Dieunomia triangulifera

Dieunomia triangulifera is a species of sweat bee in the family Halictidae.^[2][3][4] It is found in the central United States from central Illinois and Minnesota westward to Utah and southern New Mexico.^[5] Adult Dieunomia triangulifera closely resemble Dieunomia nevadensis, specifically Dieunomia nevadensis arizonensis.^[5]

Dieunomia triangulifera
Conservation status
Vulnerable  (NatureServe)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Halictidae
Genus:	Dieunomia
Species:	D. triangulifera
Binomial name
Dieunomia triangulifera (Vachal, 1897)
Synonyms[2]
Nomia triangulifera Vachal, 1897

Life cycle

Prepupa

In the early stages of its life cycle, Dieunomia triangulifera spends the winter underground as a prepupa in a state of diapause, allowing it to survive harsh conditions.^[5] This prepupa can be distinguished from that of Nomia melanderi by sharper dorsal prominences on the thorax,^[5] and is butter-yellow with bands of orange between segments.^[5]

Pupa

The insect then begins the process of becoming a pupa.^[5] For around two to four days after the termination of diapause it makes occasional tiny flexing movements.^[5] It then sheds the prepupal skin, a process that takes from one to six minutes in healthy prepupae.^[5] This results in a soft, white, and motionless pupa.^[5] This then hardens and pigments over a period of time.^[5] It then sheds its skin again, over about 5-10 minutes, to emerge as an adult.^[5]

Adult

The newly emerged adult has soft, white wings and must remain, motionless, in the cell for about 2 days in order for them to harden.^[5] Once this is complete the bee tunnels to the surface: males usually leave within an hour, but females wait at least 24 hours before emerging, spending most of this time just below the surface.^[5] The males fly low flights just above the surface, seizing the females as they emerge from the ground and attempting to forcibly mate with them: this usually results in the escape of the female, and copulation takes place rarely or never.^[5] Actual courtship occurs later.

Nesting

Dieunomia triangulifera often establishes thousands of nests at a site, preferring to nest in knolls or gentle slopes if possible.^[5] They can nest in a wide variety of soil types and moistures, including sand, sandy loam, loam, silt loam, and clay loam.^[5] Each female of the species constructs her own nest.^[5]