Metallic flea beetles

Overview

Altica is a large genus of small beetles known as metallic flea beetles. They occur almost worldwide, on every continent except Antarctica, but there are only a small handful of records in South America. There are about 300 Altica species worldwide, about 70 species in North America north of Mexico, and at least 5 species in Minnesota.

The biology of most Altica species in North America is poorly documented. They are usually found near water.

Description

Metallic flea beetles are small, ⅛″ to ⅜″ (3 to 9 mm) long. Females are usually larger than males. They look very much alike and are best identified by the host plant on which they are found. Barring that, dissection and microscopic examination of the genitalia is necessary.

The body is elongate oval and metallic blue or bluish green with purple and bronze reflections.

The eyes are round. The antennae are thread-like and have 11 segments.

The exoskeletal plate on the first segment of the thorax (pronotum) has a deep furrow at the base that extends almost to the lateral margins.

The hardened wing covers (elytra) have a distinct, knob-like projection (tubercle) in the shoulder (humeral) area. The elytral surface is dotted with pits (punctate), but the punctures are not arranged in rows or in any other discernible pattern.

The hind legs are powerful.