Texas Beetle Information

Return to Texas Entomology - Compiled by Mike Quinn

Cobalt Milkweed Beetle

Chrysochus cobaltinus LeConte

Family Chrysomelidae, Subfamily Eumolpinae, Tribe Eumolpini

cf: C. auratus

Trail Creek Cyn, White Mountains, Esmeralda Co., NV
June 12, 2005 (M Stangeland & K Davis)

Chrysochus cobaltinus State Records

Map Source: Riley et al, 2003

Range: High Plains west to California and British Columbia. (Not present in Texas.)

Adult Activity: Adults emerge in early summer and persisting in host plant patches for approximately six weeks

Larval Hosts: C. cobaltinus readily eat both Apocynum spp. and milkweeds, including Asclepias speciosa and A. eriocarpa.

Biology: Larvae are obligate root feeders, and adults eat the leaves of larval host plants. Females are highly polyandrous, males engage in extended periods of postcopulatory mate guarding.

Similar Species: This genus includes 19 species and is Holarctic in distribution (Arnett et al, 2002)

North American Taxa:

Chrysochus auratus (Fabricius) - Throughout the eastern North America, west to the Rocky Mountains
Chrysochus cobaltinus LeConte - High Plains west to California and British Columbia

Weblink:

Photo of Chrysochus auratus male mating with Chrysochus cobaltinus female - Merrill Peterson's Homepage

Photo:

Chrysochus sp. Milkweed Beetle - Alex Wild

Type Specimen:

Chrysochus cobaltinus LeConte, 1857

References:

Arnett, R.H., Jr., M.C. Thomas, P.E. Skelley & J.H. Frank. (editors). 2002. American Beetles, Volume II: Polyphaga: Scarabaeoidea through Curculionoidea. CRC Press. 861 pp.

Cabrera-Mireles, H. 1998. Most Polyandrous pages 89-91 in: Walker (editor) University of Florida Book of Insect Records, University of Florida, Gainesville.

Clark, S.M., D.G. LeDoux, T.N. Seeno, E.G. Riley, A.J. Gilbert & J.M. Sullivan. 2004. Host plants of leaf beetle species occurring in the United States and Canada (Coleoptera: Megalopodidae, Orsodacnidae, Chrysomelidae exclusive of Bruchinae). Coleopterists Society, Special Publication no. 2, 476 pp.

Dickinson, J.L. 1995. Trade-offs between postcopulatory riding and mate location in the blue milkweed beetle. Behav. Ecol. 6: 280–286.

Dussourd, D.E., & T. Eisner. 1987. Vein-cutting behavior: insect counterploy to the latex defense of plants. Science 237:898–901.

Peterson, A. 1951. Larvae of Insects: Part II, Coleoptera, Diptera, Neuroptera, Siphonaptera, Mecoptera, Trichoptera. Edwards Bros., Inc., Ann Arbor. 416 pp.

Peterson, M.A., S. Dobler, J. Holland, L. Tantalo, & S. Locke. 2001. Behavioral, Molecular, and Morphological Evidence for a Hybrid Zone Between Chrysochus auratus and C. cobaltinus (Coleoptera: Chrysomelidae). Annals of the Entomological Society of America, 94(1): 1-9

Riley, E.G., S.M. Clark, & T.N. Seeno. 2003. Catalog of the leaf beetles of America north of Mexico (Coleoptera: Megalopodidae, Orsodacnidae and Chrysomelidae, excluding Bruchinae). Coleopterists Society, Special Publication no. 1, 290 pp.

Weiss, H.B., & E. West. 1921. Notes on insects of the spreading dogbane, Apocynum androsaemifolium L., with a description of a new dogbane midge by Dr E. P. Felt. Canadian Entomologist, 53: 146-152.