Insect of the Week: the American Lady

Adapted from page 49 of Butterfly Gardening:

Some American Ladies overwinter as adults in northern climates, so sightings of this wide-ranging butterfly often begin early in spring. The actual northern limit of American Lady overwintering has not been firmly established, and questions persist regarding the life stage in which they overwinter. Some reports suggest that only adults overwinter, while others indicate that both adults and chrysalides overwinter. Additionally, American Ladies are migrants, so as the weather warms each spring, butterflies from the south move northward, laying eggs as they progress. However, one fact is clear; American Ladies are widespread and common in gardens!

This patch of Parlin’s pussytoes had only recently been planted before an American Lady stopped by to lay eggs.
Photo credit: Jan Dixon.

To the nascent butterfly watcher, American Ladies look quite similar to Painted Ladies, or in the western United States, to West Coast Ladies as well. Painted Lady, with more than 100 recorded host plants, needs no special planting plans, and West Coast Lady caterpillars accept a variety of plant, some of which are weeds, but if you wish to watch the life cycle of American Lady, you will need to provide its caterpillar food plants. These are native plants that are lovely to include in gardens—western pearly everlasting, some of the species of pussytoes, and the similar but rather unattractively named cudweed.

Pussytoes are a group of plants that are easy to incorporate into gardens or wild plantings—their cultural needs are not great, and in fact they can be used as a ground cover in dry areas with poor soil. Approximately 40 different species of pussytoes are native in the United States, although many are not commonly for sale. Native-plant nurseries usually carry at least one species, with shale barren pussytoes, rosy pussytoes, and the oddly named woman’s tobacco being fairly common.

Butterfly Gardening: The North American Butterfly Association Guide
By Jane Hurwitz

Butterfly gardening creates habitats that support butterflies, connecting us with some of the most beautiful creatures in the natural world and bringing new levels of excitement and joy to gardening. In this engaging and accessible guide, lavishly illustrated with more than two hundred color photographs and maps, accomplished butterfly gardener Jane Hurwitz presents essential information on how to choose and cultivate plants that will attract a range of butterflies to your garden and help sustain all the stages of their life cycles.

An indispensable resource for aspiring and experienced butterfly gardeners alike, Butterfly Gardening is the most gardener-friendly source on the subject, covering all the practical details needed to create a vibrant garden habitat that fosters butterflies. It tells you which plants support which butterflies, depending on where you live; it describes what different butterflies require in the garden over the course of their lives; and it shows you how to become a butterfly watcher as well as a butterfly gardener.

While predominantly recommending regionally native plants, the book includes information on non-native plants. It also features informative interviews with experienced butterfly gardeners from across the United States. These gardeners share a wealth of information on plants and practices to draw butterflies to all kinds of gardens–from small suburban gardens to community plots and larger expanses.

Whether you are a gardener who wants to see more butterflies in your garden, a butterfly enthusiast who wants to bring that passion to the garden, or someone who simply wants to make their garden or yard friendlier to Monarchs or other butterflies, this is a must-have guide.

  • An essential guide for aspiring and experienced butterfly gardeners
  • Encourages readers to rethink gardening choices to support butterflies and other pollinators in their gardens and communities
  • Introduces gardeners to butterfly watching
  • Includes regional lists of plant species that are time-proven to help sustain butterflies and their caterpillars
  • Features informative interviews with expert butterfly gardeners from across the United States

 

 

Insect of the Week: Question Marks

Adapted from page 46 of Butterfly Gardening:

Butterfly guides describe the Question Mark as a butterfly found in and at the edges of woodlands, and specifically moist woodlands. Even if your garden does not happen to be ideally situated next to a bucolic, damp, woody wonderland, Question Marks can still be drawn to parks and yards if their caterpillar foods—elms, hackberries, or nettles—are readily available. Since nettles are renowned for stinging, and elms (still susceptible to Dutch elm disease) are not commercially available, you will probably want to check native-plant nurseries for one of the many species of hackberry tree. As a bonus, if you live within their range, a hackberry may also reward you by attracting the less-common butterflies Hackberry and Tawny emperors, Empress Leilia, or American Snout.

A Question Mark (left) and a two Hackberry Emperors share a juicy watermelon slice. Photo credit: Mike Wetherford.

Question Marks rarely visit flowers for nectar; instead, they gain energy by drinking liquids from rotting fruit, tree sap, and even animal droppings. An interesting way to see Question Marks in a garden setting is to set up a butter y feeder, which can be as simple as a slice of watermelon set out on a plate where animals and people will not disturb it. Other gardeners create more elaborate arrangements for butterfly feeding.

Butterfly Gardening: The North American Butterfly Association Guide
By Jane Hurwitz

Butterfly gardening creates habitats that support butterflies, connecting us with some of the most beautiful creatures in the natural world and bringing new levels of excitement and joy to gardening. In this engaging and accessible guide, lavishly illustrated with more than two hundred color photographs and maps, accomplished butterfly gardener Jane Hurwitz presents essential information on how to choose and cultivate plants that will attract a range of butterflies to your garden and help sustain all the stages of their life cycles.

An indispensable resource for aspiring and experienced butterfly gardeners alike, Butterfly Gardening is the most gardener-friendly source on the subject, covering all the practical details needed to create a vibrant garden habitat that fosters butterflies. It tells you which plants support which butterflies, depending on where you live; it describes what different butterflies require in the garden over the course of their lives; and it shows you how to become a butterfly watcher as well as a butterfly gardener.

While predominantly recommending regionally native plants, the book includes information on non-native plants. It also features informative interviews with experienced butterfly gardeners from across the United States. These gardeners share a wealth of information on plants and practices to draw butterflies to all kinds of gardens–from small suburban gardens to community plots and larger expanses.

Whether you are a gardener who wants to see more butterflies in your garden, a butterfly enthusiast who wants to bring that passion to the garden, or someone who simply wants to make their garden or yard friendlier to Monarchs or other butterflies, this is a must-have guide.

  • An essential guide for aspiring and experienced butterfly gardeners
  • Encourages readers to rethink gardening choices to support butterflies and other pollinators in their gardens and communities
  • Introduces gardeners to butterfly watching
  • Includes regional lists of plant species that are time-proven to help sustain butterflies and their caterpillars
  • Features informative interviews with expert butterfly gardeners from across the United States

 

Insect of the Week: Skipper Butterflies

Adapted from page 55-58 of Butterfly Gardening:

Skippers are small, fast-flying butterflies that many people initially think are moths. Skippers have relatively thick bodies and short wings and their flight is often characterized as fast, darting, or jerky—obviously thought by some to be a “skipping” motion.

The vast majority of the skippers in the United States lack colorful scales and so tend to be orange, white, brown, black, or gray. Many skippers are smaller than the familiar and colorful garden visitors that initially come to mind when thinking “butterfly,” but once you notice skippers, you will appreciate the motion and activity they add to the garden.

A Common-Checkered Skipper in a typical spread-wing stance. Photo credit: Alan Schmierer.

Two subfamilies of skippers visit gardens in the United States: spreadwing skippers and grass-skippers. The spreadwing skippers generally perch with both forewings and hindwings open flat, while grass-skippers sit perkily with all wings closed or with the forewings open at a 45-degree angle to the flat hindwings. It is possible to get a peek at the open wings of a grass-skipper when it basks in the sun, a common behavior. Grass-skippers are also equipped with exceedingly long tongues, allowing them to nectar at many types of flowers.

Common Checkered-Skipper is likely the most widespread skipper in the United States, and its caterpillars feed on plants in the Mallow Family. This spreadwing skipper inhabits many different settings, from prairies and meadows to yards and pastures. Open, sunny, often disturbed places are what Common Checkered-Skippers prefer.

Butterfly Gardening: The North American Butterfly Association Guide
By Jane Hurwitz

Butterfly gardening creates habitats that support butterflies, connecting us with some of the most beautiful creatures in the natural world and bringing new levels of excitement and joy to gardening. In this engaging and accessible guide, lavishly illustrated with more than two hundred color photographs and maps, accomplished butterfly gardener Jane Hurwitz presents essential information on how to choose and cultivate plants that will attract a range of butterflies to your garden and help sustain all the stages of their life cycles.

An indispensable resource for aspiring and experienced butterfly gardeners alike, Butterfly Gardening is the most gardener-friendly source on the subject, covering all the practical details needed to create a vibrant garden habitat that fosters butterflies. It tells you which plants support which butterflies, depending on where you live; it describes what different butterflies require in the garden over the course of their lives; and it shows you how to become a butterfly watcher as well as a butterfly gardener.

While predominantly recommending regionally native plants, the book includes information on non-native plants. It also features informative interviews with experienced butterfly gardeners from across the United States. These gardeners share a wealth of information on plants and practices to draw butterflies to all kinds of gardens–from small suburban gardens to community plots and larger expanses.

Whether you are a gardener who wants to see more butterflies in your garden, a butterfly enthusiast who wants to bring that passion to the garden, or someone who simply wants to make their garden or yard friendlier to Monarchs or other butterflies, this is a must-have guide.

  • An essential guide for aspiring and experienced butterfly gardeners
  • Encourages readers to rethink gardening choices to support butterflies and other pollinators in their gardens and communities
  • Introduces gardeners to butterfly watching
  • Includes regional lists of plant species that are time-proven to help sustain butterflies and their caterpillars
  • Features informative interviews with expert butterfly gardeners from across the United States

 

Insect of the Week: the Great Spangled Fritillary

Adapted from pages 85 to 87 of Butterfly Gardening:

The Great Spangled Fritillary is a large, showy butterfly found throughout a large section of the United States from southern Canada down to northern California on the western half of the continent, with the range extending down across the country to North Carolina on the East Coast. Within its range, the Great Spangled Fritillary can be considered a common garden butterfly that is on the wing during the summer months and through the early fall.

Violets are the only plant that Great Spangled Fritillary caterpillars will eat. Great Spangled Fritillaries do not care whether the violet flowers are blue, yellow, or white, though it does matter to egg-laying butterflies that the violets are native. African “violets,” which are grown as houseplants, and pansies, which are sold at garden centers as outdoor bedding plants, are not suitable for Great Spangled Fritillary caterpillars. Since most violets spread enthusiastically, you may regard them as weeds or wildflowers, but native violets are the kind needed to feed Great Spangled Fritillaries as well as a number of other fritillary species that have smaller ranges.

A Great Sprangled Fritillary laying eggs near a violet. Photo credit: Jane Hurwitz

Butterflies bearing the common name “fritillary” can be confusing; since they all share a name, one could conclude that they all belong to the same genus, and therefore share similar characteristics. But things are not that tidy in the butterfly world, or in the gardening world either, and the fritillaries mentioned so far are actually all a bit different.

Great Spangled Fritillary belongs to the genus Speyeria. They have one brood per year and their caterpillars eat only violets. Hosting Great Spangled Fritillaries requires gardeners to hold off on vigorous flowerbed cleaning in the fall. By leaving leaf litter undisturbed surrounding violets, gardeners preserve caterpillar overwintering habitat, ensuring that any unseen caterpillars are able to remain near violets and complete their life cycle. Since Great Spangled Fritillary produces only one generation per year, if your yard is cleared each fall and spring by landscape crews, or by overenthusiastic family members sent outside on a fine fall day, the potential to lose overwintering caterpillars is high.

 

Butterfly Gardening: The North American Butterfly Association Guide
By Jane Hurwitz

Butterfly gardening creates habitats that support butterflies, connecting us with some of the most beautiful creatures in the natural world and bringing new levels of excitement and joy to gardening. In this engaging and accessible guide, lavishly illustrated with more than two hundred color photographs and maps, accomplished butterfly gardener Jane Hurwitz presents essential information on how to choose and cultivate plants that will attract a range of butterflies to your garden and help sustain all the stages of their life cycles.

An indispensable resource for aspiring and experienced butterfly gardeners alike, Butterfly Gardening is the most gardener-friendly source on the subject, covering all the practical details needed to create a vibrant garden habitat that fosters butterflies. It tells you which plants support which butterflies, depending on where you live; it describes what different butterflies require in the garden over the course of their lives; and it shows you how to become a butterfly watcher as well as a butterfly gardener.

While predominantly recommending regionally native plants, the book includes information on non-native plants. It also features informative interviews with experienced butterfly gardeners from across the United States. These gardeners share a wealth of information on plants and practices to draw butterflies to all kinds of gardens–from small suburban gardens to community plots and larger expanses.

Whether you are a gardener who wants to see more butterflies in your garden, a butterfly enthusiast who wants to bring that passion to the garden, or someone who simply wants to make their garden or yard friendlier to Monarchs or other butterflies, this is a must-have guide.

  • An essential guide for aspiring and experienced butterfly gardeners
  • Encourages readers to rethink gardening choices to support butterflies and other pollinators in their gardens and communities
  • Introduces gardeners to butterfly watching
  • Includes regional lists of plant species that are time-proven to help sustain butterflies and their caterpillars
  • Features informative interviews with expert butterfly gardeners from across the United States

 

Jane Hurwitz on Butterfly Gardening

Butterflies are regarded by many as canaries in our ecological coal mine: they provide visual signals indicating the relative health and diversity of a habitat. Improving our local fragmented and degraded habitats in order to promote butterflies may seem like an onerous task, but in Butterfly Gardening: The North American Butterfly Association Guide, Jane Hurwitz presents simple steps to create more vibrant and dynamic environments that encourage wild butterflies to flourish—and provide gardeners of all levels with inspiration and pleasure.

Why did you write this book?

I am a life-long gardener who has had the good fortune to work for an organization that actively promotes gardening for butterflies. During the years I directed the North American Butterfly Association’s Butterfly Garden and Habitat Program,  I was exposed to a wealth of information on butterfly gardening that changed the way I view all aspects of gardening. A large part of my work with the program involved daily communication with people of all skill levels concerning their NABA certified gardens. In fact, the second half of the book revolves around specific butterfly gardeners living in different regions of the United States; there is so much to be learned from other gardeners regardless of their location or garden size.

Writing this book allowed me to explore the connection between how we take care of our landscapes, whether our private gardens or public spaces, and how those choices impact butterflies. Very little is static in a garden, a fact that is accentuated when butterflies—or any insects, for that matter—become part of the garden’s focus. Butterfly gardening is a gardening method that allows the interplay between the natural world and human-made habitats to expand in ways that allow wildlife to flourish. Learning the interconnections between plants and butterflies is fascinating and works as a catalyst to deepen our connection to our natural surroundings. The creation of habitats for butterflies is an ongoing process, not a fixed point that will ever be perfectly attained; as such, butterfly gardening provides an open ended opportunity for constant experimentation and learning.

Who is this book for?

Anyone with an interest in butterflies and gardening—even if they’re only mildly curious! Gardening books are often quite prescriptive, providing chapter after chapter on how to grow specific plants or how to achieve a particular garden style. Butterfly Gardening takes a more flexible approach, imparting basic information on butterfly and plant biology, butterfly watching, and plant selection in an accessible way that allows the reader to make their own informed choices on how best to create a habitat for butterflies within the constraints of their location and budget. Whether one’s focus is on creating habitat for monarchs, installing a school garden, or simply making a suburban yard more butterfly-friendly, once equipped with the essential information it is easy to implement changes that will lure these beautiful and fascinating creatures into our lives.

What are some of the first steps in creating a great butterfly garden?

Eliminating the use of pesticides, particularly those in the class of insecticides known as neonicotinoids, is the first item on any butterfly gardening checklist. Of course, there may need to be exceptions; if my home has termites, for example, I am probably going to need to use pesticides, but as a general rule they are best avoided. In fact, taking pesticides out of our garden toolkits is one of the very few things we must do in order to provide a habitat for butterflies.

Identifying the butterflies that are common to your locale and learning their names would be a second step to consider. There are many ways to accomplish this; some people start with a butterfly guide book and work from their own observations, while others find information through local sources such as nature centers, NABA chapters, or the Extension Service.

Learning the names of butterflies will enable you to communicate better with other butterfly gardeners and will also inform you about which caterpillar food plants to install. Many butterfly gardeners, however, skip this step, at least in the early stages. For many, butterfly gardening begins with the plants (and there are so many good ones!); rather than identify possible butterfly visitors to their garden and plan specifically for that group, they jump right into planting nectar sources, and see what comes to visit. As I emphasize throughout the book, there are no rules about how to start or organize a butterfly garden, but most gardeners do eventually become interested in naming their butterfly visitors and learning about their life cycles.

What would you say is the benefit of butterfly gardening?

A garden represents different things to different people. By using the methods detailed in Butterfly Gardening, a layer of ecological relevance can be added to a pleasurable and revitalizing activity. We can make our gardens a refuge for butterflies as well as ourselves.

 

Jane Hurwitz  is the editor of Butterfly Gardener magazine and the former director of the Butterfly Garden and Habitat Program for the North American Butterfly Association. She lives in northern New Jersey.

Anurag Agrawal: Monarch butterflies—out of sight, but not out of mind!

By Anurag Agrawal

1

The annual migratory calendar for monarch butterflies in eastern North America.

As winter approaches, monarch butterflies are not in sight for most Americans. Beginning in the fall, hundreds of millions of butterflies east of the Rocky Mountains oriented south and began their migration. And indeed the story of how they navigate is truly remarkable: the little insect uses a sun compass that is adjustable depending on the time of day to find its way. Details of the migration and much more are in Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and their Remarkable Story of Coevolution. And 2017 was a spectacular fall season for monarch butterflies. As far as most monarch biologists can remember, this was perhaps the biggest summer season on record, with monarchs in epic numbers congregating and flying south.

2

Southward migrating monarchs in Ontario during autumn. Although monarchs are usually dispersed in the summer, as the fall migration takes hold, butterflies congregate in larger clusters.

As the holiday season approaches, it is useful to keep in to keep in mind where monarchs are and what they are doing.  Cool and concentrated, they huddle en masse for nearly five months.  Will the numbers of butterflies overwintering in Mexico this year show a rebound from their precipitous decline?  If the migration was successful, yes, we all expect (hope!) the numbers to be up.  But only time will tell, as the official numbers are typically announced each February by World Wildlife Fund Mexico.  The monitoring of these unimaginable aggregations of butterflies has been a critical piece in the conservation puzzle for monarchs.

3

The state license plate in Michoacán State, Mexico.

In November around the Day of the Dead and leading to American Thanksgiving, monarchs arrive to their overwintering grounds in the highlands Michoacán, Mexico. And legend has it that the butterflies are the returning souls of loved ones. They form clusters that are so dense, they weigh down the Oyamel Fir trees they inhabit above 10,000 feet of elevation in these exquisite sites. The sites are terribly small, with all of them fitting into area smaller than New York City.

4

A congregation of monarchs within the Monarch Butterfly Biosphere Reserve, a UNESCO World Heritage Site. Most wings are closed, but look for the orange spots of open butterfly wings.

But before 1975, there was no conservation conversation about monarchs, because scientists simply did not know where monarchs went in the winter (of course native Mexicans of the region have known for centuries).  More importantly, we didn’t know how restricted and sensitive their overwintering sites are. The story of how the monarchs were found is too lengthy to recount here, but it is an astonishing story. In short, Professor Urquhart from the University of Toronto was hot on the trail, and knew that they flew south into Mexico during the fall.  Nora and Fred Urquhart marshaled a citizen science campaign that included a massive effort to engage folks far and wide in the search for the overwintering grounds.  In fact, in 1973, they wrote an article in an English language newspaper in Mexico City requesting help in finding the monarch overwintering sites.

5

6

I obtained this reproduction of the original article outlining monarch butterfly biology and requesting help finding the overwintering grounds from the Library of Congress. It came on microfiche and was a treasure to hold and read.

Still, it was another two years before the overwintering colonies were found and reported to the world. After thirty years of tagging butterflies, enlisting thousands of citizen scientists, and much speculation, shortly after new year’s day in January 1975, the great discovery was made. The Urquharts wrote to their thousands of volunteers: “We now wish to announce to our associates, that, after these many years of intensive study, after having tagged thousands of migrants, we have, finally located the exact area where they overwinter, with the very able assistance of Ken Brugger and Cathy Brugger of Mexico City”. And the rest is history.

Anurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He lives in Ithaca, New York.

Agrawal

Anurag Agrawal: Summer in the milkweed patch

AgrawalAnurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He lives in Ithaca, New York. His latest book, Monarchs and Milkweed, is available now.

It’s peak season for milkweed and the village of insects that make milkweed its home.  In my book on Monarchs and Milkweed, I devote an entire chapter to these diverse and fascinating other milkweed insects.  Below are photos from two days last week (July 6 and 7th), one set from my front yard and the other from Shawangunk National Grassland Preserve, both in NY State. All but two of the 11 specialized milkweed herbivores was seen on these four species of milkweed. Do you know which two species are missing?

1
The butterfly weed, Asclepias tuberosa.  Likes it dry.
2
Common milkweed, Asclepias syriaca, >90% of monarchs that make it to Mexico eat this as a caterpillar.
2b
A. syriaca, mis-named because it was thought to be from Syria.
3
The purple milkweed, Asclepias purpurescens, rare in NY State, this spectacular individual was near the shawangunks.
3b
Vegetative swamp milkweed, Asclepias incarnata.
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Flowering swamp milkweed, Asclepias incarnata, complete with the swamp milkweed beetle, Labidomera clivicollis.
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The poke milkweed, Asclepias exaltata, loves the partial shade. Note the nearly mature monarch.
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The four-eyed milkweed longhorn beetle, Tetraopes tetrophthalmus. Note the four functional eyes!
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Like all chewing insects on milkweed, Tetraopes deactivates the latex by clipping the veins.
8
Drippy toxic gooey stuff.
9
A little egg laid upon a leaf.  Monarch inside.
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The first day or a monarch’s life, it makes a latex-free island before starting to feed on the leaf tissue inside the circle.
11
A week later, the monarch has grown 2000 times its original size.  This caterpillar has parasitic wasps eating it from the inside out.
13
The only fly known to eat milkweed, a leaf miner, feeds between layers of the leaf (larva is hidden here): Liriomyza asclepiadis.
14
Euchaetes egle, the milkweed tussock moth, a misnomer since it’s in the woolly bear family, Arctiidae.  Egg clutches hatch into hundreds of caterpillars… note the foamy fluff that the egg mass was delivered in.  These turn into large hairy orange and black caterpillars. Hmmmmm…. same colors as adult monarch butterflies.
15
A dead bee, like so many that get stuck in milkweed’s flowers. Why do they get stuck?
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A tourist, not a real herbivore of milkweed.
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Adult of the milkweed leaf beetle, Labidomera clivicollis, here on common milkweed.
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Larva of the milkweed leaf beetle, Labidomera clivicollis.  Larvae of this species are apparently polymorphic, with grey or orange coloration. Closely related to the Colorado Potato Beetle.
18b
An adult of the elusive milkweed stem weevil, Rhyssomatus lineaticollis, chewing on apical leaves of common milkweed.
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Sometimes they poke the stem, as here on the poke milkweed, A. exaltata. No egg inside this one.
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Other times eggs are laid in a row in the stem.
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A trenched stem with milkweed stem weevil, Rhyssomatus lineaticollis, eggs.
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Inside the stem, larval feeding and frass of the milkweed stem weevil, Rhyssomatus lineaticollis.
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The milkweed stem weevil, Rhyssomatus lineaticollis, also deactivates the latex.  All the chewing herbivores of milkweed do it… more or less the same way, but with there own special twist.
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No seed pods yet, but the small milkweed bug, Lygaeus kalmii, feeds on last year’s seeds and sucks milkweed’s sap (not the latex!) … The large milkweed bug has not yet arrived to NY State… it apparently cannot overwinter in the frozen north.
25
Aphis asclepiadis, one of three aphids that eats milkweed.  This species is greenish to brown to grey, typically lives on top of the plant, and is nearly always tended by ants.
26
And the Oleander aphid, Aphis nerii, usually bright yellow-orange.  Here with a winged adult, just founding a colony in Ithaca, NY.

Anurag Agrawal: Monarchs vs. Milkweed

by Anurag Agrawal

Coevolution is a special kind of evolution. And monarchs and milkweeds exemplify this special process. In particular, what makes coevolution special is reciprocity. In other words, coevolution is one species that evolves in response to the other, and the other species evolves in response to the first. Thus, it is a back-and-forth that has the potential to spiral out of control. In some arms races, the two organisms both benefit, such as that between some pollinators and flowering plants. But coevolution is more common among antagonists, like predators and their prey.

When biologists first described coevolution, they likened it to an arms race. An arms race, such as that between political entities, occurs when two nations reciprocally increase their armament in response to each other. So how does an arms race between monarchs and milkweeds, or between cats and mice, or between lions and wildebeest, or between plants and their pathogenic fungi, proceed? When coevolution occurs, it proceeds with “defense” and “counter defense.” And one of the few rules of coevolution is that for every defense that a plant or prey mounts, the predator mounts a counter defense, or an exploitative strategy to overcome the defense.

Once a monarch butterfly lays an egg on a milkweed plant, the natural history of coevolution unfolds. For every defense that the plant mounts, milkweed mounts a counter defense. Once the caterpillar hatches, it must contend with a bed of dense hairs that are a barrier to consumption of the leaf. But monarchs are patient, and have coevolved with the milkweed. So their first strategy is to shave that bed of hairs such that the caterpillar has access to the leaves that lie beneath.

Agrawal

For every defense there’s a counter defense. But next, when the monarch caterpillar sinks its mandibles into the milkweed leaf, it encounters a sticky, poisonous liquid called latex. In this video we will see how the monarch caterpillar deactivates the latex bomb that the milkweed puts forward.

And so the arms race continues, with reciprocal natural selection resulting in coevolution between monarchs and milkweeds. In my book, Monarchs and Milkweed, I outline the third level of defense and counter defense between these two enemies. Milkweed next mounts a remarkable and highly toxic defense chemical called a cardiac glycoside. But, yes, again the Monarch has evolved the means to not only not be poisoned by the cardiac glycoside, but to sequester it away and put it to work in defense of the Monarch itself from its enemies, such as predatory birds. For more on the Monarch – Milkweed arms race see this video, filmed in Ithaca, New York outside of Cornell University where we conduct our research.

AgrawalAnurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He is the author of Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.

Anurag Agrawal: The oldest butterflies?

by Anurag Agrawal

It’s unclear when humans became humans. Presumably it was a gradual growth of our consciousness over the eons. There are some things, however, that appear to distinguish us from most other animals. For example, our artistic depictions. From the deepest, darkest caves have emerged pictures of humanity from thousands of years ago. And in an Egyptian tomb, that of Nebamun, on a painting called “Fowling in the marshes” (from around 1350 BCE) comes one of the oldest human depictions of butterflies. It happens to be of the African Monarch, Danaus chrysippus, sometimes called the plain tiger, a close relative of our beloved North American Monarch butterfly, Danaus plexippus.

Agrawal
I stumbled on this lovely scrap of history when a friend and colleague, Harry Greene, gifted me a book: Nabokov’s Butterflies (2000), a collection of unpublished and uncollected writings. Some explanation is in order. Harry is an extraordinary naturalist and big thinker in ecology and evolution. Like many senior scholars, his predicament was the lack of shelf-space in his office. And so I was the beneficiary of Nabokov’s Butterflies. Vladimir Nabokov, a Russian-American author, and noted entomologist, was most famous for his writings, for example, Lolita, and his celebrated translation of Pushkin’s novel in verse, Eugene Onegin. His ideas about biology were diverse, he was a passionate lepidopterist, and he often intermixed his literary writing and entomological excursions. Lolita is said to have been written primarily on butterfly collecting trips in the American west. Nonetheless, Nabokov also clung on to other ideas that held little merit in the scientific sphere. Most prominently, Nabokov rejected evolution by natural selection as a driver of certain organismal traits that he deemed ‘coincidental, miraculous, or too luxurious.’

Agrawal

Nabokov was a professor at my own Cornell University in the decade following WWII. Although he taught literature and had well-known students at Cornell (including U.S. supreme court justice, Ruth Bader Ginsburg), his entomological interests continued. In fact, after he retired from Cornell in the mid-1960s, Nabokov had sketched out an outline of a book: The Butterflies of Europe. And although the book never came to be, the outline was recapitulated in Nabokov’s Butterflies. Flipping through the book, I stumbled on his entry for Danaus in which he wrote, “This butterfly has the distinction of being the oldest known to have been represented by man. Seven specimens of it (with typical white-dotted Danaus body but somewhat Vanessa cardui like wingtips) are shown flitting over the papyrus swamp…” (page 603).

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I later asked another friend, Harvard’s Lepidopterist, Naomi Pierce: did Nabokov have it right? On the money, she independently pointed to the similarity of Danaus chrysippus and the painted lady, Vanessa cardui, wondering if the butterflies on this three thousand year old tomb painting were Danaus or Vanessa. She concluded, as did Nabokov, that the African Monarch ruled. Detailed assessment of the color patterns on the wings were informative to both entomologists. The oldest human depiction of a butterfly? Perhaps not. Naomi mentioned some evidence of butterflies in Minoan artifacts from Crete, a thousand years earlier than Nebamun, and likely in Pyrenees cave paintings, some 10-30 thousand years earlier!

Of course, there is nothing special about being the oldest depiction of a butterfly by Homo sapiens. But suffice it to say, butterflies, metamorphosis, wing patterning, and the beauty of nature have been on our minds for a very long time. Thanks Harry and Naomi! And thanks Nabokov. Who knows what becomes of those side hobbies and obsessions we all hold.

Nabokov

AgrawalAnurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He is the author of Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.

Anurag Agrawal: Monarch overwintering

by Anurag Agrawal

The estimates of the monarch butterfly overwintering population were announced February 9th by WWF Mexico. The butterflies are so dense at their dozen or so mountain-top clustering sites that overwintering butterflies cannot be individually counted. Instead, the area of forest that is densely coated with butterflies (at about 5,000 butterflies per square meter looking up into the canopy) is estimated as a measure of monarch abundance. Butterflies arrive in Mexico around early November and stay until March.

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This winter season (2016-2017), there were approximately 2.9 hectares of forest occupied with dense monarchs (somewhere in the neighborhood of 300,000 million overwintering butterflies). This estimate is down 27% compared to last year. Nonetheless, the previous two years were a 600% increase over the all-time low recorded in the winter of 2013-2014.

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Where does this leave us? This year’s population was higher than predicted by many. The season started with a late spring storm that killed an estimated 5-10% of monarchs in March 2016, and many reported low numbers of adults last summer. Nonetheless, the lower numbers this season compared to last are within the range of year-to-year variation, and overall, the population seems to be relatively stable over the past decade. With these 24 years of data, there are various ways to plot and assess the trends. Below I have plotted the four year averages for six periods beginning in 1992. Any way you slice it, the trend has been negative, and the population is not nearly what it once was. Nonetheless, the downward trend seems to have lessened this last period. Is this the new norm? How dangerously low are these numbers? And what can we do to reverse the trend?

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AgrawalAnurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He is the author of Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.

 

 

 

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Anurag Agrawal on Monarchs and Milkweed

AgrawalMonarch butterflies are one of nature’s most recognizable creatures, known for their bright colors and epic annual migration from the United States and Canada to Mexico. Yet there is much more to the monarch than its distinctive presence and mythic journeying. In Monarchs and Milkweed, Anurag Agrawal presents a vivid investigation into how the monarch butterfly has evolved closely alongside the milkweed—a toxic plant named for the sticky white substance emitted when its leaves are damaged—and how this inextricable and intimate relationship has been like an arms race over the millennia, a battle of exploitation and defense between two fascinating species. Check the PUP blog each Monday for new installments in our “Monarch Monday” blog series by Anurag Agrawal.

What makes monarchs and milkweeds so special?

AA: Monarchs and milkweed are remarkable creatures, they’re on a wild ride! From the monarch’s perspective, its only food as a caterpillar is the milkweed plant. This makes them highly specialized, highly evolved, and very picky eaters indeed. They’re actually not that unique among butterflies, but they are extreme. Milkweed does everything in its power to defend itself against being eaten by monarchs. They make sandpapery leaves, toxins that can stop a human heart, and a thick poisonous goo that can glue an insect’s mouth shut. Again, although milkweed is not unique among plants, it is extreme. In what is called a coevolutionary arms race, monarchs and milkweed have been continually evolving over the eons to keep up with each other. As such, they have a lot to teach us about the way nature works, the way plants and animals interact, and about the various paths that evolution can take different species. And this is all to say nothing of the monarch’s spectacular annual migration, often over 3,000 miles flown by individual butterflies, using the sun to navigate, and having stored away milkweed’s poisons to protect themselves from being eaten by birds. Monarchs and milkweeds are royal representatives of all interacting species.

Why did you write this book?

AA: After studying monarchs and milkweed myself for over 15 years, I felt like I had a lot I wanted to share, especially with non-scientists and nature lovers. Monarchs and milkweed are such fascinating organisms, and yet so much of their beautiful biology is not widely known. I also wrote the book because there are areas of my own knowledge about monarchs and milkweed that I wanted to immerse myself in, but that I had not yet done any research on. So as an author, getting to visit the overwintering sites in Mexico, to study the population decline of monarch butterflies, and to understand their mating rituals were all fascinating detours from my everyday research life at Cornell University. The book was incredibly fun to write, and getting to work with artists and historians made it all the more rich. I hope that anybody that has an appreciation for nature, an interest in science, or just a curiosity about the ecology of plants and butterflies will enjoy this book. Working on this project has surely altered the course of my own research, the classes I teach, and how I see the natural world.

Why have you highlighted some of the personalities of the scientists studying monarchs and milkweeds in this book?

AA: One of the most amazing things about monarchs and milkweeds is the scientists who have studied them. They were such remarkable characters, especially those pioneering studies back in the 1950s: tremendously creative, sometimes competitive, and with some of their discoveries worthy of a Nobel prize. Getting to know them, both from their discoveries and their personalities, and how they interacted, has enriched my appreciation for how science is done. It also highlights the meandering and sometimes serendipitous nature of discoveries. I wanted to share the thrill of science, its ups and downs, and the process by which it is done with the curious reader.

Can you share one of your ah-ha! moments from studying monarchs and milkweeds?

AA: One of my favorites was from when I was an assistant professor at the University of Toronto. One day I was eating lunch by myself in a small downtown garden. Just by chance, I happened to sit on a bench beneath a very tall milkweed plant that had a very large monarch caterpillar feeding away. Without giving away all the details, that one hour encounter, in the middle of a city with 3 million people, changed my perspective on monarchs and milkweed forever. It was so unlikely an event, perhaps 1 in a 1,000 that a butterfly had been flying by and happened to lay an egg on this Toronto milkweed, and then a further 1 in 100 chance of that egg hatching and surviving to be that large caterpillar that I could watch it. And probably a 1 in a million event that I would happen to be eating lunch there, that day, to observe the events. In biology one has to work hard, be patient, and occasionally get very lucky! Throughout my studies on monarchs and milkweed, I have had tremendous luck in encountering wonderful biology that has had profound consequences.

Is the monarch butterfly going extinct?

AA: The answer to this very important and timely question is both simple and complex. On the simple side, there is no way the monarch butterfly is going extinct anytime soon. Having said that, the butterfly, and especially the long-distance migration that occurs every fall from Southern Canada and the USA, all the way to Mexico’s highlands in Michoacán, is indeed declining at a rapid pace, and we should all be worried about the sustainability of the annual migration. There’s so much information and misinformation floating around in the news these days about the causes of the monarchs decline. What I’ve tried to do in the book is outline the best knowledge that we have to date and to examine the facts critically, so we can really understand what might be going on. Unfortunately, we don’t have all the answers, but we can reject some of the most prominent explanations for the population decline of the monarch butterfly. As I argue in the book, planting milkweed certainly won’t hurt, but it is unlikely to save the monarchs annual migratory cycle. It is perhaps ironic that I spend eight chapters of the book discussing and detailing the importance of milkweed for monarchs, and nothing could be more true than their intertwined and intense evolutionary battle, but at this stage, and thinking about their conservation, it does not appear that milkweed is what is limiting the monarch’s population. Monarchs will persist for a very long time, but given that they are migratory butterflies that taste their way across North America, their declining population is something we must try to understand. Much more than the monarch is at stake, these butterflies are sentinels for the health of our continent!

Anurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He lives in Ithaca, New York. He is the author of Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.

Sunny, Spring Book List

The Bee
Say goodbye to cold, dreary winter and hello to spring. Welcome the season by checking out Princeton University Press’s selection of natural history books. Wondering what bird you hear chirping? Download BirdGenie Backyard Birds East and West and find out. Some choices to get you out of the house and into nature:

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The Bee:
A Natural History

Noah Wilson-Rich
With contributions from Kelly Allin, Norman Carreck & Andrea Quigley
“The natural history of solitary, bumble, honey and stingless bees is as gripping as our lengthy alliance, as urban beekeeper Noah Wilson-Rich and contributors show in this charming compilation. They cover evolution, biology (including a unique proboscis made of two organs), behaviours (such as honey bee ‘quacking’), the causes of catastrophic die-offs, and more.”–Barbara Kiser, Nature

 

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Birds of Australia:
A Photographic Guide

Iain Campbell, Sam Woods & Nick Leseberg
With photography by Geoff Jones
“Written primarily for the visiting birder, reading a copy of this book will fire up anyone’s desire to get out into the field to see more of our fabulous birds.”–Sean Dooley, Australian Bird Life

 

bookjacket Britain’s Butterflies:
A Field Guide to the Butterflies of Britain and Ireland

Fully Revised and Updated Third edition
David Newland, Robert Still, Andy Swash & David Tomlinson
“The images in this pocket-sized photo-guide are excellent and include pictures of eggs, chrysalids and caterpillars of all breeding species. Comparing very similar species can be difficult, but computer mock-ups helpful place specimen in situ. Clear text and page design make the book easy and fun to use.”BBC Wildlife magazine

 

bookjacket Britain’s Hoverflies:
A Field Guide

Revised and Updated Second edition
Stuart Ball & Roger Morris
Praise for the previous edition: “The latest field guild from the excellent Wildguides. . . . Beautifully and clearly laid out.”–Charlie Moores, Talking Naturally