A Butterfly's Flashy Colors

Male monarch butterfly

(Danaus plexippus)

© Beatriz Moisset

People fall in love with monarch butterflies because of their bright black and orange pattern. Many monarch enthusiasts are busily raising these butterflies in their gardens and homes. Some have become real experts on these insects and their life cycle. They are profoundly distressed when something goes wrong and one of them fails to make it to adulthood and freedom.

Some particularly despise butterfly enemies. If they catch a predatory bug sucking the juices out of an unfortunate caterpillar, they rage against the predator. Parasitic flies also generate a violent reaction. It is hard to believe, but monarchs owe their beautiful colors to their enemies. Here is the whole story.

Monarchs feed on milkweeds. They are dependent on these plants and cannot digest others. Milkweeds, like many plants produce powerful toxins as a defense against herbivores. These toxins go by the name of cardiac glycosides because they cause heart paralysis. As an additional defense they produce a sticky milky-looking substance that gives them their name. The milk is present in most tissues of the plant and bleed easily, gumming the yaws of a hungry attacker that tries to eat the milkweed plant.

This is enough to deter most plant eaters, but monarch butterfly caterpillars and more than a dozen other creatures have learned to overcome such defenses. Earlier milkweeds, millions of years ago, had milder forms of the toxins. That was all they needed, but some early insects learned to tolerate them and proceeded undeterred to feed from these plants. Thus, milkweeds were forced to create stronger and stronger glycosides and, in turn their feeders found ways to deal with the more powerful toxins. Arms races of this type abound in the natural world.

The monarch butterfly adapted itself to these plants by several means: it avoided the most toxic plants or their most toxic parts; it developed enzymes that could deal with the toxins, or it stored them in parts of its body where they could do no harm. In doing all this, it became dependent on milkweeds. This dependence added a bonus to the monarch's survival, its body is loaded with bad tasting, toxic glycosides, which constitute a powerful defense against its enemies. Most predators avoid the toxic butterfly. However a handful of these predators developed ways to handle the monarch's toxins by eating only the parts with less glycosides, or by evolving enzymes that neutralize these toxic substances. This is another case of the arms race at work.

This is not all. The monarch advertises its toxicity and horrid taste to possible predators. Birds who never saw a monarch butterfly before eagerly take a bite of one. The immediate reaction is that of disgust, spitting up the morsel and shaking their heads or rubbing their beaks in an effort to remove the unpleasantness. They have no trouble remembering the strikingly colored creature and its bad taste. They are not likely to repeat such experience.

Large milkweed bugs (Oncopeltus fasciatus)

on milkweed seed pod. Adults and nymphs

© Beatriz Moisset

Milkweed beetle (Tetraopes tetrophthalmus)

© Beatriz Moisset

The monarch butterfly is not the only animal that advertises its bad taste by sporting bright colors. Other insects that feed on milkweeds, like the milkweed beetles and milkweed bugs, are also colorful, in red and black; we can be sure that they are just as bad tasting. Similar cases abound in nature, not only insects but also vertebrates. Most frogs are green or have brown spots, colors that blend well with vegetation and help them remain unnoticed. The so-called poison dart frogs are the exception. Their backs are glossy red. The name tells you that these frogs produce powerful toxins, so much so, that native peoples use them to smear the tip of their darts in order to make them more lethal.

Dendrobatid frog, Peru

© Tim Ross. Wikicommons

Polished Lady Beetle (Cycloneda munda)

Ladybeetles are another example of

brightly colored bad tasting insects

© Beatriz Moisset

So, as I said at the start, a monarch's lovely colors are due to a constant battle with their enemies. In a perfect world (perfect for monarchs, that is) these butterflies wouldn't need to be loaded with toxins, nor would they need to tell their enemies to keep away. In such a perfect world, monarchs would have plain colors. Is this what we want?

The monarch caterpillar is also toxic

and also has bright warning colors

© Beatriz Moisset

Further readings:

List of articles
Monarchs and their Enemies
The Monarch's Breadbasket

Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2017

Butterfly Pollination

Fritillary butterfly on butterfly weed

© Beatriz Moisset

When you mention pollinators to people, the immediate answer is: bees and butterflies. Bees, yes, the 20,000 species or so do a huge percentage of pollination. Some plants depend entirely on bees for this function. However, when it comes to butterflies, a different story emerges. Other insects, such as flies, wasps and moths are known to do a respectable amount of pollination, probably far more than butterflies do. Some of the mentioned insects are indispensable to certain plants, such as figs, cacao and yucca. Some flies are used in farming.

A great variety of pollinators and flower visitors

© Beatriz Moisset

Butterflies visit flowers but that alone doesn't make them good pollinators. They are easily noticed because of their large size and color. That is why the general public takes notice, but biologists have not paid a lot of attention to the role of butterflies as pollinators. So it would be nice to know a little more about them and how much credit they deserve.

Bumble bee on Helenium

© Beatriz Moisset

Let us compare a bumble bee with a butterfly in a field full of ragworts, for instance. Ragworts are pretty, daisy-like, rather weedy yellow flowers. A bumble bee hastily gathers pollen and nectar and moves on quickly from blossom to blossom in one plant, next it moves on to the next plant and the next, without wasting any time. It finally rushes home to feed a hungry brood with the gathered supplies. A butterfly, on the other hand, is free from family obligations. It only needs some nectar to quench its thirst so it lazily sits on a flower, unfolds its long tongue and drinks at leisure. It takes off and wanders away apparently aimlessly. Farther down it may finally land on another flower and drink some more nectar. Later on it may visit another plant a good distance from the previous ones and so on.

It is obvious that the bumble bee performs more pollination because of its diligent behavior. However, the butterfly is doing something important by transporting pollen to plants that are a good distance from each other. It is performing cross pollination and ensuring a good mixing of genes. Plants benefit from this increase in genetic diversity. Furthermore, recently researchers have learned that the pollen, stuck to a butterfly's long tongue, stays fresh for a good time and ensures this valuable pollination at a distance.

Red banded hair streak butterfly on Helenium

© Beatriz Moisset

Butterflies seem to do more pollination in tropical regions than in temperate ones. Butterflies and hummingbirds are good at finding nectar inside long-necked or trumpet shaped flowers. They are attracted by red flowers, which are rather common in the tropics. Bees are color blind to the red color and prefer yellow and blue or purple ones. Butterflies, like hummingbirds, have a good vision for the red color.

A number of flowers are completely dependent on butterflies for pollination. Some South African orchids fall in this category. Another flower dependent on a butterfly for pollination is a member of the pea family, the Peacock Flower that grows in the Caribbean.

Orange sulphur butterfly on asters

Notice the long tongue

© Beatriz Moisset

In summary, butterflies, while not the most efficient pollinators, are important, even essential, in some instances.

Also see:
Pollinator Foraging Behavior and Gene Dispersal in Senecio (Compositae) (contribute to cross pollination, farther distances than bumble bees)

Zebra Longwing Butterfly (Heliconius charitonia)

Fritillary: A Pretty Butterfly and a Good Pollinator

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2017

It is Cold Outside. Where did all the Butterflies Go?

Great spangled fritillary (Speyeria cybele)
Its tiny caterpillars will survive the winter
© Beatriz Moisset

Winter has arrived. What happened to all the six legged creatures we saw in summer? Where did the crawling, scuttling, flitting, buzzing multitudes go? Those of us who live in temperate and colder climates notice the disappearance of practically all insects when the weather gets cold. We are talking about the ones that live outdoors, not about those aggravating creatures that turn our houses into their homes.

Red admiral (Vanessa atalanta), one of the travelers
© Beatriz Moisset

Some of our favorite butterflies illustrate three different winter strategies.
1. Most adult butterflies die, the next generation lives on
2. A few migrate to warmer climates
3. Even fewer hunker down and wait for spring to come

Read the whole article

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2016
 

The Most Invasive Butterfly: Cabbage White Butterfly (Pieris rapae)

A flock of cabbage butterflies

(Pieris rapae)

© Beatriz Moisset

If you see a pretty white butterfly, more likely than not you are seeing an invasive species that was accidentally introduced to this country and to many other parts of the world more than a century ago.

The cabbage white butterfly is noticeable, pretty and soft, it visits gardens, meadows, you name it. Perhaps the only places beyond its reach are higher elevations. It starts flying early in the season and produces several generations throughout the summer and fall. No wonder it is seen so often.

Cabbage butterfly

(Pieris rapae)

© Beatriz Moisset

The name refers to the plant its caterpillar feeds on, cabbage. It also eats other members of the mustard family, such as cauliflower and kale and it is regarded as a serious pest. It also feeds on a number of wild, non cultivated mustards, including the invasive garlic mustard.

The cabbage butterfly is related to a group of native butterflies, the so called whites, yellows and sulphurs or family Pieridae. Their colors, as the names indicate are either whites or yellows. The caterpillars of most of them also feed on plants of the mustard family. A total of 58 species lived in North America before the arrival of this newcomer. Nowadays, the cabbage white is seen as often as all of them combined. One wonders if the growing numbers of this invader are having an impact on the populations of native Pieridae butterflies.

Orange sulphur butterfly

(Colias)

© Beatriz Moisset

In summary, it has the qualities of so called weedy species, with high rates of reproduction, very adaptable to different food sources and a variety of habitats.

Virginia white butterfly

Pieris virginiensis

© Beatriz Moisset

The cabbage butterfly reminds me of several insect species that were brought to this country intentionally or accidentally and proceeded to become incredibly widespread in a relatively short time. Now, some of them are more abundant than any of their native relatives. Here are a few examples: the Asian ladybug, the Chinese mantis, the giant resin bee, the European paper wasp, the drone fly, and the brown marmorated stink bug.

David Quammen, a distinguished journalist who has written extensively on conservation and ecology, has coined the term “Planet of Weeds,” meaning that the ecological changes caused by humans are having a severe impact on the flora and fauna of the entire planet. We had transported unprecedented numbers of species of plants, animals and bacteria beyond their natural distributions with the consequence that many of them have become established in their new surroundings. Not only do they become established but spread out from the original place of introduction, thus deserving the name of invasive species. They impact the local flora and fauna, bringing up the extinction of many species. In this way we are causing a mass extinction, comparable to some of the most serious mass extinctions of the past.

Specialist species are more vulnerable to extinction. The ones that have the best chance for survival are the weedy ones, the adaptable generalists. We are creating an impoverished world, gradually losing precious biological diversity, biodiversity for short. It may take millions of years for this biodiversity to raise back to the present levels. The human species may never see that.

Drone fly (Eristalis tenax)

One of many introduced, widespread species

© Beatriz Moisset

List of articles

Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2016

Beginners Guide to Pollinators

The Amazon edition of Beginners Guide to Pollinators and Other Flower Visitors came out just in time for Pollinator Week, 2015.

Sample pages below:

Mass Appeal and Pollination

Some of the many visitors to goldenrod.  © Beatriz Moisset

Many flowers are not particularly selective; they welcome all kinds of visitors. They are wide open, easily accessible, thus many insects can reach the nectar and/or pollen regardless of whether their tongues are long or short. Such flowers provide a convenient standing platform to save their visitors the inconvenience of hovering over them. Their structure is simple so the pollinators don’t need to figure out how to open them in order to reach their rewards. Goldenrod is a fine example.

Monarch butterfly on goldenrod. © Beatriz Moisset

 I have spent countless happy hours observing goldenrods and photographing their numerous visitors. The one most common in my area is the Canada goldenrod. Several hundreds of species visit their flowers. Bear in mind that not all flower visitors qualify as pollinators. Some are not efficient at carrying pollen, or sit in one place for a long time and never make it to another plant. Such is the case of ambush bugs, whose only concern is to snare hapless pollinators to make a meal out of them. If you are interested on photographing and identifying pollinators this is a good place to start.

Metallic green bee. © Beatriz Moisset

 This plant blooms in the fall. It often gets blamed for allergies, but the real culprit is another plant that grows close by, sometimes intermingled with goldenrods, ragweed. Its flowers are inconspicuous because its pollen gets carried by the wind, not by officious pollinators. This is how it gets into our nostrils and causes our suffering. The much maligned goldenrods have larger, heavier and stickier grains of pollen that cannot get airborne and that require help from visitors.

Two states, Kentucky and Nebraska, have the goldenrod as their state flower. It is not clear which species of goldenrod Kentucky picked, but it is likely the Canada goldenrod (Solidago altissima). Nebraska’s choice is clearer, the giant goldenrod (Solidago gigantea). South Carolina, not satisfied with a state flower, also has a state wildflower. It is the Canada goldenrod. It is worth mentioning that Delaware has a state herb, the anise-scented or sweet goldenrod (Solidago odora).

Bumble bee on sunflower. © Beatriz Moisset

Coreopsis. © Beatriz Moisset

 Two other state flowers also have mass appeal. Like goldenrod, they are members of the daisy or aster family, easy to access by different kinds of visitors. They are Kansas’ sunflower (Helianthus annuus) and Maryland’s Black-eyed Susan (Rudbeckia hirta). It is worth mentioning here that two states, Florida and Mississippi, chose the tickseed (Coreopsis spp.) as a state wildflower in addition to their official state flowers, the orange blossom and the magnolia, respectively.

Kentucky: Goldenrod

Nebraska: Goldenrod

South Carolina (wildflower): Goldenrod

Delaware (herb): Goldenrod

Kansas: Sunflower

Maryland: Black-eyed Susan

Florida (wildflower): Coreopsis

Mississippi (wildflower): Coreopsis

The indiscriminate pollination strategy represented by all these flowers has advantages and also disadvantages. They suffer no shortage of pollinators. If one species is doing poorly one year, as it often happens in the insect world, there are plenty more to fill in the deficiency. However, sometimes too much of a good thing can be bad. Some of these non-specialized pollinators may be visiting a variety of flowers instead of being faithful to just one species so they end up carrying the wrong kind of pollen in such cases.

Blossoms with such mass appeal give me the opportunity to introduce the reader to the main groups of pollinators. They are all well represented on these mass appeal flowers.

Andrenidae bee © Beatriz Moisset

Bumble bee. © Beatriz Moisset

 Let us start by getting acquainted with bees. More than 80 species have been seen on goldenrods. Some of them deserve mention. Bumble bees are larger than other bees, plump, dark with yellow or white stripes, and hairy. Metallic green bees are small and gorgeously colored. They may escape notice if one isn’t very observant; but it is easy to become captivated by their shiny aspect. Mason bees and leaf-cutting bees carry pollen on their underbelly, unlike most other bees that carry it on their hind legs. Most of them are dark, nearly black and about the size of honey bees or slightly smaller.

Wasp. © Beatriz Moisset

 Wasps are related to bees and sometimes people confuse them. Most wasps are less hairy than bees and have narrow waists. They raise their young on a diet of insects or spiders, instead of pollen and nectar as bees do. Adult wasps need nectar to fuel their flight. Thus, they are frequent flower visitors and accomplish some pollination.

Syrphid fly. © Beatriz Moisset

Syrphid fly. © Beatriz Moisset

Many types of flies, including mosquitoes and gnats visit flowers to feed on their nectar. Some are good pollinators. The Syrphid flies, also called flower flies, are among the most assiduous flower visitors. Most of them mimic bees or wasps and are frequently mistaken for them. However, they don’t sting and there is no reason to fear them.

Buckeye butterfly on goldenrod. © Beatriz Moisset

Pyrausta moth on sunflower. © Beatriz Moisset

Yellow collared scape moth on goldenrod. © Beatriz Moisset

 Butterflies, skippers and moths have extremely long tongues that they can use like drinking straws when sipping nectar. They favor long necked flowers and carry pollen from one to another.

Polished lady beetle on sunflower. © Beatriz Moisset

Soldier beetle on goldenrod. © Beatriz Moisset

Finally, beetles, although not well specialized for pollination, are also capable of doing so in special circumstances. We already mentioned magnolia pollination by beetles. They also visit other flowers and can do a reasonably good job in some cases.

In the following chapters we’ll see flowers that have chosen a different strategy. They are pickier or more selective. Some attract a handful of visitors; a few go to the extreme of having relationships with only one species of pollinators.

Pollinators of Official State Flowers

References

Goldenrods and Asters: Great PollinatorPlants for the Fall. Penn State Extension

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2015

Beginners Guide to Pollinators

Read the review by Kathy Keatley Garvey at the Bug Squad website, For Beginners, a Guide to Pollinators

So many flowers.  So many pollinators. So many floral visitors.
On every field trip, we see something new and different.
With so much interest in pollinators, it's good to see that biologist Beatriz Moisset has written a downloadable book, "A Beginners Guide to Pollinators and other Flower Visitors." It's meant for young adults and beginners.

Beginners Guide to Pollinators and other Flower Visitors available at:

Barnes & Noble
Lulu.com

iTunes
Amazon 

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.

List of Articles
Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 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.

Common Buckeye (Distribution)
Cloudless Sulphur (Migration and Overwintering)

Globetrotting Butterflies
Globetrotting Skippers

List of Articles
Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 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

The Milkweed Community

List of Articles

Beginners Guide to Pollinators and Other Flower Visitor

© Beatriz Moisset. 2013