Miagrammopes
O. Pickard-Cambridge, 1870
Species Guides
1Miagrammopes is a of cribellate orb-weaving spiders in the Uloboridae, first described by O. Pickard-Cambridge in 1870. These spiders are distinguished by their reduced complement—retaining only four of the original eight eyes—and their highly modified web-building . Rather than constructing traditional orb webs, they spin single horizontal threads with viscid capture silk, employing a unique hunting strategy of maintaining tension and releasing the line with a snap to entangle prey. The genus currently includes 71 recognized and is distributed across tropical and subtropical regions.
Pronunciation
How to pronounce Miagrammopes: //miːəˈɡræməˌpiːz//
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Identification
Distinguished from other uloborid by combination of: (1) reduced number—only four functional eyes in two unequal transverse rows, with eyes minute or obsolete (often visible only as small dark pigment spots); (2) eye row recurved with median eyes widely separated; (3) broad and sloping, equal in width to two or more diameters of posterior median eye; (4) unique web architecture of single horizontal thread with tension-release prey capture mechanism; (5) calamistrum as broad lobe with entire spinning field. Differs from genera constructing traditional orb webs (e.g., Uloborus) by absence of and spiral capture silk. Separated from other reduced-web uloborids by specific leg proportions and eye arrangement.
Appearance
longer than wide, low, and weakly convex above; cephalic region broad and obtusely rounded anteriorly. Thoracic region with nearly subparallel sides, truncated posteriorly. elongated, often tubular in form. Sternum elongated and divided into two unequal sternites. Legs long and unequal: leg formula 1423, with first pair stoutest and longest, fourth pair long and laterally compressed, second and third pairs short and thin. of first and fourth legs strongly developed, exceeding in length. IV laterally compressed with comb of short spines. Calamistrum occupies most of compressed fourth metatarsus, consisting of single sinuous series of curved bristles on thin keel. Males with rows of stout spines on front tibiae.
Habitat
Arboreal; constructs webs between branches or twigs in vegetation. Tropical and subtropical forest .
Distribution
Tropical and subtropical regions worldwide. Specific records include Parque Nacional Natural Serranía de Chiribiquete (Colombia).
Diet
; feeds on flying insects captured on viscid silk threads.
Life Cycle
Female carries cylindrical -sac until spiderlings emerge. No further details of developmental stages documented.
Behavior
Constructs horizontal single-thread web between two branches or twigs, with thick band of viscid silk and cribellate silk in central section. Maintains thread under tension while hanging upside down near attachment point. When prey contacts thread, spider releases line with snap to entangle victim, followed by rapid jerking and sudden sagging of capture thread. Some tropical (e.g., M. brevicaudus) construct three-thread webs; these spiders position at end of upper thread and approach mid-section only in darkness.
Ecological Role
of flying insects in arboreal ; contributes to dynamics.
Similar Taxa
- UloborusAlso in Uloboridae, but constructs traditional orb webs with and spiral capture silk rather than single horizontal threads; retains eight .
- HyptiotesAnother uloborid with reduced web structure, but builds triangular sector of orb web with tension-release mechanism; differs in web geometry and arrangement.
More Details
Calamistrum structure
The calamistrum—a specialized comb of bristles used to hackle cribellate silk—is uniquely modified in Miagrammopes: a broad lobe with entire spinning field, occupying most of the length of the laterally compressed fourth , with bristles arranged in a single sinuous series on a thin keel.
Eye reduction
Reduction to four is unusual among spiders and represents a derived condition within Uloboridae; eyes are , visible only as pigment spots in some specimens.