Wild Things: Reddish potato beetle (Leptinotarsa rubinigosa)
This small beetle is more than reddish, it is a bright dark red, with black eyes, legs, and antennae. It is less than ½” long as an adult. Its range is limited to New Mexico, Texas, and Arizona. The beetle is a member of the Chrysomelidae, or leaf beetle family, containing over 37,000 species. Reddish potato beetles and their larvae feed on a variety of plants in the nightshade family. Adults are normally found on the leaves but the grubs also feed on the roots of these plants and work their way up to the leafy stems.
Nightshades are the source of common vegetables such as eggplant, tomatoes, bell peppers, chile peppers, potatoes, as well as tobacco. While these vegetables are dietary staples and healthy for human consumption, the leaves and stems contain a substance, solanine, which can be toxic in large amounts. The beetles are undeterred, however, and thrive on the leaves, stems, and roots.
The reddish potato beetle can be locally damaging to vegetable crops but its limited range reduces the overall impact. Natural predators such as lady bug beetles and stink bugs take some potato beetles but don't make a significant reduction in population numbers. The bright red coloration serves as a warning to potential bird predators that the beetle is distasteful, perhaps because of the accumulation of the toxic glycoalkaloid solanine in its tissues.
Reddish potato beetle larvae go through a number of developmental stages as they feed, after which they burrow into the soil and pupate, to emerge in the spring as adults.