Coccinella septempunctata looks like a typical ladybug: it is medium sized, has orangish-red elytra (wing coverings) and black spots. This species can be identified by several unique characteristics. It usually has seven black spots, though it can range from 0 to 9. There is one spot near the top of the elytra that extends across the two elytra, and there are two white patches on either side above this spot. There are three spots on each elytra, though they can vary in placement. The underside of its body is black. Males have small hairs on the last segment of the body. (Angalet, et al., 1979; Cantrell, 2011; Gordon, 1985; Angalet, et al., 1979; Cantrell, 2011; Gordon, 1985)
The larvae of C. septempunctata can be several colors, depending on temperature, but they are generally dark with many body segments. ("Coccinella septempunctata L.", 2011; Angalet, et al., 1979; Beverley, et al., 2012; Cantrell, 2011)
The pupa is slate grey to black, sometimes having white or orange markings on the outside. It has a hard exoskeleton which develops from the last larval stage. It is about the size of the adult Coccinella septempunctata. ("Coccinella septempunctata L.", 2011; Cantrell, 2011)
Coccinella septempunctata is originally from Europe and Asia, but it is now found throughout the Middle East, India and North America (U.S. and Canada). C. septempunctata was intentionally brought to the United States between 1951 and 1971 to control the populations of crop damaging aphids. None of those introductions were though to be successful in creating a population until 1973 when a population was found in Hackensack Meadowland, New Jersey. However, this population was thought to have been started by accident. Populations continued to appear in the eastern U.S. and Canada in the following years. Since then, this species has become one of the most common lady beetle species across North America. (Gordon, 1985; Honek and Martinkova, 2005; Maredia, et al., 1992)
Coccinella septempunctata can be found wherever large numbers of prey, particularly aphids, are present. This normally includes small plants, shrubs and trees in open fields, grasslands, marshes, farm land, suburban gardens and parks. The typical habitat for Coccinella septempunctata during the winter is an open area with sheltering boulders, small clusters of plants, or hedgerows of dense grasses that are south-facing, with the most possible sunlight hours. (Cantrell, 2011; Hodek and Michaud, 2008; Hoebeke and Wheeler, 1983; Honek and Martinkova, 2005; Honek, et al., 2007; Turnock, et al., 2003)
Coccinella septempunctata goes through complete metamorphosis. Its life stages are egg, larva, pupa, and adult. After the egg hatches, a larva will stay with its egg casing, eat it, and eat any nearby eggs that haven't hatched. Larvae go through several stages called instars. As the instars develop, they shift from sucking the liquids from aphids, and instead eat the entire insect. There are four instars for this species, and the time of each instar is effected by the amount of aphid prey and temperature. Before the fourth instar pupates, it stops eating for 24 hours and attaches itself to a surface, such as a leaf, with the tip of its body. After pupation, C. septempunctata comes out as an adult. At this point, the elytra, which cover the wings, are very soft and lack color. The red/orange color develops over time. ("Coccinella septempunctata L.", 2011; Beverley, et al., 2012; Cantrell, 2011)
Coccinella septempunctata reproduces sexually, with each male and female breeding with multiple partners during a breeding season. Males try to attract female mates with a 5 step process: approach, watch, examine, mount and mating attempt. During the approach stage, a male will come within 1 cm of a desired female and watch her without making contact. The male will then examine the female by feeling her antennae and mouth with his own. If the female accepts the male as a mate, the male will climb onto the female from behind and attempt to mate.
Females that are not ready to mate will reject males. Females that have recently mated or about to lay eggs will also reject males. Females that do mate with males can mate up to 4 to 6 times a day. Each female will mate with many males during her life. Females of Coccinella septempunctata are known to produce spermatophores, which are usually a mass containing sperm and other nutrients. Often females eat them to gain nutrients, but this species does not eat them. It is not known why C. septempunctata has spermatophores. ("Coccinella septempunctata L.", 2011; Beverley, et al., 2012; Omkar and Srivastava, 2002)
Once a female has fertilized eggs she will begin to lay them around her environment. Some males and females will mate just before winter. Since this species goes into hiding during the winter (overwintering), females can store the sperm from the males in their bodies. In the spring, this sperm will fertilize the eggs of the female, and then eggs can be laid in the spring, instead of just before winter, giving the eggs a better chance to survive. A female might lay anywhere from 250 to 500 eggs in her lifespan. Coccinella septempunctata females usually lay eggs in areas without other eggs of the same species. Females can detect chemicals or scents from eggs of the same species, and know to not lay their eggs in the area. A maximum of 15 eggs are laid in each location. With less eggs in an area, this means that the larvae that hatch have less larvae to compete with for food. ("Coccinella septempunctata L.", 2011; Beverley, et al., 2012; Cantrell, 2011; Hodek and Michaud, 2008; Omkar and Srivastava, 2002)
Adults of Coccinella septempunctata provide nutrients in the eggs for the development of the offspring. Females also lay eggs in places that are safe and have resources for the larvae once they hatch. Aside from this, adults do not provide any more parental care. ("Coccinella septempunctata L.", 2011; Hodek and Michaud, 2008; Omkar and Srivastava, 2002)
Coccinella septempunctata is a mobile beetle that can fly, and is mainly active during the day. When overwintering, groups of C. septempunctata will gather to wait out the winter in grasses or in between boulders. Adults will form groups of 10 to 15 usually, though groups of over 200 have been found. (Angalet, et al., 1979; Cantrell, 2011; Hodek and Michaud, 2008; Honek and Martinkova, 2005; Honek, et al., 2007)
Chemicals and pheromones are very important to Coccinella septempunctata. When these beetles gather in groups for the winter, they use a chemical to attract other individuals to the group. This pheremone is 2-isopropyl-3-methoxy-pyrazine. By attracting other beetles to the overwintering sites, this guarantees that there will be beetles to mate with when spring arrives. Several chemicals are also used to find prey, particularly aphids. When threatened, aphids release an alarm pheromone to let other aphids know that there is danger. C. septempunctata uses this chemical to find aphids. When plants are being eaten by aphids, they often also release chemicals to communicate with other plants. C. septempunctata also detects these chemicals to find plants with aphids. C. septempunctata can also detect cues from eggs of the same species, which prevents them from laying eggs too close to other groups of eggs. This decreases the amount of competition for food, as well as cannibalism of the eggs and larvae. (Cantrell, 2011; Peterson, et al., 2005)
Coccinella septempunctata mainly eats aphids and other similar scale insects. When there are not enough aphids, adults will eat pollen. Some adults will even eat eggs or larvae of the same species. Larvae also eat aphids, but will eat larvae of other lady beetle species if aphids are not available. (Honek and Martinkova, 2005; Honek, et al., 2007; Omkar and Srivastava, 2002; Peterson, et al., 2005)
Coccinella septempunctata has very few predators as an adult. Like most lady beetles, C. septempunctata can release toxic chemicals from the joints of its legs when threatened by predators. The typical bright colors of lady beetles act as warning signals to predators, called aposematic coloring. Many predators know that brightly colored insects are poisonous, and are less likely to attack them. Common lady beetle predators include birds and small mammals. Spiders are also known to prey on Coccinella septempunctata larvae. Cannibalism on eggs and larvae of the same species are also a significant threat. Other lady beetle species, Coccinellidae, also prey on the eggs and larvae of C. septempunctata. (Abassi, et al., 2001; Angalet, et al., 1979; Cantrell, 2011; Hodek and Michaud, 2008; Honek, et al., 2007; Kindlmann, et al., 2000; Miura, 2009; Peterson, et al., 2005; Riddick, et al., 2009)
Coccinella septempunctata is a predator of plant harming aphids and scale insects. C. septempunctata can control the population size of these insects because it eats so many of them. This helps to protect plants from damage, which is helpful to the ecosystem. These plants are often important to other organisms in the habitat. C. septempunctata is eaten by many bird, small mammal, and spider species, as well as other lady beetles. (Abassi, et al., 2001; Peterson, et al., 2005; Riddick, et al., 2009)
Coccinella septempunctata is as host to a large variety of parasites and parasitoids. Parasitic wasps of the families Eulophidae and Braconidae, and flies of the family Phoridae parasitize the larvae of C. septempunctata. The braconid wasps Perilitus coccinellae and Dinocampus coccinellae are the most well known species that are parasitoids of Coccinella septempunctata. P. coccinellae develops along with and inside the larvae and/or adult of the ladybird beetle, until the wasp emerges and kills the lady beetle host. D. coccinellae eggs are usually laid within the body of a female of Coccinella septempunctata and then hatch within the beetle and eat the eggs within the female. The host is unaffected by this until the wasp larva pupates in the leg of the lady beetle, and then emerges as an adult up to 9 days later. Normally, this kills the infected C. septempunctata, but sometimes the beetles are able to survive this. (Abassi, et al., 2001; Riddick, et al., 2009; Triltsch, 1996)
Since Coccinella septempunctata can live in many different habitats, it is taking this habitat space away from many native lady beetle species. This is causing problems for native beetle species, which have access to less and less food and land. This is also upsetting the overall health and balance of the ecosystem. This could eventually be costly to humans as the natural ecosystem is disrupted. Coccinella septempunctata is also a problem in the wine industry, as it is sometimes accidentally caught on crops during the wine making process. Chemicals produced by C. septempunctata ruin the taste and quality of wine. ("Coccinella septempunctata L.", 2011; Botezatu, et al., 2013; Honek and Martinkova, 2005; Peterson, et al., 2005; Tatchell, 1989)
Coccinella septempunctata is a common species used on farms to prevent crop destruction by aphids, a major agricultural pest. C. septempunctata eats large numbers of aphids, which prevents the crops from being destroyed. Aphids also harm plants by transferring diseases and fungi. C. septempunctata has been used across the U.S. to control aphid populations. Since C. septempunctata can live in so many different habitats, it is especially useful in controlling aphid populations in many different areas. ("Coccinella septempunctata L.", 2011; Honek and Martinkova, 2005; Peterson, et al., 2005; Tatchell, 1989)
Coccinella septempunctata is not an endangered species. Instead, it is considered an invasive species, since it is not originally from the areas that it now lives, and is taking away resources from native species.
Tatia Bauer (author), University of Michigan Biological Station, Angela Miner (editor), Animal Diversity Web Staff.
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