Dictyna major is a small spider (9,10) native to many northern locations, including Canada(4,6), Alaska(12), the western contiguous United States(4,6,10,15), a large portion of Europe(4,14), and part of northern Asia(6); its range extends north as far as Disko Island in Greenland (9) and northern Russia (6). It can be found in a variety of habitats, from grasslands(10) to sandy shores (14). This spider, which is dull brown (7) and only about 2.5-3.5 millimeters (0.1-0.14 inches) long (5,9), shares many characteristics with other Dictyna species, including a wide abdomen and short legs, and has a light line going through its cardiac mark (the abdominal marking over the heart (13))(9). Where their ranges overlap in the North America (2,3,10,15), Dictyna major is especially difficult or even impossible to distinguish from Dictyna coloradensis in the wild (10,15). When an adult Dictyna majorspider emerges in the spring or summer (10,14,15), it builds its irregularly-shaped web (10) on grass(12), flowering plant stalks(10), shrubs(9), or rocks(9), gradually increasing the size of the web rather than rebuilding it each day(10). Like those of some other groups of spiders(11), these webs are made in part of an ancestral form of silk known as cribellate silk (1,8,15), each thread of which contains hundreds or even thousands of tiny fibers with dry-adhesive properties used for snagging insects(1,11). In the western United States, the insect predation of Dictyna major, as well as that of Dictyna coloradensis, turns problematic in areas where insects are used to control the spread of dangerous invasive species such as spotted knapweed (Centaurea maculosa) and yellow starthistle (Centaurea solstitialis)(15). This problem is compounded by the fact that the two spiders collectively have been shown to greatly proliferate in grasslands invaded by spotted knapweed, apparently due to the especially good web-building sites that the large, rigid, and relatively long-lasting stalks of the weed provide(10).
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