Backyard Pollinators

 My wild backyard, shot from opposite ends.  Early May & early June.

Last year's adventure with monarchs... 
...became desire that our yard always have native wildflowers in bloom, 
...which became interest in the native bees which depend on those flowers (an itch scratched by reading Our Native Bees by Paige Embry), 
...which sent me into the garden in May to photograph visitors to our backyard flowers, 
...which became hours standing over sunlit flowers with my camera and posting the results to iNaturalist.  

Now I have a pretty good idea who the neighbors are!  I imagine that my pollinators will overlap with yours the nearer you live to my neck of the woods in similar (urban/suburban) habitat.

Insects are famous for their enormous diversity (about 75% of all animals are insects!), so I'd never really attempted to learn any before.  And identifying most insects is formidable: my old insect guide helps only to the family level.  (For comparison, Hominidae--the tiny family of mammals that includes humans--contains us, chimps and bonobos, gorillas, orangutans and gibbons.)  But iNaturalist makes identification simple: just post decent photos online and leave it to the pros and serious hobbyists out there!  And staying in my own yard and concentrating on critters that visit flowers makes for a manageable group.  

Here, grouped by taxa, are my visitors so far: first the dozen-odd bees, and then the flies.  There are probably more to come: I've omitted a few whose identity is still unclear.

The Common Eastern Bumble Bee is the only bumble bee (of the 40 or so native to the US) I've notice around here in 2 or 3 years of looking.  Like many bees, it forms only small colonies that last for the season.  Nests underground.

 common eastern bumble bee (Bombus impatiens)

Twenty-nine species of Small Carpenter Bees (genus Ceratina) are listed for this subgenus alone--and God only knows which species I have.  (Nor whether I have more than one kind.)  Not much info available, but they seem to make nests for their kids in broken or burned twigs or stems.  These small, dark bees with their metallic greenish sheen are among the most common visitors to our flowers.

 small carpenter bees of subgenus Zadontomerus Ceratina sp.

Nomad Bees.  The genus Nomada contains a bazillion species--all "cuckoo" bees, since they parasitize other bees by laying their eggs on stored pollen in those other's nests.  My red-with-yellow-markings nomad bees drink nectar for themselves, but, like other Nomada, have no need of pollen baskets since they don't supply their young with food.  Among their victims are bees of Andrena and Agapostemon, which also visit my flowers.

 nomad bees Nomada sp.

Most of the rest of my bees are Sweat Bees of one sort or another (family Halictidae)--named for their habit of flying in people's faces in search salt.  This trait that annoys me when walking trails, but I haven't been bothered at home. 

Ligated Furrow Bees are eusocial (a bit like honey bees) in creating colonies that last over generations and have division of labor in caring for the brood.  They nest underground.

ligated furrow bee Halictus ligatus

Similar to the closely-related ligated furrow bees, Orange-legged Furrow Bees are solitary (rather than social) in cooler regions.

orange-legged furrow bee Halictus rubicundus

Metallic Sweat Bees of subgenus Dialictus of genus Lasioglossum.  I only saw these bees one day in late May.  The 600-plus species of Dialictus are very difficult to distinguish.  They vary widely in sociability.

 metallic sweat bee of Dialictus (genus Lasioglossum)

Another suspected Metallic Sweat Bee (Lasioglossum) of subgenus Dialictus.  My opinion; iNaturalist folk have yet to weigh in.

 metallic sweat bee(?) genus Lasioglossum of subgenus Dialictus

Females of the Bicolored Striped Sweat Bee have either all-black abdomens or black with whitish bands, whereas the male has yellow stripes.  They nest underground.  There is little other info.

 bicolored striped sweat bee Agapostemon virescens

Blood Bees--named for their color--are kleptoparasites (like cuckoo bees) of other bees (mainly Lasioglossum, Halictus and Andrena--all of which frequent my yard).  This explains the lack of pollen baskets, just as for nomad bees.

 blood bees (Sphecodes sp.)

 The Pure Green Sweat Bee really is the unearthly neon metallic green you see.  (Like the striped sweat bee, it can be identified by eye.)  According to Wikipedia, it forages on a variety of plants, inhabits rotten logs, and can produce three broods in a year.

 pure green sweat bee Augochlora pura

Nason's Mining Bee has no specific information, but as a member of the ginormous genus Andrena (1300-odd species!), it digs a nest in sandy soil for its young, constructing cells and laying each egg in a cell on a mass of pollen and nectar.  The young overwinter as prepupae. They forage on many different flowers, and overwinters as a pre-pupa (whatever that is).  I may have other species of Andrena, since I have some photos that have only been identified as belonging to that genus.

 Nason's mining bee Andrena nasonii  [1st photo; others also Andrena]

The Unequal Cellophane Bee is a common plasterer bee (family Colletidae), so called because the underground cells it makes for its young are lined with a bodily secretion.  In the case of this species, the females line the cells with a polyester secretion.

 unequal cellophane bee Colletes inaequalis

Mason Bees (genus Osmia) are largish solitary bees that partitions-off cells in naturally-occurring spaces such as hollow reeds or the gaps between stones using a concrete of clay, mud or chewed plant material.  An egg is laid on pollen in each cell.  They seem to need below-freezing temperatures to mature in their cells, ready to emerge the following spring.  Good pollinators, they are one of the few groups of bees deliberately raised for agricultural purposes.

 bufflehead mason bee Osmia bucephala

Flies

The Clubbed Mydas Fly is native to eastern temperate North America.  The orange mark on the abdomen is distinctive.  It is a Batesian mimic of certain spider wasps, and so bold in its movements. (In Batesian mimicry, a species mimics a noxious species, so that predators avoid it even though it is actually harmless.)

 clubbed mydas fly Mydas clavatus

Hoverflies mimic wasps and bees for their own protection, but are harmless.  The often "hover" above flowers in search of nectar and pollen.  The family (Syrphidae) is large.  Here are four hoverflies worked out to species, and a firth worked out only to tribe.

 transverse flower fly Eristalis transversa

 Hoverflies Eristalis sp.

 hoverflies (tribe Syrphini)

Margined Calligrapher.  According to Wikipedia, "Toxomerus marginatus is a common species of hoverfly.  It is found in many parts of North America.  The larvae are predators of thrips, aphids, and small caterpillars.  Adults feed on a wide range of flowers."

 margined calligrapher Toxomerus marginatus

The Eastern Calligrapher is similar to its relative, the margined calligrapher.

 eastern calligrapher Toxomerus geminatus

The Narcissus Bulb Fly is a bumble bee mimic that is Holarctic: occurring in the arctic around the world.  It often flies low, and rests on bare ground.

 narcissus bulb fly Merodon equestris

kelp, march and thick-headed flies (family Conopidae)
I found no information on the species Myopa clausa or even the genus; the family has hundreds of species that are mostly mimics of noxious insects, and probe for nectar using a proboscis that is often long.

one of the thick-headed flies Myopa clausa

march flies (family Bibionidae)

Bibio vestitus (a St. Mark's fly) visited my dandelions in great numbers in May.  I have seen them much less often at other flowers.

one of St. Mark's flies Bibio vestitus

You might remember learning the nested levels of taxonomic classification in school: kingdom, phylum, class, order, family, genus, species.  Gluttons for punishment might wish to know how that system applies to so large a group of animals as bees or flies.  To accommodate so many species, levels have been inserted between the familiar seven.  For example, the class Insecta is divided into "subclasses," one of which contains the ants, bees, wasps and sawflies that make up the order Hymenoptera, which has various "suborders" which in turn are divided into "infraorders," and further into "superfamilies," one of which contains the "epifamily" Anthophila: the bees.  Within the bee family Apidae are subfamilies containing tribes which are composed of genera.  Genera can be so large they are divided into subgenera before we finally reach the species.  Instead of seven levels, to get from the kingdom of Animals to the Common Eastern Bumble Bee (for instance) takes us through sixteen taxonomic levels.

Here is the classification of the bees in my backyard from Family on down.  (Relatives are clustered, so that an empty box is usually the same as the box above; except an empty species box reflects that a critter has not yet been identified to species--or sometimes even to genus.).

Bees (epifamily Anthophila)

Family	Tribe	Subfamily	Genus	Subgenus	Species
honey bees, bumble bees, & allies. Apidae	Apinae	Bombini	Bombus	Pyrobombus	common eastern bumblebee Bombus impatiens
	carpenter bees Xylocopinae	Ceratinini	small carpenter bees Ceratina	Zadontomerus
	cuckoo bees Nomadinae	Nomadini	nomad bees Nomada
sweat bees Halictidae	Halictinae	Halictini	furrow bees Halictus	Odontalictus	ligated furrow bee Halictus ligatus
			Lasioglossum metallic sweat bees	Protohalictus Dialictus	orange-legged furrow bee Halictus rubicundus
			striped sweat bees Agapostemon	Agapostemon	bicolored striped sweat bee Agapostemon virescens
			blood bees Sphecodes
		Augochlorini	Augochlora		pure green sweat bee Augochlora pura
mining bees Andrenidae	Andreninae		Andrena	Simandrena	Nason’s mining bee  Andrena nasonii
plasterer bees Colletidae	Colletinae		cellophane bees Colletes		unequal cellophane bee Colletes inaequalis
mason, leafcutter, carder, & resin bees Megachilidae	Megachilinae	Osmiini	Osmia	Melanosmia	bufflehead mason bee Osmia bucephala

  And here are the flies.

Flies (order Diptera)

Suborder	Infraorder	Superfamily	Family	Subfamily	Tribe	Genus
Brachycera	Orthorrhapha	Asiloidea	Mydidae	Mydinae	Mydini	clubbed mydas fly Mydas clavatus
	muscoid flies Cyclorrhapha	(zoosection Aschiza)	hoverflies Syrphidae	Eristalinae	Eristalini (subtribe Eristalina)	transverse flower fly Eristalis transversa
						Eristalis sp.
			hoverflies Syrphidae
					Toxomerini	margined calligrapher Toxomerus marginatus
						eastern calligrapher Toxomerus geminatus
					Merodontini	Narcissus bulb fly Merodon equestris
		(zoosection Schizophora) Sciomyzoidea	kelp, marsh, & thick-headed flies & allies Conopidae	thick-headed flies Myopinae		Myopa clausa
Nematocera	gnats & allies Bibionomorpha		march flies Bibionidae			St. Mark’s flies Bibio vestitus