Spider of the Year 2011
The common labyrinth spider
Agelena labyrinthica (Clerck, 1757)
Since the genus Tegenaria was first used as a representative of the funnel-web spiders back in 2008 (European Spider of the year 2008), a further representative of this family has been chosen for 2011: the labyrinth spider Agelena labyrinthica).
The labyrinth spider is one of 1146 funnel-web spiders (Family Agelenidae) found world-wide. In Europe there are 180 species and in central Europe about 30.
An important family character is the prominent pair of two-segmented posterior spinnerets. In the labyrinth spider these are further elongated – with the second segment almost twice the length of the basal segment. For spider experts the presence of at least four fine, sensory hairs (the so-called trichobothria) on the upper side of the last segment, or tarsus, of the first pair of legs are an important difference to other families. In terms of size, the funnel-web spiders can be regarded as moderately large: males typically reach 8-12; females 10-14 mm body length. The cephalothorax is yellow-brown and bears two, broad longitudinal stripes which narrow strongly towards the front. The basic colour of the abdomen is grey-brown; a grey longitudinal line associated with pairs of white chevrons runs along the midline – creating a sort of “fishbone” pattern. Mature animals are typically found in July and August.
The labyrinth spider lives in sunny, dry habitats with low vegetation and sparse shrubs and bushes. It can also be found in forests and on the edges of pathways, as well as in dry grassland. In central Europe the labyrinth spider is widely distributed and thus commonly encountered.
The labyrinth spider builds characteristic webs, typically spanned between grass and low vegetation; usually close to the ground and rarely up to about 1 m in the bushes. A flat web surface merges funnel-like into a tubular retreat and/or escape route. Above the web surface there is a three-dimensional network of fine silk for stopping prey.
If an insect lands on the web surface, the spider rushes out of its retreat and subdues or kills it with a bite. It orientates itself on the vibrations produced by the prey. Smaller insects which get caught in the labyrinth threads above the web, but which are not in contact with the web surface itself, can also be localised by the spider. This occurs with the help of the trichobothria hairs, which also function as a long-distance sensory system. Possibly even slow-flying insects can be attacked since the spider has a very quick reaction time (on average 160 msec). For finding its way around the web the eyes are also important. The spider reacts to obvious pale or dark objects in its vicinity. Furthermore the anterior median eyes can detect the plane of polarised sunlight, which also helps with orientation.
During the mating period, typically in the middle of July, the male taps on the web of the female with his pedipalps in order to advertise himself as a mate. If the female is ready to copulate she remains quietly in her retreat, where the actual mating process takes place. About a month later, in early to late August, the female creates a large, white egg sac. The inner cocoon (the actual egg chamber with 50-130 eggs) is supported at the edges with multiple radiating bands of silk and attached to the edges of the nest where it hangs, free and elastic. The wall of the egg sac comprises thick strands of silk and is additionally camouflaged (e.g. with leaf litter). The spiderlings hatch in the same year and overwinter in the nest; nourished from the egg yolk now stored in their abdomen. The young spiders leave the protection of the nest in the next spring.
It won’t be hard to find the labyrinth spider during a walk in the country in summer 2011, lurking in the retreat of its fascinating funnel-web ready to overpower prey with rapid, skillful movements – and we look forwards together to discovering it!
Christoph Hörweg & Jason Dunlop
Contact for Europe
Dr. Milan Řezáč
Biodiversity Lab, Crop Research Institute
161 06 Praha 6 – Ruzyně
84 jury members from 24 countries:
Albania, Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Great Britain, Hungary, Ireland, Italy, Liechtenstein, Netherlands, Norway, Poland, Portugal, Sweden, Switzerland, Serbia, Slovakia, Slovenia, Spain.
ARABEL – Belgische Arachnologische Vereniging (link)
ARAGES – Arachnologische Gesellschaft (link)
BAS – The British Arachnological Society (link)
ESA – European Society of Arachnology (link)
GIA – Grupo Ibérico de Aracnología (link)
NATURADATA – Biodiversidade online (link)
SPINED – European Invertebrate Survey-Nederland (link)
Maps and photos
Pictures and photo galleries
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