Hyptiotes
Walckenaer, 1837
Triangle Web Spiders, Triangle Spiders
Hyptiotes is a of small in the Uloboridae, commonly known as triangle web spiders. These are distinguished by their unique triangular webs— webs consisting of four connected to a single anchor thread. They are notable as the only spiders in North America that lack glands, relying instead on specialized to capture and subdue . females measure 3-4 mm, while males are 2-3 mm. Four occur in North America, with three primarily western and one eastern species (H. cavatus).
Pronunciation
How to pronounce Hyptiotes: //haɪpˈti.oʊtiːz//
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Identification
The triangular web shape is diagnostic—unlike the circular webs of most orb-weavers, Hyptiotes constructs only a triangular sector. The combination of tiny size, (visible as fuzzy, non-sticky threads), and the 's habit of sitting at the web's holding the anchor thread taut further distinguishes this . The lack of glands, unique among North spiders, cannot be observed directly but is a biological characteristic. Distinguished from related Uloborus by web geometry: Uloborus builds more complete, though reduced, orb webs rather than simple triangles.
Images
Appearance
Very small with females 3-4 mm and males 2-3 mm in length. as broad as long, weakly convex above, highest and broadest at the second row. narrowed and rounded anteriorly, widely rounded posteriorly. Eight eyes in two unequal transverse rows: row from , nearly straight dorsally, with small close together and widely separated ; row much wider, , with large median eyes as widely separated as anterior lateral eyes. broad and sloping. triangular, longer than wide, truncated and widest anteriorly, tapering evenly to blunt point between slightly separated posterior . sub-oval and moderately to strongly arched in females, more slender in males. Anterior much larger than posterior pair. Legs short and stout; female legs without except few on , male legs longer with and spines. occupies most of flattened fourth metatarsus length, consisting of single series of curved bristles.
Habitat
Vegetation in open areas including goldenrods, asters, and ornamental trees. Webs constructed between leaves on plants, on twigs of trees and shrubs, on bridges and other structures, typically at waist height.
Distribution
North America with four : three primarily western in distribution, one eastern species (Hyptiotes cavatus). Records also from northern Europe (Denmark, Norway, Sweden).
Diet
Flying that collide with the web; specific not documented.
Life Cycle
-sac flattened, mottled , attached to surface of twig. Developmental details otherwise unknown.
Behavior
Constructs triangular web with four connected to single anchor thread. sits at web holding anchor thread taut with tension maintained by coiled . When impacts web, spider instantly releases anchor thread, causing web to rebound and further entangle prey. Spider then wraps prey in specialized wrapping silk. Related Uloborus observed to spend approximately 10 minutes wrapping even small prey in extensive silk. Web construction involves drawing tangled silk spans through slowly, then 'ratting' with ; spiral construction takes hours.
Ecological Role
of small flying ; capture method represents unique evolutionary solution to web-building in reduced spaces.
Human Relevance
Non-venomous and harmless to humans due to complete absence of glands. Too small to be conspicuous; occasionally encountered by naturalists and arachnologists.
Similar Taxa
- UloborusAlso in Uloboridae with and reduced webs, but constructs more complete orb webs rather than simple triangular sectors; web geometry is the primary distinguishing feature
More Details
Cribellate Silk
possess an additional spinning organ, the , adjacent to normal . The cribellum produces specialized that is 'fluffed up' using the (-like organ on hind legs). The capture silk is not sticky but tangled, apparently equally effective as adhesive droplets at trapping .
Venom Absence
Uloboridae, including Hyptiotes, are the only in North America that completely lack glands. subjugation relies entirely on extensive wrapping and possibly enzymatic digestion after immobilization.