Variable Ladybird Beetle

Description:

These ladybirds are bright orange-yellow with four variable black dots on each wing-covers. There is a black line at the meeting edges of the wing-covers.

Notes:

Most adult lady beetles are easily identified, broadly oval in shape and often brightly colored. Most species are spotted, and the amount of spotting usually is characteristic of the different species. However, there are some important exceptions. For example, the smaller lady beetles that feed on mites (Stethorus) or scales (Coccidophilus, Scymnus) usually are uniformly black or dark brown. A few lady beetle species are even striped. Lady beetles, as all beetles, develop in a pattern known as ‘complete metamorphosis’. This involves eggs, mobile feeding-stage larvae that molt four times as they develop, transition-stage pupae that undergo changes to the final form, and ultimately the familiar adults. Most lady beetle eggs typically are spindle-shaped and yellowish or orange-red in color. They are laid in clusters on leaves or other surfaces near aphids and other prey. Lady beetle eggs are distinctive and easily separated from most other insect eggs. However, a few species of leaf beetles produce egg masses of generally similar form--such as the Colorado potato beetle, cottonwood leaf beetle and elm leaf beetle. Small differences in size and color differentiate these from lady beetle eggs. In addition, these leaf-feeding insects restrict their egg laying to the few plants on which they develop; whereas lady beetle eggs can be laid wherever there is nearby insect prey. As with all insects, the development rate depends on temperature and the lady beetle egg stage typically lasts five to seven days. Shortly before eggs hatch, the color changes to more greyish. Lady beetles that feed on scale insects or spider mites do not lay their eggs in masses. Instead, eggs are laid singly on leaves or under the cover of the scale insect. Most lady beetle larvae are elongated in form and slightly pointed at the rear. Their legs stick out prominently from the sides, giving the appearance of being somewhat bow-legged. Overall color is gray or black, but most have some distinct spotting of yellow, orange or blue. Fleshy projections extend from the bodies of some lady beetles, notably the twice-stabbed lady beetle and multi-colored Asian lady beetle. The larvae of lady beetles that feed on aphids found in dense colonies of curled leaves, and those that feed on mealybugs ,often are covered with waxy strands and appear similar to mealybugs. Larvae complete their development in three stages (instars), each separated by molting that typically occurs over the course of 10 to 14 days. After lady beetle larvae finish feeding, they attach themselves to a solid surface by the hind end, head down. They remain motionless and shrink in form, appearing more compact. This stage, called the prepupa, lasts for a couple of days before the insect molts to the pupal stage. Lady beetle pupae usually are round in shape, attached to a surface by their hind end. The old split skin of the previous larval stage may still partially cover the pupa or, more often, slough off around the base of the pupa. Lady beetle pupae usually are dark orange or red, often with spots. Although the pupa is fixed to the surface at its base and does not crawl or feed, it is not completely immobile and often reacts with a jerk if disturbed. During summer, development of the pupa typically may take about five to eight days. After the adult emerges from the pupal skin, it is light colored and soft (teneral adult). Over the course of a day or two, the beetle wing covers harden and darken. Most lady beetles have two to three generations annually and occur throughout the growing season. However, previous to irrigation many common lady beetles are thought to have only one generation per year, synchronized with the flush of aphid populations occurring in spring. At the end of the season, or when food runs out, adult lady beetles move to winter quarters. This typically is protected sites such as under plant debris, behind bark flaps or walls of homes. During this period (which may last six months or more) the development of the beetle is temporarily suspended, a condition known as diapause. Some lady beetles also may migrate for winter cover and travel long distances. This habit is particularly notable among the convergent lady beetle, Hippodamia convergens. This species may make summer migrations to the mountains where they spend the winter. Often they will aggregate in large groups, usually around prominent points and often at high elevations, above 9,000 feet. Such mass aggregations annually occur in several Front Range locations in Colorado. Interestingly, they are not observed in the state west of the Continental Divide. Lady beetles that have only one generation per year live about one year. However, some lady beetles (Stethorus species) are known to occasionally go into diapause and survive a second year. A small number of species spend the winter as larvae. Perhaps the most common example is Coccidophilus atronitens, a predator of pine needle scale.