Alaus oculatuseyed click beetle
Geographic Range
Alaus oculatus is found throughout the eastern United States, from Quebec to Florida and west to Texas and South Dakota.
Habitat
Beetles are found around deciduous woods and in areas with many hardwood trees, such as cherry, apple, or oak, especially in areas with a lot of rotting logs (Milne and Milne 1995).
- Terrestrial Biomes
- forest
Physical Description
Adults reach a length of 24-45 mm . The adult beetle is long and thin (Arnett, et al 1980). Alaus oculatus has distinctive eyespots that cover about one third the length of the pronotum. These large spots are black with a white ring. They provide a distinctive coloration pattern that make the beetle appear to have large eyes on its back, affording it a little extra protection from predators who may be startled at the sight of seemingly threatening "eyes" (Woodruff 1999). The beetles are covered in minute scales that function well as protective coloration (Encarta 1999).
Larva of Alaus oculatus are slender and are up to 2 inches long, hard-shelled, yellowish to dark brown, and jointed (Nielson 1997). The larva have dark heads and appear segmented. They have three pairs of legs. The last four segments are dark brown and the 9th segment has what appear to be pronged teeth, while the 10th segment has two anal hooks, 10-12 spines, and seta (Woodruff 1999).
- Other Physical Features
- ectothermic
- bilateral symmetry
Reproduction
Beetles lay eggs in the soil and produce slow-growing larva (wire worms). The larva pupate in rotting logs or below the ground. The beetles emerge in the spring and are commonly found until September (Borer and White 1970, Nielson 1997).
Behavior
This species of beetle has a unique method for righting itself after it has been flipped on its back. The beetle has a hinged joint between the head and thorax of its body that allows it to arch its back and then quickly snap the hinge and slam a hard extension of its back into the ground, thus propelling the beetle into the air up to six inches and allowing it to flip over (Evans and Bellamy 1996).
Alaus oculatus is often considered a pest around house lights during its peak season in mid- to late-summer. Often homeowners complain about the numbers of beetles attracted to lights, and about those beetles who choose to enter houses, especially in wooded areas. This problem can be alleviated by turning lights off, replacing and improving screens over windows, and aerosol sprays (Day 1996).
Click beetles include several genera in the family Elateridae. Their ability to "click" by moving their prothorax and a lobe of their prothorax has earned them their common name (Borror and White 1970).
Food Habits
The beetles themselves eat nectar from flowers (Day 1996). The larva are great crop pests, as they eat the roots of corn, root vegtables, and some flowers. The larva are also found in and around the stumps of hardwood trees such as cherry trees, apple trees, and oak trees, where they eat the larva of some wood-boring beetles
(Milne and Milne 1995).
Economic Importance for Humans: Negative
The larval stage of the click beetle, or Alaus oculatus, is commonly called a "wireworm." It can live in the soil and may eat the roots and seeds of many different types of plants, including corn, grains, wild grasses, potatoes, beets, carrots, beans, lettuce, onions, turnips, and certain kinds of flowers. Poorly drained sod fields are more prone to wireworms than other types of fields. Wireworms usually destroy crops by eating the germ of the seed, thus causing germination to not occur. If the larva do not totally disallow germination of a crop, the crop may thin out and die later because the worms eat underground parts of the stem or roots of the plants. The larva may also eat rotting logs or the larva of some other types of beetles (Nielson 1997).
Conservation Status
-
- IUCN Red List
- No special status
-
- US Federal List
- No special status
-
- CITES
- No special status
Contributors
Gabrielle Frey (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.
Glossary
- Nearctic
-
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
References
1999. Click Beetle. Encarta Encyclopedia.
Arnett, R., N. Downie, H. Jaques. 1980. How to Know the Beetles. Dubuque, Iowa: Wm. C. Brown Company Publishers.
Borror, D., R. White. 1970. Peterson Field Guides. Insects. Boston: Houghton Mifflin Company.
Day, E. 1996. "Virginia Cooperative Extension" (On-line). Accessed Feb. 19, 2000 at http://www.ext.vt.edu/departments/entomology/factsheets/clickbee.htm;.
Evans, A., C. Bellamy. 1996. An Inordinate Fondness for Beetles. New York, New York: Nevraumont Publishing Company.
Milne, L., M. Milne. 1995. National Audubon Society Field Guide to North American Insects and Spiders. New York City, New York: Chanticleer Press, Inc.
Nielsen, G. 1997. "Wireworms" (On-line). Accessed Feb. 19, 2000 at http://ctr.uvm.edu/ctr/el/el86.htm.
Woodruff, R. June 1999. "Featured Creatures" (On-line). Accessed Feb. 19, 2000 at http://www.ifas.ufl.edu/~insect/trees/beetles/click_beetle.htm.