''Parachartergus apicalis'' is a species of

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. Th ...

in the

Polistinae The Polistinae is a subfamily of eusocial wasps belonging to the Family (biology), family Vespidae. They are closely related to the more familiar wasps (“yellowjackets” as they are called in North America) and true hornets of the subfamily V ...

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

, found in the

Neotropics The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropics, tropical Ecoregion#Terrestrial, terrestrial ecoregions of the Americas and the entire South American temperat ...

. It was first described by

Johan Christian Fabricius Johan Christian Fabricius (7 January 1745 – 3 March 1808) was a Danish zoologist, specialising in "Insecta", which at that time included all arthropods: insects, arachnids, crustaceans and others. He was a student of Carl Linnaeus, and is cons ...

in 1804. In

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...

, they are known as ', which translates into English as "white wings".

Behaviour

They have been observed to

swarm Swarm behaviour, or swarming, is a collective behaviour exhibited by entities, particularly animals, of similar size which aggregate together, perhaps milling about the same spot or perhaps moving ''en masse'' or migrating in some direction. ...

when they move between nests, with the behaviour occurring between April and May in

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...

. At times they form temporary compact clusters along the route of the swarm; each cluster is evenly spaced and individuals move from one clump to the next, with the clumps at the back shrinking, whilst those at the front grow. It is uncertain how they navigate between the clumps, but it is thought they use either visual or olfactory cues. False swarming can also occur when strong winds prevent foragers from entering the nest. Parachartergus apicalis treehopper tending

Parachartergus apicalis treehopper tending

They have been recorded to tend species of

treehopper Treehoppers (more precisely typical treehoppers to distinguish them from the Aetalionidae) and thorn bugs are members of the family (biology), family Membracidae, a group of insects related to the cicadas and the leafhoppers. About 3,200 species ...

plant sap Sap is a fluid transported in xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from latex, resin, or cell sap; it is a sepa ...

-feeding insects, during the daytime, an example of a mutualistic relationship. The wasp protects the treehopper

nymph A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are ty ...

s from predators and parasites and in return feeds on honeydew which is produced by the nymphs. At night the

carpenter ant Carpenter ants (''Camponotus'' spp.) are large () ants indigenous to many forested parts of the world. They build nests inside wood consisting of galleries chewed out with their mandibles or jaws, preferably in dead, damp wood. However, unlik ...

species, '' Camponotus atriceps'' will tend the nymphs. During the day, ''P. apicalis'' will attack these ants, preventing them from tending the treehoppers. Each wasp is loyal to one group of treehopper nymphs, and will only leave them for less than 10 minutes at a time. The closely related species, ''

Parachartergus fraternus ''Parachartergus fraternus'' is a neotropical, swarm founding, polistine wasp species that is distributed throughout Central and South America.Leonardo, Paula C., Flavio R. Andrade, and Fabio Prezoto. "Foraging Behavior in the Neotropical Swarm- ...

'' also tends treehoppers. The

genitalia A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...

of males can perform movements of "startling complexity". The

aedeagus An aedeagus (plural aedeagi) is a reproductive organ of male arthropods through which they secrete sperm from the testes during copulation with a female. It can be thought of as the insect equivalent of a mammal's penis, though the comparison ...

is flexible and can move from side to side, as well as rotating 180° on its long axis, making the slightly bulbous tip move either to the left or the right. There are also two finger-like digiti which can move independently of each other and the aedeagus. West-Eberhard described the movements of the genitalia as being the "most fluid and subtly modulated movements" that she had ever observed in wasps. She also suggested that males may stimulate the females with their genitalia during courtship. They may be necrophagic, but this is based on an observation that one of their nests smelt of rotting meat and no direct observations of necrophagy have been recorded.

Mimics

''P. apicalis'' is mimicked by two species of

Lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...

, '' Sphecosoma aliena'' and '' Myrmecopsis strigosa''. These are thought to be examples of

Müllerian mimicry Müllerian mimicry is a natural phenomenon in which two or more well-defended species, often foul-tasting and sharing common predators, have come to mimic each other's honest warning signals, to their mutual benefit. The benefit to Müllerian ...

, since predators pay a high penalty for mistaking a Lepidopteran for the wasp and there is a small reward from correctly identifying the Lepidoptera, since they are bitter tasting and covered in scales.

References

{{Taxonbar, from=Q1817601 Vespidae Hymenoptera of South America Insects described in 1804