Identification of Eastern North American Bee Genera in the Family Halictidae

A guide to their Identification in Eastern North America

Acknowledgements
This presentation has been put together by a consortium of North American bee biologists
This presentation has developed over many years and the original web picture acknowledgements were lost, if you see one of your pictures let us know and we will add your picture credit
Correspondence can be sent to Sam Droege at sdroege@usgs.gov

Format
Each Genus has an information page followed by a page of illustrations and a map of the distribution of Eastern North American species; western populations of Eastern species are shown, but the Western species are not mapped.
The number of Eastern species are listed at the top of the page

Halictidae Groups of Genera
Agapostemon – 4 species
Augochlora pura - 1
Augochlorella - 3
Augochloropsis - 3
Halictus – 6
Lasioglossum – 115 or so
Sphecodes – 34 or so
Dieunomia - 3
Nomia - 2
Dufourea - 3

Agapostemon
Larger than the other bright green halictids
Has a prominent raised line or carina that circles the OUTSIDE of the rear face of the propodeum
Males with alternating bands of black and yellow on the abdomen
Common in fields, much less common in urban areas
A. virescens is usually the most common and females easy to identify because of its black abdomen (the others are green)
Males and green females take some practice to differentiate due to often subtle differences
Similar genera: Augochlora, Augochlorella, Augochloropsis

Agapostemon – 4 Biggest of the green bees Common Fields Male Female

Augochlora pura
Common, particularly in wooded regions, nests in decaying logs
Shape and color (all black) of the tip of the female’s mandibles is distinctive
Rim of S4 in the males is straight across unlike the concave or emarginate shape of S4 in Augochlorella , its most common look-alike
Clipped tip of the marginal cell is useful when processing many specimens, but Augochloropsis also has this feature
Similar genera: Augochlorella, Augochloropsis, Agapostemon

Augochlora pura – Woodlands and edges Common, trimmed tip of marginal cell Female Male

Augochlorella
Usually the most common bright green bee
A. aurata, the most common, but care must be taken to pull out the other 2 species where their ranges overlap
The smallest of all the green Halictids
Males have a concave S4 rim
Tip of marginal cell lays directly on the rim, a good character for sorting out the common green bees
Similar genera: Augochlora, Augochloropsis, Agapostemon

Augochlorella – In Every Field - 3 Way Abundant!

Augochloropsis
Regular, but usually the least common of the bright green bees
Some species and individuals can take on distinct blue/purple metallic overtones
A. metallica is the most common, but recent genetic analyses indicate that there is more than one species involved
The non-oval tegula is distinctive and easy to see
The band of straight hairs (fimbria) fringing the rims of the tergites is usually distinctive in most specimens, but can be very sparse in some
Tip of marginal cell is trimmed similar to Augochlora pura
Similar genera: Agapostemon, Augochlorella, Augochlora

Augochloropsis – Least Common - 3 Green Bee

Halictus
Some of the most common bees, usually associated with fields
The large headed H. ligatus and its look-alike H. poeyi have distinct projections on their lower cheeks that makes identification easy
Because H. confusus is a dull metallic green rather than black or brown it is often confused with Lasioglossum species in the Dialictus group
Told from Lasioglossum by having all of the crossveins of the submarginal cells being the same thickness and having the short, thick, white, appressed hairs that lie on the surface of the abdomen originating on the RIM of the tergites rather than from the base
Similar genera: Lasioglossum

Halictus – Every Open Place - 6 Abundant

Lasioglossum
Overall the most common group of bees encountered when using bowl traps, because they are very small they are often netted at relatively lower numbers
Many of the most common species are only 4-6mm in size
All species have at least the outermost crossvein in the outer submarginal cell thinner or weaker than the other veins; unfortunately, in males this character is much less clear
Told from Halictus by the weakened crossvein(s) of the submarginal cells and having the short, thick, white, appressed hairs that lie on the surface of the abdomen originating on the BASE of the tergites rather than from the rim, often this results in a band of white hairs emerging from UNDERNEATH the rim of the preceding segment
Some species, however, lack these appressed hairs completely
This group is being revised and several species changes will be made over the coming years
Similar genera: Halictus

Lasioglossum Groups
There are several groups within Lasioglossum that, in the past, have, at times, been given genera status
Sensu strictu – Very large, Black, one weakened crossvein
Evylaeus – Black, 2 weakened crossveins
Dialictus – Blue, green, gold, 2 weakened crossveins, identification to species often difficult
Paralictus – Blue or green, parasitic, 2 weakened crossveins
Sphecodogastra – Black, Oenothera specialists, sparse scopal hairs
Hemihalictus – 2 submarginal cells

Lasioglossum - 115 Abundant, many species, everywhere, difficult id’s

You too can see weak veins – OK maybe not – In this male only the last vein is weakened and its hard to detect

Some Black Lasioglossums Sensu Strictu Group Evylaeus Group Evylaeus Group

Sphecodes
All species are regular but uncommon and parasitic on other Halictid species
While the females do not have pollen carrying hairs per se , their rear legs contain a fair amount of short hair which upon very close inspection often contain small short spines along the length of the tibia
Almost all of the females are characterized by a red to orange-red abdomen, however, many males are entirely black, but can be told by heavy surface sculpturing and widely spaced antennae
None of the species have the small, thick, white, appressed hairs found in Halictus and Lasioglossum
All wing veins are the same thickness (strong) in a similar way to Halictus
Identification to species is difficult and several taxonomic issues at the species level remain unresolved
This group is being revised and several species changes will be made over the coming years
Similar genera: Lasioglossum, Halictus

Sphecodes – 34 - Lasioglossum parasite ALMOST all with red red abdomen

Dufourea
Extremely uncommon group of species in the East
The low placement of the antennae on the face is distinctive, particularly in conjunction with the wide clypeus
Has a pre-episternal groove, which most other species lack but unfortunately is often difficult to see
Similar genera: Halictus

Dufourea - 3 Uncommon plant specialists

Dieunomia
Uncommon to rare group of summer and fall species
Very large, the size of bumblebees
Often specialists on composites such as sunflowers and almost always associated with sandy soils
The arched basal vein so prominent in most of the other genera of Halictids is weak to absent
Males have greatly modified legs with flanges and extensions to the normal tibia shape, consequently, often mistaken for wasps
Females have non-oval tegulae and often have scopal hairs on the underside of their abdomen in addition to those on their legs
Similar genera: Andrena, Melitta

Dieunomia - 3 Sand specialists, large uncommon, composites

Nomia
Uncommon to rare group of species in the East
The mother-of-pearl band along the rims of the tergal segments is distinctive
Some males have expanded and flanged tibiae similar to Dieunomia
Similar genera: None

Nomia – Pearl Rims - 2 Southern, uncommon

Resources
Species lists, Identification Guides, and Maps for genera and species are available at:
http://www.discoverlife.org/20/q?search=Apoidea
A guide to the genera of the bees of Canada is available at:
http://www.biology.ualberta.ca/bsc/ejournal/pgs_03/pgs_03.html
Mitchell’s 1960’s books on the bees of the Eastern United States is available as a series of pdf files at:
http://insectmuseum.org/easternBees.php
A slightly out of date guide to the identification of the genera of ALL of North and Central America is available at:
http://www.knoxcellars.com/Merchant5/merchant.mvc?Screen=PROD&Store_Code=KCNP&Product_Code=BGNA&Category_Code=BL

http://www.slideshare.net	75
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Identification of Eastern North American Bee Genera in the Family Halictidae

by Sam Droege on Jan 07, 2009

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Identification of Eastern North American Bee Genera in the Family Halictidae — Presentation Transcript