African Wasp Is the name given to the different types of insects belonging to the order Hymenoptera that are not considered ants or bees and whose place of origin is especially to the south of the African continent or Afrotropical region (Noort, 2015).
At present, in Africa, 14 suborders of Hymenoptera Apocritas have been classified, which include at least 60 different families of African wasps, among which are the Apocrita Parasitic (parasitic) suborders as well as Apocrita Aculeata (with sting) ( Goulet & Huber, 1993).
The different types of African wasp are mostly in arid and semi-arid zones, characterized by biomes with diverse and irregular vegetation whose development depends on the rain, altitude and latitude cycles of the area.
Most African wasp species are endemic to the subregions they inhabit, that is, they are found nowhere else in the world, and stand out as both pollen wasps and species of hunting or parasitic wasps.
Pollen wasps live in biomes or arid and semi-arid ecological units, and resemble bees in that they feed their larvae with pollen and nectar; On the other hand, hunting or parasitic wasps inhabit biomes similar to those inhabited by bees (Gess & Gess, 2014).
Both African pollen wasps and hunters or parasites depend on vegetation to survive. Therefore, the presence of floral plants is necessary for the consumption of pollen or the presence of other insects with which the hunting wasps can be fed.
Geographic location
Most African wasps can be found in the south of the African continent, as well as in the southern parts of the Arabian Peninsula, the islands west of the Indian Ocean and Madagascar. Other places where you can commonly find species of African wasps are the islands of Cape Verde and the Gulf of Guinea.
In the case of the northern region of the continent, the wasp variety is small and there are no species typical of the region. Some species can be found at the height of Kenya and even Ethiopia. This situation can be referred to as a bio-polarization of the region as most of the endemic species are found in the south of the continent.
Some entomologists such as Dr. Michael Kuhlmann claim that this bio-polarization of the population of both wasps and African bees corresponds to the humidity conditions of the air. The zones of greater humidity are centers for the reproduction and permanence of the majority of species of Hymenoptera in Africa (Kuhlman, 2007).
Delimitation of the Afrotropical region where most African Wasps species inhabit (Noort, 2015)
Delimitation of the Afrotropical region inhabited by most African Wasps species (Noort, 2015).
African wasp morphology
Principal morphological division of Hymenoptera Apocrita. Dorsal view. (Goulet & Huber, 1993).
The adult African wasp has a complex morphology that is generally composed of three body segments: the head, the thorax and the abdomen.
- Head: is the anterior division of the body of the wasp and always retains a vertical position. It has a semi-hexagonal shape and is contained in a tough sclera capsule.
African wasp species have a pair of antennae located on the head, a pair of compound eyes, and generally three ocelli grouped in the upper central part of the head.
- Thorax or Mesosoma is the middle division of the body of the wasp that allows the head to be rotated freely, increasing the visual range and reach of the wasp's jaws.
As a general rule, African wasps have six legs connected to the body in the thoracic division.
- Abdomen or Metasoma: is the posterior division of the body of the African wasp. It is connected to the thorax by a thin, flexible segment.
In the abdominal cavity of the females is located the ovopositor apparatus, which can be internal or external depending on the type of African wasp. In some species of wasps, however, the ovopositor apparatus has been changed by a stinger and is not used to deposit eggs.
African wasps have four wings located in the thorax or mesosome, a characteristic that differentiates them from other species of flying insects such as flies. Likewise, they have sensorial receivers in the antennas to detect tactile and olfactory stimuli and possibly humidity and temperature.
One of the most notable features of the African wasp is the presence of strong jaws also contained in resistant sclerotic capsules. These jaws are curved appendages located under the eyes that function as a pair of pliers or pliers to bite, cut, chew or load food and materials.
Feeding
Importance of Plants and Flowers
The feeding of the adult African wasp depends directly on the nectar it takes from the flowers. Some females require additional small amounts of nectar as a source of protein for the production of eggs. In the case of African pollinating wasps, flowers play a fundamental role, as they require pollen and nectar for breeding of larvae.
The parasitic wasps or hunters depend directly and indirectly on plants as a source of food. This is because the plants can supply energy to adult wasps and a space to catch the prey necessary for feeding the larvae.
However, no wasp feeds completely on the nectar of flowers or any kind of plant plants. Most wasps limit their feeding to the intake of a limited number of plants, without this implying the dependence of a single species of plant.
For some species of African wasps, the relationship with plants goes beyond feeding, since they form their nests in a parasitic way, deposit eggs and / or raise their larvae (Jones, 1940).
Tusks
The different species of African wasps are mostly polyphagous and predatory. This means that your diet is not limited to the consumption of a single type of food. Among the most common dams are spiders and other insects. Unlike other groups of insects, for wasps the consumption of a single type of prey is unusual, since their diet is broad
Most wasps use their sting or jaws to hunt their prey. Unlike bees, wasps can use their sting to prick their prey several times.
African wasp prey includes phytophagous and non-phytophagous species, that is, African wasps feed on both plant-eating insects and those consuming other types of food (Gess & Gess, 2014).
Table 1: List of phytophagous species consumed by African wasps in southern Africa (Gess & Gess, 2014).
Table 2: List of non-phytophagous species consumed by African wasps in southern Africa (Gess & Gess, 2014)
Nesting and social structure
A nest is defined as the place or structure in which an insect, bird or fish deposits its eggs or gives birth to a baby (McShea, 2001). Most wasps use nests constructed wholly or partly by a single female. Very few wasp species build nests cooperatively.
In the case of African wasps, there are two different ways of nesting without building a nest:
- The female deposits its eggs in the nest of the prey once it has paralyzed it, thus leaving the prey as food for the future larvae.
- The female deposits its eggs in the nest of another species and lets the larva grow by eating the offspring of the host species. Wasps that opt for this nesting mode are known as parasites.
In the case of wasp species that build a nest, there are several types of structures and materials used for this purpose. Sometimes, wasps build their nests completely and in other cases they appropriate cavities located in plants and modify them according to their nesting needs.
In general, the nesting pattern of wasps is characterized by three stages: nest building, feeding of larvae and location of eggs.
Nest built by excavation
In the arid and semi-arid zones of Africa there is a type of nest commonly used by different species of wasps. This nest is made by excavation of sandy terraces easy to drill.
In this case, the female wasp hunts and paralyzes a prey, transports it to the point where it will build the nest, dig the nest, locate the prey, deposit the eggs and finally close the nest. The place where the nest is built is usually near the place where the prey is caught, this prevents it from being stolen by another predator.
This category does not include any African wasp whose feeding depends on pollination and flower nectar.
Aerial nests
Aerial nests are characterized by being built before catching a prey or taking the nectar from the flowers. These nests are generally constructed entirely by the female and are usually more commonly made by pollen wasps.
Species of wasps that build their nest before obtaining food for their larvae have less risk of their prey being stolen. However, when closing the nest, they must have the necessary materials inside the nest, otherwise they may run the risk that their eggs or the prey hunted for future larvae will be attacked by another species.
Positioning of eggs
Most nests made by African wasps are characterized by a single cell. Although the number of prey that is included inside the cell can vary, the amount of eggs deposited in the same one is invariable. A female wasp deposits only one egg per cell.
Depending on the species of wasp and the type of nest is placed first the egg or the prey inside the cell. In the case of pollinating wasps, a layer of pollen and nectar is always deposited first and the egg is deposited on it.
Social structure
Most African wasp species are solitary, although some social species may be found. Social wasps occupy less than 1% of the wasp species in the world and tend to build colonies that function as do most ant mounds or bee hives.
Solitary wasps do not form colonies and tend to hunt prey or to take pollen and nectar from plants without the cooperation of other wasps. On the other hand, social wasps tend to work cooperatively and have a pheromone release system that allows them to send messages to other colony wasps in hazardous situations (National Geographic, s.f.).
Cause of death and extinction
During the last 20 years different strategies have been generated for the preservation of the pollinating Hymenoptera species (wasps and bees) worldwide. The reduction in population of these pollinating species can directly affect food production and biodiversity conservation both on the African continent and on other continents.
One of the main causes of the death of pollinating wasps in Africa is the lack of knowledge about their importance to the ecosystem. Most efforts to preserve species are focused on mammals, reptiles and birds. However, the attention given to insect preservation is limited.
In 1990, John LaSalle and Ian Gauld organized a symposium on the importance of Hymenoptera species for the preservation of biodiversity. During this symposium, the first evaluations were presented on the effects of land overuse on different species of wasps and pollinating bees (LaSalle & Gauld, 1993).
Initiatives for the protection of wasps in Africa
In 1999, the African Pollinator Initiative (API) was created to generate awareness about the importance of pollinating insect species and to promote their conservation. This initiative sought to construct the ideal soil conditions for the reproduction and permanence of pollinating species (Gess & Gess, 2014).
References
- Gess, S. K., & Gess, F. W. (2014). Wasps and bees in southern Africa. SANBI Biodiversity Series , 16-17.
- Goulet, H., & Huber, J.T. (1993). Hymenoptera of the world: an identification guide to families. In H. Goulet, & J. T. Huber, Hymenoptera of the world: an identification guide to families. Ottawa, Ontario: Minister of Supply and Services Canada.
- Jones, M. (1940). Parasitic Wasps. 4-H Club Insect Manual , 34-35.
- Kuhlman, M. (2007). Revision of the bees of the Colletes fascitus-group in southern Africa (Hymenoptera: Colletiday). African Invertebrates 48 , 121-165.
- LaSalle, J., & Gauld, I.D. (1993). Hymenoptera and Biodiversity. . In J. LaSalle, & I. D. Gauld, Hymenoptera: their biodiversity, and their impact on the diversity of other organisms. (Pages 1-26). London: International Institute of Entomology.
- McShea, C.A. (2001). Intermediate-level parts in insect societies: adaptive structures that ants build away from the nest. Insectes Sociaux , Volume 48, Issue 4, pp. 291-301.
- National Geographic. (S.f.). National Geographic . Retrieved from animals.nationalgeographic.com.
- Noort, S. v. (2015). WaspWeb . Retrieved from"WaspWeb": waspweb.org.