Roesel’s katydid

Becoming increasingly common

One generation per year: Late June through October

Meadows, grassy fields, edges of pastures, ditches, and roadsides

Roesel’s katydid is a small, short-winged, shield-backed katydid. It is native to Europe, where it is called Roesel’s bush-cricket. In 1953 it was reported at two locations in Quebec. These were the first North American records. It has spread and now occurs in southern Canada from Prince Edward Island to Manitoba, and in the northern United States from Maine to Minnesota south to Maryland and Iowa. Adults are found from late June through October in meadows and grassy fields, at the margins of pastures, and in ditches and roadsides. They require a moist area with tall grasses that is undisturbed by mowing or grazing.

Adults are ½″ to 1″ (13 to 26 mm) in length. They are usually dark brown, sometimes yellow. They are rarely completely green but are often tinged with green.

The face is vertical. The antennae are thread-like and long, as long or longer than the body. They are attached high on the face and far apart. The antennae bases are closer to the compound eyes than to each other. On each side of the head there is a black patch that wraps above and behind the compound eye. The patch s split above the eye by a cream-colored line.

The exoskeletal plate covering the first segment of the thorax (pronotum) is brown on top, black with brown mottling on the sides. There is a broad, cream-colored line around the margins of each side (lateral lobe). There are three pale green or yellow spots on each side of the thorax.

The abdomen is mostly dark brown. The leathery front wings (tegmina) are elongated-oval. They are held roof-like over the body. A small area at the base of the tegmen is horizontal and very dark. On the male, this is the stridulatory field. There is a row of bumps (a file) on the underside of the tegmen and a sharp edge (blade) on the upper side of the lower wing. By rubbing the file against the blade, the male produces its distinctive song. The female tegmina are similar but do not have these two sound-producing structures. On most adults the lower wings are reduced, shorter than the body, and not functional. These adults are flightless. A very small number of adults, less than 1%, have long, functional wings. More winged adults occur following a hot summer. The wings, when present, are membranous, broad, and longer than the body.

On the female the ovipositor is shorter than the abdomen, flattened, curved upward.

The front legs are short, the middle legs a little longer, the hind legs much longer. The third segment (femur) of the front leg has one or more spines on the upper side. The end section of the leg (tarsus), corresponding to the foot, has four segments.

Mostly grasses, but also other plants and small insects

The female deposits eggs on a blade of grass. She may also pierce the stem of a forb or shrub with her ovipositor and insert an egg into the stem. The eggs overwinter and nymphs emerge in late May and June.

Sources: 24, 29, 30, 82, 83.

Some authors list this as Roeseliana roeselii.

Until recently the genus Metrioptera and almost all of the North American shield-backed katydids were placed in the subfamily Decticinae. That subfamily is no longer recognized.

Location: Woodbury, MN