They are commonly known as ladybugs in North America and ladybirds in the United Kingdom; "lady" refers to mother Mary.

The name Coccinellidae, created by Pierre André Latreille in 1807,[4] is derived from the Latin word coccineus meaning 'scarlet'.

[6][7] Mary ("Our Lady") was often depicted wearing a red cloak in early art, and the seven spots of the species Coccinella septempunctata (the most common in Europe) were said to represent her seven joys and seven sorrows.

[16][17] Being beetles, they have hardened, non-overlapping forewings, known as elytra, which cover up the more fragile hindwings when the insects are not in flight.

[16] As adults, these beetles differ from their closest relatives with the following morphological characteristics:[20] Coccinellids are often distinctively coloured and patterned.

Light areas are typically yellow, red, orange or brown, and the spots vary in size and shape and numbers.

[20][7] Their colouration varies from grey, blue-grey, grey-brown or brown and spotted with white, yellow, red or orange.

[25] Although molecular clock estimates have placed their origin in the Cretaceous, the oldest fossils of the group are known from the Oise amber of France, dating to the Early Eocene (Ypresian) around 53 million years ago, which belong to the extant genera Rhyzobius and Nephus.

[25] The Coccinellidae are within the superfamily Coccinelloidea, which in turn is part of the infraorder Cucujiformia, a group containing most of the plant-eating beetles.

[29] Lymexyloidea Tenebrionoidea Cleroidea Chrysomeloidea Curculionoidea Cucujoidea Bothrideridae and allies Latridiidae Akalyptoischiidae Alexiidae Corylophidae and allies Endomychidae Coccinellidae Coccinellidae have historically been divided into up seven subfamilies (Chilocorinae, Coccidulinae, Coccinellinae, Epilachninae, Microweiseinae, Scymninae and Sticholotidinae) and 35 tribes based on morphology.

The study suggests that the crown group appeared some 143 Mya in the Early Cretaceous, and that the group diversified rapidly during the Late Cretaceous, perhaps because the growth in diversity of angiosperm plants then encouraged the radiation of insects of the clade Sternorrhyncha such as aphids, on which ladybirds could feed.

[32] Microweiseinae Monocoryninae Stethorini Coccinellini other tribes An earlier 2009 study concluded that consumption of scale insects is the most basal diet of Coccinellidae.

In warmer temperate regions, reproduction may occur in spring, fall and winter; tropical species reproduce during the wet season.

Eggs tend to be bright yellow, and the females lay them close together, standing upright and near where they can access food.

[42] The larva eventually transitions into a pupa; which involves the development of a hunch, the fusion of the legs to the body, and the attachment of the posterior to the surface.

[7] Adult coccinellids develop much of their final colouration within hours, but may not fully darken for weeks or months.

Overwintering insects can be found both in lowland areas, aggregating under dead vegetation, and at the tops of hills, hibernating under rocks and on grass tussocks.

Aphid-eaters tend to be generalist; they have a high voracity and can multiply quickly in response to outbreaks, and switch to other prey when the ephemeral aphids become scarce.

Predators of scale insects tend to be less voracious and are slower breeders and developers; matching their prey.

[58] Non-animal matter consumed include leaves, pollen, nectar, sap, fungi, and honeydew.

A 2015 study of five ladybird species found that their colouration honestly signalled their toxicity, implying the warning is genuine.

When disturbed, ladybirds further defend themselves with reflex bleeding, exuding drops from their tibio-femoral (knee) joints, effectively presenting predators with a sample of their toxic and bitter body fluid.

[68] The similarity of coccinellid patterning in red and orange with black markings has led to suggestions that they and some species of chrysomelids[69] form Müllerian mimicry rings[70] particularly to defend them from birds.

Some species can live in extreme environments such as high mountains, arid deserts and cold regions.

Climate change may lead to smaller larvae, as well as increase energy and metabolic needs and interspecific predation.

[7] The larva of the species was introduced to California in 1887 from Australia, to protect citrus trees from cottony cushion scale.

The project was markedly successful, costing $1,500 in 1889,[79] making it "a textbook example of the great potential of classical biological control as a tactic for suppressing invasive pests."

[75] In North America, this species begins to appear indoors in the autumn when they leave their summer feeding sites to search out places to stay for winter.

Typically, when temperatures warm to the mid-60s °F (around 18 °C) in the late afternoon, they swarm onto or into buildings illuminated by the sun from nearby fields and forests.

As few as 1.3 to 1.5 coccinellids per 1 kilogram (2.2 lb) of grapes can affect wine quality when they are present during the wine-making process.