Archive for the ‘flower visitor’ Category

Flower Longhorn Beetles

August 11, 2012

Strangalepta abbreviata on Wild Hydrangea

Yellow-horn Strangalia on Button Bush

Longhorn beetles get their name because of their thin and long antennae, usually as long as their bodies or even longer. Among them there is a group often found on flowers, the flower longhorns. One interesting characteristic of flower longhorns is that they are all very slender, almost tubular shaped. Adults feed primarily on pollen and nectar; that is why they frequent flowers. They are mid sized beetles between 1/2 and 3/4″ in length, not including the antennae.

The Yellow-horn Strangalia is among the thinnest ones. Its long antennae are yellow, and they have a pattern of dots or marks on the wings. Found in the eastern states.


Strangalepta abbreviata is stouter, black with orange lengthwise stripes. There is great variation of markings: some are all black or almost all orange. Eastern and central states only.

Cortodera is similar to Strangalepta abbreviata but it is found only in the West.

Banded Longhorn beetle on Wild Hydrangea

The Banded Longhorn has a pattern similar to that of the Yellow-horn but it is easy to tell apart because of its stouter shape. It is still leaner than most beetles one is familiar with. Rich brown color with yellow-orange cross bands Sometimes the bands are reduced to spots. Eastern and central states only.

Habitat: Fields, openings, with flowers, adjacent to woodlands.

Season: From May to August, most abundant in June and July.

Flowers: Flowers of the carrot family, rose family, aster family. The Banded Longhorn has a special preference for Echinacea.

Flower longhorns
Yellow-horn Strangalia
Strangalepta abbreviata
Banded Longhorn

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Hornets and yellowjackets

August 3, 2011

Common Aerial Yellowjacket on goldenrod

There are a number of species of wasps with bold designs of black or dark brown and yellow or black and white which go by the names of hornets or yellowjackets. They are narrow waisted strong fliers that fold their wings when in repose.

Baldfaced Hornet on goldenrod

There are several species of these wasps and the pattern varies depending on the species, but they generally present stripes. They are about half an inch in size or longer. They are feared for their painful sting, although they are not prone to attacking when at flowers. They build large nests, with a queen and many female workers and also some males.

Eastern Yellowjacket on Queen Anne's lace

Some build their nests underground (terrestrial), others hanging from tree branches or inside a tree hole (aerial) and still others build either aerial of terrestrial nests, depending on the circumstances. They are defensive of their nests and that is when they can be dangerous. They hunt insects to feed the young and also visit flowers for the nectar that fuels their flight. Some are lesser pollinators.

Habitat. Meadows, fields, gardens, areas with some trees.

Season. March to November, year round in southern states. Most abundant in August and September.

Flowers. Most wide open flowers, such as those in the Apiaceae and Asteraceae families. Goldenrod and Queen Anne’s lace seem to be their favorites.

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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

Bumble bee’s enemies

July 10, 2011

Bombus bimaculatus paralyzed by ambush bug

The life of a pollinator can be quite hazardous. There are plenty of creatures willing to devour one of them, from insects and spiders to birds. In addition to that, there are many parasites and other pathogens. Perhaps the highest mortality comes from the so called parasitoids and cuckoos. Parasitoids behave somewhere between a parasite and a predator; they parasitize the host, feeding on it, and eventually killing it, while predators kill and eat the prey all at once. Cuckoo bees and wasps, just like cuckoo birds take over the nest, lay their eggs and let the workers of the host species take care of the brood. Many cuckoos are related species, mainly other bumble bees; in some cases they mimic the appearance of the host species.

In general, most birds seem to avoid bumble bees; although there are a few species that specialize on bees. Skunks, voles and moles can attack their nests and eat their reserves and grubs. These creatures destroy a good number of nests. There is a story about Darwin saying that the British armies owed a lot to old spinsters. This was his explanation: Old spinsters owned cats which ate field mice. Fewer mice meant that more bumble bee nests survived. In turn, the bumble bees pollinated the alfalfa that fed the cattle that fed the soldiers and kept them strong and healthy. It was just an unproven entertaining hypothesis, but still a nice illustration of the intricate web of life.

Crab spider on thistle

Crab spiders are so called because they look and move like crabs. They are among the most common predators. They build no webs; instead they hide inside blossoms, waiting patiently for prey and ready to pounce on the first flower visitor that comes within reach. They are well camouflaged and are capable of changing their colors if they have to move to another flower.

Ambush bug on multiflora rose blossom

Ambush bugs deserve the name. They sit for long hours, well hidden inside a flower or cluster of small flowers, waiting for flower visitors. Their contour is jagged making it hard to detect them. They are very good at holding still, tucked in between petals. Their front claws look like those of a preying mantis and they have a sharp beak used for stabbing their prey and sucking vital juices. Their venom must be very powerful because they can paralyze a bumble bee twice their size in the blink of an eye.

Conopid fly on common milkweed

Some flies of the Conopidae family parasitize bumble bees. They hang around flowers waiting for bumble bees and lay just one egg in the narrow space between body segments. The egg hatches, the larva gets inside the unfortunate bee and proceeds to feed on its blood, (its real name is hemolymph because it is more similar to lymph than to blood). As it grows it starts eating the tissues, eventually killing the host.

Bee wolf Philanthus gibbosus

Bee wolf wasps attack many types of bees, bumble bees included, and also other insects. They overpower them and take them to their nests to feed their young. They have a very thick, pitted body cover that serves them as armor.

cuckoo bumble bee, Bombus citrinus

Other enemies of bumble bees are bumble bees themselves, the so called cuckoo bumble bees. There are several species of them. They build no colonies, nor have any workers. A queen attacks and subjugates a colony of honest, hard working bumble bees. She usually kills the resident queen and destroys any eggs. Then proceeds to lay eggs of her own which are nurtured by the workers of the host species.

Bumble bees also suffer from many of the pathogens that afflict honey bees, such as mites, fungi, nematode worms, bacteria and viruses. The life of a pollinator is not an easy one.

Bumble bees. Introduction

Beginners Guide to Pollinators and Other Flower Visitors

Bumble bees life cycle

July 9, 2011

With about fifty species in North America it is hard to generalize. However most bumble bees are colonial; there is a queen and workers living together in a hive, with the queen being the mother of all the workers. The colonies can vary in number from no more than a couple of dozens to a few hundreds.

Early in the spring the adult queen that was born and mated the previous season emerges from its wintering place, hidden under bark or in some other safe place. It starts looking for the right place to raise its family. This can be a rodent’s burrow or a similar hole. In some cases just a tussock of grass will do. Once she finds a satisfactory locale she starts redecorating her property, making it more suitable for her babies.

She builds some wax containers, which she fills with food, nectar and pollen and she builds a larger mass or brooding cell, made of a mixture of wax, pollen, nectar and her own saliva. This is where she lays a batch of eggs. For the next two weeks or so, she takes care of this brood by adding more food as needed and by keeping it warm during the night or colder weather. She does this, as brooding birds do, by lying on top of the egg mass. Her belly has even a hairless patch, just like such birds, which helps to transfer the heat from her body to the brooding cell where the growing larvae are.

Bumble bee nest. © Scott Nacko (Bugguide image 421344)

The larvae grow rapidly on that nutritious mixture and soon a half dozen or a dozen adults emerge from this brood. They are smaller than the queen and they are all worker females. They set to work right away taking care of housekeeping and going out for more nectar and pollen. Now the queen doesn’t need to go out and hardly does so from then on. She simply stays home laying more eggs and being attended by the workers.

Worker with a load of pollen

The colony keeps growing and by the fall the queen lays eggs which will become the future queens and also lays some male eggs.

When the new queens emerge, they don’t do any work in the colony. They just go out and mate with males, possibly from another colony. After that they start looking for a safe place where to spend the winter. The old queen, all the workers and the males die shortly afterward.

Bumble bees. Introduction

Beginners Guide to Pollinators and Other Flower Visitors

Bumble bees as pollinators

July 6, 2011


Impatient bumble bee and impatiens. It fits like a glove

Bumble bees collect nectar and pollen to feed the babies and that is how they pollinate many flowers. Some are generalists that visit many different kinds of flowers while others are more specialized. The species with longer tongues show a preference for flowers with deeper throats although they can also reach the nectar of flatter flowers. Those with shorter tongues are more limited in their choices. Body size also matters; larger bumble bees may keep the smaller ones from visiting favorite flowers.
buzz pollination

Turtlehead. In and out with great skill

Because of their wide geographic distribution and long season (from spring to fall), they are pollinators of a wide array of wild flowers, as well as some important crops such as tomatoes, eggplants, alfalfa and clover.

One interesting feature of bumble bee pollination is that they can practice the so called buzz pollination, a deed that honey bees never mastered. Some flowers don’t have ready available pollen; instead they keep it inside the anthers. Only a pore at the tip of the anther allows the pollen to escape. For that it is necessary to shake the anther, just like a saltshaker. Bumble bees and a number of native bees are pros at this shaking. They use their flight muscles to cause a vibration, easily heard if you are near. Plants in the tomato family, such as tomatoes, peppers, eggplants, and members of the Ericaceae family, such as azaleas and rhododendrons, blueberries, cranberries and a few other berries, require this form of pollination.

Buzz pollination of azaleas. Notice the buzzing sound

Bumble bees. Introduction

Buzz pollination of Senna

Beginners Guide to Pollinators and Other Flower Visitors

Bumble bees: the pandas of the insect world? Part III

July 5, 2011


Bumble bees are almost cosmopolitan. They are more abundant and represented by a larger number of species in the northern hemisphere, especially in temperate zones. They prefer relatively drier climates.

Originally they were absent only in Antarctica, Australia and New Zealand. But in the last century they were introduced in New Zealand to help with alfalfa pollination. Attempts to introduce them to Australia years ago failed. Nowadays, green house tomato growers are pressing for permission to import European bumble bees; but they face strong opposition from those who oppose the entry of alien species. Recently bumble bees became established in Tasmania, after making their way there, either illegally or accidentally. There is strong surveillance to prevent the species from entering the mainland, but occasionally a bumble bee queen makes its way there. Perhaps it is just a matter of time.

In North America there are approximately fifty species. Some can prosper in a wide range of habitats others are more limited. Some are found only in the West Coast, others in the East. There are northern and southern species, for instance the tricolored bumble bee is mostly a northern species, seldom found south of Pennsylvania. There is a species, the polar bumblebee or Bombus polaris, found within the Arctic Circle; it takes full advantage of the explosion of little flowers that occurs in such latitudes through a very brief period. In that short time it has to raise a family and complete its full life cycle. This species has only small colonies. Other bumble bees do well in arid regions or at fairly high elevations.

Bumble bees can be found in farms, in suburban gardens and even in cities. Anywhere that flowers bloom, it is likely that there are bumble bees. The most serious limitation to their existence in cities is the lack of appropriate nesting sites; however some hardy souls manage to prosper in the concrete jungle.

Sadly, there are signs that not everything is well with bumble bees populations. Despite our limited knowledge, there are some evidences of declines, maybe even extinctions, of some populations. In England, where bumble bees are better studied than in the United States, there is clear evidence of the loss of some populations of bumble bees. There are even two species that are believed extinct in Great Britain, although the same species are still represented in the continent.

Bumble bees. Introduction

Beginners Guide to Pollinators and Other Flower Visitors

Bumble bees: the pandas of the insect world? Part II

June 9, 2011


The scientific name for a bumble bee is Bombus, we will have to use this name when talking about different species of bumblebees because some of them don’t have a common name.

Bombus ternarius

The tricolored bumblebee (Bombus ternarius) is very striking, with a bright band of orange in its abdomen alternating with the white and black of the rest of its body. As I said, it is easy to make mistakes; there are some similarly colored ones, such as the well named red belted bumble bee (Bombus rufocinctus). As if that wasn’t enough there are also a couple of more species with a similar bright orange belt on their abdomens: Bombus huntii and Bombus melanopygus.

Bombus impatiens

A very common bumble bee is the impatient bumblebee, Bombus impatiens; I guess that it gets its name for its quick and very active movements, but, please, don’t quote me. Its other name is common eastern bumble bee, which is self explanatory. If you live in the eastern United States that is the one that you see most often.

Bombus griseocollis

bombus bimaculatus on Monarda

It is possible to mistake the impatient bumble bee with the brownbelted bumble bee or Bombus griseocollis. Although in this case a reddish touch, visible in some cases, sets it apart. Another one that I find somewhat similar to the last two is the twospotted bumble bee (Bombus bimaculatus).

Bombus perplexus

Ironically, the confusing bumble bee (Bombus perplexus) doesn’t look confusing to me. It seems to have more yellow and less black than most of them.

Bombus sp

Sometimes you just can’t be certain and simply have to guess between two or more species, such as Bombus vagans, perplexus, or sandersoni. This is the case more often than not.

Not all bumble bees are industrious pollen collectors and caretakers of their babies. Some have taken the easy way out. They victimize their relatives, other bumblebees, and lay their eggs on their nests or take possession of their colonies and use the workers of their victims as servants.

Bombus fernaldae

There are several species of these cuckoos; they get this name because their behavior is so similar to that of cuckoo birds. They are so used to this easy life style that they have lost their pollen baskets and their ability to build nests; on the other hand they have become quite warrior-like to subdue their hosts.

Bombus citrinus

They also have become adept at imitating the appearance of some of their victims, making it harder for other bumble bees as well as for human observers to tell the difference.
Here are two of these cuckoo bumble bees, the Fernald cuckoo bumblebee (Bombus fernaldae) above left and the lemon cuckoo (Bombus citrinus) right.

The Bumble bee organization has put up a very nice chart to help recognize species of North american bumble bees

Bumble bees. Introduction

Beginners Guide to Pollinators and Other Flower Visitors

Bumble bees: the pandas of the insect world?

June 8, 2011

Bumble bees, those fuzzy industrious flying insects, are part of our culture in a number of ways: from Nikolai Rimsky-Korsakov’s “Flight of the Bumble Bee” to cute Halloween costumes, waving antennae and all. Stuffed toy bumble bees are ubiquitous in every nursery and most children libraries seem to carry at least one book about bumblebees. Songs and fairy tales involving bumblebees abound.


Bumble bees are plump and furry insects, usually striped black and yellow or black and white and yellow. Some even have some orange to brighten things up a little more.
They have two large eyes and, if you look very carefully, you will see three smaller eyes at the top of the head, between the large ones. The mouth has jaws which the females use for some tasks such as kneading wax and building little pots that they use to store pollen and nectar.
Insects have three pairs of legs and bumblebees are no exception. The back legs of the females are very peculiar, with a broader, flattened section surrounded by stiff hairs forming a sort of basket; as we will see later on, that is exactly how bumble bees use them. The wings are transparent, crossed by thin dark veins. There are four wings, two on each side of the thorax; but most of the time the back and front wing are joined by tiny hooks along the edges and look and act as one. Wings are a lot stronger than they appear and can carry the busy animal for several miles a day in its constant search for nectar and pollen; however, after several weeks of constant use they begin to fray along the far edge. Look for bumblebees on flowers and after a while you will be able to tell the ones that are very young and look spanking new from the older, worn out ones. In early spring most of them are young and the opposite is true near the end of the season.

We must be careful when we talk about bumble bees; at first sight we may think that they are all the same. We may even make the mistake of assuming that the larger, glossier and blacker carpenter bees are also bumble bees. As we’ll see later they are not and they have a very different life style.
There are about fifty species of bumble bees in North America; it would be nice to tell them apart at a glance but in many cases the differences are very subtle and we need help from the experts. They will tell us that it can be very difficult and that they may need to examine the specimen carefully under the microscope before making a diagnosis. So we won’t worry too much about identifying the species all the time.

See also:
Bumble bees part II
Bumble bees part III
Bumble bees as pollinators
Bumble bee’s intelligence
Life cycle

Beginners Guide to Pollinators and Other Flower Visitors

Pieridae Butterflies: Whites and Sulphurs

June 3, 2011

West Virginia White butterfly

Cabbage White butterfly

Some of the most common and easy to recognize butterflies are the whites and sulphurs. In fact the name butterfly probably comes from “butter colored flies” referring to some of the yellow ones. There are several variations, but most are white, like the Cabbage White butterfly, or yellow, like the Clouded Sulphur. The wings are roundish, some have orange or black tips and dots. They are midsized butterflies with a wingspan of about an inch.

Orange Sulphur butterfly on asters

Whites and sulphurs are found in every garden visiting flowers. They also like to gather in groups at mud puddles. They often can be seen chasing each other in a spiral flight, circling around each other while raising toward the sky, and then one of them dropping down.

There are many native species, but the Cabbage White butterfly was introduced from Europe and, as its name suggests, it is a pest of cabbages and related plants.

Habitat. Gardens, fields, open areas, from beaches to mountains.

Season. From April to October, year round in southern states.

Flowers. Long throated flowers: monarda, butterfly bush, butterfly weed, mints, clover and also flat open flowers: daisies, sunflower, dandelion, thistles, goldenrod, etc. Also, look for them at mud puddles.

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Beginners Guide to Pollinators and Other Flower Visitors