Lasioglossum cressonii

The thorax and heads of female L. cressonii appear to be a brassy green color, but the area below the ocelli appears dull. They are also characterized by deep, distinctive, and coarse punctures on the face that get smaller as they move outwards from the center. The scutellum is medially rugoso-punctate and becomes more distinctly punctate on the sides. Its wings have a glassy appearance and its veins and stigma have a dull brick-red color. The abdomen and legs are glossy brownish black, and the abdomen is nearly impunctate.[3] Females can be distinguished from others by the golden green color of their thorax and heads and their very coarse mesoscutal punctures that are relatively dense between parapsidal lines.[5]

The thorax and heads of male L. cressonii are dark olive green and look nearly blue in certain areas. The abdomen is black and the scutellum is slightly grooved in the middle where it is more punctate, but on the sides of the abdomen the punctures are more less dense. Male veins and stigma are also a dull brick-red color. The bottom portion of the legs are glossy brownish black while the upper portion is also a dull brick red. The abdomen is shiny and essentially impunctate.[3] In order to distinguish males, one can look for clypeal hairs that do not obscure the surface and punctures on the anterior portion of the mesoscutum.[5]

Queens regulate the sex ratios of the broods depending on the time in the cycle; earlier in the cycle there is a female bias and later in the cycle there is a male bias in the sex ratio. In addition, the queen must manage the body sizes of her daughters as well. It is possible that this is done by allocating different amounts of pollen to the different broods. Generally, female worker bees are smaller than the foundress bees that come along in the reproductive broods later on. Queens also stop foraging once the first brood emerges.[6]

L. cressonii are eusocial bees, meaning that not all of their attributes are social. Foundresses are bees who have stored sperm from the mating season and are destined to be queens of their own colony. They perform the tasks of founding nests, excavating burrows, constructing cells, protecting the nest, and foraging for pollen and nectar.[6]

Worker bees are a part of the earlier broods brought forth by the queen. Their behavior as workers is influenced by the queen's behavior, and they are generally smaller than foundresses. They allocate pollen and nectar to the cells in the nest.[6]

Eusocial bees have a queen, which are at the top of the hierarchy. The foundresses and worker bees can then be found beneath the queens within this hierarchy.[6]

L. cressonii have reproductive broods after the initial worker broods. Within these reproductive broods there will be females who mate with males and then enter diapause. They will hold the sperm in their spermatheca until the next spring and will be able to act as overwintering gynes or reproductive females later on.[6]

With the decline in honeybees there has been concern about how certain plants will continue to get pollinated. In a study of different bee species visiting apple orchards across New York, it was found that L. cressonii were among the bees who pollinated apples in apple orchards.[2]

L. cressonii pollinate flowers and use their nectar and pollen for their broods.[6][8] Lasioglossum cressoni has been observed pollinating the following species of flower: Apocynum, Azalea, Barbarea, Berteroa, Brassica, Chrysanthemum, Cirsium, Claytonia, Daucus, Evonymus, Fagopyrum, Geranium, Houstonia, Hydrangea, Illex, Melilotus, Pedicularis, Potentilla, Rubus, Salvia, Solidago, Taraxacum, Vagnera, Viburnum. Alisma, Amelanchier, Cacalia, Capsella, Chaerophyllum, Crataegus, Cryptotaenia, Hypoxis, Isopyrum, Ludwigia, Melilotus, Prunus, Ptelea, Ranunculus, Rhus, Ribes, Salix, Sassafras, Symphoricarpos, Virbascum, Viola, Zanthoxylum, Amorpha, Philadelphus, Pyrus malus, Rhododendron and Vacinium.[3]

The effects of tree clearing on bees has been found to be helpful as opposed to harmful. In areas where there was logging, there was an increase in the diversity of bees in that area, including L. cressonii. While human intervention can often be harmful for bees, in this case the clearing of trees allows for more sunlight and an increase in different types of flora which attracts a diverse group of bees native to the area because of these increased foraging and nesting sites.[9]