Monday, December 28, 2009

POLLINATORS. Robbers and thieves

Some flowers allow only specialized pollinators. They place their nectar out of the reach of most visitors and only those with a long enough tongue can reach it. Such is the case of the bee balm or monarda; a flower visited by hummingbird moths and bumblebees
A hummingbird moth unfurls its long tongue and sticks it inside the equally long throat of a bee balm flower.

The tongue of a bumblebee isn't as long as that of moths or butterflies, but by burying itself into the flower this visitor can reach the store of nectar without difficulty.
These visitors approach the flower the "legitimate" way, meaning that they touch the pollen carrying parts and also the female parts of the flower by entering it this way. When they do so they carry pollen from some flowers to others and accomplish pollination. Everybody benefits; the insects get nourishment and the flowers are pollinated. However this flower's strategy may backfire when clever and lazy flower visitors take a shortcut and steal the nectar. One very common robber is the carpenter bee; with its powerful jaws it can easily slash through a flower's tissues. Here a female carpenter bee is opening the throat of a bee balm flower. When this bee goes directly to the nectar bypassing the sexual parts of the flower it doesn't pick up or carry pollen. As a consequence, it doesn't help the flower at all.
A carpenter bee stealing some nectar
Pollinators: Partners and Robbers
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© Beatriz Moisset. 2010

Wednesday, December 16, 2009


In most cases the relationship between flowers and their pollinators is a wonderful partnership in which everybody wins; but there are exceptions. In some cases, insects exploit flowers and take their offerings without returning the favor and in other cases it is the flowers that exploit their visitors.
Many orchids use a wide range of deceptions; some, such as the lady slippers, engage in a rather innocuous deceit that only causes the insect a minor inconvenience. This flower has a very peculiar shape, with the lower petal expanded into a bag. The purpose of this bag is to act as a temporary trap.

The drawings show a flower cut through the middle to illustrate what happens.
It is not known exactly what the attractant is, but it is powerful enough that several kinds of bees come to the flower seduced by its appeal.
The bee perches on the edge of the sac and often loses its footing and falls inside; once there it struggles to get out but the inside is slippery and the curled lip of the bag makes it hard to get out. Fortunately for the bee there is a escape route.
Toward the back of the flower there is a ladder made of hairs that leads to a tunnel. There is a sort of skylight at the end of it to guide the disoriented bee, so even though the passage is narrow the bee strives tenaciously headed toward the light. In doing so it rubs its body against the pollen sacs, called pollinia, which get glued to its back.
Once outside the bee flies away; its little brain can remember the unhappy experience long enough to travel some distance from the plant that it has just visited. But most likely, it will repeat this adventure when it finds another lady slipper some time later. At this point it will leave behind the pollinia that it has been carrying inadvertently, performing pollination of the lady slipper and getting no reward for its labor.

Sunday, December 6, 2009

Hummingbird Moths. Where do They go in Winter?

Not all moths fly at night; some choose to do it during the day. One of them is the hummingbird moth, so called because it looks and flies and even hums like a diminutive version of a hummingbird when hovering in front of flowers. Just like their feathered namesakes hummingbird moths love long throated flowers, such as bee balm or horse mint. But unlike them, they don’t migrate south when the cold weather arrives. They resort to a different strategy to survive the harsh weather and lack of food.

Like all moths and butterflies they have a complex life cycle with dramatic transformations, called metamorphosis. The distinctive stages are called egg, larva or caterpillar, pupa and adult or imago. The one you are most familiar with is the adult, that colorful flying marvel; the other stages are wingless and prefer to remain out of sight and out of danger. The larva’s job is to eat almost non-stop and to grow; the pupa goes through a resting period and later through a tremendous remodeling job where all the parts are transformed to turn into the active, winged creature which we see during the summer. The flying adult’s whole purpose is to find a mate and to start the next generation; for that they need nourishment, nectar, which they find in flowers.

It is in the resting state of pupa that they choose to spend the winter. After the caterpillar reaches full size feeding on any of its favorite plants, such as hawthorn, black cherry or wild rose, it drops to the ground. There it spins a loose cocoon that lies partially buried under the leaf litter. Leaf litter is very important to this species; it provides some protection against the winter weather and against predators. When birds or squirrels go through leaf litter, scattering it here and there, they may very well be looking for one of these nutritious morsels.

If the pupa survives these attacks, it will complete its metamorphosis and emerge as a winged adult next spring, when nectar-laden flowers are blooming again.

Moths as Pollinators
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© Beatriz Moisset. 2010

Monday, November 30, 2009


Where do pollinators go in winter? When all the flowers that pollinators feed on are gone and when the cold grips the land, what do the pollinators do? They have to find refuges and hanker down until the next season. There are many different strategies at their disposal, many sheltered places, many options as to spend the winter months as eggs, larvae, pupae or adult. But they all make themselves invisible for several months of the year, hoping that no predator or parasite gets to them and hoping that the next season be bountiful and take care of their needs.
Here is just one example of a wintering pollinator, a pretty butterfly that you may see flitting around the garden during summer months: a fritillary butterfly Speyeria cybele.

Adult fritillaries are colorful butterflies of orange and black patterns, often mistaken for monarchs. Their long tongues enable them to reach for nectar hidden in long throated flowers such as horse mints, however they are not about to pass out a good opportunity to drink nectar from more accessible blossoms. You may start seeing them as early as May; by October they will be mostly gone or will look rather worn out, missing wing scales or even a piece of wing where a hungry bird took a stab and missed the body.
In late summer and early fall the females start looking for places to lay their eggs. Their babies feed exclusively on violets, so they need to find these plants and lay their eggs nearby. But by this time of the year violets are drying up or they are all but gone; only the roots remain under ground in many cases. This does not deter the egg laying females; either they have a formidable sense of smell that enables them to detect the roots of violets, or, in some cases, they just take a chance scattering their eggs on the leaf litter in shady places that are most likely to grow violets. In this case, some eggs will be lost, but there will be plenty left which will find their target.

The eggs are no bigger than a period at the end of this sentence; the caterpillar that emerges from it shortly afterward is about the size of a comma. Packaged inside this tiny body is all the genetic information needed to make all the colors and the beauty that will visit your garden fluttering from flower to flower during the warm months. There is no food for this baby during the winter months. So what is there to do? It promptly buries itself in the leaf litter seeking safety from the many small predators and parasites that hunt it in that dark and mysterious world that is the soil of your garden. There, it has nothing to do for several long, cold months; so it goes to sleep.

Probably many, perhaps most won’t make it through the winter; but the mother had laid so many eggs that there will still be plenty to keep the species going. By the end of winter it will be aroused, by some unknown cues. By then, violet plants are beginning to grow. Long before they start blooming, this caterpillar goes to work, feeding and growing for a couple of months. It will eventually emerge as a fully grown butterfly.

More on fritillaries life cycle in:
Pollinators welcome blog
Pollinator of the month
List of articles © Beatriz Moisset. 2012

Tuesday, November 17, 2009

Only friends welcome here

The wildflower Beardtongue or Penstemon gets its name from the hairy area that runs along the floor of its "mouth" looking like a bearded tongue. It is one of those flowers designed just for bumblebees. The size fits them like a glove; the length of its throat, where nectar is stored, is just right for the length of a bumblebee's tongue and the sexual parts of the flower are arranged so they rub the pollen against the back of the visiting bees so they carry it to the next flower.

But when it comes to other insect visitors they are not so welcoming. The outside of the flower is coated by glandular hairs, with shiny droplets of a gooey fluid at their tips. They feel sticky to the touch and, to a small insect, they are a death trap from which they can't disentangle themselves. I assume that they do it for protection although I can't imagine what protection they need from midges and the like.

Here you have one performing both functions at the same time, a welcoming host and a killer all at once.

Thursday, November 12, 2009


When October comes along we stock up on bird seed for the winter and try to make the right choices; some cheap brands are no good. A visit to the Cornell University Ornithology lab website would help us know what is best. Here we learn that some of the most common seeds are: sunflower, safflower, millet, cracked corn, peanut hearts, flax, sorghum and rape seed.

A house finch eating sunflower seed
Sunflower tops the list of preferred bird food because it is nutritious and rich in oils, badly needed by winter birds to generate the energy that keeps them warm. Some types of millets and flax are regarded as fillers and the Cornell lab doesn’t recommend them.

Woodpecker feasting on peanuts
The visitors to your bird feeder are wild animals that can survive on their own without your handouts. They are resourceful and can find wild foods through the winter; in fact many of them simply have no access to birdfeeders. They eat wild seeds similar to the ones you provide and berries of many sorts. If you are a birdwatcher you know that a good way to spot finches and other small birds in winter is to look at shrubs, preferably the ones laden with berries.

Let us examine these foods from a different angle. It is said that thirty percent of all the food that humans eat comes to them courtesy of pollinators primarily bees, what about bird food?

Long-horned bee pollinating a sunflower
Millet, corn and sorghum are cereals; the plants that produce them are wind pollinated. All the other bird seeds are from flowering plants that require the services of pollinators to produce seed. We are familiar with the flashy sunflowers and may have seen bees visiting them. Safflower is a type of thistle, also a blooming plant. Peanuts are members of the pea family with complicated flowers that require skilled pollinators to trip them and get to the pollen; these plants sometimes dispense with pollinators and simply fertilize themselves, but they produce more seed when pollinators are present. Rape is mustard, also dependent on pollinators. Finally, berries are dependent on pollinators.
So this is the true story of the birds and the bees.

Thursday, November 5, 2009

Bees in the Garden

A bee house for mason bees. These bees are solitary, meaning that each one tends to her own brood, about six to eight babies, and all each one needs is a hole the size of a pencil in a block of wood. They do not live in large hives with thousands of workers like honey bees. You can get fancy and create a handsome bee house like the one my son in law did for me.

Watching the comings and goings of your little tenants can be almost as much fun as watching birds at your bird house, and there is no reason to fear their stings. Unlike honey bees they are very gentle; I have let them climb on my hand without problems. They emerge in early spring and are busy through April and May and, perhaps early June. You won't see more activity until next year. You can see the video.

This one emerged from its long winter sleep shortly before Easter, so I call it my Easter bunny bee.

Let us provide a habitat for some of the numerous helpers to our gardens, pollinators, a few tips provided by:
Urban Bee Gardens
Selecting Plants for Pollinators

You may also want to build nest boxes for those bees that make their homes in cavities.
There are instructions in several websites:
National Wildlife Federation
Audubon. Bring on the Bees.

Or you may choose to buy a bee house from one of the several companies that make them, such as:
Northwest Nature Shop
Mason Bee Homes
Knox Cellars
(I am not endorsing any one, just saving you some leg work or mouse work).

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Saturday, October 10, 2009

Of Bees and Honey. What is Honey for?

Solitary bee, halictid or sweat bee, gathering food for her babies
In the beginning there were wasps, no bees at all. Wasps trapped bugs and used them to feed their babies, who grew strong and healthy in that rich protein diet. Many adult wasps also visited flowers and fed on nectar, a rich fuel that gave them enough energy to do all that flying needed to hunt their prey.

Once upon a time, some wasps discovered that the pollen they had accidentally picked up and carried back home on their bodies turned out to be just as nutritious as their prey. So they switched to pollen and gave up chasing after bugs. One advantage of pollen is that it doesn’t run away or fight back.

They became hairier and developed baskets to pick up and carry pollen home, thus a new creature was born, different enough from wasps to belong in a different category: a vegetarian wasp, the mother of all bees. Notice that I haven't mentioned honey yet. That came later. In those days all bees were solitary and short lived. The adults usually died at the end of the summer season. Only the next generation lived through the winter, feeding on its pollen reserves and sleeping quietly in a safe and secluded place, perhaps wrapped into some sort of cocoon.

Honey bee collecting pollen and nectar for the colony or hive, to feed her sisters and queen and store reserves for the winter
Finally some bees developed societies that lasted several years and had queens and workers and drones, all living together in a large colony. In order to survive the winter they needed to store supplies, mostly nectar (to keep burning fuel through the winter and stay warm) and also some pollen. But the nectar straight from the flower is very watery and would use too much space, so they developed techniques to get rid of most of the water. They spit the nectar out in a big bubble and swallow it back again and again until it becomes concentrated through evaporation until it can be stored in cells. In the process they also add some preservatives and fungicides to increase the shelf life of this precious commodity. Yes, that is what honey is; maybe you lost your appetite for it. But, wait, it gets worse, sometimes when there is a shortage of nectar, bees collect secretions from aphids, you may call it aphid poop, and use it to make honey.

Only social bees make any significant amount of honey. The stored supplies sustain them through the winter, when there is no other food available. The domestic bee and a few relatives from Asia belong to the social category as do several kinds of stingless bees from Central America and tropical South America. Bumblebees are also social, although they never build colonies as large as those of honey bees. They live for a few months and make some honey but not much. They store their golden treasure in little clay pots in their underground nests. Local people don't hesitate to eat this honey when they find it.

Interestingly, several types of wasps from Central and South America form colonies or hives that last longer than a year. They also make honey, but this is very unusual for a wasp. Their paper nests resemble those of hornets and the honey is hard to remove from the combs. You just pop up a piece of wasp nest in your mouth and chew until all the honey is gone. Then you spit up the wad of paper. I know it; I have done it. The honey is delicious and worth the minor paper-chewing inconvenience.

Oh, yes! Some ants make honey and have a very peculiar way of storing it. Some members of the colony, called "repletes," eat enormous amounts of honey, fed to them by their sisters, until their bellies are perhaps ten times larger than normal. They hang from the ceilings of store chambers inside the anthill and serve as "honey pots" always ready to vomit and pass some of this material to their nest mates. Honey ants are found on dry regions of several continents, including the American Southwest. The natives relish this sweet treat.

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© Beatriz Moisset. 2012

Thursday, October 8, 2009

A Busy Pollinator and a Relaxed One

An industrious little bee gathering food for her babies and pollinating flowers along the way. It methodically collects pollen without missing any and then promptly flies to the next flower.

The bee is very industrious and visits many flowers in a very short time. The flower fly, on the other hand, takes its precious time gobbling up pollen, so it visits fewer flowers overall.

Monday, September 28, 2009

BUMBLEBEES. Are Some Bumblebees Going the Way of the Dodo?

Who doesn't like a bumblebee? With their plump, fuzzy bodies and striking black and yellow or black and white stripes they easily capture people's hearts, especially when they are seen buzzing around from flower to flower.

What most people don't know is that some species of bumblebees are in decline. We have heard about the plight of its relative, the domestic honey bee; but haven't paid much attention to the situation of this wild cousin. Why should we care? It isn't just because bumblebees are charismatic, but also, and more importantly, because they play key roles in certain ecosystems. So far, we know of only a few species that are showing a reduction in numbers, both in North America and in Europe. It isn't as if all the species of bumblebees were going extinct overnight; fortunately some species are doing well, even in unexpected places such as suburban gardens. But, perhaps we should start paying attention to what is happening now rather than when it is too late. Besides, it is possible that many other species of wild bees are suffering similar declines in their numbers and we have no way to estimate what is happening because we know so little about them.

Here are some of the things that bumblebees do: they pollinate 15% of our food crops, worth about 3 billion dollars; they also pollinate countless wild flowers. Wildflowers are important not just for their beauty, but also for the seeds and berries that they produce. They become food for many species of wildlife, from birds and small rodents to large animals such as bears. Birds don't know what percentage of their food crops are pollinated by bumblebees, but it is possible that for some species is closer to 90% than to 15%. If we are not worried about our own food, we should worry about all the many species of birds and other wildlife that may be suffering because of a reduction on the numbers of wild bumblebees.

Goldfinches and many others owe their food to hard working pollinators such as bumblebees.
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© Beatriz Moisset. 2010

Saturday, September 26, 2009

The Life of a Flower

© Beatriz Moisset
Let us take a simple flower, the simplest you can think of, the one you drew when in Kindergarten. A yellow circle surrounded by petals. It looks like a daisy or a sunflower or an aster or a number of flowers with petals arranged like sun rays and a circle or disk at the center. Well, there is a surprise here; such a flower is far from simple. It has a very complex structure, in fact it isn't just a flower but a whole bunch of tiny flowers. Look at the little parts that comprise that yellow center. What a surprise! Each one looks like a tiny flower all by itself: five petals and a center with little things inside that resemble the center of many other flowers that you have observed at various times. Well, that is exactly what they are. Each one is a flower, called a floret; they are all clustered together.
Each floret contains all flower parts: petals, anthers, stigma
© Beatriz Moisset

You may wonder about the petals that surround this cluster of flowers. Here is the answer: there are two kinds of flowers in this interesting bouquet; only the ones that make the outside rim have petals, the large petals that we see. They are called ray flowers while the ones in the center are called disk flowers. It would be nice if all technical jargon were as obvious as this.
In a newly opened sunflower or helenium, the disk flowers are just like little knobs. The next day the outer line of disk flowers has opened and you can see the sex parts, the pollen and seed producing parts, sticking out. Afterward, each day or so a new row of flowers open. The old ones begin to wilt; they look open and a little dry. Eventually one smaller circle after another opens and passes its prime.
Now let us observe the pollinators that come and visit the flower. They go directly to the freshly opened florets. They have nothing to do with the unopened ones, nor with the wilted ones. They find pollen and nectar only there and they know it. All this goes according to the plans of the flower; this works just right to ensure pollination.

© Beatriz Moisset
One interesting thing is to look at the older flowers that have completed their cycle. The ray petals stay fresh and bright for a few days longer although that flower is no good to pollinators any more and it doesn't need visitors either; right now it is busy growing the seeds that will mature later on.
You may wonder why it continues to look attractive to pollinators. The reason is that a large clump of flowers is more likely to attract pollinators that are passing by than a smaller clump, with many dry blossoms in between. It is like you going shopping; a mall where many stores are closed or vacant is likely to drive you away rather than attract you. Once there, you aim for the store that interests you. Pollinators do the same; they notice the larger displays of flowers than the smaller ones, with the certainty that they will find some food there.
Helenium. The flower on the left is young, only a few florets opened
The one at right is older, most florets are past their prime
© Beatriz Moisset
Such flowers are skilled engineers, and good marketers. They know their clients and how to satisfy their demands, and they get good returns. Other flowers are arranged differently; they use different attractants; their timing varies; but they all know how to maintain a successful partnership with their pollinators.
The clients, on the other hand, know how to use this resource. You can see a bee visiting methodically all the florets and probing them with its long articulated tongue in this video

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© Beatriz Moisset. 2010

Sunday, September 20, 2009

Bugs in the Garden. Hornworm: Friend or Foe? Friend and Foe

Do you grow tomato plants? Who is your worst enemy in that case? Probably the tomato hornworm or the tobacco hornworm. Those fat green caterpillars with a funny looking horn at the rear end, red in the case of tobacco hornworms, blue in tomato hornworms. Besides that minor difference they look very similar; they both attack your precious plants with gusto and grow healthy and vigorous in such a diet. They also feed on tobacco, potato, peppers and other plants of the Nightshade family.

The moths that emerge from those caterpillars after they are done growing and after a period of rest called pupation are called hawk moths or sphinx moths. They are very beautiful, mostly brown and white with orange markings on the sides of their bodies, five in the tomato hornworm and six in the tobacco one; once again not a big difference.

Naturally you hate the worms, fear to find and infestation of them in your garden and would like to exterminate them forever. Fortunately, Nature has provided a few enemies of hornworms that help you in your battle for control but you are very likely not to know them and even accidentally eliminate your little helpers in an effort to combat the worms. So, it is important to know both.

Occasionally you find a hornworm all covered with white little oval things that you might mistake for eggs. Those are not eggs at all; they are your friends. It is fascinating to learn how they got there, although I must warn you: be prepared for some gore.

There is a tiny wasp, so small that if you drop a handful of them on a white piece of paper they look like the marks you could make with a regular pen, no bigger than some scribbles. This wasp lays its eggs inside the body of a caterpillar. The poor thing feels the prick and goes back to eating and growing for a while, without knowing that it is doomed. Eventually it becomes lethargic and later catatonic. It stops moving but continues to cling to the stem of one of your tomato plants.

In the interim the wasp’s eggs have turned into minute grubs that start doing a lot of eating and growing of their own at the expense of the caterpillar. When they are fully grown, something out of the movie “Alien” takes place. Remember a scene, early in the movie? An astronaut, that had suffered an encounter with the alien creature, seems fully recovered. Then, all of the sudden, he screams and writhes in pain. A blood covered hideous creature, a parasite, the alien in question, bursts out of his chest and scurries away. They must have gotten the idea from the parasitic wasp.

The full grown grubs emerge from the body of the caterpillar after making little holes. They cling to the body for safety, and spin cocoons around themselves. By then the caterpillar is too far gone to care. The wasp’s larvae need a period of repose inside their cocoons to turn into winged adults. They emerge in a few days ready to go and infest another caterpillar. I told you that it wasn’t pretty!

But it works to your benefit. Be thankful to the wasps that keep the population of hornworms down and prevent serious damage to your tomato plants. Hold the pesticides! You don’t want to kill these friends of yours along with your enemies.

There is still another twist to this story. As I said, the unwanted pest that devours your plants turns into a handsome moth. The transformation is so complete that people even end up calling it by a different name; in the case of the tobacco hornworm it becomes the Carolina sphinx moth. It flies at night visiting flowers such as morning glories, sweet potatoes, Nicotiana, etc. in search of nectar. It hovers on front of them, unfurls its long tongue and drinks deeply. In doing so it pollinates them. It has gone from foe to friend, from tomato destroyer to pollinator. We have to think twice about our desire to eliminate the hornworm entirely. Perhaps Nature works best by keeping a delicate balance by means of parasites.

Thursday, September 17, 2009

THE WEB OF LIFE. The Bear, the Waxwing and the Bee

You may be wondering what bears, waxwings and bees have in common. We'll get to that later.

Let us start with a black bear, the formidable resident of forests and broad spaces. An encounter with one of them can be an unforgettable experience. It is surprising to realize that an animal built up with such powerful claws and jaws is seldom a hunter; in fact perhaps only 10 or 15 percent of its diet consists of animal matter and a good part of that is carrion or insects. So, what does a bear eat? With great versatility it finds a wide range of plant food in the course of the year. In early spring, fresh out of hibernation it may find skunk cabbage to its liking as well as sprouts from plants in the pea family, horsetails and sedges. Later in the season it will find the growing cow parsnips and dandelions, as well as flowers of several kinds. It may supplement this vegetarian diet with some animal protein, from caterpillars to the occasional newborn elk; but still about 80 percent of the summer diet is vegetable. In the fall, it is the time to feast on berries; blueberries, raspberries and everything in between. It can devour enormous quantities of this food because it needs to fatten for the long winter ahead. It is hard to believe that such diet can become many pounds of fat in the short period of a couple of months.

And now for cedar waxwings, those attractive birds that are so much fun to watch. They are especially interesting when they are engaging in their peculiar tradition of passing berries from one to another. Cedar waxwings eat an assortment of berries through the year. In summer, when they are raising young, they enrich their diet with insects; but berries are the main staple of their diet.

Finally, let us talk about bees. Let us make it clear that I am not referring to the domestic honeybee but to any of the numerous native bees and bumblebees that feed on pollen and nectar of wild flowers. If we want to be more specific we can choose the blueberry bee. This industrious little bee is very specialized on the pollen it chooses to feed her family. It goes almost exclusively to blueberry flowers. When doing so it carries some pollen from flower to flower and from plant to plant, providing the plant an invaluable service, pollination. Once the flowers are pollinated they can start setting seeds and developing fruits.

Now, you see the link between bees and birds such as the cedar waxwing and larger animals such as the black bear. They feed on the berries that have been pollinated by the bees or, in the case of the bear, on other plant parts that also require pollination to multiply.

Experts on pollination remind us frequently that one third of our food comes to us courtesy of pollinators; most fruits and vegetables require the services of these little go-betweens, most of them bees. What they forget to mention is the large number of other species that also depend on pollinators for a good part of their diet. The bear and the waxwing are just two examples of a very long list that intertwines the little bees with the more visible birds and mammals.

Another twist in this intricate web, the bear and the waxwing digest the berries but not the seeds. So they end up dropping them farther from the mother plant and surrounded with an amount of excellent fertilizer. So, the pollinator, in turn, also depends on the seed dispersers.

But the final, and perhaps most marvelous twist, is that the plants, so dependent on pollinators and seed dispersers are actually making use of them. They are very skilled in attracting their attention and supplying their needs, either with rich pollen and nectar or with juicy, nutritious fruits. At the same time, they make sure that not all the pollen gets eaten and that the seeds can safely go through the intestines of the berry gluttons.
Thus the web is complete: flowering plants need the pollinators and the seed dispersers; bees need the flowers and the seed dispersers and, finally, bears and birds need the plants and the pollinators. When you walk through the woods or the meadows, think about this invisible web and what it is doing to make everything possible.

Bear feeding: BearDiet

Cedar waxwing feeding: Appalachian Mountain Club: Bird of a Feather...

Sunday, August 30, 2009

Metallic green bee, a good pollinator

The pure golden green bee, Augochlora pura, is a singular bee, smaller than a honey bee and looking like a shiny metallic little robot bee. There are several other metallic green bees related to this, they compete in beauty and they are all good pollinators of many wild flowers.

In the spring she builds her nest under the bark of rotten logs. If you thought that dead trees or large dead branches had no use you were wrong. To this very nice pollinator they are prized real estate, just the right place to raise her family safely and well protected. She searches for the right dead tree diligently and, if your garden is one of those perfectly manicure ones, you will not have the pleasure of her and her family's company.

She builds a small chamber in the space between the loose bark and the solid wood using her own saliva and secretions. She packs it with a storage of pollen and nectar very carefully kneaded and shaped as tiny loaves. She encrusts the inner walls of the chamber with these loaves arranged like tiles. When she has enough to feed one baby from birth to maturity she lays a small egg and shuts the chamber. She surrounds it with loose debris which abounds in such places and starts the construction of other chambers. You may find a couple of rows of four or five of these cells. The mother bee dies at the end of the summer and the new generation spends the rest of the year comfortable and safe until the next spring.

Tuesday, August 25, 2009

FLOWER FLIES. Very Good Friends of the Gardener

There are some little flies that visit flowers with great frequency. Naturally, they are called flower flies; although the British prefer the name "hover flies", which describes their behavior very accurately. They are very numerous in the garden; but if you dislike house flies you don't need to worry about flower flies; they are rather pretty. You probably didn't notice their presence thinking that they were bees, rather than flies.They are excellent impersonators of stinging insects such as bees and wasps and they probably fool hungry birds into thinking that they may get stung but these little "bees". This strategy seems to work very well for them, so they can go feeding on flowers unmolested by these winged predators.


In their visits to flowers they accomplish some pollination. They may not be as efficient as bees, but their sheer abundance makes them important pollinators of wild flowers. But there is something else that these flies do that makes them very welcome in the garden: The larvae of some of them feed on aphids.

This is such an important task that they deserve more attention than they get from plant lovers. We don't appreciate them enough.

Monday, August 24, 2009

Partners and Robbers

A jewelweed blossom is worth examining carefully; it is a little marvel of engineering, with a shape perfectly adapted to its pollinator, a plump bumblebee with a very long tongue and a thirst for nectar.

The shape of the little sac fits the body of the bumblebee like a glove; the side petals open like a pair of curtains to allow its entrance; the length of its spur, full of nectar is just right for the tongue of the bumblebee. And, finally and most important to the plant, the anthers (that carry the pollen) and the stigma (which receives the pollen) are placed so that the hairy back of the bumblebee rubs against them when entering the flower. The pollen is deposited on the bee and later on it is transported to other flowers.

For pollination to take place the bee has to enter the front of the flower otherwise it would fail to touch the parts of the flower that matter.

Despite this marvelous system, some very nice pollinators can turn into robbers and cheat the flowers that they usually serve diligently. This happens when the pollinator chooses to take a shortcut and bypass the well planned scheme of the flower. Such is the case of this bumblebee. When it takes nectar by slashing the spur from the outside it doesn't come near the pollen carrying organs and doesn't perform pollination.

Pollinators: Robbers and Thieves
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Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2012