(Acanthepeira stellata)
Conservation • Description • Habitat • Biology • Distribution • Taxonomy
Conservation Status |
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IUCN Red List | not listed |
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NatureServe | NNR - Unranked |
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Minnesota | not listed |
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Description |
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There are four species of starbellied orb-web spiders (genus Acanthepeira), all of them occurring in southeastern United States. Starbellied orbweaver (Acanthepeira stellata) is the only one whose range extends into northern United States and southern Canada. Starbellied orbweaver is a common but not abundant, medium-sized spider. It occurs in the United States and southern Canada east of the Great Plains, in Mexico, and there is a disjunct population in southern Arizona. It is found in summer and fall in open sunny areas, including fields, meadows, woodland edges, and agricultural crops, and sometimes on buildings. It is most easily found in the early morning when its web is covered with dew. Females are ¼″ to ⅝″ (7 to 15 mm) in length and have a ⅜″ to ⅝″ (9 to 15 mm) legspan. The overall color can be brown, brownish-orange, or grayish-brown. The following description is of the brown color phase. The front part of the body (cephalothorax) is low, narrowed in front, and much smaller than the abdomen. The upper side (carapace) is dark brown with narrow pale margins and is covered with whitish hairs. There is no depression in the middle.The head region is highest, appearing swollen. There are eight eyes arranged in two parallel rows of four eyes each. The front (anterior) row is strongly curved forward and the rear (posterior) row is strongly curved backward. All of the eyes are small, but in the anterior row the middle (median) eyes (AME) are the smallest. The corners of the head are extended forward over the anterior outer (lateral) eyes (ALE). The abdomen is large, oval, rounded, and highest in front. The outer edge has twelve prominent, cone-shaped, outward pointed humps (tubercles); one in front projecting over the carapace, one at the rear projecting over the spinnerets, and four on each side. The first tubercle on each side is doubled, two closely spaced tubercles joined at the base. The upper side of the abdomen is brown with light and dark markings. At the front margin there is a white Y-shaped or V-shaped mark bordering a dark interior. Toward the rear there is a dark leaf-shaped mark (folium). The common name of the spider may refer to the shape of the folium or to the star-like shape of the abdomen. The legs are short, spiny, and yellowish, with distinct brown rings. The front two pairs project forward, the hind two pairs project backward. The last segment (tarsus) on each leg has three claws at the tip, though these are not visible to the naked eye. The male is much smaller, 3⁄16″ to 5⁄16″ (5 to 8 mm) in length. The carapace has a shallow, indistinct depression. The finger-like sensory appendages attached to the mouth (palps) are enlarged. |
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Size |
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Female Body Length: ¼″ to ⅝″ (7 to 15 mm) Male Body Length: 3⁄16″ to 5⁄16″ (5 to 8 mm) Legspan: ⅜″ to ⅝″ (9 to 15 mm) |
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Web |
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The female constructs a large oval web. It is called an “orb”, which gives this family of spiders its common name. The web is 6″ to 10″ (15 to 25 cm) in diameter and has about 25 radii. It hangs vertically, within four feet of the ground, in the upper half of vegetation, usually tall grasses or low shrubs. The center of the hub is closed or nearly closed. A retreat is constructed in the dead head of one of the plants that supports the web. At night, the female hangs head down in the center of the web. During the day she may be found there, but she is usually found in the retreat. |
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Similar Species |
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Habitat |
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Fields, meadows, woodland edges, agricultural crops, and buildings |
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Biology |
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Season |
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Summer through fall |
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Behavior |
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Adults are active at night but can often be found in the center of their web in the early morning. When disturbed, the spider drops to the ground, tucks in its legs, and feigns death. Its coloration provides excellent camouflage among the leaf litter and tangled grasses. |
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Life Cycle |
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Eggs are attached to nearby leaves. Eggs overwinter, and spiderlings hatch in the spring. Spiderlings disperse by “ballooning”. They climb a branch, blade of grass, or fencepost, and release a long thread of silk. The silk thread catches the wind or even a light breeze and the spiderling floats to a new site. The male matures earlier than the female. Adults are active from summer to the first frost or hard freeze. |
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Food |
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Flying insects |
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Distribution |
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Sources |
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3/10/2023 | ||||
Occurrence |
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Common |
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Taxonomy |
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Class | Arachnida (arachnids) | ||
Order |
Araneae (spiders) | ||
Suborder |
Araneomorphae (typical spiders) | ||
Infraorder | Entelegynae | ||
Superfamily | Araneoidea (orbweavers and allies) | ||
Family |
Araneidae (orbweavers) | ||
Subfamily |
Araneinae (typical orbweavers) | ||
Genus |
Acanthepeira (starbellied orb-web spiders) | ||
Synonyms |
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Acanthepeira venusta Araneus stellata Cyrtarachne dugesi Cyrtarachne mexicana Epeira nobilis Epeira stellata Marxia nobilis Marxia stellata |
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Common Names |
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starbellied orbweaver star-bellied orb weaver star-bellied orbweaver |
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Glossary
Carapace
The hard, upper (dorsal), shell-like covering (exoskeleton) of the body or at least the thorax of many arthropods and of turtles and tortoises. On crustaceans, it covers the cephalothorax. On spiders, the top of the cephalothorax made from a series of fused sclerites.
Cephalothorax
The front part of the body of various arthropods, composed of the head region and the thoracic area fused together. Eyes, legs, and antennae are attached to this part.
Folium
On some spiders, the leaf-shaped marking on the upper side of the abdomen.
Palp
Short for pedipalp. A segmented, finger-like process of an arthropod; one is attached to each maxilla and two are attached to the labium. They function as sense organs in spiders and insects, and as weapons in scorpions. Plural: palpi or palps.
Tubercle
On plants and animals: a small, rounded, raised projection on the surface. On insects and spiders: a low, small, usually rounded, knob-like projection. On slugs: raised areas of skin between grooves covering the body.
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Starbellied orbweaver |
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2020 10 27 Acanthepeira stellata Star bellied Orb-weaver Hari Krishna |
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About
Oct 28, 2020 |
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Created: 3/2/2023
Last Updated: