California Native Plant Society
in collaboration with East Bay Municipal Utility District
Flies
(All writing from May Chen's posts)
Female Margined Calligrapher Hoverfly
A female Margined Calligrapher, Toxomerus marginatus (family Syrphidae) lands on a blade of grass.
Toxomerus marginatus, also known as the Margined Calligrapher is a common species of hoverfly found in North America. These are small hoverflies, measuring 5-6 mm in length. The abdomen is black and yellow, and is narrowly margined with yellow. Adults are found in diverse habitats such as forests, fields, meadows, marshes, deserts, and alpine areas. They are highly adaptable and can occur is very disturbed habitats. Larvae prey on aphids, thrips, mites, and small caterpillars. Adults visit flowers for nectar and pollen.
Female Oblique Streaktail Hoverfly
An Oblique Streaktail, Allograpta obliqua (family Syrphidae) has landed on a senescing manzanita inflorescence. Although small in size, the hover fly is easy recognizable for the unique pattern on its black-and-yellow abdomen. It is a female, as evident from its dichoptic eyes (not meeting each other on top of the head), and the plumper abdomen with a pointed tip.
The Oblique Streaktail, Allograpta obliqua is a common North American species of hover fly. Adults, 6-7 mm long, visit flowers for nectar and pollen, and are pollinators. Females lay eggs on plant surfaces near aphids. Larvae feed on the aphids.
Female Sedgesitter Hoverfly
Female Sedgesitter, Platycheirus sp. (family Syrphidae). In this photo, her abdomen greatly distended, the Sedgesitter is obvious a gravid female. She goes around the rim of the flowerhead, feeding on the pollen from the only opened flowers - the ray florets. The Platycheirus hoverfly is commonly found in grass and herb vegetation. Adults of many species feed on pollen of wind-pollinated plants, such as Salix, Plantago, Poaceae, Cyperaceae, but they visit other flowers also. Many stay active during cold and rainy weather. Larvae feed on aphids.
Short-haired Leafwalker Hoverfly
It is an uncommon species of hover fly found throughout North America and Europe. The adults have black thorax, legs and wings, enlarged femora, and a bright red abdomen. They are mimics of wasps, specifically Astata, a spider wasp. They visit flowers for nectar and pollen. The flies tend to move toward hilltops and other open, high areas for mating. Larvae have been identified from sappy hollows from Larix and Pinus.
Bluebottle Fly
Though hardly ever talked about, the Bluebottle Fly, Callifphora sp. (family Calliphoridae) is probably one of the most common visitors to the manzanita flowers.
The Calliphoridae are variously known as blow flies, carrion flies, greenbottles, and bluebottles. Adults are usually brilliant with metallic sheen, often with blue, green, or black thoraces and abdomens. There are three cross-grooves on the thorax; calypters are well developed. Females visit carrion both for proteins and egg laying. The larvae that hatch feed on dead or necrotic tissue, passing through three instars before pupation. After the third instar, the larva leaves the corpse and burrows into the ground to pupate. Adult blow flies are occasional pollinators, being attracted to flowers with strong odors resembling rotting meat. The flies use nectar as a source of carbohydrates to fuel flight.
Root-maggot Fly
Leucophora sp. (family Anthomyiidae).
Antho- is a prefix derived from the Greek anthos for “flower”. So why aren’t these flies called flower flies instead of the dreadful common name they have been given? The name flower flies are sometimes used for members of the hoverfly family, Syrphidae.
Members of the family Anthomyiidae are commonly called Root-maggot Flies. They are small to medium-size flies that resemble house flies but are somewhat more slender. They are usually dull gray or black and silver in color. The larvae typically feed in stems and roots of plants. Many are considered crop pests, and may attack root crops such as onions or rutabagas. Other species may feed on decaying matter, on feces, or are predators of other insects. Adult flies are important pollinators, usually feeding on nectar and pollen.
Greater Bee Fly
Bombylius major ( famly Bombyliidae)
A Greater Bee Fly, Bombylius major (family Bombyliidae) is hovering in front of a Blue Dicks flower. With the macro lens jammed on my camera, I have to take this still shot and video up close. Guess what’s that blurry yellow thing in the back, atop the other flower?
Bombylius major, commonly known as the Greater Bee Fly is a parasitic bee mimic fly in the family Bombyliidae. It derives its name from its close resemblance to bumble bees. Its flight is quite distinctive - hovering in place to feed, and darting between locations. The species has long skinny legs and a long rigid proboscis held in front of the head. Bombylius major is easily distinguished from the other local species of Bombylius for having wings with dark leading edge, hyaline trailing edge with sharp dividing border. This feature is visible even as the fly is hovering. Adults visit flowers for nectar (and sometimes pollen) from a wide variety of plant families, excelling at small tubular flowers, and are considered good generalist pollinators. Often the pollen is transferred between flowers on the fly’s proboscis.
The bee fly larvae, however, have a sinister side. They are parasitoids of ground-nesting bees and wasps, including the brood of digger bees in the family Andrenidae. Egg deposition takes place by the female hovering above the entrance of a host nest, and throwing down her eggs using a flicking movement. The larvae then make their way into the host nest or attach themselves to the bees to be carried into the nest. There the fly larvae feed on the food provisions, as well as the young solitary bees.
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Dance Fly
(super family Empidoidea)
The Empidoidea are a very large, diverse group of flies consisting of over 11,000 described species worldwide. Most of these flies are predatory. Adults range in size from 1 mm to 15 mm, and are generally slender flies with long legs, beak-like predatory mouthparts, large compound eyes (sometimes covering the entire surface of the head). These flies tend to be associated with moist, temperate habitats. Some adult Dance Flies also visit flowers for nectar. At least a few groups obtain all their protein needs by feeding on pollen. Larvae are generally found in moist soil, rotten wood, dung, or in aquatic habitats and also appear to be predacious on various arthropods. Predaceous empidoid flies are important natural and biological control agents of various pest insects. Empidoids are commonly called Dance Flies for their “dancing” courtship behavior, with males often presenting prey to females as nuptial gifts. Classification within the superfamily is still in a state of flux - many taxa require revision and few keys are available to distinguish species. Currently there are 7 recognized families, the main ones being the Empididae and the Hybotidae. Empidids normally have a thick beak pointing down. Hybotids have a thinner beak, or a thick beak pointing forwards or diagonally. The two families also differ in their wing venation.
The Hybotid Dance Flies belong to the superfamily Empidoidea and were formerly included in the Empididae as a subfamily. Empididae generally have a thick beak pointing down, while Hybotidae have a thinner beak, or a thick beak pointing forwards or diagonally. Some crucial wing venation further distinguishes the two families. Precious little is known about the life cycle and biology of Hybotids because they are not considered of economic consequence. I have observed that members of the genus Anthalia mostly feed on nectar and pollen, and may be important pollinators for small wildflowers such as Miner’s Lettuce, Wild Geranium, California Saxifrage, Buttercups and False Lily of the Valley.
Why the name “dance fly”? This is derived from the mating swarms of males of many species. They gather in clouds over prominent objects, each individual seeming to bounce or “dance” in mid-air. Many other flies do this, notably midges, but the Empidids and the Hybotids got the moniker.