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 parks, gardens, and forest edges, of treelines, and under the 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. punctata 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.
Anatomy and physiologyEdit
An adult seven-spot ladybird may reach a body length of 7.6–10.0 mm (0.3–0.4 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.
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 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's since spread by natural dispersion to New York and Connecticut and to Oklahoma, Georgia and Delaware by recolonization.
- "Coccinella septempunctata (Linnaeus,1758:365). Seven-spotted lady beetle; Seven-spotted ladybug". Discover Life. Retrieved November 29, 2010.
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- Savoiskaya, G.I., Coccinellid Larvae (Coleoptera, Coccinellidae) of the Fauna of the USSR (Nauka, Leningrad Branch, Leningrad, 1983) (Keys to the Fauna of the USSR, Published by the Zoological Institute of the Academy of Sciences of the USSR, No. 137) [in Russian].
- Ben Quinn (November 7, 2006). "Home-grown ladybirds put to flight by alien invasion". The Daily Telegraph.
- Parkinson, Justin (5 March 2016). "Could the ladybird plague of 1976 happen again?". BBC News Magazine. Archived from the original on 16 October 2016.
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- J. Blount; H. Rowland; F. Drijfhout; J. Endler; R. Inger; J. Sloggett; G. Hurst; D. Hodgson; M. Speed (2012). "How the ladybird got its spots: effects of resource limitation on the honesty of aposematic signals". Functional Ecology. 26 (2): 1–9. doi:10.1111/j.1365-2435.2012.01961.x.
- N. B. Nikitsky and А. S. Ukrainsky, 2016 The Ladybird Beetles (Coleoptera, Coccinellidae) of Moscow Province ISSN 0013-8738. Entomological Review, 2016, Vol. 96, No. 6, pp. 710–735 ISSN 0013-8738 online pdf