Araneidae (Family)

Overview

The orb-weaver spiders (family Araneidae) are the builders of spiral wheel-shaped webs often found in gardens, fields and forests. Their common name is taken from the round shape of this typical web. Orb-weavers have eight similar eyes, legs hairy or spiny and no organs. The family is cosmopolitan, including many well-known large or brightly colored garden spiders. There are more than 2,800 species in over 160 genera worldwide, making this the third largest family of spiders known (behind Salticidae and Linyphiidae).

The Orb-Web

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Argiope sp. sitting on the stabilimentum at the cente r of the web

Spiderlings in the web near where they hatched

Generally, orb-weaving spiders are three-clawed builders of flat webs with sticky spiral capture silk. The building of a web is an engineering feat, begun when the spider floats a line on the wind to another surface. The spider secures the line and then drops another line from the center, making a "Y". The rest of the scaffolding follows with many radii of non-sticky silk being constructed before a final spiral of sticky capture silk. The third claw is used to walk on the non-sticky part of the web. Characteristically, the prey insect that blunders into the sticky lines is stunned by a quick bite and then wrapped in silk. If t he prey is a venomous insect, such as a wasp, wrapping may precede biting.

Many orb-weavers build a new web each day. Generally, towards evening, the spider will consume the old web, rest for approximately an hour, then spin a new web in the same general location. Thus, the webs of orb-weavers are generally free of the accumulation of detritus common to other species such as black widow spiders.

Some orb-weavers do not build webs at all. Members of the genera Mastophora in the Americas, Cladomelea in Africa and Ordgarius in Australia produce sticky globules, which contain a pheromone analog. The globule is hung from a silken thread dangled by the spider from its front legs. The pheromone analog attracts male moths of only a few species. These get stuck on the globule and are reeled in to be eaten. Interestingly, both types of bolas spiders are highly camouflaged and difficult to locate.

The spiny orb-weaving spiders in the genera Gasteracantha and Micrathena look like plant seeds or thorns hanging in their orb-webs. Some species of Gasteracantha have very long horn-like spines protruding from their abdomens.

One feature of the webs of some orb-weavers is the stabilimentum, a crisscross band of silk through the center of the web. It is found in a number of genera, but Argiope, which includes the common garden spider of Europe as well as the yellow and banded garden spiders of North America, is a prime example. The band has been hypothesized to be a lure for prey, a marker to warn birds away from the web and a camouflage for the spider when it sits in the center of the web.

Most arachnid webs are vertical and the spiders usually hang with their head downward. A few webs, such as those of orb-weaver in the genus Metepiera have the orb hidden within a tangled space of web. Some Metepiera are semi-social and live in communal webs. In Mexico such communal webs have been cut out of trees or bushes and used for living fly paper.^{[citation needed]}

Natural History

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The oldest known true orb-weaver is Mesozygiella dunlopi, from the Lower Cretaceous. Several fossils provide direct evidence that the three major orb weaving families, namely Araneidae, Tetragnathidae and Uloboridae, had evolved by this time, about 140 million years ago. They probably originated during the Jurassic (200-140 million years ago). All three families very likely have a common origin.^[1]

Systematics

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Main article: List of Araneidae genera

The categorization into subfamilies and tribes follows Joel Hallan's Biology Catalog.

The Nephilidae have been elevated to family status in 2006. Some researchers also consider the genera Leviellus, Parazygiella, Stroemiellus and Zygiella to reside in the family Zygiellidae.

Araneinae Simon, 1895

Argiopinae

Cyrtarachninae Simon

Cyrtarachnini Simon
Mastophorini

Cyrtophorinae

Gasteracanthinae

Caerostrini
Gasteracanthini

Micratheninae

incertae sedis

Artonis Simon, 1895
Colphepeira Archer, 1941
Enacrosoma Mello-Leit�o, 1932
Encyosaccus Simon, 1895
Melychiopharis Simon, 1895
Micrep eira Schenkel, 1953
Parmatergus Emerit, 1994
Pronous Keyserling, 1881
Sedasta Simon, 1894
Singafrotypa Benoit, 1962
Tethneus Scudder, 1890 � (fossil, oligocene)

Tethneus guyoti (Scudder, 1890) �
Tethneus henzii (Scudder) �
Tethneus robustus (Petrunkevitch) �

Gallery

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Photos

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Taxonomy

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The Family Araneidae is a member of the Superfamily Araneoidea. Here is the complete "parentage" of Araneidae:

Domain: Eukaryota Whittaker & Margulis,1978 - eukaryotes
- Kingdom: Animalia Linnaeus, 1758 - animals
  - Subkingdom: Bilateria (Hatschek, 1888) Cavalier-Smith, 1983 - bilaterians
    - Branch: Protostomia Grobben, 1908 - protostomes
      - Infrakingdom: Ecdysozoa Aguinaldo Et Al., 1997 Ex Cavalier-Smith, 1998 - ecdysozoans
        Superphylum: Panarthropoda Cuvier
        Phylum: Arthropoda Latreille, 1829 - Arthropods
        Subphylum: Arachnomorpha Heider, 1913
        Infraphylum: Cheliceriformes
        Superclass: Chelicerata
        Class: Arachnida Cuvier, 1812 - Arachnids
        Subclass: Micrura
        Order: Araneae Clerck, 1757 - Spiders
        Suborder: Opisthothelae - Modern Spiders
        Infraorder: Araneomorphae
        Superfamily: Araneoidea
        Family: Araneidae - Orb Weavers

The Family Araneidae is further organized into finer groupings including:

Genus (171): Acacesia · Acantharachne · Acanthepeira · Acroaspis · Acrosoma · Acrosomoides · Actinacantha · Actinosoma · Aculepeira · Acusilas · Aethriscus · Aethrodiscus · Aetrocantha · Afracantha · Agalenatea · Agathostichus · Alcimosphenus · Alenatea · Allocyclosa · Alpaida · Amazonepeira · Anepsion · Arachnura · Aranea · Araneus · Araniella · Aranoethra · Area · Argiope · Artonis · Aspidolasius · Atea · Augusta · Austracantha · Basilica · Bertrana · Caerostris · Carepalxis · Celaenia · Cercidia · Chaetacis · Chorizopes · Cladomelea · Cnodalia · Coelossia · Colaranea · Collina · Colphepeira · Cryptaranea · Cyclosa · Cyphalonotus · Cyrtarachne · Deione · Dolophones · Dubiepeira · Ebaea · Ectypa · Edricus · Enacrosoma · Encyosaccus · Epeira · Epeiroides · Eriophora · Eriovixia · Eustacesia · Eustala · Exechocentrus · Faradja · Friula · Gasteracantha · Gastroxya · Gea · Gibbaranea · Gibber · Glyptogona · Heterognatha · Heurodes · Hingstepeira · Homalopoltys · Hypognatha · Hyposinga · Hypsacantha · Hypsosinga · Ideocaira · Isoxya · Kaira · Kapogea · Kilima · Larinia · Lariniaria · Larinioides · Lewisepeira · Lipocrea · Macracantha · Madacantha · Madrepeira · Mahembea · Mangora · Manogea · Mecynogea · Megaraneus · Metazygia · Metepeira · Micrathena · Micrepeira · Micropoltys · Milonia · Molinaranea · Nemoscolus · Nemosinga · Nemospiza · Neoarchemorus · Neogea · Neoscona · Nicolepeira · Novakiella · Novaranea · Nuctenea · Ocrepeira · Ordgarius · Paralarinia · Paraplectana · Paraplectanoides · Pararaneus · Parawixia · Parazygiella · Parmatergus · Pasilobus · Perilla · Pherenice · Pitharatus · Poecilarcys · Poecilopachys · Poltys · Pozonia · Prasonica · Prasonicella · Pronoides · Pronous · Pseudartonis · Pseudopsyllo · Pycnacantha · Rubrepeira · Scoloderus · Sedasta · Singa · Singafrotypa · Siwa · Spilasma · Spinepeira · Spintharidius · Taczanowskia · Talthybia · Tatepeira · Tethneus · Thelacantha · Thorellina · Togacantha · Tukaraneus · Umbonata · Ursa · Verrucosa · Wagneriana · Witica · Wixia · Xylethrus · Yaginumia · Zealaranea · Zilla · Zygiella · Zygniella
Species: ZipcodeZoo has pages for 4,809 species and subspecies in the Family Araneidae.

Araneidae

Overview

The Orb-Web

Natural History

Systematics

Gallery

Photos

Taxonomy

Genera

Acacesia

Acantharachne

Acanthepeira

Acroaspis

Acrosoma

Acrosomoides

Actinacantha

Actinosoma

Aculepeira

Acusilas

Aethriscus

Aethrodiscus

Aetrocantha

Afracantha

Agalenatea

Agathostichus

Alcimosphenus

Alenatea

Allocyclosa

Alpaida

Amazonepeira

Anepsion

Arachnura

Aranea

Araneus

Araniella

Aranoethra

Area

Argiope

Artonis

Aspidolasius

Atea

Augusta

Austracantha

Basilica

Bertrana

Caerostris

Carepalxis

Celaenia

Cercidia

Chaetacis

Chorizopes

Cladomelea

Cnodalia

Coelossia

Colaranea

Collina

Colphepeira

Cryptaranea

Cyclosa

Cyphalonotus

Cyrtarachne

Deione

Dolophones

Dubiepeira

Ebaea

Ectypa

Edricus

Enacrosoma

Encyosaccus

Epeira

Epeiroides

Eriophora

Eriovixia

Eustacesia

Eustala

Exechocentrus

Faradja

Friula

Gasteracantha

Gastroxya