Agelena consociata
Encyclopedia
Agelena consociata is a social
Social spider
A social spider is a spider species whose individuals form relatively long-lasting aggregations. Whereas most spiders are solitary and even aggressive toward conspecifics, some hundreds of species in several families show a tendency to live in groups, often referred to as colonies, and continue to...

 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of funnel web spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...

 that occurs in tropical forests in West Africa and lives in colonies
Colony (biology)
In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...

 of one to several hundred individuals.

Distribution

This species is found in rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...

 habitats in Gabon
Gabon
Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west...

. It favours dense forests along creeks where colonies can build huge complex webs
Spider web
A spider web, spiderweb, spider's web or cobweb is a device built by a spider out of proteinaceous spider silk extruded from its spinnerets....

.

Description

Male and female spiders are similar in size but there are fewer males than females. This spider is a dull brown colour with two broad lateral grey stripes. The legs are banded in brown and black. Both body and legs are covered with short hairs.

Ecology

The web structure consists of individual nests connected by flat sheets of silk
Spider silk
Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...

 supported by vertical scaffolding threads. There are a number of retreat holes leading into the nests and groups of nests are often joined by more sheets of webbing and scaffolding.

Although these spiders live in colonies consisting of many individuals, each spider acts and breeds individually and there is not any specialization of role as there is with social insects
Eusociality
Eusociality is a term used for the highest level of social organization in a hierarchical classification....

. The spiders cooperate in the maintenance of the web and the catching of large prey
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

. As many as forty spiders have been seen feeding on one victim and adults often regurgitate to feed juveniles that are not their own offspring. In fact there is considerable tolerance of the young which continues into adulthood in a way that is not seen in non-social spiders. When spiders are introduced into a colony from elsewhere, they are accepted; it is the species that matters, not the origin. This again is in contrast to social insects which defend their nests against outsiders. The spiders communicate through the use of pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...

s and also through the vibrations of the web structure.

A new colony can be started by a single female spider, a group of immatures or by a group of adults and juveniles. Eggs are laid at times of high humidity and there are a large number of cocoons between November and January.

No evidence was found of active dispersal from a colonial site. New colonies are usually founded as a result of accidental destruction of an existing colony by storm or falling branches. Another means of dispersal over larger distances is likely to be passive transport of spiders by bat
Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

s or other vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...

s. On examination of the genetic makeup of the colony, it was found that colonies separated by thirty metres were likely to be as genetically distinct as colonies separated by many kilometres.

The web structure may appear empty during the day because the spiders lie hidden, emerging at nightfall to repair the web and hunt. Most of the prey is caught at night.

It is thought that this species may have developed colonial behaviour because of the difficulty of dispersal in the rainforest environment. Other reasons might be the individual cost of repeatedly repairing a web frequently damaged by tropical downpours and particularly, because of the continuity of generations that occurs, a thing that is not possible in cooler climates.
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