''Argiope bruennichi'', commonly known as the wasp spider, is a species of orb-weaver spider found across Central and

Northern Europe The northern region of Europe has several definitions. A restrictive definition may describe northern Europe as being roughly north of the southern coast of the Baltic Sea, which is about 54th parallel north, 54°N, or may be based on other ge ...

, several regions of

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

and

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

and the

Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...

. Like many other members of the same genus '' Argiope'', this species features distinctive yellow, white and black markings on its abdomen.

Web

The spider builds a spiral orb

web Web most often refers to: * Spider web, a silken structure created by the animal * World Wide Web or the Web, an Internet-based hypertext system Web, WEB, or the Web may also refer to: Computing * WEB, a literate programming system created by ...

at dawn or dusk, most often in long grass just above ground level. The zigzag-shaped web decoration, named the

stabilimentum A stabilimentum (plural: stabilimenta), also known as a web decoration, is a conspicuous silk structure included in the webs of some species of orb-web spider. Its function is a subject of debate. Origin Likely, the use of stabilimenta evolved ...

, is featured at the centre of the orb. Its function is not currently known, though studies have indicated that the webs containing stabilimentia are damaged less often by birds flying through them. When prey gets trapped in the web, the spider immobilizes it by wrapping it in silk. The prey is then bitten and injected with a paralyzing

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 ...

and a protein-dissolving

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

. Wasp spider (Argiope bruennichi) underside, showing stabilimentum.jpg, female on web, showing stabilimentum Wasp spider (Argiope bruennichi) female dorsal.jpg, With wrapped prey, female dorsal side Wasp spider (Argiope bruennichi) female ventral.jpg, With wrapped prey, female ventral side

Population

During the summer of 2006, research found that there had been an influx of wasp spiders in the UK. The colouration of this population is similar, although the yellow stripes are more cream-coloured. Besides the

nominate subspecies In biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. ...

, there is one subspecies currently recognized: * '' Argiope bruennichi nigrofasciata'' Franganillo, 1910 (Portugal)

Sexual dimorphism

''Argiope bruennichi'' exhibit

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

. The males average a length of approximately 4.5 mm while the females average 15 mm. The small size of the male spiders allows them to enter into a female's web undetected in order to mate; a major fitness advantage.

Mating

Certain male ''Argiope bruennichi'' have developed an adaptation to ensure that they are the only male whom the female can produce offspring with. They are able to "plug" the female after they have mated with her to prevent other males from copulating with the female. This plugging involves losing one of his

pedipalp Pedipalps (commonly shortened to palps or palpi) are the secondary pair of forward appendages among Chelicerata, chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to ...

s, thus allowing him to mate only twice. This explains the rushed behaviour a male exhibits after the female has completed her final

moult In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is a process by which an animal casts off parts of its body to serve some beneficial purpose, either at ...

. With males always waiting around for the females to reach full maturity, the race is on for the male who is small enough to not be detected, yet is also able to "plug" the female, as to prevent other males from reproducing with the same female. Because of the damage caused to the male spiders when this act takes place, these spiders are usually

monogamous Monogamy ( ) is a relationship of two individuals in which they form a mutual and exclusive intimate partnership. Having only one partner at any one time, whether for life or serial monogamy, contrasts with various forms of non-monogamy (e.g. ...

. If the females are only able to reproduce once, they must develop a method to produce more offspring at one time (per clutch). This can be caused by multiple things, including a

sex ratio A sex ratio is the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is typically about 1:1 in species which reproduce sexually. However, many species deviate from an even sex ratio, ei ...

that forces these males to make sure they have at least one female to produce their offspring simply because there are not as many females present.They need to develop this larger clutch size to ensure that their genes are passed down based on the survivability of her first clutch. ''Argiope bruennichi'' participate in

sexual cannibalism Sexual cannibalism is when an animal, usually the female, Cannibalism, cannibalizes its mate prior to, during, or after Copulation (zoology), copulation. This trait is observed in many arachnid orders, several insect and crustacean clades, Gastro ...

. The females of this species, typically much larger than the males, almost always consume their male counterparts after copulation. To combat this, males often wait in or near an immature female's web until she completes her final

and reaches sexual maturity. After moulting, the female's

chelicerae The chelicerae () are the arthropod mouthparts, mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated ...

will be soft for a short period and the male may mate without the danger of being eaten. A study into the mating behaviors of ''A. bruennichi'' showed that this tactic raises the chances of the male's survival from 20% (with conventional mating) to 97%.

Effects of micronutrients

Females that consumed a small supplement of dietary essential

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

s produced offspring that survived simulated

overwintering Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activ ...

conditions significantly longer than offspring of other treatments. Results suggest that dietary essential amino acids, which may be sequestered by males from their diet, could be valuable supplements that increase the success of the offspring of cannibalistic females.

References

External links

* * * {{Authority control bruennichi Cosmopolitan spiders Spiders described in 1772 Spiders of Africa Spiders of Asia Spiders of Europe Taxa named by Giovanni Antonio Scopoli Articles containing video clips