BUG-THE BEETLE FAMILY

Coccinellidae is a family of beetles, known variously as ladybirds (UK, Ireland, Australia, Sri Lanka, Pakistan, South Africa, New Zealand, India, Malta, some parts of Canada and the US), or ladybugs (North America). Scientists increasingly prefer the names ladybird beetles or lady beetles^[2] as these insects are not true bugs. Lesser-used names include God's cow, ladycock, lady cow, and lady fly.^[3]

Ladybugs, ladybirds, or lady beetles—whatever one calls them—are favored by farmers as voracious pest-eaters.

Coccinellids are small insects, ranging from 1 mm to 10 mm (0.04 to 0.4 inches), and are commonly yellow, orange, or scarlet with small black spots on their wing covers, with black legs, head and antennae. A very large number of coccinellid species are mostly, or entirely, black, grey, or brown and may be difficult for non-entomologists to recognize as coccinellids. Conversely, many small beetles are easily mistaken for coccinellids, such as the tortoise beetles.

Coccinellids are found worldwide, with over 5,000 species described,^[4] more than 450 native to North America alone.

A few species are considered pests in North America and Europe, but they are generally considered useful insects, as many species feed on aphids or scale insects, which are pests in gardens, agricultural fields, orchards, and similar places. Harmonia axyridis (or the harlequin ladybug) was introduced into North America from Asia in 1916 to control aphids, but is now the most common species as it is out-competing many of the native species.^[5] It has since spread to much of western Europe, reaching the UK in 2004.^[5][6]

A common myth is that the number of spots on the insect's back indicates its age.

Habitats

Coccinellids are generally considered beneficial to gardeners, as they typically eat aphids, scale insects, mealybugs, and mites throughout the winter. As in many insects, ladybugs in temperate regions enter diapause during the winter, so they often are among the first insects to appear in the spring. Some species (e.g., Hippodamia convergens) gather into groups and move to higher land, such as a mountain, to enter diapause. Predatory ladybugs are usually found on plants where aphids or scale insects are, and they lay their eggs near their prey, to increase the likelihood the larvae will find the prey easily. Ladybugs are cosmopolitan in distribution, as are their prey.

Coccinellids also require a source of pollen for food and are attracted to specific types of plants. The most popular ones are any type of mustard plant, as well as other early blooming nectar and pollen sources, like buckwheat, coriander, red or crimson clover, and legumes like vetches, and also early aphid sources, such as bronze fennel, dill, coriander, caraway, angelica, tansy, yarrow, of the wild carrot family, Apiaceae. Other plants that also attract ladybugs include coreopsis, cosmos (especially the white ones), dandelions and scented geraniums.

Coccinellids are sensitive to most synthetic insecticides. If food sources are limited, oviposition is reduced. A larva uses its sharp jaws to crush an aphid's body and sucks out the aphid's juices.