Agelena labyrinthica
Encyclopedia
Agelena labyrinthica is a species of spider
in the family Agelenidae, which contains 1146 species of funnel-web spiders. It is a widespread species in Europe
, where there are 180 species, and in Central Europe, where there are 30 species currently known.
Funnel-web spiders typically range in size from 8–12 mm (0.31496062992126–0.47244094488189 ) for males and 10 millimetre for females. Agelena labyrinthica, however, has a body length of up to 18 mm (0.708661417322835 in). The abdomen is dark with a pale central band flanked by white chevron marks. The cephalothorax
is yellow-brown and bears two, broad longitudinal stripes positioned towards the front of the spider.
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.
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.
orientation, as well as directional cues such as gravity, to gain its bearings no matter where it is.
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, which is then transported outside and hung from the edges of the web with multiple radiating bands of silk. The egg sac is allowed to hang freely, camouflaged with grass and leafs, until the newly born spiders hatch from the egg sac. 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. 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.
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...
in the family Agelenidae, which contains 1146 species of funnel-web spiders. It is a widespread species in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, where there are 180 species, and in Central Europe, where there are 30 species currently known.
Funnel-web spiders typically range in size from 8–12 mm (0.31496062992126–0.47244094488189 ) for males and 10 millimetre for females. Agelena labyrinthica, however, has a body length of up to 18 mm (0.708661417322835 in). The abdomen is dark with a pale central band flanked by white chevron marks. The cephalothorax
Cephalothorax
The cephalothorax is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax...
is yellow-brown and bears two, broad longitudinal stripes positioned towards the front of the spider.
Range and habitat
A. labyrinthica build flat 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 1.5 metres (4.9 ft) from the ground, however, the majority are found approximately 60 centimetres (23.6 in) 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
Common to all spiders in the family Agelenidae, is the prominent pair of two segmented posterior spinnerets. 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 intermadia, 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 cheliceraeChelicerae
The chelicerae are mouthparts of the Chelicerata, an arthropod subphylum that includes arachnids, Merostomata , and Pycnogonida . Chelicerae are pointed appendages which are used to grasp food, and are found in place of the chewing mandibles most other arthropods have...
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 trichobothriaTrichobothria
Trichobothria are elongate setae, present in the arachnids, and various orders of insects, that function in the detection of airborne vibrations and currents.-Morphology:...
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 idiotheticIdiothetic
Idiothetic literally means "self-proposition" , and is used in navigation models as in the phrase "idiothetic cues" to indicate that path integration was used to determine the present location instead of allothetic, or external, cues...
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 pedipalpPedipalp
Pedipalps , are the second pair of appendages of the prosoma in the subphylum Chelicerata. They are traditionally thought to be homologous with mandibles in Crustacea and insects, although more recent studies Pedipalps (commonly shortened to palps or palpi), are the second pair of appendages of the...
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, which is then transported outside and hung from the edges of the web with multiple radiating bands of silk. The egg sac is allowed to hang freely, camouflaged with grass and leafs, until the newly born spiders hatch from the egg sac. 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. 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.