Coccinella transversoguttata is a medium-sized, round, oval beetle, measuring 5 to 7.8 mm in length. It has a red or orange body and black markings on its elytra, which cover the wings. This species has a long black stripe near the top of its elytra. The pronotum, the section between the head and the elytra, is black with white markings on either side. The head is black with two white spots. Antennae are quite short.
Eggs are small (about 1.0 mm) and generally yellow.
The larvae of Coccinella transversoguttata are black and long, with many body segments. There are several orange spots along the middle of its back. There are small spikes called scoli along the length of the body. (Gordon and Vandenberg, 1995; Gordon, 1985; Hagan, 1962; Hesler, et al., 2009; Obrycki and Tauber, 1981)
Coccinella transversoguttata is native to North America, with populations in western Canada, western United States, and into Mexico. They can now also be found in Europe, Asia (except China), and Central America. In the past, Coccinella transversoguttata covered much of the eastern United States and Canada, but non-native lady beetle species that have moved into North America have caused populations of C. transversoguttata to decrease significantly. (Alyokhin, et al., 2008; Day and Tatman, 2006; Hesler, et al., 2009; Obrycki and Tauber, 1981; Turnock, et al., 2003)
Coccinella transversoguttata lives in open areas, such as old fields, agricultural fields, meadows, and marshes, where it feeds on pest insects. It is often found on woody plants, crops, and other flowering plants. (Colunga-Garcia, et al., 1997)
Coccinella transversoguttata goes through complete metamorphosis, with life stages of egg, larva, pupa, and adult. Eggs are laid in early spring, when average temperatures reach 12°C. C. transversoguttata develops through four larval instars, pupates, and then emerges as an adult. Adults go into hiding for winter and then come out in early spring to mate and lay eggs. Development and growth of C. transversoguttata is effected by the amount of prey available, as well as temperature. (Obrycki and Tauber, 1981; Storch, 1976; Yasuda, et al., 2004)
Coccinella transversoguttata often produces pheromones to attract mates and at close distances may use sight. This species is polygyandrous; both males and females will mate with many other individuals. After mating, males do not do anything to stop other males from mating with that female. (Gordon and Vandenberg, 1995; Kajita and Evans, 2009; Kajita, 2008; Kajita, et al., 2009; Obrycki and Tauber, 1981)
The reproductive behaviors of Coccinella transversoguttata are very similar to other lady beetle (Coccinellidae) species. Eggs are laid in groups of 20 to 30 eggs. C. transversoguttata will usually lay several of these groups, sometimes laying more than 1000 eggs. It will often lay the eggs near aphid populations so that the larvae have food to eat once they hatch. This species mates throughout the spring and summer. There are typically two generations of C. transversoguttata per year. (Evans, 2003; Gordon and Vandenberg, 1995; Kajita, 2008; Kajita, et al., 2009; Michaud, 2000; Obrycki and Tauber, 1981; Yasuda, et al., 2004)
Most lady beetles do not provide parental care for their offspring after the eggs are laid. The eggs do contain nutrients for the growth and development of the offspring, and C. transversoguttata will lay its eggs near aphid populations, so that the larvae will have food once they hatch. (Banks, 1957; Gordon, 1985; Hagan, 1962; Hodek, 1996)
There is no information available about how long Coccinella transversoguttata lives, but like most lady beetles, individuals will probably only live one season. Beetles that are still alive when winter starts will go into hiding and come out again when spring arrives. (Gordon, 1985)
Coccinella transversoguttata lives by itself, only meeting with other beetles to mate. It is an active predator that moves around mostly during the day. This species will fly from plant to plant to find prey. Over the winter, it goes into hiding (overwintering). The time at which it goes into hiding is determined by the amount of light in the environment. Since days get shorter during fall and winter, these beetles will overwinter once daylight hours drop below 10 to 13 hours per day. (Biddinger, et al., 2009; Dixon, 2005; Gordon, 1985; Sloggett and Majerus, 2000; Storch, 1976)
Coccinella transversoguttata does not do anything to protect its territory. It moves through its habitat freely. There is little information about the size of its range. (Dixon, 2005; Gordon, 1985; Sloggett and Majerus, 2000)
Coccinella transversoguttata finds mates by detecting pheromones released by other lady beetles. Sight is also used to find mates and other individuals. C. transversoguttata finds prey by sight, smell, and detecting chemicals. Adults use their antennae to feel objects, prey, and other insects. Larvae also use touch to find prey, by using their legs and mouths. (Gordon, 1985; Storch, 1976)
Coccinella transversoguttata feeds almost completely on aphids and will occasionally eat scale insects. (Adriano, et al., 2009; Campbell and Cone, 1999; Davidson and Evans, 2010; Dixon, 2005; Obrycki, et al., 2009; Sloggett and Majerus, 2000)
Other lady beetle species, particularly invasive species such as Harmonia axyridis and Coccinella septempunctata, are often predators of the eggs and larvae of C. transversoguttata. To defend itself, C. transversoguttata can release toxic chemicals from the joints in its legs. The red or orange color of its elytra is a warning signal to predators. Predators often know that brightly colored insects are poisonous, so they are less likely to attack them. (Gordon, 1985; Riddick, et al., 2009; Yasuda, et al., 2004; de Jong, et al., 1991)
Coccinella transversoguttata is a predator in its native range, feeding on aphids that eat plants. It can control the size of an aphid population. This role is decreasing as non-native lady beetle species such as Harmonia axyridis and Coccinella septempunctata move into the range of C. transversoguttata and use its resources. Harmonia axyridis and Coccinella septempunctata also prey on all life stages of C. transversoguttata. Several parasites also use C. transversoguttata as a host. Ectoparasitic fungi and ectoparasitic mites have been found on lady beetles all over the world. Mites of the genus Coccipolipus have also been found on this species. Male-killing bacteria including Rickettsia, Spiroplasma, Wolbachia, Flavobacteria, and γ-proteobacterium have been found on lady beetles species. The braconid wasp Dinocampus coccinellae is a major parasitoid on C. transversoguttata, causing the death of beetles that it infects. The Tachinidae fly Strongygaster triangulifer may also be a parasitoid of this species. (Gordon, 1985; Hagan, 1962; Riddick, et al., 2009; Sloggett and Majerus, 2000)
There are no known negative effects of Coccinella transversoguttata on humans.
Coccinella transversoguttata is a predator of insects that can destroy crops (aphids and scale insects). Because they eat so many of these pest species, C. transversoguttata can control the population, which benefits the agricultural industry by preventing damage to crops. (Dixon, 2005; Obrycki and Kring, 1998; Obrycki, et al., 2009; Sloggett, 2008)
Coccinella transversoguttata is not an endangered species. However, because many Asian beetle species are taking over the habitat of C. transversoguttata, its population has gotten significantly smaller. Conservation to prevent extinction will likely be needed. (Gordon, 1985; Hesler, et al., 2009; Turnock, et al., 2003; Yasuda, et al., 2004)
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