Adults of Leptinotarsa decemlineata are oval shaped, and can be 8 to 10 mm in length. They have five thick brown stripes running front to back on each elytra, which cover the wings. The thorax, which is between the head and body, is orange with a pattern of black spots. Antennae are shorter than its body. Larvae typically have a row of black spots down the side of the body, which is very large and plump, when compared to the head and thorax. Eggs look like orange or yellow footballs. They are about 1.7 to 1.8 mm long and 0.8 mm wide. (Alyokhin, 2008; University of Kentucky, 2010)
Leptinotarsa decemlineata, the Colorado potato beetle, is currently found throughout North America east of the Rockies, as well as some of Europe and Asia. Originally, Leptinotarsa decemlineata was found only in the southwestern United States into Mexico. As potatoes were planted in more and more places for farming, the Colorado potato beetle followed the potatoes that it eats, spreading through farm land in North America, Europe, and Asia. In the future, L. decemlineata could also expand its habitat into Korea, Japan, parts of Africa, and much of the Southern Hemisphere. (Alyokhin, et al., 2008; Alyokhin, 2008; Jolivet, 1991; Vlasova, 1978; Worner, 1988)
The Colorado potato beetle lives in farm fields where crops in the family Solanaceae grow, such as potatoes, tomatoes, tobacco, eggplants and peppers. It can also be found on plants in the Solanaceae family that are not grown on farms, but grow in the wild in open grasslands. (Alyokhin, et al., 2008; Casagrande, 1987; Kramer, et al., 2009)
Leptinotarsa decemlineata goes through complete metamorphosis, with egg, larva, pupa, and adult stages. Adults of Leptinotarsa decemlineata that are still alive when winter arrives move to the edge of fields and bury themselves in the soil. They stay there throughout the winter. Adults then emerge again in spring, and walk the short distance to the crop fields. They eat and lay eggs within 5 to 6 days. Development from egg to adult can take from 14 to 56 days, depending on the temperature. After the eggs hatch, the larvae go through four stages, called instars, where they constantly eat the host plant. After about 21 days, larvae drop off the plant to the ground, and burrow 2 to 3 cm into the ground. After about 2 days they pupate, and then come out of the ground about 5.8 days later as adults. Adults then mate and lay eggs to complete another generation of beetles. By the middle of summer, all life stages can be found. (Alyokhin, et al., 2008; Alyokhin, 2008; Fasulo, 2009; Ferro, et al., 1991; Hazzard, et al., 1991; University of Kentucky, 2010; Voss and Ferro, 1990)
Both males and females of Leptinotarsa decemlineata mate with many other beetles over their lives. Adults usually mate before going into hiding for the winter. Females can store the male sperm in their bodies during winter, and then use it to fertilize their eggs in the spring. However, females will also sometimes mate after emerging in the spring, even before walking to the crop fields. Males have hairs on their legs that they use to hold on to females while mating. However, these hairs make it harder to hold on to host plants, and females are better at holding on to host plants to feed. (Alyokhin, et al., 2008; Roderick, et al., 2003; Voigt, et al., 2008)
After spending the winter in crop fields and gardens, the Colorado potato beetle becomes active in the spring, often in May. Adults eat for a few days, and then lay eggs. Females can lay up to 300 to 800 eggs, which they lay on the under side of the plant leaves. Eggs are laid together in groups of 10 to 30. Eggs may be laid over several weeks. (Alyokhin, et al., 2008; Ferro, et al., 1991)
Leptinotarsa decimilineata provides nutrients in the eggs for the offspring to grow and develop. Otherwise, adults provide no more parental care.
Adults of Leptinotarsa decemlineata live for a few weeks during the summer after emerging from pupation. Adults that are still alive at the end of summer go into hiding for the winter, so these adults have a longer lifespan, though they are mostly inactive during the winter. A few adults even remain in hiding for a second or even third winter. (Alyokhin, et al., 2008; Kramer, et al., 2009)
Adults of Leptinotarsa decemlineata can fly, but the amount they fly depends on a few things. Beetles that emerge in spring after hiding for the winter may fly to a new location. When there are many beetles gathered together, some beetles will also fly to new locations, as far away as several kilometers away. This increases the beetles chances of finding new host plants. Females that have mated do not fly or move as often, staying in areas where there are host plants. Males that have mated move around more than females, to try and find new mates.
While in a crop field, Leptinotarsa decemlineata moves freely throughout its environment. These beetles will both walk and fly for short distances. Adults and larvae do not move around much at night, with most of their feeding taking place during the day. Larvae and adults often gather in large numbers on host plants while they feed. When threatened, larvae do certain behaviors such as walking away, standing up, regurgitating food, wiggling, and defecating. (Alyokhin, et al., 2008; Hazzard, et al., 1991; Ramirez, et al., 2010)
This species does not have a specific territory and does not do anything to defend it. They move freely in areas of host plants.
To communicate with other beetles and to view its habitat, Leptinotarsa decemlineata uses sight and smell. To find host plants, it detects chemicals produced by the plants. Vision is important to identify plants and mates, and these beetles can sense ultraviolet light, as well as the visible colors that human see. They also can probably see polarized light. After a male beetle has found a host plant to eat, it releases a pheromone that attracts other males and females to the same plant. It is also used to attract potential mates. Larvae can also detect this pheromone, and use it to gather in groups to feed. Females produce a different pheromone to attract male mates. (Boiteau, et al., 2003; Dickens, et al., 2002; Dickens, 1992; Dickens, 2006; Hammock, et al., 2007; Oliver, et al., 2002; Otalora-Luna and Dickens, 2010)
Leptinotarsa decemlineata eats Solanum plants. It eats all the leaves, leaving only the roots and stems. L. decemlineata mostly eats the potato, Solanum tuberosum, which gives the beetle its common name, the Colorado potato beetle. This species originally ate Solanum rostratum and Solanum augustifolium. Other plants that it eats include Solanum melongena (eggplant), Lycopersicon esculentum (tomato), peppers, tobacco, and other wild hosts such as Solanum dulcamara, S. carolinense, S. sarrachoides, S. elaeagnifolium, and Hyoscyamus niger. (Alyokhin, et al., 2008; Fernandez and Hilker, 2007; Hamilton and Lashomb, 1996; Hare, 1990; Hitchner, et al., 2008; Hough-Goldstein, et al., 1993; Mitchell and Low, 1994)
There are many known predators that eat Leptinotarsa decemlineata. Many arachnids, including spiders and daddy long legs eat the eggs and larvae (Phalangium opilio, Xysticus kochi, Peucetia viridans, Misumena, 2 species in the family Thomisidae). Lacewings eat the eggs (Chrysoperla carnea and Chrysoperla rufilabris). Wasps of Polistes eat larvae, and ants of genus Formica eat adults and larvae.
True bugs, including stink bugs, eat the larvae and eggs (Perillus bioculatus, Podisus maculiventris, Oplomus dichrous, Oplomus severus, Stiretris anchorago, Perilloides confluens, Zicrona coerules, Pinthaeus sanguinipes, Nabis roseipennis, Nabis alternatus, Geocoris punctipes, and species of Deraecoris). Many beetles, including lady beetles, eat all life stages of the Colorado potato beetle (Lebia grandis and at least 8 other species of Lebia, Pterostichus chalcites, Calledia decora, Coleomegilla maculata, Hippodamia convergens, Coccinella septempunctata, Coccinella transversoguttata, Harmonia axyridis, and Aiolocaria miriabilis (in USSR), Collops quadrimaculatus).
In the United States, the lady beetle Coleomegilla maculata is a significant predator that eats the eggs and small larvae of L. decemlineata. C. maculata can kill up to 58.1% of eggs in a generation. Since L. decemlineata can destroy the plants that it feeds on, many species have been used to decrease the population size. Predaceous stink bugs such as Perillus bioculatus and Podisus maculiventris attack beetle larvae, and can decrease the population by 62%. Other beetles such as Lebia grandis feed on eggs and larvae of the Colorado potato beetle, while the larvae of Lebia grandis act as parasitoids on the pupae of Leptinotarsa decemlineata.
The Colorado potato beetle may produce a toxic substance, leptinotarsin, that protects the larvae and adults from predators. Unlike some other beetles, L. decemlineata does not get this toxic substance from the plants it eats. (Alyokhin, et al., 2008; Armer, 2004; Boiteau and McCarthy, 2010; Bruni, et al., 2000; Brust, 1994; Canas, et al., 2002; Coll, et al., 1994; Drummond and Casagrande, 1989; Drummond, et al., 1990; Gollands, et al., 1991; Greenstone, et al., 2010; Groden, et al., 1990; Hamilton and Lashomb, 1996; Hare, 1990; Hazzard, et al., 1991; Hillbeck and Kennedy, 1996; Hillbeck, et al., 1997; Hough-Goldstein and McPherson, 1996; Hough-Goldstein, et al., 1993; Hsiao and Fraenkel, 1969; Hu, et al., 1999; Ignoffo, et al., 1982; Klinger, et al., 2006; Long, et al., 1998; Lopez, et al., 1997; Lopez, et al., 1993; Matlock, 2005; Munyaneza and Obrycki, 1998; O'Neil, et al., 2005; Ramirez, et al., 2010; Saint-Cyr and Cloutier, 1996; Snyder and Clevenger, 2004; Weber, et al., 2006; Weber, 2012)
Leptinotarsa decemlineata eats Solanum plants, especially the potato, Solanum tuberosum. It can also eat Solanum rostratum, Solanum augustifolium, Solanum dulcamara, Solanum melongena (eggplant), Lycopersicon esculentum (tomato), peppers, tobacco, Solanum carolinense, Solanum sarrachoides, Solanum elaeagnifolium, and Hyoscyamus niger. It is a major crop pest, since it damages the plants by eating and removing the leaves.
Eggs, larvae, and adults of L. decemlineata can serve as hosts to a variety of parasites and parasitoids. Parasites of the Colorado potato beetle include a couple of mites, Chrysomelobia labidomerae, which feeds under the elytra, and Pyemotes tritici, the straw itch mite, which causes paralysis and death within 2 to 7 days. Bacillus thuringiensis can be used to control population size of the Colorado potato beetle, since it kills larvae, and Beauveria bassiana, a fungus, infects larvae and adults.
Parasitoids are similar to parasites, but kill their host, while parasites keep their host alive. Many insects act as parasitoids of Leptinotarsa decemlineata. These include species of flies (Myiopharus aberrans, Myiopharus australis, Myiopharus doryphorae, Myiopharus macella, all Tachinidae that are parasitoids on larvae, usually emerging from adults), beetles (larvae of Lebia grandis act as parasitoids on pupae), and wasps (Edovum puttleri, an egg parasitoid, Brachymeria truncatella, and Anaphes fuscipennis, which parasitizes eggs). Leptinotarsa decemlineata is prey to many other insects, including species of lacewings, true bugs, beetles, and wasps and ants. Many arachnids also feed on L. decemlineata. (Alyokhin, et al., 2008; Drummond, et al., 1990; Gollands, et al., 1991; Groden, et al., 1990; Hamilton and Lashomb, 1996; Hare, 1990; Hough-Goldstein, et al., 1993; Hu, et al., 1999; Ignoffo, et al., 1982; Klinger, et al., 2006; Long, et al., 1998; Lopez, et al., 1997; Lopez, et al., 1993; O'Neil, et al., 2005; Weber, et al., 2006)
Leptinotarsa decemlineata is considered one of the most important crop pests. Since the Colorado potato beetle feeds almost entirely on crop plants and removes the leaves when eating, it can do serious damage to a large area of crops. These crops include tomatoes, eggplants, and, of course, potatoes. Both larvae and adults feed on the leaves of host plants, leaving only roots and stems. To stop the damage, farmers use insecticides to kill the beetles, which costs farmers millions of dollars each year. This species has been a huge pest problem throughout the country and is a problem each year for farmers. Because farmers have used so much insecticide, some groups of the Colorado potato beetle have become resistance to the insecticides, meaning that the insecticides no longer kill these populations. This creates a new problem, as these populations continue to reproduce, producing more beetles that can not be killed by the traditional insecticides, which means farmers have to develop new ways to fight the crop damage these beetles cause. (Alyokhin, et al., 2008; University of Kentucky, 2010)
There are no known positive effects of Leptinotarsa decemlineata on humans.
Leptinotarsa decemlineata is not an endangered species.
Huge amounts of information is available for Leptinotarsa decemlineata because it is a major crop pest. The information here is an introduction to the biology of Leptinotarsa decemlineata. Further information can be found using the references listed here.
Brandon Bodnariuk (author), University of Michigan Biological Station, Brian Scholtens (author), University of Michigan Biological Station, Angela Miner (editor), Animal Diversity Web Staff.
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