Synoeca Cyanea

''Synoeca cyanea'', commonly known as the marimbondo-tatu in Brazil, is a swarm-founding eusocial wasp. Native to Brazil and Argentina, ''S. cyanea'' is one of the largest and most aggressive species of social wasps and is feared in many rural areas. It begins its colony cycle in the early spring and continues until nest abandonment. Throughout its life, ''S. cyanea'' forage sugary substances and animal carcasses for food and wood pulp for its nest. ''S. cyanea'' is also known for its strong venom, which is enough to cause haemolytic activity.

Taxonomy and phylogenetics

Johan Christian Fabricius, a Danish zoologist, classified ''S. cyanea'' in 1775. The genus ''Synoeca'' is a part of the paper wasp tribe Epiponini and consists of five species (''S. chalibea'', ''S. virginea'', '' S. septentrionalis'', '' S. surinama'', and ''S. cyanea''). ''Synoeca'' is a basal genus in the tribe. Cyanea, the adjective describing the species, translates to “dark blue,” referring to the metallic blue patches on the exterior of ''S. cyanea''.

Description and identification

''S. cyanea'' is black with metallic blue patches on its body. In addition, ''S. cyanea'' has a red clypeus. While other species in the genus ''Synoeca'' do not demonstrate caste differences, ''S. cyanea'' sometimes shows differentiation between the size of workers and the queen. A queen of a nest that is early in development will often be the same size as the workers and intermediates as it has not fully developed its reproductive organs. As the colony and nest grow, the queen also grows in size, due to ovarian development, until it is larger than the workers and intermediates. When males are present, they are also smaller than the queen.

The Nest

''S. cyanea'' composes its nest out of a single comb with the cells directly attached to a tree. These types of nests are known as astelocyttarous nests. A corrugated, protective envelope made of wood pulp covers the nest, with the entrance on the superior portion of the nest. It is suggested that the architecture of the nest serves as protection against the predation of ants.

Distribution and habitat

While the genus ''Synoeca'' is found from Mexico to Argentina, ''S. cyanea'' is native to almost the whole country of Brazil. Typically, nests are found in the Restinga and the Atlantic Rain Forest. However, ''S. cyanea'' has been known to forage and make nests in mangrove areas.

Colony cycle

''S. cyanea'' starts a new colony cycle during the spring as it gets warmer. The first stage of a new colony is known as the pre-emergence state, in which workers have not been produced. No adult offspring are present and the larvae are still very young. A pre-emergent colony can have one or more queens.

Following the pre-emergent state, the colony grows to the emergent stage. Workers are present along with larvae of different ages and multiple adult generations. In nests with fewer queens, intermediate females can be found.

''S. cyanea'' males are present in the colony during the male-producing stage.

Upon nest abandonment during the late summer, the colony shifts to the quiescent stage, i.e. the nest site no longer houses wasps.

Behavior

Dominance hierarchy

The hierarchy of ''S. cyanea'' is based on physiology, specifically ovarian development. Wasps containing undeveloped filamentous ovarioles, slightly developed oocytes, or some mature oocytes are considered workers and intermediates. Wasps with well-developed and longer ovarioles with mature oocytes become queens. The number of queens in the colony determines the development of a queen’s ovaries. If there are more queens present, the ovaries are at a lower degree of development. One benefit to this is that as a swarming insect, queens with smaller abdomens are able to fly more easily than queens with larger abdomens. This makes the queen less susceptible to predators.

Foraging

Foraging activity for the swarm-founding wasp ''S. cyanea'' begins early in the morning and stops in the evening. During the hottest hours of the day, activity of the wasps is highest. In addition to temperature, ''S. cyanea'' increase their activity with decreased levels of humidity and heightened intensities of light. While foraging, the wasps collect water for temperature control, wood pulp for building and repairing the nest, sugary substances for both the larvae and adults and finally animal protein for larvae.

Nest repair

Following damage by rain to the nest, ''S. cyanea'' will seal a leak of water with their mouth-pieces. Individuals begin by suctioning the water from the wall of the nest and then finish by expelling the water to the exterior of the colony. The hole is then repaired using wood pulp.

Kin selection

Worker-queen conflict

In ''S. cyanea'', discrimination between the queen and workers is often not determined by morphology, but by physiology. Young females in the colony can develop ovaries at different points in the cycle, so castes must be determined by the adult wasps rather than at the larval stage. Often, adult wasps will manipulate young females and suppress their ovaries because a wasp becomes a queen once she has mated. The number of queens allowed in a nest often fluctuates. When queen repopulation is not needed workerpolicing helps to prevent female egg-layers through egg-eating and aggressive behaviors.

Interaction with other species

Diet

The wasps forage for sugary substances to feed to both larvae and adult wasps. Additionally, necrophagy is a common practice for swarm-founding Neotropical bees and wasps, and one species that practices this is ''S. cyanea''. ''S. cyanea'' feed larvae the animal proteins collected. The wasps are predators of the coffee-leaf-miner, ''Leucoptera coffeella''.

Defense

Characteristic to the genus, ''S. cyanea'' will sound an alarm when disturbed. This sound is made when the wasps scrape their mandibles on the carton of their nest. In addition, as one of the most aggressive social wasps, ''S. cyanea'' often will bite and sting when threatened. Their barbed sting often remains in the skin as the wasp pulls away.

Human importance

Venom

''S. cyanea'' venom is strong enough to cause haemolytic activity. Rhabdomyolysis and hemorrhage may also occur. In mice, abdominal spasms, ataxia, defecation, dyspnoea, hyperactivity, hypoactivity, sweating, and throes were observed following venom injection. ''S. cyanea'' venom also contains some antibacterial activity.

Bites and stings

Human accidents with wasps can occur one of two ways. Either a human may receive no more than one or two stings, or a swarm may attack a human. Symptoms following the attack can range from inflammatory reactions to severe allergic reactions resulting in anaphylactic shock. In some cases, death may occur following several bites and a large amount of venom injection; however, a wasp sting typically will not produce a reaction more severe than local symptoms that affect only the skin.

Biocontrol Agent

In Brazil, the fruit fly ''Zaprionus indianus'' is a common pest species that inflicts damage to multiple types of fruit trees. Since ''S. cyanea ''may obtain many nutrients from these fruit trees, researchers have observed the predatory nature of these wasps on ''Z. indianus''. When ''S. cyanea'' detect the fruit fly larvae, they soften, remove, and transport them back to the colony. For this reason, many fruit farmers consider ''S. cyanea'' a prospective candidate for use in pest management.

References

{{Taxonbar, from=Q10375500

Vespidae
Insects of South America
Insects described in 1775
Taxa named by Johan Christian Fabricius