InDialogue with Thomas Seeley and Nick Haddad: Why is insect conservation important?

The PUP Ideas blog is pleased to announce our new InDialogue series. In keeping with our mission to provide a range of perspectives and voices, each month we’ll be posing a big question to a pair of authors. With Earth Day fast approaching, we’ve asked a series of questions to our natural history authors on issues from the central role of oceans to climate science. Today we asked PUP authors Thomas Seeley and Nick Haddad to sound off on why insect conservation is important, and to reflect on the magnitude of the loss of key populations. Watch this space for more Earth Day posts in the coming days.

Being stewards to the bees

Thomas D. Seeley

There is no doubt that humans are now the primary movers and shakers of the natural world.   We are busy tearing down the planet’s forests and, in one way or another, we are appropriating some 40 percent of the solar energy captured by plants.  But we are not self-sufficient.  We depend on what Edward O. Wilson has called “the little things that run the world”:  the insects and other invertebrates, which together form most of the biomass in terrestrial habitats.  If humans were to disappear from the planet, then life on Earth would certainly go on.  Indeed, it would begin to heal itself.  But if insects were to disappear, then our species and countless others would go extinct, because most of the flowering plants—including those that produce the fruits and vegetables we eat—would die out for lack of pollination.   

There is one insect whose pollination services are especially important to us:  the honey bee, Apis mellifera.  This bees’ paramount value to humans was recently quantified in an authoritative, 59-author paper on the contributions of various bee species to crop pollination.  It reports that honey bees provide nearly half of all crop pollination services worldwide.  Remarkably, this one species’ contribution to humanity’s food production nearly equals the combined contributions of the many thousands of other bee species.  Clearly, the conservation of honey bees merits special attention. 

One way we can support Apis mellifera is by conserving forests.  They provide habitat for wild colonies of honey bees, and these colonies are important to their species’ long-term survival.  Recent studies of the population genetics of honey bees in the southern and western states of the U.S. have found that wild colonies—those living on their own in hollow trees and the walls of buildings—have far higher genetic diversity than the managed colonies in these states.  This is because commercial beekeepers typically replace the queens in their colonies every year or so using queens purchased from large-scale queen producers, and these replacement queens are the daughters of a small number of “breeder queens” (ca. 600 for the entire U.S.).  These practices create a genetic bottleneck in the population of managed honey bee colonies within the U.S. 

Other studies have revealed recently that the wild colonies of honey bees—those not living in beekeepers’ hives—possess effective mechanisms of resistance to a species of parasitic mite (Varroa destructor) introduced from east Asia.  The females of this species feed on the adult and immature honey bees.  They also spread a virus that deforms the bees’ wings and destroys their health.   Approximately 40% of the managed colonies in the U.S. die each year from infections of the deformed wing virus.  The wild colonies are also infested with these mites, but they have better survival because they have experienced strong natural selection for mechanisms of resistance to Varroa destructor.   These include chewing the legs off adult mites and destroying cells of bee brood infested with mites.

Besides conserving forests that support populations of wild colonies, we can help Apis mellifera by revising the practices of beekeeping, to find a better balance between the needs of bees and the desires of beekeepers.  Most of the practices of conventional beekeeping—such as encouraging colonies to grow extremely large, and packing them close together in apiaries—boost the productivity of colonies as honey makers and crop pollinators, but also increase their vulnerability to parasites and pathogens, including deadly Varroa destructor.   To conserve Apis mellifera, we must build a new relationship between human beings and honey bees.  We must revise our methods of beekeeping to bring them more in harmony with the honey bee’s natural way of life.  Only then will we be truly responsible stewards of Apis mellifera, our greatest friend among the insects.

Thomas D. Seeley is author of The Lives of Bees. He is the Horace White Professor in Biology at Cornell University. He is the author of Following the Wild BeesHoneybee Democracy, and Honeybee Ecology (all Princeton) as well as The Wisdom of the Hive. He lives in Ithaca, New York.

 

The value of the rarest butterflies

Nick Haddad

When I began writing The Last Butterflies in 2013, I worried that the title was over the top. After all, I was writing about just a handful of the rarest butterflies in the world. The five rarest butterflies number from a few hundred to a few tens of thousands of individuals. Could these be in any way representative of the last butterflies on the earth?

One way they are not representative is in their “value”. Their value might be to ecological systems. However, the earth’s thirty thousand individual Fender’s Blue butterflies might weigh as much as a basketball. These simply cannot be of consequence to interactions with other plants or animals as parts of functioning foodwebs. They are not effective pollinators or herbivores of, or food sources for, other species in their environments. Perhaps their value is in the bigger lessons the understanding of their declines holds for the declines of other butterflies. If so, then knowledge accrued during their decline can provide guidance to avert catastrophic declines of other insects.

Also when I started writing this book, I did not imagine broad implications to other insects that have economic value that can be measured. Data had not yet amassed to support the “insect apocalypse,” a phrase used to refer to catastrophic loss of abundance and diversity of insects. Then in 2014, reports surfaced that Monarchs reached epic low numbers, 97% below their peak two decades earlier. Later that year, a more general survey found declines across butterfly and insect species at the rate of 10% or more per decade. Such broad losses across insects must have substantial cost.

In this context, the rarest butterflies have higher value. Most of what we know about the insect apocalypse is what we know about butterflies. Are the rarest butterflies and Monarchs representative? A chilling picture has emerged. My former student Tyson Wepprich just completed an analysis of butterfly abundances using data collected across Ohio in surveys conducted every week for two decades. He found that butterfly abundances are declining by 2%  / year; abundances are now a third lower than twenty years ago. This is not an isolated case. Tyson reviewed other, decades-long studies in the UK, the Netherlands, and Spain. All of them have found 2%/ year decline in butterfly abundances. It appears that, after all, The Last Butterflies is an appropriate book title.

This rate and magnitude of loss is perhaps the best indicator of the cost of insect decline. Considered together, butterflies are the best known group of the earth’s 5.5 million insects. The less substantial evidence that exists for other insects points in the same downward direction. Like butterflies, those insects are herbivores, prey, and pollinators (and, of course, many are predators). They are exposed to the same levels of habitat loss, pesticides, and climate change. The scale of loss of butterflies, even if it is only partially representative of loss of other insects, will cause catastrophic loss of functioning ecosystems on which we all depend.

Circling back around to the rarest butterflies in the world: what is their value? It is certainly not in their importance within their ecosystem, at least not now. Their decline has generated some value in the sense that is provides some guidance for conservation of other insects, animals, and plants. Their true value, however, is intrinsic; when driven to extinction by global environmental changes, loss of value will be to people, and to the earth.

Nick Haddad is author of The Last Butterflies. He is a professor and senior terrestrial ecologist in the Department of Integrative Biology and the W. K. Kellogg Biological Station at Michigan State University. He lives in Kalamazoo, Michigan. Twitter @nickmhaddad

Anurag Agruwal: Great News for Monarch Overwintering Population

The estimates of the monarch butterfly overwintering population were announced today (Wed. Jan. 30th 2019) by WWF Mexico.  The butterflies are so dense at their dozen or so mountain-top clustering sites that overwintering butterflies cannot be counted individually.  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 to Mexico around the day of dead in November and stay until March each year as part of their annual migratory cycle.  Butterflies have been declining over the past three decades, and the annual announcement is a welcome addition to our understanding of the long-term dynamics of our beloved monarch.

The annual multi-generational migratory cycle of the monarch butterfly. The southernmost red dot indicates the high elevation overwintering grounds in central Mexico where populations are censused. North pointing arrows indicate the spring and summer generations that migrate, breed, and eat milkweed. Learn more in my book Monarchs and Milkweed.

This winter season (2018-2019), there were approximately 6.05 hectares (nearly 15 acres) of forest occupied with dense monarchs in the Mexican highlands (somewhere in the neighborhood of 300,000 million overwintering butterflies).  The monarchs end up congregating in a tiny area, with the bulk of the butterflies concentrated among twelve mountain massifs (clusters of peaks) within three hundred square miles (eight hundred square kilometers), an area smaller than New York City. In other words, most of the monarchs from eastern North America, from Maine to Saskatchewan, and south to Texas, probably covering two million square miles, funnel down and overwinter in a location 0.015 percent the area that they occupy in the summer!  Unbelievable. This year’s estimate is well over double compared to last year, great news for monarchs!

Where does this leave us?  The good news is that this year’s population was huge in the summer months throughout the USA and Canada, and the resulting migration and overwintering population in Mexico was the highest in 12 years, higher than predicted by many.  The season started with a very early spring and a far reaching northern migration.  As I have previously argued, there is often a disconnect between summer breeding populations of monarchs and the overwintering population — that seems to not be the case this past year.

With 26 years of data, there are various ways to plot and assess the trends.  Below I have plotted four year averages for seven periods working backwards (so the first average on the left is only for 2 years).  Any way you slice it, the trend has been negative, and the population is not what it was.  Nonetheless, the extreme downward trend seems to have bumped up in the last period of four years.  Is this the new norm, a winter population hovering between two and five hectares?  How dangerously low are these numbers? And what can be done to continue to reverse the trend and buffer the population?  I have recently written more about this issue in a scientific article as a well as my book.

For now, let’s celebrate. The government is open, and thus the Fish and Wildlife Service will be deciding on the petition to list monarchs as threatened under the Endangered Species Act this summer. Looking forward to seeing butterflies and their caterpillars once Ithaca, NY thaws in spring. Thanks for reading! 

Anurag 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 and lives in Ithaca, New York.

 

 

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

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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.

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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.

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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.

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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.

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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.

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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?

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The butterfly weed, Asclepias tuberosa.  Likes it dry.
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Common milkweed, Asclepias syriaca, >90% of monarchs that make it to Mexico eat this as a caterpillar.
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A. syriaca, mis-named because it was thought to be from Syria.
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The purple milkweed, Asclepias purpurescens, rare in NY State, this spectacular individual was near the shawangunks.
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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.
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Drippy toxic gooey stuff.
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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.
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A week later, the monarch has grown 2000 times its original size.  This caterpillar has parasitic wasps eating it from the inside out.
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The only fly known to eat milkweed, a leaf miner, feeds between layers of the leaf (larva is hidden here): Liriomyza asclepiadis.
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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.
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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.
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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.
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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.
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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.

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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.

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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.’

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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.

butterflies

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?

butterfly

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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