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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.

Saturday, December 7, 2013

Globetrotting Skippers


Fiery skipper (Hylephila phyleus). © Beatriz Moisset
 You probably thought I was running out of migratory butterflies after my last two posts. Not quite, there are more. But now I want to turn to skippers and talk about two species that also deserve the name of globetrotters.

Skippers are related to butterflies and often they are called by that name. The clearest difference between the two is that the end of a skipper's antennae ends in a hook, while that of a butterfly ends in a knob. Most are not as colorful as butterflies, they skip along when flying, hence their name.

Butterflies, skippers and moths belong to the order Lepidoptera, which literally means "scaly wings." You can tell them apart from all other insects by this feature. Perhaps, in a future post I will deal with migratory moths. Yes, there are some of those, too. In fact, a few perform amazing trekking feats.

As I mentioned, we know very little about the itineraries and distances covered by migratory butterflies, other than monarchs. We know even less about skippers. The only fact we are certain of about the ones I want to discuss today –the fiery skipper and the long-tailed skipper– is that they travel long distances, not just locally.

Fiery skipper (Hylephila phyleus) is one of the so called grass skippers because its caterpillar feeds on grasses. It has a bright orange color. It lives in temperate and tropical areas and can be found from North America to Brazil and Argentina. Let me clarify that this is its geographic distribution and it doesn't mean that it travels that far. The ones that live in South America are different populations. However, as I said before, it travels north in the spring from the southern states to northern areas. It is thought that many of those migrants don't make it back. Instead, they freeze and die when the weather gets cold.

Long-tailed skipper (Urbanus proteus). © Sean McCann. Bugguide
 The long-tailed skipper (Urbanus proteus) is unusual in two respects, each hind wing has a long projection that gives it its name, and its caterpillar feeds on members of the pea family. This latter characteristic doesn't endear it to farmers. The caterpillar is often called the bean leaf roller because it finds shelter by wrapping itself inside a leaf of this plant. It is just as widespread as the fiery skipper. Once again, it is not known if the ones that travel north or their progeny ever make it back to the South.

Years ago, it was thought that some of the travelers mentioned in previous articles failed to return south when the weather deteriorated perishing at the end of the season. Later on, additional observations showed that painted ladies, red admirals and a few others, do indeed return south in the fall.  I hope that, as we find out more about these two species, we learn that they too are capable of escaping the winter weather by migrating south in the fall.

Butterflies and Moths of North America (Range)
Long-tailed Skipper or Bean Leafroller (Distribution)
Migration: The Biology of Life on the Move (Urbanus proteus migration)

Globetrotting Butterflies
More Globetrotting Butterflies

Monday, December 2, 2013

More globetrotting butterflies


Monarch butterfly, the most famous traveler. © Beatriz Moisset
In my last post I discussed two butterflies, the red admiral and the painted lady, that rival the monarch in their annual journeys. If you found this information surprising, you would be even more surprised to learn that there are several other butterfly globetrotters. Other insects capable of long range migrations are several species of dragonflies. There may be many others.

Let us look at a few more migratory butterflies.

Cloudless sulphur. © Lynette Schimming. Bugguide.net
Sulphurs are butterflies that range in color from lemony yellow to orange. The name refers to their color. One among them, the cloudless sulphur (Phoebis sennae), travels from Canada to Texas, Florida, and Mexico in the fall. It also lives in South America, as far south as Argentina. We don't know much about the migration of the cloudless sulphur, other than when going south in the fall, they move steadily and purposely, hardly stopping to eat. We know even less about the ones that live in South America, whether they travel much and whether they mix with the North American populations.

Common buckeye. © Beatriz Moisset
Another lovely vagabond is the common buckeye (Junonia coenia), so called for the distinctive spots on its wings. Not content with one pair of eyespots, it has three. Not visible when the wings are folded, they make quite a display when it decides to spread them. It must be a scary sight to a hungry bird, which may induce it to leave the morsel alone.

Common Buckeye. View of the underside. © Beatriz Moisset
When the monarch butterfly shows in large numbers in Cape May, NJ, every October and November, so does the common buckeye. I am just as happy to see one as the other. It lives year round in the southern states, as well as in Central America and Colombia. Apparently, some don't travel much; others get the urge to go north, as far as Canada. Their descendants head south in the fall. Once again, we don't know much more about its movements.


A gaggle of buckeyes takes a rest on their way south
  © Beatriz Moisset
It is curious to me that only one globetrotter, the monarch butterfly, has caught the public imagination, leading to numerous observations. Nowadays, we know quite a bit about its complicated trips north and south. I am just as eager to learn about other tiny organisms' urge to cover large distances that seem to exceed their capabilities. I hope this awakens your appetite for more information on all these adventurous little souls.

Friday, November 22, 2013

Globetrotting Butterflies



Red admiral (Vanessa atalanta) on snake root
© Beatriz Moisset
Name a lovely butterfly found throughout North America and also an intrepid traveler, capable of crossing the entire continent from north to south. You probably had the answer before I completed my question. The monarch is the best known butterfly in the United States. Its migration from Mexico to Canada and back, involving several generations and taking months each year, fascinates us all.


Painted lady (Vanessa cardui) on mountain mint
© 2013 Beatriz Moisset
Now, name another lovely butterfly just as widely distributed and also a remarkable migrant. Can you name just one? What about two? Now, what if these two butterflies could be seen in Africa, Europe and Asia in addition to North America? In those continents they would travel from Africa to Europe or from South Asia to farther north. The two species I refer to bear unusually pretty scientific names, Vanessa atalanta and Vanessa cardui. We know the first one as red admiral and the latter as painted lady.


Red admiral caterpillar feeding on nettle
© Beatriz Moisset
As we know, the monarch caterpillar feeds only on milkweeds. The Vanessa caterpillars also have some favorite food plants; however they can dine on members of several other plant families as well. The red admiral prefers nettles and the painted lady goes for thistles. In fact the scientific name cardui comes from cardus, which means thistle in Latin. I hope you have an assortment of native nettles and thistles in your garden for the benefit of these delightful visitors and their families. If you don’t, they can resort to other members of the aster, pea or mallow families.


Red admiral caterpillar
safe and sound inside a nettle leaf
© Beatriz Moisset

These two species of butterflies are just as beautiful and adventurous as the monarch, so their lack of popularity surprises me. Perhaps all they need is a little publicity. They are brightly colored in black, orange and white, and slightly smaller than monarchs. If there was a beauty contest I would probably vote for the gorgeous red admiral. I would also insist in calling it by its sweet scientific name, Vanessa atalanta.

I already mentioned that you can see them, at least part of the year in your area, wherever you live. You may have already noticed them in your wildlife garden. Perhaps you even thought you were seeing a monarch, a common mistake. I have watched them nectaring on asters, coneflowers, snakeroots and mountain mints among others.
Red admiral on cone flower. ©  Beatriz Moisset
We happen to know a lot more about the comings and goings of monarchs than of painted ladies and red admirals. Maybe this will change in the future because research continues. In fact, you can contribute your observations if you are interested in being a citizen scientist by participating in the Iowa State University program at the "Red Admiral and Painted Lady Research Site". In Europe the "Insect Migration & Ecology Lab" is also following the red admiral migration in that area.

American lady. © Beatriz Moisset
We know that they fly north in the spring and south in the fall. How far they go or whether some hunker down and spend the winter in colder areas is not known. Years ago it was thought that the ones that migrated to northern latitudes never made it back, just died without descendants; but that may not be the case. The migration of the painted lady in Europe is better studied. There, it is capable to fly in the fall all the way from England to North Africa, a deed as impressive as that of the monarch.

I hope you are as intrigued as I am about these globe trotting butterflies. This may inspire you to join the efforts to unravel the mystery of their migration and also provide habitat for them. Next year, enjoy your Vanessa butterflies that come to call.


Monarch butterfly (Danaus plexippus) for comparison
© Beatriz Moisset

References

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.


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 ofgenetically engineered crops on pesticide use in the U.S. -- the first sixteen years. Environmental Sciences Europe (2012)
Brower, L.P. Understanding and Misundersrtanding theMigration 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)




Saturday, October 5, 2013

When did "Common Milkweed" Become Common?

Monarch on common milkweed. © Beatriz Moisset. 2010

The prairies of this continent used to be rich in biodiversity before they were plowed under and turned into cropland. We can only guess at the structure of those lost plant communities by studying the remaining plots of prairie. A couple dozen species of milkweed (Asclepias) prospered in the Midwest two centuries ago, each adapted to its own habitat. Certain species preferred high moisture, others, drier spots. Some showed a preference for coarse, loose, damp, or undisturbed soils; still others did well on almost any soil type. Some needed more sunlight than others. A few survived drought or fire better than others.

Among this variety of habitat preferences, common milkweed, Asclepias syriaca, a "weedy" or pioneer species, does best in disturbed areas, patches that, for a variety of reasons, have lost their established vegetation. In a few years, it is displaced by other species when the ecological succession continues. Two hundred years ago, disturbed spots must have been rather uncommon. Everything changed when the prairie became farmland and was annually plowed. Many species of these plants lost ground under the new treatment. However, plowing created ideal conditions for the common milkweed. It can grow between rows of plantings and along edges, and its deep rhizomes, underground stems, allow it to survive year after year despite plowing. Is this when common milkweed earned its name?

For many years, farming practices in the Midwest continued to disrupt the land creating the conditions that this plant prefers. Farmers dislike this plant for its tenacity. It is said that farmers rejoice at the sight of big fat yellow and black caterpillars devouring the cursed weed. By now, you probably guessed that those caterpillars are monarchs.

USDA map of corn production

Monarch butterflies feed on most types of Asclepias, but Asclepias syriaca is by far their main food source. Perhaps, when the prairie became our breadbasket, it also became the monarch's breadbasket, who took advantage of the spreading weed.

In the meantime, all along the Eastern United States, forests were being cut down. A tree-covered area is not the right habitat for any types of milkweeds. When forests were cleared, the conditions favored by common milkweed emerged. Populations of monarchs must have grown along with the expansion of this plant.

If all this is true, and much of it may be just speculation, then these butterflies must have benefited from these man-made changes. We must ask ourselves: what were the monarch's populations like before the expansion of common milkweed numbers? Were they as abundant before the early 1800s as in recent times? What were the population sizes in their overwintering sites in Mexico? We became aware of the monarch butterfly migration in the past one hundred years. The whole story of their incredible trip to Mexico became known only in recent years. Curiously, no references to monarchs in Mexico can be found until 1890. By then, the transformation of the Midwest with its expansion of common milkweed was well underway. Were their numbers in Mexico so low before this time to escape notice?

Present day discussions about monarchs and their preferred food plant, common milkweed, seem to accept the numbers reported around the 1950s as the norm. Those were the highest numbers ever recorded, and it is assumed that these had remained the same for a long time, perhaps from the days when glaciers receded, tens of thousands of years ago. However, we must consider the possibility that milkweeds and monarchs were never as abundant as in the twentieth century; that this is largely a man-made phenomenon. The numbers of both, plant and butterfly have been going down steadily in recent years. Is the new normal similar to the old normal of hundreds of years ago?

Monarch caterpillar on common milkweed. © Beatriz Moisset. 2010


List of Articles

Beginners Guide to Pollinators and Other Flower Visitor

© Beatriz Moisset. 2013

Sunday, September 22, 2013

Official State Insects


Honey bee. © Beatriz Moisset
Did you know that most states have an official insect? Probably not. You may have heard of state birds and state flowers, or even state butterflies. But, who would have thought of state insects! Actually most states have an official insect, or, at least an official butterfly. Some even have both. Just for fun, try to imagine which insect you would select to represent your state. Take a few minutes before reading further or checking this complete list. Think harder; are you drawing a blank? I will tell you later my choice for the state of Pennsylvania.

If you picked the honey bee, you are in the majority. Seventeen states made the same decision, not a very imaginative one. That is almost half of all states with an official insect. Tennessee, not satisfied with two state insects, the firefly and the ladybug, added the honey bee as its official agricultural insect. Kentucky did the same.

The notion that the honey bee could represent a state surprises me because it isn't a native insect. Europeans introduced it to this continent in the 1600s. It is an agricultural species, not a member of the local wildlife. Tennessee and Kentucky seem to be the only ones that got it right when making it their official agricultural insect. It shouldn't be so hard to find a useful native insect to represent each state considering that there are thousands of them.

Monarch butterfly © Beatriz Moisset

Seven states have chosen the monarch butterfly; not surprising considering that the monarch is so well known and loved. Actually three of those states (Minnesota, Vermont and West Virginia) picked the monarch as their state butterfly, in addition to their official insect. I wonder which is truly well known: the butterfly itself or just its iconic image. Most people can't tell a monarch from one of its look-alikes, the queen, the soldier, or the viceroy butterflies. In fact, many see a fritillary and think it is a monarch despite clear differences in pattern and size. Kudos to Kentucky whose official butterfly is the Viceroy! They really know their insects.

Where this list of official state insects gets amusing is when the "insect" in question refers to dozens or even hundreds of related species. The ladybug has been selected by six states ignoring the fact that ladybugs, better called lady beetles, include around 500 species, not all charming or beneficial. Did you know that a few species eat plants, rather than insect pests? They are pests themselves, like the Mexican bean beetle and the alfalfa beetle. Also, did you know that a couple of dozens were introduced from other lands? North Dakota deserves congratulations for choosing the convergent lady beetle. They, too, know their insects.

Convergent lady beetle © Beatriz Moisset

In addition to North Dakota and Kentucky, a few other states show their knowledge of insects, for instance, Maryland with the Baltimore Checkerspot Butterfly (Euphydryas phaeton). This handsome creature well deserves its name because of its checkerboard pattern. South Carolina chose the Carolina mantis, another brilliant choice.


Carolina mantis. © Kaldari. Wikicommons
I promised to tell you my preference for the state of Pennsylvania. The state insect is the firefly, not bad; but with 150 species of fireflies, later on it was narrowed down to the species Pennsylvania Photuris (Photuris pensylvanica). Did you know that some fireflies are diurnal and have no light?


Ellychnia corrusca, winter firefly, diurnal or active during the day. © Beatriz Moisset
I would choose a beautiful little metallic green bee. It is small and goes easily unnoticed to the point that it doesn't even have a common name. Its scientific name, Augochlora pura, means "magnificent pure green bee." The public may not know about this little beauty, but it can be quite common. Mountain mint flowers can act as magnets for this hard-working pollen gatherer. Recently I saw as many as a hundred bees on each bush of mountain mint in a garden with more than a dozen such plants.

The magnificent pure green bee. © Beatriz Moisset

Would you have any suggestions for the official insect of your own state?

List of articles


© Beatriz Moisset. 2013