''Anoplius viaticus'', commonly known as the black-banded spider wasp, is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
spider wasp
Wasps in the family Pompilidae are commonly called spider wasps, spider-hunting wasps, or pompilid wasps. The family is cosmopolitan, with some 5,000 species in six subfamilies. Nearly all species are solitary (with the exception of some group-ne ...
. These wasps are known as spider wasps because the females capture spiders to provide their offspring with food. The paralysed spider is cached in a burrow, the wasp lays an egg on it, and when this hatches, the developing wasp
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
consumes the spider. This species is found in sandy heathland across most of Europe.
Description
''A. viaticus'' is a large species of spider-hunting wasp and measures about in length.
The head and thorax are black and the
propodeum
The propodeum or propodium is the first abdominal segment in Apocrita Hymenoptera (wasps, bees and ants). It is fused with the thorax to form the mesosoma. It is a single large sclerite, not subdivided, and bears a pair of spiracles. It is strongl ...
is fused to the thorax and bears erect black hairs. The first three
terga
A ''tergum'' (Latin for "the back"; plural ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'ma ...
of the abdomen are red with black rear margins and the remainder of the abdomen is black.
Diet
Adult ''A. viaticus'' feed on nectar from flowers. Wasps in this species predominantly prey on spiders from the wolf spider family
Lycosidae
Wolf spiders are members of the family Lycosidae (). They are robust and agile hunters with excellent eyesight. They live mostly in solitude, hunt alone, and do not spin webs. Some are opportunistic hunters, pouncing upon prey as they find it or ...
, but they also take ground spiders (
Gnaphosidae
Ground spiders comprise Gnaphosidae, the seventh largest spider family with over 2,000 described species in over 100 genera distributed worldwide. There are 105 species known to central Europe, and common genera include ''Gnaphosa'', ''Drassodes ...
), grass spiders (
Agelenidae
The Agelenidae are a large family of spiders in the suborder Araneomorphae. Well-known examples include the common "grass spiders" of the genus ''Agelenopsis''. Nearly all Agelenidae are harmless to humans, but the bite of the hobo spider (''Erat ...
), crab spiders (
Thomisidae
The Thomisidae are a family of spiders, including about 170 genera and over 2,100 species. The common name crab spider is often linked to species in this family, but is also applied loosely to many other families of spiders. Many members of thi ...
) and jumping spiders (
Salticidae
Jumping spiders are a group of spiders that constitute the family Salticidae. As of 2019, this family contained over 600 described genera and over 6,000 described species, making it the largest family of spiders at 13% of all species. Jumping spi ...
).
Biology
''Anoplius viaticus'' is unusual in that it overwinters as an adult, hibernating in a deep burrow. This enables it to emerge and become active earlier in the year than other related species. In southern England, it is on the wing from March onwards.
[
The female ''A. viaticus'' searches for a suitable ]spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
with which to provision its nest. The spider is injected with venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...
to paralyse it and is dragged back to the chosen nesting location. The wasp puts the spider down and digs a shallow burrow. The spider is then dragged into the burrow, the wasp lays an egg on its still-living body and plugs the burrow with soil. Further similar single cell nests are excavated and provisioned, usually in close proximity to the first.prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...
before it is brought to the nest site, or they may take it while the nest is being excavated. Wasps have been observed to deposit their paralysed prey in grassy areas, where it is perhaps less visible to conspecifics
Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species.
Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organis ...
, while the nest burrow is dug. Even after the burrow is sealed, it is not entirely safe, as other wasps may try to unseal it and lay their eggs on the prey, a practice known as brood parasitism
Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own ...
. Female wasps defend their nesting site and drive away conspecifics that come too close. They seem to be concerned for the safety of their future offspring because they frequently interrupt their hunting to return to the nest site, and the clustering of the burrows makes their defence easier.[
]
References
Further reading
* A series of photos showing ''Anoplius viaticus'' trapping a spider and fighting off other predators, in order to lay her egg.
{{Taxonbar, from=Q1472112
Pompilinae
Hymenoptera of Europe
Wasps described in 1758
Taxa named by Carl Linnaeus