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Arrow-shaped Micrathena Spider (Micrathena sagitatta)


Detailing the physical features, habits, territorial reach and other identifying qualities of the Arrow-shaped Micrathena Spider.


 Updated: 1/31/2018; Authored By Staff Writer; Content ¬©www.InsectIdentification.org



  Arrow-shaped Micrathena Spider  
Picture of Arrow-shaped-Micrathena-Spider


The huge pointy spines on the abdomen of the Arrow-shaped Micrathena Spider are just the first of many wonders that make this spider so attractive.





Arrow-shaped Micrathena Spiders are everything their name suggests. Instead of a round abdomen, seen in typical spiders, abdomen is longer and generally triangular in shape, like the head of an arrow. Like other Micrathenas, this species' female has sharp spines on it that resemble rose prickles. They protrude from the edges of the abdomen. These spines are believed to ward off predators, but some sources suggest they may add to her ability to conceal herself in her web. Two large points extend from the bottom of the abdomen and angle away from each other. They are thick and intimidating with red bases and black tips. Males do not have spines of any kind; their abdomens have rounded edges.

Male are mostly black with white edges, but females abound in color and pattern. The head, legs and most of the body are red. The center of the arrow-shaped abdomen is bright yellow with small red spots. Most of the medium and large spines are tipped with black. Females are twice as large as males. Both genders spin orb-shaped spiral webs that lie in a vertical plane (up-and-down). These webs may only be a few feet off the ground. A thick, short, zigzagged strand of webbing, called a stabilimentum, is usually just above the center of the web. Many spiral strands radiating from the center allow the spider to tread easily on its web. Orbweavers are known to rebuild their webs every day.

In autumn, a female Arrow-shaped Micrathena Spider will lay fertilized eggs on the edge of her web, usually on a leaf right next to it, and then die before they hatch. The eggs will overwinter in the egg sac and hatch the next spring. They prefer outdoor habitats with vegetation to help hide them. Look for them in forests.
Basic Information
Common Name: Arrow-shaped Micrathena Spider
Other Name(s): Arrow Spider
Scientific Name: Micrathena sagitatta
Category: Spider


General Identification
Size (Adult; Length): 4mm to 9mm (0.16in to 0.35in)
Colorwheel Graphic
Identifying Colors: red; yellow; black; orange; white
Additional Descriptors: pointy, holes, thorny, spiny, venomous




Taxonomic Hierarchy
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Family: Araneidae
Genus: Micrathena
Species: sagitatta


Spider Anatomy (Typical)
Graphic showing basic parts of spider anatomy
1
Legs: Spiders have four pairs of legs and these are attached to the cephalothorax.
2
Pedipalps: Small appendages near the mouth used as taste and smell organs.
3
Cephalothorax: Contains eyes, head, mouthparts, and legs.
4
Abdomen: Contains various organs related to digestion, reproduction, and web-making.
5
Spinnerets: Used in the production of spider silk for fashioning webs or catching prey.
NOTE: Unlike insects, spiders have both an endoskeleton (internal) and exoskeleton (external).


Territorial Reach (A-to-Z)
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed below as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections below indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Canadian National Flag Graphic
Alberta
British Columbia
Manitoba
New Brunswick
Newfoundland and Labrador
Nova Scotia
Ontario
Prince Edward Island
Quebec
Saskatchewan
Mexican National Flag Graphic
Mexico


Territorial Area Map (Visual Reference Guide)
The map below showcases (in red) the states and territories of North America where the Arrow-shaped Micrathena Spider may be found (but is not limited to). This sort of data can be useful in seeing concentrations of a particular species over the continent as well as revealing possible migratory patterns over a species' given lifespan. Some species are naturally confined by environment, weather, mating habits, food resources and the like while others see widespread expansion across most, or all, of North America.
Alaska  
Hawaii  
Prince Edward Is.  
State of Alabama graphic
State of Arizona graphic
State of Arkansas graphic
State of California graphic
State of Colorado graphic
State of Delware graphic
State of Florida graphic
State of Georgia graphic
State of Idaho graphic
State of Illinois graphic
State of Indiana graphic
State of Iowa graphic
State of Kansas graphic
State of Kentucky graphic
State of Louisiana graphic
State of Maine graphic
State of Maryland graphic
State of Michigan graphic
State of Minnesota graphic
State of Mississippi graphic
State of Missouri graphic
State of Montana graphic
State of Nebraska graphic
State of Nevada graphic
State of New England graphic
State of New Jersey graphic
State of New Mexico graphic
State of New York graphic
State of North Carolina graphic
State of North Dakota graphic
State of Ohio graphic
State of Oklahoma graphic
State of Oregon graphic
State of Pennsylvania graphic
State of South Carolina graphic
State of South Dakota graphic
State of Tennessee graphic
State of Texas graphic
State of Utah graphic
State of Virginia graphic
State of Washington graphic
State of West Virginia graphic
State of Wisconsin graphic
State of Wyoming graphic
Canadian territory of Alberta graphic
Canadian territory of British Columbia graphic
Canadian territory of Manitoba graphic
Canadian territory of New Brunswick graphic
Canadian territory of Newfoundland and Labrador graphic
Canadian territory of Ontario graphic
Canadian territory of Quebec graphic
Canadian territory of Saskatchewan graphic
Territory map graphic of the country of Mexico
Contiguous United States shape map layer graphic


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