Of the 4000 or so species classified, about 470 occur in North America, 125 in California. Most ladybirds are predators, feeding mainly on aphids and scale insects. In 1888, one of these, the Vedalia Ladybird from Australia, was successfully introduced to save California's threatened citrus industry from the Cottony-cushion Scale which had arrived from Australia 20 years earlier. Seven states have declared ladybirds their state insect (our state insect is the California Dogface Butterfly).
Insects have 3 body divisions - the head, thorax and the abdomen. The thorax consists of three fused segments, the first of which is called the prothorax. For beetles, the upper surface of the prothorax is called the pronotum. The front wings, or the elytra, are attached to the front of the second segment and form a sheath which protects the membranous hind wings which, if present, are attached to the third segment.
Beetles begin life in an egg. Juvenile insects, or larvae, go through a series of stages, called instars, each separated by a molt. Ladybird larvae can be very active as they crawl around searching for prey. Many ladybird larvae have a flattened, elongated, dragon-like form, but some look much like mealybugs. When the time is right the ladybird larva pupates (the pupal stage for a butterfly is also called a chrysalis), and these pupae can often be found attached to leaf surfaces. Beetles undergo complete metamorphosis, which means that, over a period of time, each insect reorganizes itself, almost completely, inside its pupal case before emerging as a adult. At least several hours elapse before the newly emerged beetle's wings have expanded and body has hardened enough for it to fly. Attaining full adult coloration takes longer.
Three species - the Convergent Ladybird, the California Ladybird, and the Western Blood-red Lady Beetle - are commonly found near the Nature Center. Several other species, notably the Mealybug Destroyer, have been encountered but with much less regularity.
If you drew a ladybird beetle, it would probably look much like the Convergent Ladybird. The elytra are orange to orange-red in color and usually have a number of black spots, 12 in this case although these may be reduced or absent. The pronotum is marked with two short whitish lines, angled with respect to one another. This ladybird is slightly more elongated than the other two common species. In the west, adult Convergent Ladybirds form large aggregations up in the mountains where they hibernate over the winter. (Other species also form aggregations, but it is usually the Convergent Ladybird that is collected and sold commercially for aphid control.) In the spring, they ride on favorable breezes back to the lowlands to feed on aphids and lay their eggs. Adults consume about 50 aphids per day. Around the Nature Center, adults can be found throughout the season, but they are much more abundant in the late spring.
The California Ladybird has orange to orange-red elytra which have no spots. The front corners of the pronotum are marked with whitish squares. The adults are slightly larger than those of the other two species.
The Western Blood-red Lady Beetle is the smallest of the three species. My references indicate that the elytra can be pale, but the only individuals I have seen have had deep red elytra, which sometimes appear translucent. The elytra have no spots. The lateral edges of the pronotum are outlined with white, and have a white dot near them. Considered over the whole season, this beetle is probably the one encountered most frequently.
Watch for these colorful insects around the Nature Center.
Ron Lyons (volunteer 1990-1999)