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Showing posts with label pollinator. Show all posts
Showing posts with label pollinator. Show all posts

Monday, May 16, 2016

Early Spring Pollinators and their Flowers

Bluebells and carpenter bee
© Beatriz Moisset

Many gardeners are developing a new concern for pollinators. They look for ways to help them. Aware that a perfectly manicured, pesticide-laden lawn is not good for pollinators they enthusiastically adopt a scattering of dandelions in the early spring.

This is certainly beneficial to pollinators. However some of the passionate claims that accompany this activity are somewhat exaggerated. It is not true that pollinators “need” dandelions. They would prefer other flowers if they had a chance.

Spicebush in bloom
© Beatriz Moisset
Spicebush and pollinator
© Beatriz Moisset
Before dandelions were introduced from Europe and before lawns became so rampant in our suburbs, early spring pollinators were faced with a smorgasbord of early spring flowers. Here is an incomplete list of the so-called spring ephemerals prevalent where I live, in the Mid-Atlantic region: spring beauty, trout lily, trillium, columbines, rue anemones, Dutchman's britches, bloodroot and bluebells. These and others can still be found in nature areas, although they have become extremely rare in gardens and parks. Perhaps even more important to early spring pollinators are a number of trees and shrubs, such as willows, maples (some, not all of them), serviceberry, sassafras, spicebush, redbud, and a little later, azaleas and dogwoods, just to name a few.

Spring beauty and spring beauty Andrena
© Beatriz Moisset
This assortment of flowering plants offers a rich and diverse diet to newly awakened queen bumble bees, early Andrena bees, and other bees and flies seeking pollen and nectar. Some pollinators are specialists on just one or a limited variety of flowers. The spring beauty Andrena, trout lily Andrena and several willow blossom devotees would look at dandelions in despair, not being able to make any use of them.

Trout lily, frequently visited
by the trout lily Andrena
© Beatriz Moisset
The biotic community described above not only nourishes early-riser pollinators but also provides food and habitat for local wildlife. For instance, the red maple serves as a host plant for more than 100 moth species, willows provide food for several hundred species of moths. In turn, these caterpillars nourish birds and other wildlife. By contrast a lawn with dandelions is an impoverished ecosystem with very limited ecological value, more similar to a refugee camp than to a healthy, lively community.

Azalea and its specialist
the azalea Andrena
© Beatriz Moisset
If the goal is to help pollinators we would reduce the size of the lawn and grow some of the plants mentioned above rather than simply allowing dandelions among the blades of grass.

Bloodroot and Red-necked False Blister Beetle
© Beatriz Moisset
Such a goal is hard to achieve for most gardeners and probably impossible or nearly impossible for many of them. So, reducing the use of pesticides and allowing dandelions, as well as a few other small lawn “weeds,” is a good decision. But anybody seriously committed to protecting, not just pollinators, but entire ecosystems would do well to take a look at other alternatives.



Dandelion visited by a cuckoo bee
© Beatriz Moisset
Dandelion and ants
© Beatriz Moisset

Monday, February 9, 2015

Pollinators of Official State Flowers

A tale of pollinators and pollination

as told by the official state flowers

 


We love flowers for their beauty and for the impact they have on diverse aspects of our lives. That is why we honor them by choosing an official state flower for each state of the union. A look at the list of state flowers reveals an amazing variety of shapes, colors, perfumes and blooming seasons. Some flowers are open and rather flat; others are elongated, trumpet like, with spurs, or intricately shaped. They may be grouped in clusters or stand alone. They come in a rainbow of colors and their scents are equally varied. Some bloom briefly in just one season, others do it for a longer time.

Why do plants have flowers and why is there such a variety? We seldom think about a flower’s function.  Some even feel that they were put here for our enjoyment. The fact is that their whole purpose is to attract pollinators, those love messengers that carry pollen from blossom to blossom ensuring the development of fruits and seeds and thus the future of the plant’s species. The great variety of flowers is a sign of the diversity of their pollinators. Both the flower and the pollinator complement each other to the point that, in some cases, only one kind of pollinator can perform the job for a particular kind of plant. This mutual fine tuning is the result of a long process of co-evolution. Often one can tell the type of pollinator by looking at the structure of the flower. For instance, flat, open flowers can be pollinated by short tongued insects; longer ones require longer tongued visitors. Tubular flowers are often pollinated by hummingbirds or very long-tongued moths. Night-bloomers are pollinated by night-flyers such as hawk moths or bats.

We often think of the honey bee as the ultimate pollinator and we seldom recognize the fact that many other insects, as well as some other creatures perform that job, in fact many plants have absolutely no use for honey bees. It is true that honey bees are incredibly adaptable and that they visit a wide array of flowers through several seasons, we could say that they are “Jacks of all trades” but we must remember the second half of that saying: “and masters of none”. In many instances flowers fare better in the absence of honey bees because some of them have developed a long standing partnership with their respective pollinators. Honey bees could interfere with such specialized pollinators.

Years ago, I was looking at a book on state flowers and was astonished at their variety. It occurred to me that it was possible to teach an entire course on pollination using state flowers as examples. All it takes is one look at the assortment of state flowers to see that there must be a similar diversity of pollinators belonging to several different groups of animals, not just bees, but also flies, butterflies, moths, beetles, and even bats and birds. Maybe some day, the states will recognize the importance of pollinators and decide to honor them also. After all, flowers would not exist without pollinators.

Some flowers accept a variety of pollinators, for instance, black eyed Susan (Maryland’s state flower) and goldenrod (state flower of Kentucky, Nebraska and South Carolina). Others are more selective, such as the flowering dogwood (state flower of North Carolina and Virginia). A few are extremely specialized like the yucca (state flower of New Mexico), which needs a tiny moth. No one else can do the job. Still others require unusual pollinators like the saguaro (state flower of Arizona) whose main pollinators are bats, or columbines (state flower of Colorado) which are pollinated by hummingbirds.

Curiously, thirteen states have chosen official state flowers that are not native and therefore not truly representative of the state. Fortunately seven of them decided to add an official state wildflower, for instance, the state flower of Ohio is the carnation and its wildflower is the white trillium. I will mention a few of them because they contribute something valuable to this tale of pollination. In other cases, I will refer to the state tree if it bears flowers that add something to the pollination story.

One may wonder why some states chose flowers native to the old world rather than those that represent the state flora. It seems that state flowers were chosen more for their beauty, or economic importance. Perhaps part of the explanation is that this is such a nation of immigrants that many people are more familiar with the rose or the carnation than with any local flowers. Economic importance counts too. Thus, it comes as no surprise that Florida chose the orange blossom as a state flower.

In a few cases there is some confusion about the choice of state flower. This is not surprising considering that legislators are not botanists. The common name could include only one or several species of similar plants. Which one of several violets is the state symbol? Those states that chose the rose, were they thinking of a native species of rose, or one of the common cultivated varieties? Different sources give slightly different interpretations to these choices. In general, I will follow the scientific nomenclature used by the United States National Arboretum, but I may include other interpretations in some instances if they illustrate an interesting pollination point.

Here is the story of pollination and pollinators as told through the examples of official state flowers. In the next post I will describe the kind of pollination that took place long before there were any insects or other animals to do the job, in fact, long before there were flowers. Then, I will examine the earliest forms of insect pollination. In following posts I will cover an assortment of floral strategies, from the ones that attract hordes of different pollinators to the specialists that prefer to deal with a select number of helpers or even just one. I will include some strategies that include nasty tricks played on pollinators and also an intriguing phenomenon, toxic nectar. It makes one wonder why a flower would want to make its pollinators sick. I haven’t forgotten pollinators of a different kind, non-insect ones, birds and bats. Finally, to wrap up this tale, I will take a look at state flowers and pollinators of economic importance.

More on pollinators and state flowers




 
References
State Symbols, USA
Dowden, Anne O. State Flowers. 1978
Cooper, Jason, The Rourke Guide to State Symbols. Flowers. 194

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2015

Monday, October 20, 2014

Blowflies are Pollinators Too

Mating Lucilia flies. © Beatriz Moisset

A bright metallic green insect lands on one of the flowers in your garden. It has large red eyes. Aside from the interesting colors, it looks like a plump house fly. You can't decide whether you like it or not. Its scientific name is Lucilia, its common one is greenbottle blowfly. It is unusual for a scientific name to be prettier than the common name. You dislike the common name even more when you find out its meaning. According to the Free Dictionary a blowfly is "any of several flies of the family Calliphoridae that deposit their eggs in carcasses or carrion or in open sores and wounds." Carrion? Open sores? Definitely not pretty.


Lucilia on common milkweed. © Beatriz Moisset

So, it is agreed, Lucilia is an ugly fly despite its startling colors. But, does it have some redeeming features? Fortunately, it does. Its habits are put to full advantage in forensics. By examining the Lucilia's maggots found in a corpse it is possible to determine the time of death. Another use is in medicine. This may cause you some revulsion, but it isn't as bad as it seems. Open wounds that don't heal and begin to accumulate dead tissue can be cleaned up by blowfly larvae. Let me clarify that only maggots raised in perfectly sterile conditions are used for this purpose. The larvae feed only on the dead cells and leave the healthy tissue untouched. This method is superior to that of the most expert scalpel held by a surgeon.


© Beatriz Moisset

But this is a blog about pollinators, so let us get into this subject. Blowflies, Lucilia in particular, are good pollinators of certain flowers. You see them frequently visiting a variety of blooms in your garden. They are more efficient than bees in pollinating onions and cabbages. I wonder why they show such preference for plants so notorious for their strong odor. Perhaps there is a connection between these plants' fragrance and that of smelly dead things fowever I haven't found any references so far. Most pollinators don't fair well in greenhouses. Lucilia, on the other hand, is easy to raise and to maintain in these conditions, so this is the preferred pollinator of the mentioned plants.

Two Lucilia flies pollinating Allium. © Beatriz Moisset

In summary, blowflies aren't that bad at all. In fact, they are so beneficial that we may begin to see their beauty. Let us welcome them in our gardens.
Lucilia on mountain mint. © Beatriz Moisset


List of articles
Beginners Guide to Pollinators and Other Flower Visitors

See:
Onion pollination by blowflies


© Beatriz Moisset. 2014

Tuesday, July 22, 2014

Flower Longhorn Beetles, the Elegant Crowd


Strangalia luteicornis on buttonbush
© Beatriz Moisset
 Most beetles we are familiar with are roundish or oval-shaped hard shelled insects. Think ladybugs or Japanese beetles. Others are a little longer and cigar-shaped. An entire group of beetles distinguishes itself for its elegant streamlined figure; these are the so called flower longhorns. The name refers to their love of flowers as a hangout and to their long antennae. No, they don't have real horns, just antennae like other insects. Sometimes these organs can be longer than their entire body.

Strangalia famelica, the hungry strangalia
© Beatriz Moisset
Flower longhorns are the fashion models of the beetle world. Their slender and highly stylized outline is reminiscent of that of wasps; although they would never be mistaken by such because they have the characteristic hard shell (elytra) of all beetles covering their membranous wings. In their elegance they would make a nice fashion parade. Some carry their slenderness to the extreme of appearing anorexic. In fact one of them was given the scientific name of famelica, which means starved one in Latin. By contrast, the banded longhorn (Typocerus) and Brachyleptura appear almost obese, although they are still rather slender when compared to most beetles.

Brachyleptura rubrica covered with pollen
© Beatriz Moisset

The banded longhorn, Typocerus velutinus on milkweed
© Beatriz Moisset
Flower longhorns love flat open blossoms of the umbrella type, such as the members of the carrot family. They also like flowers of the rose and aster family as well as wild hydrangea. They feed on their pollen. Sometimes you find several different types amiably mingling together on these flowers. They are regarded as lesser pollinators of such plants. It is not surprising, when you see some of them coated with pollen.


A couple of Metacmaeops vittata on wild hydrangea
© Beatriz Moisset
Their larvae don't have such wholesome habits. They are wood borers, meaning that they feed on wood. However none has been reported as a serious pest of trees. Perhaps trees have enough defenses against them or there are enough enemies to keep their numbers from getting out of control.

Analeptura lineola on wild hydrangea, with pollen on its back
© Beatriz Moisse
Flower longhorn beetles are a beautiful addition to the biodiversity of forests, well integrated with the remaining members of the community.

For more on pollinators and other flower visitors read the e-book:
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2014

Friday, December 13, 2013

Roadside Pollinator Gardens and Traffic


Mountain laurel. © Beatriz Moisset
Pollinator gardens are blooming along many highways. Perhaps the idea originated with Lady Bird Johnson and her beautification program. But it goes well beyond that. Planting wildflowers along highways has many advantages besides the esthetic ones. With the growing loss of pollinator habitat, it is a blessing to use the wasteland of roadsides as wildflower gardens to take care of the needs of pollinators.

Butterflies and bumble bees are more abundant where wildflowers bloom than in areas where grasses are dominant and where mowing and pesticide treatments are routine according to many reports. The possible downside is that larger numbers of dead butterflies, and perhaps bumble bees are found along highways with abundant wildflowers. How serious is the problem? Do the benefits outweigh the damages?

Skipper on asters. © Beatriz Moisset
It isn't easy to assess all the aspects of the situation. But the weight of opinion is that the deaths by vehicles are not much higher than those by natural causes. The increase in food supplies and shelter for the pollinators benefits them and contribute to larger populations. So, those who study the matter feel that it is worth to continue creating habitat for pollinators along highways.

Other advantages of such roadside pollinator gardens are a reduction in mowing frequency once the gardens are established and a reduction in pesticide use. Did I mention that the view is also more pleasant to the eye? Perhaps, this improves the mood of the drivers and brings down accident frequency.

Milkweeds. © Beatriz Moisset

References

Pollinators and Roadsides. Xerces Society. 
Manage your Roadsides for Bees & Butterflies. 
Use of Roadside Prairie Plantings by Native Bees. Iowa State University. 
Roadsides as Habitat for Pollinators: Management to Support Bees and Butterflies. Jennifer L. Hopwood.
A Sticky Situation for Pollinators. Minnesota Conservation.

Friday, November 8, 2013

The Monarch's Breadbasket



Monarch on milkweed © Beatriz Moisset
For years the so called Corn Belt has been our breadbasket, as well as that of the monarch butterfly. Despite farmers' efforts to remove all weeds, common milkweeds proved well adapted to corn fields and prospered year after year, encouraged, rather than hindered by annual plowing. Other milkweeds, with different habitat demands lost ground to the point of becoming endangered. But common milkweed (Asclepias syriaca) and its rich accompanying fauna, including the monarch butterfly, continued to do well.



Monarch caterpillars need milkweed,
which used to grow in relative abundance
in corn fields of the Midwest
© Beatriz Moisset
Recently this changed with the advent of genetic modifications that make corn and other crops resistant to weed killers called glyphosates, mainly Roundup. Nowadays, approximately 90% of corn and soy seeds are genetically modified. Now farmers can use Roundup freely on these resistant crops. This radical change in farming practices is having unpredictable impacts in ecosystems. One effect of herbicides used in this manner is that it finally became possible to wipe out populations of common milkweed that previously had managed to prosper in cultivated fields and along field edges. What is good for the farmers may prove devastating for the monarchs.

According to some recent studies, most of the monarchs in Canada and the East Coast (fourth and fifth generations) are descended from the ones born in the Corn Belt (second and third generations). It seems that the weakest link in the chain is the Midwest where herbicide-resistant crops plus herbicides are decimating the common milkweed. Trying to strengthen the other links may be futile.


Monarchs used to be numerous in Cape May, NJ,
during fall migration, but no more despite abundant nectar
© Beatriz Moisset
Our milkweeds and nectar plants, here in the East, are almost devoid of monarch butterflies. The same thing applies to the oyamel forests of Mexico where overwintering monarchs used only a small fraction of the available habitat last year (2012).


Common milkweed patch in Southeastern Pennsylvania
Very few monarch caterpillars this year, 2013
© Beatriz Moisset
 If we want to save the monarchs, we need to save their breadbasket by stopping the use of herbicides in our own breadbasket.

References
Benbrook, C.  Impacts of genetically engineered crops on pesticide use in the U.S. -- the first sixteen years. Environmental Sciences Europe (2012)
Brower, L.P. Understanding and Misunderstanding the Migration of the Monarch Butterfly (Nymphalidae) in North America: 1857-1995. Journal of Lepidopterists' Society. First observations page 306. Mexico, pages 312-213
Pleasants, J., Oberhauser, K. Milkweed loss in agricultural fields because of herbicide use: effect on the monarch butterfly population. Insect Conservation and Diversity (2012)

Sunday, September 1, 2013

Buzz Pollination of Fabaceae Flowers


Flower of Senna. Observe the pores at the tip of the anthers
© Beatriz Moisset
It is interesting how several families of plants have evolved anthers that require buzz pollination, also called sonication, independently of each other. The organ that contains the pollen or anther of most flowers splits open when the pollen is ripe, making it available to the flower visitor. Buzz pollinated flowers do it differently. The anther remains closed, except for a pore at its tip. The only way to extract the pollen is by shaking the anther with just the right kind of vibration. Bumble bees are pros at doing this. Honey bees never developed the technique.

Close-up of the anthers © Beatriz Moisset
We are most familiar with the members of the tomato and potato family, Solanaceae. So much so, that some gardeners resort to a tuning fork or just an electric toothbrush to ensure pollination of the tomato flowers. Seeing pollen fly from the anthers during this process is a sight worth seeing. Another family with members that require buzz pollination is the Ericaceae; Blueberries, cranberries, azaleas and rhododendrons use this process.

Senna plant. © Beatriz Moisset
Perhaps, it is less known that some members of the pea family, Fabaceae, in the Caesalpinioideae subfamily also resort to this process. The genera Senna and Cassia, belong to this group. Recently I observed a bumble bee visiting the bright yellow flowers of a Cassia and was able to record the buzzing. The sound is unmistakable, quite different from the buzzing of flying. Watch the video of bumble bee on Senna and pay attention to the sound. You can compare it to that of a bumble bee pollinating an azalea.

Bumble bee, probably the common bumble bee. © Beatriz Moisset


List of Articles

Beginners Guide to Pollinators and Other Flower Visitor

© Beatriz Moisset. 2013

Friday, August 16, 2013

Bumble Bees and Odor Pollution

Bumble bee and lawnmower


This morning they were mowing the lawn in my condominium. Wanting to leave the nerve racking noise behind, I headed for my favorite wildflower garden at Pennypack Ecological Restoration Trust. Instead of escaping the roar, I was treated to another dose of lawn mowing there. The weather was perfect for observing pollinators, so I stayed despite my discomfort.

Bumble bees were going about their business, gathering supplies for their brood, apparently unconcerned by the cacophony. I would like to think that they are equally immune to the fumes of gasoline, but suspect that it isn't so. When the noise stopped, I wondered: how long do the fumes remain? How far do they reach? How do they affect pollinators?

Pollinators need odor cues to find their food. Flowers emit scents to entice their favorite pollinators. These aromas are carried by the breeze, creating trails that bumble bees pick up in their wanderings. Studies show that it takes them longer to find these trails when gasoline fumes are present. It may not be apparent to observers, but lawn mowing impairs the productivity of bumble bees and other pollen seekers. Needless to say, car traffic has the same effect.
Now, you can hear the sounds of nature


References