''Araneus marmoreus'', commonly called the marbled orbweaver, is a species of

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

belonging to the family Araneidae. It is sometimes also called the pumpkin spider from the resemblance of the female's inflated abdomen to an orange pumpkin. It has a

Holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...

distribution.

Taxonomy

''Araneus marmoreus'' was first described by

Carl Alexander Clerck Carl Alexander Clerck (1709 – 22 July 1765) was a Swedish entomologist and arachnologist. Clerck came from a family in the petty nobility and entered the University of Uppsala in 1726. Little is known of his studies; although a contemporary of ...

in 1757. In the same work, he also described ''Araneus pyramidatus'', now regarded as a synonym of ''A. marmoreus''.

Description

Two main forms of this species are known. The nominate variety has an orange

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...

with black or brown marbling while var. ''pyramidatus'' is much paler, sometimes almost white, with a single dark patch towards the rear of the abdomen. The nominate variety is found throughout the species' range while var. ''pyramidatus'' is more commonly found in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

, where the two varieties are seldom found together. While the ''pyramidatus'' form is uncommon in North America, this pattern can be seen in the Northern part of the United States and into

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. The female has a body length (excluding legs) of up to 18 mm while the male is rather smaller at 9 mm. Araneus marmoreus up2

Adult female marbled orbweavers are 9 to 20 millimeters in length with very large oval, sub-spherical abdomens. The most common color morph is an orange abdomen with brown to black markings. However, this species has a wide range of colorations and folium patterns. The abdomens can be pale yellow, white, black/brown, and red in color. The cephalothorax is commonly yellow to burnt-orange with a central dark line and dark lines down either side. The femurs are often red in color with black and white banding beginning on the tibia, metatarsus, and tarsus. The legs may instead have a light brown banded pattern. The venter has a black band enclosed by white brackets. Egg cocoons, which contain several hundred eggs, are generally deposited in October and are constructed of white silk formed in a flattened sphere. Immature spiders emerge from the cocoons in spring. Adults are seen from midsummer until the first hard freeze of fall.

Webs

The webs are found in trees, shrubs and tall weeds, and grasses in moist, wooded settings and can frequently be found along the banks of streams. The webs are oriented vertically and have a "signal" thread attached to the center that notifies the spider when prey has been captured. Unlike '' Argiope'' garden spiders, ''Araneus marmoreus'' hides in a silken retreat to the side of the web (at the end of the signal thread). The retreat can be made from leaves folded over and held together with silk, silk only, or under leaves and other debris.

Distribution

''Araneus marmoreus'' has a Holarctic distribution, being found from North America through Europe to Japan. In North America, it is found throughout all of Canada to Alaska, the northern Rockies, from North Dakota to Texas, and then east to the Atlantic.

References

* {{Taxonbar, from=Q263978 marmoreus Holarctic spiders Spiders described in 1757 Taxa named by Carl Alexander Clerck