Description and Identification

Species of the genus Augochloropsis are generally between 8 to 12 mm long and often bright green in color, with some exceptions occurring regionally, such as the deep blue and purple colors of the Augochloropsis sp. inhabiting southeastern coastal areas of North America^[2].  

Augochloropsis sp. of North American can be recognized at the genus level by the presence of 3 submarginal cells and a strongly arched basal vein on the forewing, the presence of the jugal lobe on the hind wing, the presence of tibial spurs on the hind leg, the absence of a corbicula structure on the hind leg, short basitibial plates, a deep cleft dividing the pseudopygidial area of the abdomen, and the lack of a distinct carniate rim on the back of the thorax^[3].

Geographic Distribution

The vast majority of species of Augochloropsis are found primarily in the tropical and subtropical regions of the Western Hemisphere^[4]. A few Augochloropsis species are found in the temperate regions of North America, but no species have managed to successfully exploit niches present in the subarctic zone.

Three species of Augochloropsis--A. anonyma, A. metallica, and A. sumptuosa--occur in the United States^[4].

Nesting Behavior

Augochloropsis nests begin with one long main burrow, dug out of soft ground, that extends straight down. This main burrow has a lateral burrow that extends outward horizontally, perpendicular to the main. Cells all hang vertically down from this one lateral burrow, a sort of clustering that is common for all genera in the tribe Augochlorini^[5]. Aside from this, the overall structure of one main burrow and one lateral burrow is considered unique within the tribe.

Sociality

A broad spectrum of social behaviors have been observed in the tropical Augochloropsis species. These range from solitary, to communal, semisocial, and even eusocial nesting behavior^[6]. A few faunal studies have looked at North American species as well. A. sumptuosa has been studied in New Jersey and Kansas and has been found to be either communal or semisocial. Some species have even been observed to nest in aggregations, where the openings of several nests are located within just centimeters of each other^[7].

Some evidence has been found of division of labor or partitioning of social roles to some extent within this genus. An excavated nest of A. metallica in Michigan lead to the discovery of two female nest-mates with different levels of ovarian development that was determined not to be due simply to the age of the individuals. This was interpreted as strongly indicative of division of labor within this species, suggesting at least that individuals have varying levels of reproductive responsibility within a nest. This may be a larger pattern found within the social species of this genus^[6].

As noted previously, there is a large amount of behavioral variability observed within Augochlorine bees. As such, it may be possible that many species display polyethism, or differences in sociality and work activity among different members of a species^[6]. Unlike certain species who may be reliably eusocial or reliably solitary, members of Augochloropsis seem to show a lot of behavioral plasticity. It is not very well known what factors determine the sociality of an individual, but it does seem clear that individuals of this genus are quite variable in this regard.

Diet

Augochloropsis sp. are classified as polyletic,^[8] a term which indicates that Augochloropsis sp. are incredibly broad generalists that collects pollen from more than 3 families of plants.^[9] Factors that may predispose bees to a more generalist lifestyle include social lifestyles, long windows of adult activity, and species which produce more than two generations of offspring a year.^[9] Examples of these conditions associated with more generalist pollen diets among the Augochloropsis species include Augochloropsis anonyma, whose adults are active between April and September in the northern portion of its range and year round within its range in southern Florida^[2] and A. iris, which is a South American species that is primitively eusocial and engages in three rounds of brood production over the course year collectively as a species^[10].  

Floral Associations

All three Augochloropsis species have recorded floral associations with Hypericum^[2].

Additionally, Augochloropsis anonyma has been recorded in association with Baccharis, Bidens, Cirsium, Erigeron, Helenium, Ilex, Linaria, Melilotus, Metopium, Ocimum, Polygonurn, Pycnanthemum, Rhus, Rubus and Trifolium^[2]. Augochloropsis sumptuosa has been associated with Asclepias, Berlandiera, Bidens, Clethra, Crataegus, Eriogonum, Eryngium, Helianthus, Melilotus, Silphium, Stachys and Vaccinium^[2].

Augochloropsis metallica has the largest recorded floral associations of the 3 North American temperate species, with 73 floral records for the sub species A. metallica metallica and 17 floral records for the sub species A. metallica fulgida^[2] Floral records common between the two sub species of A. metallica include Aster, Chrysanthemum, Cornus, Erynigium, Geranium, Ilex, Rhus, Rubus, and Solidago^[2].

See also

• List of Augochloropsis species

References