''Agelena labyrinthica'' is a species of

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

in the family

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 (''Era ...

. It is a widespread species in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and its range extends to Central and East Asia.

Range and habitat

These spiders are fairly common in Europe and Central Europe, and are typically concentrated in areas near forests and low lying vegetation, as well as in dry grasslands. Its range extends to Central and East Asia (Mongolia, China, Korea, Japan). ''Agelena labyrinthica'' build flat plate surface webs connected to funnel-shaped retreats similar to labyrinths, which are typically constructed between low lying grass and vegetation. These webs can be at ground level, or up to from the ground, however, the majority are found approximately off the ground.

Description

Funnel-web spiders typically range in size from for males and for females. ''Agelena labyrinthica'', however, has a body length of up to . The

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

is dark with a pale central band flanked by white chevron marks. The

cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...

is yellow-brown and bears two, broad longitudinal stripes positioned towards the front of the spider. Common to all spiders in the family Agelenidae, is the prominent pair of two segmented posterior

spinnerets A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. Spinnerets are usually on the underside of a spider's opisthosoma, and ar ...

. However, in ''A. labyrinthica'' these segmented spinnerets are further elongated, with the second segment being almost twice the length of the basal segment. Another morphological feature of ''A. labyrinthica'' is the spider's venom apparatus. Showing many similarities with the species ''Loxosceles intermedia'', the venom glands of ''A. labyrinthica'' generally consists of paired structures located in the spider's abdomen. These paired structures interact with two ducts that lead into the spider's fangs. The venom glands of ''A. labyrinthica'' are considered to be relatively large, and extend out of the

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 ...

to reach the middle of the abdomen. The venom glands of ''A. labyrinthica'' also are unique in that they are long and tubular and are surrounded by a layer of muscles that encircle the glands.

Sensory organs

Different from other spiders in the family Agelenidae, the ''A. labyrinthica'', has a set of at least four trichobothria on the upper side of their tarsus of the first pair of legs. ''A. labyrinthica'' have approximately 25 trichobothria per walking leg. These hairs help the spider detect prey that has been caught in its web, or even prey that is near enough to cause vibrations in its web. The trichobothria hairs essentially act as a long-distance sensory system for ''A. labyrinthica'' that helps them detect prey with great accuracy and speed.

Spatial perception

Having to travel between its sheet web and its funnel shaped retreat, ''A. labyrinthica'' have shown signs of detour compensation that allow the spider to orient itself and navigate even in complete darkness. Using its eyes to quickly navigate its web, ''A. labyrinthica'' is able to detect the plane of polarized light present, and position itself relative to it in order to maintain its orientation. However, being a web building spider, ''A. labyrinthica'' does not rely exclusively on visual stimuli for navigation and orientation. ''A. labyrinthica'' also relies on its

idiothetic Idiothetic literally means "self-proposition" (Greek derivation), and is used in navigation models (e.g., of a rat in a maze) to describe the use of self-motion cues, rather than allothetic, or external, cues such as landmarks, to determine posit ...

orientation, as well as directional cues such as gravity, to gain its bearings no matter where it is.

Reproduction and life cycle

Typically in the middle of July, ''A. labyrinthica'' will begin its mating period. Using its

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, the male will tap on the web of the female in order to advertise himself as a potential mate. If the female is ready, she will remain in her funnel, where they then mate. During about August of the same year, the female will create a large, white egg sac, containing roughly 50–130 eggs, within the central remaining chamber of her web, suspended by multiple radiating bands of silk. The outer wall of the retreat may be camouflaged with grass and leaves. Over the winter of the same year, the young spiders survive off of the egg yolk stored in their abdomens, and leave the next spring. ''A. labyrinthica'' is similar to other species of spider in the respect that they practice

matriphagy Matriphagy is the consumption of the mother by her offspring. The behavior generally takes place within the first few weeks of life and has been documented in some species of insects, nematode worms, pseudoscorpions, and other arachnids as well ...

. During the incubation phase, the female ''A. labyrinthica'' stays with developing egg sacs, yet if the female dies before the incubation phase is over, the corpse will be eaten by the young upon hatching.

References

{{Taxonbar, from=Q1315295 labyrinthica Spiders of Asia Spiders of Europe Spiders described in 1757 Taxa named by Carl Alexander Clerck Articles containing video clips