Coccinella septempunctata, the seven-spot ladybird (or, in North America, seven-spotted ladybug or "C-7"), is the most common ladybird in Europe. Its elytra are of a red colour, but punctuated with three black spots each, with one further spot being spread over the junction of the two, making a total of seven spots, from which the species derives both its common and scientific names (from the Latin septem = "seven" and punctus = "spot").

C. septempunctata has a broad ecological range, generally living where there are aphids for it to eat. and including, amongst other biotopes, meadows, fields, Pontic–Caspian steppe, parkland, gardens, Western European broadleaf forests and mixed forests. Both the adults and the larvae are voracious predators of aphids, and because of this, C. septempunctata has been repeatedly introduced to North America as a biological control agent to reduce aphid numbers, and is now established in North America. It has been designated the official state insect of five different states (Delaware, Massachusetts, New Hampshire, Ohio, and Tennessee).
Although C. septempunctata is mainly aphidophagous it also feeds  on Thysanoptera, Aleyrodidae, on the larvae of Psyllidae and Cicadellidae, and on eggs and larvae of some beetles and butterflies. There are one or two generations per year. Adults overwinter in ground litter in parks, gardens and forest edges and under tree bark and rocks.
In the United Kingdom, there are fears that the seven-spot ladybird is being outcompeted for food by the harlequin ladybird. Conversely, in North America, this species has outcompeted many native species, including other Coccinella. Massive swarms of C. septempunctata took place in the drought summer of 1976 in the UK. The species has undergone significant declines on the island of Malta, yet it is unclear whether this decline has occurred at the same rate elsewhere.

Biology

An adult seven-spot ladybird may reach a body length of 7.6–12.7 mm (0.3–0.5 in). Their distinctive spots and attractive colours apparently make them unappealing to predators. The species can secrete a fluid from joints in their legs which gives them a foul taste. A threatened ladybird may both play dead and secrete the unappetising substance to protect itself.  The seven-spot ladybird synthesizes the toxic alkaloids, N-oxide coccinelline and its free base precoccinelline; depending on sex and diet, the spot size and coloration can provide some indication of how toxic the individual insect is to potential predators.

Anatomy and physiology

It can be found in Europe, North Africa, Australia, Cyprus, European Russia, the Caucasus, Siberia, the Russian Far East,  Belarus, Ukraine, Moldova, the Transcaucasia, Kazakhstan, Middle Asia, Western Asia, Middle East, Afghanistan, Mongolia, China, North and South Korea, Pakistan, Nepal, North India, Japan, Sri Lanka and southeast Asia. It can also be found in North America (the species was introduced to the United States) and tropical Africa.The first record of successful establishment (after numerous failed attempts to introduce the species) in the United States was in 1973. It has since spread by natural dispersion to New York and Connecticut and to Oklahoma, Georgia and Delaware by recolonization.

Distribution

Coccinella septempunctata, commonly known as the seven-spot ladybird, is considered a garden pest because its larvae and adults feed on aphids, which are also pests that damage garden plants. While the ladybirds themselves are beneficial predators, their presence in large numbers can sometimes lead to a decline in aphid populations, causing them to seek alternative food sources, including plant foliage and flowers.

garden pest

Coccinella septempunctata can be considered a crop pest because while they primarily feed on aphids, in the absence of sufficient aphid populations, they may resort to feeding on plant foliage and flowers, potentially causing damage to crops.

crop pest

Coccinella septempunctata can be considered pests because they feed on aphids, which are harmful to plants, but in the absence of sufficient aphid populations, they may resort to feeding on plant foliage and flowers, potentially causing damage to crops and gardens.

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Do seven-spotted ladybug migrate?

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