two-marked treehopper

This is a small, 3 ⁄16″ to ¼″ long jumping insect. Like other treehoppers, it has the overall appearance of a thorn.

The wings, pronotum, and legs are dark brown. The eyes are brown. The pronotum covers the thorax and abdomen, projects forward like a horn, and is slightly expanded at the tip. It has yellow spots near the center of the dorsal (upper) ridge. The first two pairs of legs are broad and flattened.

Each of the nine species of this species complex (see Coments below) inhabits a single host plant species. Six species are found in Minnesota: American bittersweet, black locust. black walnut, butternut, common hop-tree, and nannyberry,

Adults are often found on non-host plants.

The female deposits her eggs in a mass under the bark of a branch, then covers them with a foamy, white secretion (egg froth). The egg froth contains a chemical that attracts other females and signals them to deposit their eggs. Ten or more egg masses are often deposited on a single branch.

Offspring overwinter as eggs. Eggs hatch the following spring. Nymphs produce sugary secretions that attract ants. Attendance by ants in the late season significantly reduces mortality.

Adults are often seen in groups on a twig. They are usually in single file with their heads all pointing in the same direction. They puncture the twig and extract the sap.

Sources: 7, 30.

Taxonomy
This is a species complex, a group of nine species that is identical in appearance (as adults) while remaining reproductively separate. Species evolved to exploit individual host plant species while remaining geographically combined (sympatric speciation). All nine species are referred to by the binomial name Enchenopa binotata.