plant bug

Plagiognathus politus is a common, small, plant bug. It occurs in the United States and southern Canada east of the Great Plains. It is one of the most commonly collected plant bugs in the genus Plagiognathus.

Host preferences for Plagiognathus species are not well documented. Many feed on a single woody plant species, but some feed on a variety of annual plants. Plagiognathus politus has been recorded on a variety of plants. It is believed to breed primarily on plants in the Aster (Asteraceae) family. It feeds mostly on plants but also at least partly on animal material.

Plagiognathus politus has two generations per year, and each generation is a distinct color morph.

The early-season morph male is ⅛″ (3.49 to 4.02 mm) in length. That is small for a plant bug (family Miridae) but relatively large for one in the genus Plagiognathus. The body is soft, elongate, relatively broad, and more or less parallel-sided when viewed from above, flattened when viewed from the side. It is dark brown to black (dark); with whitish, brownish white, or occasionally golden (pale) areas; and it is moderately covered with recumbent, unbranched, shiny, pale hairs.

The head is short, wider than long, and dark. The top of the head (vertex) is pale on the rear margin. The mouth parts are optimized for piercing and sucking. They take the form of a long, 4-segmented beak. The first segment is dark, the second segment is dark at least at the base, the third segment is pale, and the fourth segment is dark. When not used, the beak extends from the front of the head, along the underside of the body between the legs, to the tip of the first segment (coxa) of the hind legs. The antennae are slender and relatively long, and they have four segments. The first segment is mostly dark, pale just at the tip. The second segment is entirely dark. The third and fourth segments are pale or only tinged dark.

The plate on the first segment of the thorax (pronotum) is entirely dark.

There are two pairs of wings, and they are held flat over the body when at rest. Between and at the wing bases there is a triangular plate (scutellum). The scutellum is entirely dark. The front wings (hemelytra) have a thickened section at the base and a thin membranous section at the tip with a clear dividing line between the two. The thickened basal part is comprised of a narrow area (clavus) behind the scutellum when the wings are closed, and the remaining broad marginal area (corium). At the end of the corium there is a small but distinct triangular area (cuneus). The clavus is entirely dark. The corium is mostly dark, but it always has a short, narrow, pale stripe on the inner margin at its widest point, which is near the tip of the membrane. The cuneus has a pale, crescent-shaped mark at the base. The membrane is dark. The veins are moderately to boldly contrasting with the dark membrane. The hind wings are thin and membranous.

The underside is pale with a highly variable amount of dark.

The legs are mostly pale with dark spots. The third segment (femur) is mostly dark, pale just at the tip. The fourth segment (tibia) is pale, dark just at the base. It has two rows of spines, and there is a dark spot at the base of each spine.

The late-season morph male appears lighter overall. The lateral, downward directed lobes of the pronotum are pale. The scutellum is pale. The femur is partly pale to largely pale.

The female is ⅛″ to 3⁄16″ (3.31 to 3.60 mm) in length. The body is the same width but slightly shorter, so that it appears less elongated.

Female total length: ⅛″ to 3⁄16″ (3.31 to 3.60 mm)

Male total length: ⅛″ (3.49 to 4.02 mm)

Two generations per year: early June to late September

Mostly plants but also animal material

Sources

27, 29, 30, 82, 83.

Schuh, Randall T. (n.d.). Revision of New World Plagiognathus Fieber : with comments on the Palearctic fauna and the description of a new genus (Heteroptera, Miridae, Phylinae). Bulletin of the AMNH ; no. 266. https://www.biodiversitylibrary.org/bibliography/88730

Common

This species has no common name. The common name for the family Miridae is plant bugs, and it is applied here for convenience.

Alfredo Colon
8/2/2022

Location: Albany, NY