January, 2009

Blue and Red Flea Beetle

The Chrysomelidae, which contains the leaf beetles, is one of the largest families of beetles, with over 1700 species in North America. These little insects are so small (most are under 1/4 inch in length) that they usually go unnoticed. However, there are some that have bright colors and might be easily observed in gardens. The blue and red flea beetle (Asphaera lustrans) is one of the most common species here in Austin, TX. I made up the common name, as, sadly, most of our insects do not have any simple and descriptive monikers that are in general use. There are several very distinctive subfamilies of leaf beetles, and this species is in the group known as flea beetles. The name comes from their habit of hopping, and their back legs are enlarged to help with this escape mechanism. Sometimes they hop and then fly away, so they are really well equipped to evade predators.

Most of the time, leaf beetles are not all that numerous and so the damage they cause by eating plants is minimal. Even when there are a good number, they often only do cosmetic injury to plants, as they are too small to eat up more than a little bit of the leaves. The blue and red flea beetle is not the only leaf beetle sporting warning colors of black and red. It is, however, possible to separate from similar species by the overall very shiny surface, metallic blue of the wing covers, and the orange-red of the head, pronotum (part behind the head), and legs. This is also one of the few insects that can be found in any month of the year, as long as the temperature is above freezing.