''Elaphrus viridis'', the Delta green ground beetle, is a species of

ground beetle Ground beetles are a large, cosmopolitan distribution, cosmopolitan family (biology), family of beetles, the Carabidae, with more than 40,000 species worldwide, around 2,000 of which are found in North America and 2,700 in Europe. As of 2015, it i ...

restricted to a small region within

Solano County, California Solano County () is a county located in the U.S. state of California. As of the 2020 census, the population was 453,491. The county seat is Fairfield. Solano County comprises the Vallejo–Fairfield, CA Metropolitan Statistical Area, which is ...

. Its color is a metallic-green, usually with bronze spots on its

elytra An elytron (; ; , ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometimes alterna ...

, though some lack these spots. The lack or reduction of circular pits on the elytra helps distinguish it from other ground beetles. Typical adults are about a quarter-inch (0.6 cm) in length."''Delta Green Ground Beetle, Elaphrus viridis''"
Sacramento Fish & Wildlife Office. Retrieved on 14 August 2006.
Essig Museum of Entomology - UC Berkeley. Retrieved on 14 August 2006. The Delta green ground beetle plays a useful role in its ecosystem by pollinating plants, fruits, and vegetables. The beetle's common name probably refers to the triangular marking on its

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on ea ...

. The species name, ''viridis'', comes from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word for

green Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 Nanometre, nm. In subtractive color systems, used in painting and color printing, it is created by ...

."''Species Elaphrus viridis - Delta green ground beetle''"
BugGuide. Retrieved on 14 August 2006.

Range and distribution

The Delta green ground beetle is known to only occur in Solano County, California, though it may have historically occurred throughout the Central Valley. It is known to inhabit

Jepson Prairie Preserve Jepson Prairie is a remnant natural prairie in the Sacramento Valley of the U.S. state of California, surrounded by land used in agriculture. The prairie is managed by the University of California, Davis, the Solano Land Trust, and the Nature C ...

, south of Dixon, where it is protected; however, the beetle's other known ranges are located on public land. The beetle occupies

vernal pool Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the safe ...

habitats, around which its

life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring *Life-cycle hypothesis, ...

is based: it emerges in January following the filling of vernal pools from winter rains and lies dormant in May (around when the pools dry up) as a means of surviving the summer. Specimens of the Delta green ground beetle have generally been collected in open habitats, namely the edges of vernal pools and nearby trails, roads and ditches. They may also be present in the surrounding

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

s, but the beetle's small size,

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...

against spring grass, and tendency to hide beneath low growth make it difficult to locate.

Reproduction

The Delta green ground beetle breeds through January and September, with females producing one generation per year.

Diet

The Delta green ground beetle, in both its larval and adult stages, actively hunts soft-bodied arthropods. Based on the habits of other species of ''

Elaphrus ''Elaphrus'' is a genus of ground beetle native to the Palearctic, the Nearctic, the Near East and Northern Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singula ...

'', it is likely that the beetle feeds primarily on

springtail Springtails (Collembola) form the largest of the three lineages of modern hexapods that are no longer considered insects (the other two are the Protura and Diplura). Although the three orders are sometimes grouped together in a class called Ento ...

Conservation status

The Delta green ground beetle's current

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

status is Critically Endangered, owing to the species' extremely limited range and the endangerment of its vital vernal pool habitats. Database entry includes justification for why this species is listed as critically endangered. In addition, the species has been federally listed as threatened since 1980. The destruction of vernal pool habitats in California is largely the result of agricultural development, though urbanization and grazing have played some role in their elimination. Another significant threat to the beetle is the introduced Garden lippia, which grows in dense mats in these habitats and impairs its ability to forage.

References

{{Taxonbar, from=Q1767867 Elaphrinae Endemic fauna of California Endemic insects of the United States Beetles of North America ESA threatened species Beetles described in 1878 Taxa named by George Henry Horn