Posts Tagged ‘flower fly’

Mimics of bumble bees

July 11, 2011

Syrphid fly, Mallota bautias

We think that we know what a bumble bee looks like, but often we are deceived by some very good imitators. There are a number of flies that masquerade as bumble bees despite the fact that they have only two wings, instead of four and that their antennae are significantly shorter. There are even a few moths and beetles that imitate bumble bees.

Syrphid fly, Mallota

Syrphid fly, Eristalis

Flower flies, also called hover flies or Syrphid flies visit flowers frequently and are good imitators of bees or wasps. They lack stingers, but their appearance gives them some protection from hungry birds that fear the sting of a bee and are left alone. Some are specialized to look like bumble bees. This mimicry occurs in other continents, too, with European and American flies mimicking European and American species of bumble bees respectively.

Robber fly

Robber fly, Laphria thoracica

Robber flies are ferocious predators, capable of catching some insects in flight. Among them, there are some that imitate bumble bees so convincingly that they can fool anybody, including experts. In this case, the purpose of the mimicry may be to fool their prey, as well, as their possible predators.

Bee fly, Bombylius. Notice the long tongue

Carpenter bee on swamp milkweed

Some beeflies and also tachinid flies are good mimics of bumble bees.

Carpenter bees also look very much like bumble bees. The main difference is their glossy and almost hairless abdomen, while bumble bees are covered by fuzz all over. In this case the mimicry would benefit both of them.

Cuckoo bumble bee, Bombus citrinus

Curiously enough, some species of bumble bees are mimics of each other, although they may not be closely related. Some of the cuckoo bumble bees seem to be mimics of their hosts, for instance, Bombus citrinus and its host Bombus impatiens.

Bombus impatiens

The mimicry makes it very hard to tell the species of bumble bee apart. The similarity among bumble bee species probably provides them additional protection. Predators need to learn the lesson only once instead of twice. In fact, this kind of mimicry may help the males, also, since they lack stingers.

Bumble bees. Introduction

Beginners Guide to Pollinators and Other Flower Visitors


Flower flies or Syrphid flies

April 3, 2011

Drone fly on goldenrod

Flower flies are frequent flower visitors, hence the name. In England they are called hover flies, because of their behavior when visiting flowers. At first sight they are easily mistaken by bees. The main difference is that flies have only one pair of wings while bees have two pairs. Other differences are easier to see: the eyes, are much larger in flies than bees. The antennae of flies are very short and they have a thin bristle, called arista while bee’s antennae are longer and made of a series of segments. Fly legs are usually a lot thinner than those of bees. In general flies are less hairy than bees.

Syrphus fly, a kind of syrphini fly

The drone fly is about the same size as a honey bee; it has yellow and brown markings. It is stout. Syrphini flies have a pattern similar to that of the drone fly but are more slender and a little smaller. There are several different species but they can only be told apart if captured and observed closely, preferably under a microscope.


Syrphus fly on Queen Anne's lace

Some say that the drone fly is a bee mimic while the Syrphini flies imitate wasps.
All these flies are very beneficial in the garden. The adults pollinate the flowers they visit and the larvae of some of them eat lots of aphids and other pests.

Habitat. Fields and gardens, also cities, parks. Some species are often near aphid infestations because their larvae feed on aphids. Throughout North America.

Season. From early spring to late fall. They are most abundant in the summer.

Flowers. They prefer flat, open flowers, easy to reach. They visit many members of the daisy family or the aster family. Sometimes they bask on the sun on a leaf.

A fly and a bee
A syrphid fly

Back to guide

Pollinators and other flower visitors. A field guide for young people

March 26, 2011

Insect flower visitors of many sorts

Flowers are visited by a great variety of insects, and some spiders too. Some of these insect visitors are very beneficial to the flower. They carry pollen from flower to flower performing pollination. This is what the plant needs to make seeds and thus make new plants and new flowers.
The list of flower visitors is extremely long and some of the insects are impossible to tell apart by sight only, so this guide doesn’t attempt to cover them all. I will just merely highlight some of the most common flower visitors, in particular those that pollinate flowers. You will be able to recognize some of them or, at least, you will know what group they belong to.

What do pollinators look like?

Insects have three body sections, called head, thorax and abdomen. The head carries the eyes, the mouth parts and antennae. The thorax is made of three segments and carries three pairs of legs and generally either two pairs or only one pair of wings. The abdomen is made of a series of segments.

What kind of pollinating insect is that?

Different groups of insects vary on the shape of the head, thorax and abdomen. Of special importance are the variations on the kinds of wings. Future blog entries will cover four main types of flower visitors: 1. bees and wasps, 2. flies, 3. butterflies and moths and 4. beetles.

Bee, hairy, pollen combs

Wasp, hairless, “wasp waist”

Bees and wasps have two pairs of membranous wings, they look like saran wrap. The main differences between bees and wasps are that wasps usually have a narrow waist (the separation between the thorax and abdomen) and are less hairy than bees. Female bees usually have a means to carry pollen, the so called pollen baskets or pollen combs, either on their back legs or on the underside of their abdomens. Sometimes these baskets are loaded with pollen.

Ants are related to wasps and resemble them in their appearance, but they have no wings. Only queens and males have wings, but they are seldom seen. Ants are also frequent flower visitors. They rarely can pollinate flowers because they don’t fly and are not likely to carry pollen a significant distance.

Fly, two wings, big eyes, very small antennae

Flies  are important pollinators too. Their wings are also membranous, like those of bees and wasps but they have only one pair instead of two. The flies that visit flowers often look like bees or wasps. They lack stingers so they are good mimics that try to fool hungry birds into thinking that they can sting. Some of the ways to tell them apart is by the eyes which are very large and by the short antennae, made of two separate parts. They are usually hairless and the legs are very thin when compared to those of bees.

Butterfly, wings with scales, knobs at end of antennae

Butterflies and moths  have wings covered by very tiny scales. If you touch them some of those scales come off and they look like dust. They have a very long tongue which they use as a drinking straw to sip nectar from flowers. When not in use they keep it rolled up under their chins.

Moth, wings with scales, antennae without knobs

Butterfly’s antennae end in little knobs, while the antennae of moths can either be feathery or like a string, but never with a knob at the end. Butterflies usually fly during the day, while moths fly at night, although a number of them fly during the day. Night flying moths tend to be rather colorless, but those that fly during the day can be as brightly colored as many butterflies.

Beetle, hardened wings

Beetles have two pairs of wings but the first set is modified and hardened into a wing case that covers and protects the second pair of wings.
You only see this second pair when the beetle is flying or getting ready to fly. This second pair is also membranous like those of bees, wasps and flies and they remain folded under the first pair.

Where can you find pollinators?

Field of goldenrods in the fall

Look for pollinators at flowers. The best flowers are native ones. Garden flowers, especially the double ones don’t attract many pollinators, so tulips or fancy roses are not very good for pollinators. Most pollinators are active when it is warm enough, when it isn’t windy and when the sun is shining. There are a few that fly when it is dark and visit night blooming flowers.

Common milkweed, flowers

Some flowers attract many visitors. Two of the best ones are: common milkweed and all the goldenrods.

Common milkweed blooms in June and early July. The plants can grow 6 feet tall. They have large oval leaves and bunch of flowers arranged like a ball. The flowers are pink and emit a very strong sweet scent.


Goldenrodsbloom in the fall, from September to November, depending on where you live. There are several types of goldenrods; they all have yellow flowers arranged in rods that give the name to the plant. Their scent is not particularly strong but many insects are attracted to it or to the colorful display.

Asters and related flowers attract large numbers of pollinators.

Asters, blooming in the fall

Sunflowers and skipper

These include many daisy-like flowers such as sunflowers, black-eyed Susans, ragworts, cornflowers, as well as some plants which are not native, dandelions and thistles. The above mentioned goldenrods belong to this family, too.

Mountain mint and Queen Anne’s lace are also good attractants of a variety of flower visitors.

Honey Bee
Bumble Bees
Carpenter Bees
Halictid Bee or Sweat Bee
Mason Bees and Leaf-cutter Bees
Andrenid Bees

Potter Wasps and Mason Wasps
Grass-carrying Wasps
Great Golden Digger Wasp
Hornets and Yellowjackets
Paper Wasps

Flower Flies or Syrphid Flies
Bee Flies
Blowflies. Lucilia

Tiger Swallowtail
Hair Streaks
Pieridae Butterflies: Whites and Sulphurs
Silver Spotted Skipper

Hummingbird Moth
Hawk Moths
Ailanthus Web-worm Moth
Yellow-collared Scape Moth

Tumbling Flower Beetles
Flower Long Horn Beetles
Soldier Beetles
Japanese Beetle
Ladybugs or Lady Beetles

Other frequent flower visitors
Ambush Bug
Crab Spider

Further readings
Overview of Orders of Insects
Native bees of North America
Bumble bees


You may purchase the electronic version:

Beginners Guide to Pollinators and Other Flower Visitors