Diadem Spider or Cross Orbweaver
( Araneus diadematus )


2011-0513-SP111001-ARA00104-Araneus_diadematus[1804h59s,F,S,spiderlings]{SPeden}-G.jpg

PHOTO COMMENT

IDENTIFICATION
Identification:Araneus diadematus
(Clerck, 1757)
Common Name:Diadem Spider or Cross Orbweaver
Life Stage:(S) subadult

PHYLOGENY

Phylum:Arthropoda
Class:Arachnida
Order:Araneae
Family:Araneidae
Genus:Araneus
Taxon Code:ARA00104
ITIS TSN#:851395

LOCATION DETAILS
Location
Henry Cowell Redwoods SP, Henry Cowell Redwoods SP, 101 North Big Trees Park Road, Felton
County:Santa Cruz County
ECI Site#:CASP111001
Park/Forest:Henry Cowell Redwoods SP

RECOGNITION
A. diadematus has a dorsal, white cross on the abdomen which distinguishes it from the similar spiders.
Body Length
(M) 6-13 mm. (F) 6-20 mm.
Similar Taxa
The spider is similar to the Pumpkin Spider (Araneus trifolium) and to Gem-shaped Orbweaver (A. Gemma). However, A. diadematus has a dorsal, white cross on the abdomen. All three spiders have overlapping ranges in California.
Colors
Mostly orange, especially the abdomen; with white speckling and a white cross on top of the abdomen. The head is silvery gray.

BIOLOGY
Habitat
These spiders appears in vegetated areas. Spiderlings are active in the spring but the spiders are not often noticed until the fall after a growth spurt made possible by the abundance and larger size of insects the spider fed upon during warm months.
Active Period
Spiderlings hatch in the spring. Adults may live into winter months. In captivity females may live until the following January.
Nesting
The garden spider spins a large complex orb-web, which measures up to 40 about half a meter in diameter and is used to capture insect prey. Individuals spend much of their time at the center of their web, and detect vibrations in the silk through their legs when insects become trapped. This spider wraps prey items in silk before consuming them. When this species is threatened, it rapidly shakes itself and the web up and down, and may drop to the ground on a silk thread. The web may be rebuilt every day, and the old web is consumed so that the proteins used in its construction are conserved and re-used. Spiders use densely vegetated areas or insect flyways. From spring through summer they are tiny and well-hidden - but in the Fall they grow very quickly.
Development
Males mature long before females and will remain alongside immature females until they mature. During copulation, males embrace the female's abdomen; sperm is transferred by the insertion of one of the male's palps. The gravid female falls back to her retreat to spins an egg sac which she remains with until dying. Spiderlings emerge in spring and remain in one or more dense clusters until their first molt, then disperse on air currents that pick up strands of silk released by the spiderlings.
Ecosystem
Areas near vegetated areas, including parks and gardens.
Range
The spider was introduced to the United States from Western and Northern Europe. In North America they range from southern Canada through the northern 1/3 of the USA (now including northern California). Uncommon in the Great Plains area.

HABITAT
These spiders appears in vegetated areas. Spiderlings are active in the spring but the spiders are not often noticed until the fall after a growth spurt made possible by the abundance and larger size of insects the spider fed upon during warm months.
Areas near vegetated areas, including parks and gardens.

CREDITS
Photographer
Scott Peden

REFERENCES
  • Species Araneus diadematus - Cross Orbweaver. (bugguide.net/node/view/3376). Accessed January 31, 2016. [ IMAGES ]
  • Integrated Taxonomic Information System TSN#851395
  • Araneus diadematus - Garden Cross Spider. (http://eol.org/pages/1194185/overview). Accessed January 31, 2016.
  • Gem-shaped Orb-weaver (Araneus gemma). (http://www.inaturalist.org/observations/2310278). Accessed January 31, 2016.


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