''Agelena labyrinthica'' is a species of

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 ...

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 (''Erat ...

. It is a widespread species in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

Range and habitat

''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 of the ground. 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.

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 belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

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 are ...

. 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 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 fangs, or similarly ...

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 Trichobothria (singular trichobothrium) are elongate setae ("hairs") present in arachnids, various orders of insects, and myriapods that function in the detection of airborne vibrations and currents, and electrical charge. In 1883, Friedrich Dahl ...

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 second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and ...

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 as ...

. 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 Europe Spiders described in 1757 Taxa named by Carl Alexander Clerck Articles containing video clips