umbrose seed bug
(Atrazonotus umbrosus)
Conservation • Description • Habitat • Biology • Distribution • Taxonomy
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Description |
Umbrose seed bug is a small true bug (Suborder Heteroptera) but a medium-sized dirt-colored seed bug (Family Rhyparochromidae). It is the only species in the genus Atrazonotus. It occurs in the United States east of the Great Plains, across the Southwest, and on the West Coast. It also occurs across southern Canada. It is relatively scarce wherever it occurs. Adults are active from April to October in the north. They are found in open areas with a sparse litter layer. These are temporary, subclimax habitats. Adults are 3⁄16″ to ¼″ (5 to 7 mm) in length. The body is oval, fairly hard, black, and shiny or moderately shiny. The head is wider between the eyes than it is long, and it slopes forward and down. There are two large, bulging, compound eyes and two small simple eyes (ocelli). The antennae and the tube-like mouthpart (beak) are brownish black and have four segments. The plate on the first segment of the thorax (pronotum) is flat and wider than long. The sides are strongly curved. The lateral margins are narrowly flattened and extended outwards (margined). The rear margin is concave. The plate between the wing bases (scutellum) is large and triangular. It is at least as wide at the base as it is long. The scutellum and the rear half of the pronotum are dotted with fine pits referred to as punctures (punctate). There are two pairs of wings, and they are held flat over the body when at rest. The front wings (hemelytra) have a thickened part at the base and a thin, membranous part at the tip, with a clear dividing line between the two. The thickened part of each hemelytron is comprised of a narrow area (clavus) behind the scutellum when the wings are closed, and a broad marginal area (corium). On the clavus, there are four rows of punctures. The corium is sparsely and finely punctate. The membranous portion of the hemelytron is brownish black and has five unbranched veins. The legs are mostly black. On the front legs, the third segment (femur) is thickened, and it has a single row of no more than six spines on the underside. The last part of each leg (tarsus), corresponding to the foot, is brownish black, and it has 3 segments. The last tarsal segment has a pair of claws at the tip and a pad at the base of each claw. |
Size |
Total length: 3⁄16″ to ¼″ (5 to 7 mm) |
Similar Species |
Habitat |
Open areas with a sparse litter layer |
Biology |
Season |
Number of generations per year unknown: April through October |
Behavior |
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Life Cycle |
Adults overwinter on the ground beneath logs, mullein leaves, and other sheltered places. |
Larva Food |
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Adult Food |
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Distribution |
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Sources |
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| 11/28/2024 | ||
Occurrence |
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Relatively uncommon |
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Taxonomy |
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Order |
Hemiptera (true bugs, hoppers, aphids, and allies) |
Suborder |
Heteroptera (true bugs) |
Infraorder |
Pentatomomorpha |
Superfamily |
Lygaeoidea (seed bugs and allies) |
Family |
Rhyparochromidae (dirt-colored seed bugs) |
Subfamily |
Rhyparochrominae |
Tribe |
Gonianotini |
Genus |
Atrazonotus |
Subordinate Taxa |
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Synonyms |
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Aphanus plenus Aphanus umbrosus Delochilocoris illuminatus ssp. umbrosus Delochilocoris umbrosus Dorachosa illuminatus ssp. umbrosus Microtoma atrata Microtoma carbonaria Rhyparochromus umbrosus |
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Common Names |
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shady seed bug umbrose seed bug |
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Glossary
Beak
In plants: A comparatively short and stout, narrow or prolonged tip on a thickened organ, as on some fruits and seeds. In insects: The protruding, tubular mouthpart of a sucking insect.
Clavus
On Hemiptera: The hard part of the forewing that is adjacent to the scutellum when the wings are closed. Plural: clavi.
Corium
The thickened basal portion of the front wing that lies between the clavus and the membrane of insects in the family Hemiptera. Plural: coria.
Femur
On insects and arachnids, the third, largest, most robust segment of the leg, coming immediately before the tibia. On humans, the thigh bone.
Hemelytron
The forewing of true bugs (Order Hemiptera), thickened at the base and membranous at the tip. Plural: hemelytra.
Ocellus
Simple eye; an eye with a single lens. Plural: ocelli.
Pronotum
The exoskeletal plate on the upper side of the first segment of the thorax of an insect.
Punctate
Dotted with pits (punctures), translucent sunken glands, or colored spots of pigment.
Scutellum
The exoskeletal plate covering the rearward (posterior) part of the middle segment of the thorax in some insects. In Coleoptera, Hemiptera, and Homoptera, the dorsal, often triangular plate behind the pronotum and between the bases of the front wings. In Diptera, the exoskeletal plate between the abdomen and the thorax.
Tarsus
On insects, the last two to five subdivisions of the leg, attached to the tibia; the foot. On spiders, the last segment of the leg. Plural: tarsi.
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Babette Kis |
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Atrazonotus umbrosus - Umbrose Seed Bug Atrazonotus umbrosus, known as the umbrose seed bug, is a species of dirt-colored seed bugs. On a grape leaf near the ground at Barnes Prairie, Racine Co., WI. Photographed on May 30, 2024. |
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Babette Kis |
Location: Barnes Prairie, Racine Co., WI Atrazonotus umbrosus, known as the umbrose seed bug, is a species of dirt-colored seed bugs. On a grape leaf near the ground at Barnes Prairie, Racine Co., WI. Photographed on May 30, 2024. |
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Created: 11/28/2024 Last Updated: © MinnesotaSeasons.com. All rights reserved. |