Genus Elaphrus - Marsh Ground Beetles

Bog Ground Beetles

eh-LAFF-rus

From the Greek elaphro, meaning light in weight.(1)

19 species in North America listed at nearctica.com

body length about 7-9 mm

Resemble Cicindela tiger beetles, but smaller and usually less brightly colored. Eyes large, and head wider than pronotum. Elytra have distinctive shallow pits, called foveae (2). These beetles are distinctive as a genus, but difficult to identify to species level.

Sexing specimens: "Adult males, except those of E. punctatus which lack any secondary sexual characteristics, are recognized by enlarged basal tarsomeres of forelegs with white hair-like structures ventrally, termed spongy pubescence. In most species, males have a small tooth-like projection at the base of inner spur of the mid-tibia." More information in Goulet, 233.

Much of North America, with a majority of species restricted to Alaska, Canada, and the northern United States.

Shores, mud flats, marshes, bogs. See examples:

Spring to early summer. April-May (Minnesota). March-June (E. ruscarius, North Carolina).

Larvae and adults prey on other insects, presumably.

Goulet postulates that the ancestor species arose in tropical Asia. Eventually species became extinct except for the immediate ancestor species of today's Elaphrini, which survived in Alaska and northern Siberia. From there the Elphrini radiated and evolved into current species. Today the Elaphrini are more common in Alaska, Canada, and the northern U.S. than in the southern states. (Goulet, 221.)

The most widespread species in eastern United States south of Pennsylvania is Elaphrus ruscarius, which ranges widely all the way to the Gulf of Mexico. (Goulet, 371.)

Tiger Beetles, especially genus Cicindela are similar but usually larger and lack shallow circular pits on the elytra.

Dillon p. 67, plate VII--E. cicatricosus and E. ruscarius (2)

Ciegler, pp. 32-33, fig. 44, lists E. ruscarius from South Carolina, with probably occurrence of E. californicus, which is found in North Carolina, Florida (3)

Salsbury, p. 165--photo E. ruscarius (4)

Arnett et al., pp. 75-77, fig. 199--E. ruscarius (5)

White, pp. 88-89 (6)

Sikes, pp. 50-51 lists 5 species from Rhode Island (7)

Brimley p. 116 (8)

(9) GOULET, H. 1983: The genera of Holarctic Elaphrini and species of Elaphrus Fabricius (Coleoptera:Carabidae): classification, phylogeny and zoogeography. Quaestiones Entomologicae, 19: 219-481

North Carolina State Univ. Entomology lists two species from that state: cicatricosus (1 pinned), ruscarius (73 pinned)

Insects of Cedar Creek--E. ruscarius

Insects of Quebec

Species of Elaphrus Known to Occur in Maine

Ground Beetles of Canada--Tribe Elaphrini, etc.