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United States Department of Agriculture

Agricultural Research Service

Research Project: PEST BIOLOGY, ECOLOGY, AND INTEGRATED PEST MANAGEMENT FOR SUSTAINABLE AGRICULTURE

Location: North Central Agricultural Research Laboratory

Title: Elytral macular forms of Coccinella septempunctata (Coleoptera: Coccinellidae) in North America

Authors
item Hesler, Louis
item Fothergill, Kent -
item Tindall, Kelly -
item Losey, John -

Submitted to: Proceedings of the Entomological Society of Washington
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 3, 2010
Publication Date: December 16, 2010
Citation: Hesler, L.S., Fothergill, K., Tindall, K.V., Losey, J.E. 2010. Elytral macular forms of Coccinella septempunctata (Coleoptera: Coccinellidae) in North America. Proceedings of the Entomological Society of Washington. 112(4):500-507. DOI: 10.4289/0013-8797.112.4.500

Interpretive Summary: The seven-spotted lady beetle is a widespread Eurasian species that has been introduced several times into North America within the last century. In North America, it is generally considered to have single form with seven pots on its forewings. In this paper, we document variation in forewing color patterns of C. septempunctata based on examination of 673 (566 North American and 107 Old World) specimens of this beetle and 382 digital submissions from North American. Two beetles lacked apical spots, and 16 beetles had paired shoulder markings. Shoulder markings were consistent in position and typically lighter in color than other spots on the forewing. Fourteen of the 16 beetles with paired shoulder markings were from ten states in the United States, one was from Canada, and one was from Italy. Some specimens had asymmetrical elytral markings that included pock marks, irregular faint black markings, or both. Nineteen specimens of the seven-spotted beetle (18 North American, 1 Old World) and 16 beetles in digital images had asymmetrical markings. Some beetles with paired shoulder markings also had dark pock marks or other irregular markings. We recommend examining additional specimens of seven-spotted lady beetles from various locations to accurately estimate frequency and pattern of variation in forewing-color forms. Possible causes and implications for color variation in this beetle are discussed.

Technical Abstract: Coccinella septempunctata L. is a widespread Palearctic species that has been introduced several times into North America within the last century. It is generally considered monomorphic with seven elytral maculae in North America. In this paper, we document variation in elytral color patterns of C. septempunctata based on examination of 673 (566 North American and 107 Palearctic) specimens of C. septempunctata and 382 digital submissions of North American C. septempunctata. Two beetles lacked apical maculae, and 16 beetles had paired humeral markings. Humeral markings were consistent in position on humeri and typically lighter in color than maculae. Fourteen of the 16 beetles with paired humeral markings were from ten states in the United States, and one was from Italy. Some specimens had asymmetrical elytral markings that included pock marks, irregular fuscous markings, or both. Nineteen specimens of C. septempunctata (18 North American, 1 Palearctic) and 16 C. septempunctata in digital images had asymmetrical markings. Some beetles with paired humeral markings also had dark pock marks or irregular fuscous markings. We recommend examining additional C. septempunctata from various locations to accurately estimate frequency and pattern of variation in elytral-color forms. Possible causes and implications for elytral-color variation in C. septempunctata are discussed.

Last Modified: 9/10/2014
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