Spider of the Year 2014
The common hammock-weaver
Linyphia triangularis (Clerck 1757)
The common hammock-weaver Linyphia triangularis (Clerck 1757) belongs to the family Linyphiidae. After the jumping spiders this is, with 4,461 species, the second most abundant spider family in the world. Europe as a whole has 1,248 species of linyphiid, central Europe 493.
Hammock weavers are characterised by their web construction. All species build a hammock or canopy-shaped web which leads to their general name. The common hammock-weaver is rather untypical for members of this family through its large size and clear markings on the cephalothorax, both of which make it quite easy to identify. In Central Europe it is, by some distance, the most frequently encountered hammock-weaver.
It is found across a large part of the Palaearctic and the species’ distribution covers the temperate down to the subtropical zones. It is found in all European countries except Iceland and its altitudinal distribution ranges from plains and hills up to montane regions.
In terms of habitat, this species is fairly unspecialised and occurs as a ‘generalist’ in damp forests or in all manner of open areas such as meadows, forest edges, parks and gardens. It can occur in suitable environments in very large numbers and in terms of nature protection it is thus regarded as ‘not endangered’.
The web of the common hammock-weaver is usually spun in grass or undergrowth close to the ground. As in most examples from this family, it consists of a horizontal sheet attached from below to the ground, above which a ca. 20 cm high network of loose ‘tripwires’ is arranged. The spider almost always sits upside-down beneath the sheet. Prey usually collide with the ‘tripwires’ and then fall onto the sheet, where they are caught by the spider. Typical prey items are small insects like midges, tiny flies and beetles.
The body length of both sexes is about 5-7 mm. The cephalothorax is beige-brown in colour and has black-brown edges and a black band in the middle, which divides around the middle of the cephalothorax as it extends forwards. This marking is thus reminiscent of a tuning fork. The abdomen is yellow to white with a wide, brown dark-edged band down the middle, which is constricted a number of times such that a typical pattern of triangular patches is often visible. On the side brown bands and patches are also seen; the underside is dark brown to black. The legs are simply beige-brown. Males can be differentiated by a noticeably slimmer abdomen and enlarged mouthparts. Their colouration also tends to be more red-brown.
There is a possibility of confusing this species with Linyphia tenuipalpis which is a little smaller and prefers warmer habitats. Furthermore, adult animals occur somewhat earlier from June to October. In case of uncertainty, a precise identification is only possible through studying the genital organs under the microscope.
Mature examples of the common hammock-weaver are found from August to October. In Central Europe mating mostly takes place in September. Males hang around in the female’s web during this time. For copulation the male also sits upside down, in front of the female, and inserts his pedipalps one after the other into her genital opening. Their offspring overwinter in the cocoon.
Linyphia triangularis was predestined to be a spider of the year: it is not just the most common representative of this prominent spider family, with wonderful, easily seen sheet webs. It also shows interesting biological aspects: females attract males into the web for mating using a sex pheromone and males also show ‘mate guarding’ behaviour in that they stay for a while in the female’s web – even after mating – in order to ‘protect’ her from other males. In this way he can ensure that no other mating takes place and that it really is his genes which are passed onto the next generation.
Also in this year, autumn will be a suitable time to encounter the spider of the year. The web is the first thing you will discover, after which it’s certainly worth your while to take a closer look!
Christoph Hörweg & Jason Dunlop
Contact for Europe
Dr. Milan Řezáč
Biodiversity Lab, Crop Research Institute
161 06 Praha 6 – Ruzyně
82 jury members from 26 countries:
Albania, Austria, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Finland, France, Germany, Great Britain, Hungary, Ireland, Italy, Liechtenstein, Macedonia, The Netherlands, Norway, Poland, Portugal, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland.
ARABEL – Belgische Arachnologische Vereniging (link)
ARAGES – Arachnologische Gesellschaft – (link)
BAS – The British Arachnological Society – (link)
CAS – Česká arachnologická společnost – (link)
ESA – European Society of Arachnology – (link)
GIA – Grupo Ibérico de Aracnología GIA – (link)
NATURADATA – Biodiversidade online – (link)
SPINED – European Invertebrate Survey-Nederland – (link)
Maps and photos
– BARTH F.G. (2001): Sinne und Verhalten: aus dem Leben einer Spinne – Springer, Berlin. 424 pp.
– BELLMANN H. (2006): Kosmos-Atlas Spinnentiere Europas – 3. Auflage. Kosmos, Stuttgart. 304 pp.
– BENJAMIN S.P. & S. ZSCHOKKE (2004): Homology, behaviour and spider webs: web construction behaviour of Linyphia hortensis and L. triangularis (Araneae: Linyphiidae) and its evolutionary significance – Journal of Evolutionary Biology 17(1): 120-130
– BENJAMIN S.P., M. DÜGGELIN & S. ZSCHOKKE S (2002): Fine structure of sheet-webs of Linyphia triangularis (Clerck) and Microlinyphia pusilla (Sundevall), with remarks on the presence of viscid silk – Acta Zoologica 83(1) : 49-59
– BLICK T., R. BOSMANS, J. BUCHAR, P. GAJDOŠ, A. HÄNGGI, P. VAN HELSDINGEN, V. RŮŽIČKA, W. STARĘGA & K. THALER (2004): Checkliste der Spinnen Mitteleuropas. Checklist of the spiders of Central Europe. (Arachnida: Araneae). Version 1. Dezember 2004 – (PDF)
– HÄNGGI A., E. STÖCKLI & W. NENTWIG (1995): Lebensräume mitteleuropäischer Spinnen. Charakterisierung der Lebensräume der häufigsten Spinnenarten Mitteleuropas und der mit diesen vergesellschafteten Arten – Miscellanea Faunistica Helvetiae 4: 1-459
– HERBERSTEIN M.E. (1997). The effect of habitat structure on web height preference in three sympatric web-building spiders (Araneae, Linyphiidae) – The Journal of Arachnology 25: 93-96
– KOMPOSCH C. & K.-H. STEINBERGER (1999): Rote Liste der Spinnen Kärntens (Arachnida: Araneae) – Naturschutz in Kärnten 15, 567-618
– MALT S. (1996): Untersuchungen zur Rolle ausgewählter netzbauender Spinnen (Araneae) im trophischen Beziehungsgefüge von Halbtrockenrasen – Dissertation, Friedrich-Schiller-Universität Jena, 134 + 57 pp.
– NENTWIG W., T. BLICK, D. GLOOR, A. HÄNGGI & C. KROPF (2014): Spinnen Europas. Version 01.2014 – (link)
– PETERS H.M. & KOVOOR J. (1991). The silk-producing system of Linyphia triangularis (Araneae, Linyphiidae) and some comparisons with Araneidae – Zoomorphology 111: 1-17
– PLATEN R., T. BLICK, P. SACHER & A. MALTEN (1996): Rote Liste der Webspinnen Deutschlands (Arachnida: Araneae) – Arachnologische Mitteilungen 11: 5-31
– PLATNICK N.I. (2014): The world spider catalog, version 14.5. American Museum of Natural History – (link)
– STAUDT A. (2014): Nachweiskarten der Spinnentiere Deutschlands (Arachnida: Araneae, Opiliones, Pseudoscorpiones) – (link)
– TOFT S. (1987): Microhabitat identity of two species of sheet-web spiders: field experimental demonstration – Oecologia 72(2): 216-220
– TOFT S. (1989): Mate guarding in two Linyphia species (Araneae: Linyphiidae) – Bulletin of the British Arachnological Society 8(2): 33-37
– WIEHLE H. (1953): Spinnentiere oder Arachnoidae (Araneae). IX. Orthognatha – Die Tierwelt Deutschlands 42: 1-150