system
There is a caste system within the ''B. petiolata'' colonies. There are physiological and morphological differences between worker castes and reproductive castes. Foundresses and gynes (reproductive caste) are generally larger than workers. When workers are first born their body size is much smaller than gynes and foundresses, but later in the colony cycle, their size grows more similar to gynes. Foundresses and gynes have larger ovaries and more fat content than workers do. Workers have broad heads, while the reproductive caste wasps have broader thoraces and gasters. Typically, foundresses are larger than their subordinates. Also, about 98% of queens (foundresses) and 95% of gynes are found to be inseminated, while workers are not. They have immature ovaries that do not function in the presence of an active queen. When there is no active queen, about 11% of workers develop mature ovaries. Active queens are the primary egg layers in colonies and possess well-developed ovaries. Differentiation of castes sometimes occurs early during larval development, or it can happen during the later adult stage due to differing social communications and adult nutrition. A wasp's ability to survive winter, and its number of fat reserves, has been used to distinguish gynes from workers. Fat content is an indicator of caste.The removal of the queen
The dominance of the queen over the colony keeps the subordinant nature of worker wasps intact. When a queen dies, however, an older alpha worker, that was likely present when the colony was younger, often takes up the dominant position. The loss of a queen is also associated with the development of ovaries in 11% of worker wasps and in many alpha workers. During the pre-matrifilial stage, in colonies of ''B. petiolata'', removal of the queen led to her replacement by the second most dominant foundress, who is known as a beta-foundress, instead of a worker.Reproduction
Copulation
Mating occurs when a male wasp approaches a female, and the two undergo mutual or unilateral antennation, where the pair touches each other's antennae or the male probes the female's thorax and abdomen with his antennae. Then, the male mounts the female and begins to establish genital contact by touching the female's abdomen with his own. Copulation only lasts about five seconds.Keeping, M. G., D. Lipschitz, and R. M. Crewe. "Chemical Mate Recognition and Release of Male Sexual Behavior in Polybiine Wasp, ''Belonogaster Petiolata'' (Degeer) (Hymenoptera: Vespidae)."Journal of Chemical Ecology 12.3 (1986): 773–79. Web. 20 Sept. 2014.Ovary size
The ovarian width of gynes increased from April to July which is within the overwintering period. From July through August, mean ovarian width of overwintering females increased sharply, and then fell between late August and September. The percent of gynes with mature oocytes in their ovaries increased from 2.9% in April to 15.6% at the end of July, and then lastly to 45.7% in August. Female wasps with larger ovaries are more likely to lay eggs. Workers have thin, inactive ovaries that prevent them from ovipositing.Insemination
Workers are rarely, if ever, inseminated. None of the workers from pre-matrifilial and matrifilial colonies were observed by Keeping, M.G. (2002) to be inseminated. Overwintering gynes from Sterkfontein cave had the highest percent insemination. Lack of insemination has frequently been used as a criterion for distinguishing queens from workers in social wasps. All queens and nearly 98% of subordinate foundresses were inseminated. Workers may not be inseminated because they emerge over the period of the colony cycle when males are absent. Inseminated daughters were only recorded from late February onwards, coinciding with the period of male production. Of course, inseminated individuals are more likely to lay eggs and are seen as part of the reproductive caste.Mate recognition cues
Gynes and other female wasps have mate recognition signals, or pheromones, within their venom, thorax and heads. This causes males to be attracted to them. The pheromones within the venom seem to be very strong compared to pheromones from the thorax and head. These pheromones are often spread all over the body during grooming, further increasing the females' attractiveness to males.Keeping, Malcolm G. "Absence of Chemical Alarm in a Primitively Eusocial Wasp (''Belonogaster Petiolata'', ''Hymenoptera: Vespidae'')." Insectes Sociaux 42.3 (1995): 317–20. Web. 20 Sept. 2014.Diet
''B. petiolata'' eat solid food as well as drink nectar as a food source. They prey on grubs and other small insects. Often they chew the food and regurgitate it back up to feed others and the young brood. They also need water to survive. Queens always receive more food. They get 43.7% of liquid loads and 47.8% of solid food loads. They only fed 63.3% of this solid food to larvae and kept the rest for themselves. A lapse in solid food can cause a colony to decline. In late summer, there is often a reduction in the amount of available prey, so many wasps switch to just foraging for nectar, using this as its primary food source. Poor rainfall is often the cause for a decrease in prey abundance. Wasps are fed and enjoy mealworms when they are in captivity.Growth and development
Recently emerged individual young wasps have black or brown eyes, while older individuals have pink eyes and grow wings to fly. When workers are first born, they often huddle together in a corner to avoid aggressive acts from other workers. Workers do not perform dominance actions until they are around 17 days old. Also, the emerging young ''B. petiolata'' body sizes increase from January through March, which is the end of adult emergence. Since worker production extends until the end of January, workers arising this month were bigger in size than those born in the earlier part of the season, around November and December. Variations in reproductive capacity and body size of the female young are due to changes in the amount of food given to them when they were larvae. Growth is a function of the worker to larvae ratio. The more workers there are, the more opportunities there are for larvae to be fed. In ''B. petiolata'', this ratio increased during November and December. This is the time period when gynes were being reared, indicating that there are more workers available to give food to the young that will become a part of the highest caste and need the most nutrition. The amount of food given to larvae influences caste.References
{{Taxonbar, from=Q14423167 Vespidae Hymenoptera of Africa Insects of South Africa Arthropods of Southern Africa Cave insects Insects described in 1778