Pollinator decline is the reduction in abundance of insect and other animal pollinators in many ecosystems worldwide that began being recorded at the end of the 20th century. Multiple lines of evidence exist for the reduction of wild pollinator populations at the regional level, especially within Europe and North America. Similar findings from studies in South America, China and Japan make it reasonable to suggest that declines are occurring around the globe. The majority of studies focus on bees, particularly honeybee and bumblebee species, with a smaller number involving hoverflies and lepidopterans.
Halictidae is the second-largest family of bees with nearly 4,500 species. Halictid species are an extremely diverse group that can vary greatly in appearance. These bees occur all over the world and are found on every continent except Antarctica. Usually dark-colored and often metallic, halictids are found in various sizes, colors and patterns. Several species are all or partly green and a few are red, purple, or blue. A number of them have yellow markings, especially the males, which commonly have yellow faces, a pattern widespread among the various families of bees. The family is one of many with short tongues and is best distinguished by the arcuate basal vein found on the wing. Females in this family tend to be larger than the males.
Bombus terrestris, the buff-tailed bumblebee or large earth bumblebee, is one of the most numerous bumblebee species in Europe. It is one of the main species used in greenhouse pollination, and so can be found in many countries and areas where it is not native, such as Tasmania. Moreover, it is a eusocial insect with an overlap of generations, a division of labor, and cooperative brood care. The queen is monandrous which means she mates with only one male. B. terrestris workers learn flower colors and forage efficiently.
Halictus rubicundus, the orange-legged furrow bee, is a species of sweat bee found throughout the Northern Hemisphere. H. rubicundus was introduced into North America from the Old World during one of two main invasions of Halictus subgenera. These invasions likely occurred via the Bering land bridge at times of low sea level during the Pleistocene epoch.
The genus Halictus is a large assemblage of bee species in the family Halictidae. The genus is divided into 15 subgenera, some of dubious monophyly, containing over 200 species, primarily in the Northern Hemisphere. Most species are black or dark brown, sometimes metallic greenish-tinted, with apical whitish abdominal bands on the terga.
The genus Agapostemon is a common group of Western Hemisphere sweat bees, most of which are known as metallic green sweat bees for their color.
Sphecodes albilabris is a solitary parasitic bee that is endemic to Central and Western Europe. It also occurs in North Africa and is thought to have been introduced to the United States and Australia by accident.
Within the insect order Hymenoptera, the Halictinae are the largest, most diverse, and most recently diverged of the four halictid subfamilies. They comprise over 2400 bee species belonging to the five taxonomic tribes Augochlorini, Thrinchostomini, Caenohalictini, Sphecodini, and Halictini, which some entomologists alternatively organize into the two tribes Augochlorini and Halictini.
Bombus dahlbomii is a species of bumblebee endemic to southern South American temperate forests. B. dahlbomii is one of the largest bee species in the world, with matured queens growing up to 40 mm (1.6 in) long. Because of its size and furry appearance, the species has been described as "flying mice" colloquially, and "a monstrous fluffy ginger beast" by British ecologist David Goulson.
Halictus ligatus is a species of sweat bee from the family Halictidae, among the species that mine or burrow into the ground to create their nests. H. ligatus, like Lasioglossum zephyrus, is a primitively eusocial bee species, in which aggression is one of the most influential behaviors for establishing hierarchy within the colony, and H. ligatus exhibits both reproductive division of labor and overlapping generations.
Lasioglossum cressonii is a species in the sweat bee genus Lasioglossum, family Halictidae. Halictidae exhibit eusocial hierarchy behavior which is interesting given that eusociality in this group is hard to evolve and easy to lose. L. cressonii is found throughout North America. L. cressonii have been shown to be important pollinators for apple trees and many other North American native plants.
Lasioglossum vierecki, also known as Dialictus vierecki and Halictus vierecki, is a sand sweat bee and is part of the family Halictidae of the order Hymenoptera. It is found in the eastern half of North America from Minnesota to the New England States down to Georgia and Louisiana and up in Manitoba and Ontario. Commonly found in sandy areas, it pollinates various flowers such as grass-leaved goldenrod and rattlesnake master.
Halictus sexcinctus, commonly referred to as the six-banded furrow bee, is a species of sweat bee found throughout Europe and as far east as Asian Turkey and Iraq.The H. sexcinctus can be easily confused with the closely related species, Halictus scabiosae, due to very similar morphological features. H. sexcinctus show a social polymorphism in which different colonies can exhibit solitary, communal, or eusocial structure. Due to this large variance in social organization, it was suspected that it was not one species at all, but rather multiple, cryptic species. However, genetic analysis was able to confirm these varying populations as one species. H. sexcinctus will forage from multiple flower species, but prefers plant species with wide-open flowers. Their nests can be found dug into the ground in loamy or sandy soil.
Dialictus is a subgenus of sweat bees belonging to the genus Lasioglossum. Most of the members of this subgenus have a metallic appearance, while some are non-metallic. There are over 630 species worldwide. They are commonly found in the Northern Hemisphere and are found in abundance in North America. Members of this subgenus also have very diverse forms of social structure making them model organisms for studying the social behavior of bees.
Augochlorella is a genus in the bee family Halictidae, commonly called sweat bees. They display metallic coloration, ranging from reddish to gold to bluish green, as is typical for other genera in the tribe Augochlorini.
Halictus confusus, the southern bronze furrow bee or confused sweat bee, is a species of sweat bee in the family Halictidae. It is a primitively eusocial bee species found in open habitats in Eurasia and North America.
Lasioglossum sordidum, also referred to as the small native bee, is one of the smallest native bees found in New Zealand.
Augochloropsis is a genus of brilliant metallic, often blue-green, sweat bees in the family Halictidae. There are at least 140 described species in Augochloropsis.
Lasioglossum mataroa is a bee species that is found in New Zealand.
Megalopta is a widespread neotropical genus of bees in the tribe Augochlorini in family Halictidae, known as the sweat bees. They are the largest of the five nocturnal genera in Augochlorini. Most have pale integumentary pigmentation, and all have large ocelli, most likely a feature of their nocturnal behavior. They live in tropical Central America and the entirety of South America. The subgenus Noctoraptor is cleptoparasitic. They are not known from the fossil record.
