Time for Cranberries!

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Cranberries, especially in the form of relishes and baked goods, are a Thanksgiving tradition made possible by Cranberry (Vaccinium macrocarpon), a low-growing, creeping, evergreen shrub native to North American bogs and fens.  Cranberry lends itself well to cultivation for commercial use, making cranberry based dishes possible throughout the year.

Cranberry (Vaccinium macrocarpon)

The flowers of this native shrub bloom in early to mid-summer, a prerequisite for the fruit that will come later in the season.

Cranberry (Vaccinium macrocarpon) in flower

In order to produce the tart but luscious and festive fall fruit, Cranberry’s flowers must be pollinated with assistance from insects, primarily bees.

Cranberry (Vaccinium macrocarpon) flowers

The flowers are most efficiently pollinated by bees who are capable of sonication, or buzz pollination.  In the case of Cranberries, this process is performed by bees that are able to hang upside down from the bottom edge of the flower’s corolla (collection of petals) and vibrate their wing muscles without moving their wings.  This sets up just the right motion to release pollen from the flower like salt from a shaker dusting the bee’s underside.  When the bee moves on to the next flower, its pollen-dusted abdomen brushes the flower’s stigma (female reproductive part), depositing pollen from the previous flower.

It’s not every bee that has this special talent.  Honey Bees don’t have the skills necessary to buzz pollinate.  The best Cranberry pollinators are the native bees with which it has evolved, and who can sonicate (buzz pollinate), including several species of Bumble Bees, Sweat Bees (Halictidae) and Mining Bees (Andrenidae).  The presence of these native bees significantly increases the yield of commercial cranberry operations.

Bumble Bee getting in position to buzz pollinate a Shooting Star (Dodecatheon Meadia) flower. The structure of this flower is very similar to those of Cranberry (Vaccinium macrocarpon).

Other food we eat, including blueberries, tomatoes, eggplant, and peppers are produced by plants whose flowers are also most effectively pollinated through buzz pollination.

With the help of the bees, this tough little shrub produces abundant fruit that ripens in the fall and resists spoiling, perfect timing for inclusion in a late fall or winter feast.

Cranberry (Vaccinium macrocarpon)

In addition to being tasty and nutritious, Cranberry has medicinal value. Consumption of cranberries or unsweetened cranberry juice can help prevent urinary tract infections.

Humans are not the only consumers of cranberries.  Birds including Sharp-tailed and Ruffed Grouse, Bobwhites, Mourning Doves and American Tree Sparrows are known to eat cranberries,

Ruffed Grouse

American Tree Sparrow

as are Chipmunks.

Eastern Chipmunk

Cranberry hosts the caterpillars of several moths who can only eat the leaves of this and a few related species.  The Bog Copper butterfly is also a specialist on Cranberry and the closely related Small Cranberry (Vaccinium oxycoccus).

Cranberry is indigenous in the United States from Maine to Minnesota, south from northeastern Illinois to Delaware, and from there reaching as far south as Tennessee and North Carolina primarily through the Appalachians; it can also be found in coastal Washington state and Oregon, and Nevada county in California.  In Canada it is native from Newfoundland to Ontario, in British Columbia and the Northwest Territories.  The top five states in commercial cranberry production are Wisconsin, Massachusetts, New Jersey, Oregon and Washington.  British Columbia and Quebec are the top cranberry producing provinces in Canada.

Why is the range of this plant primarily in northern latitudes and higher elevations?  The answer lies in the fact that Cranberry is much less successful in producing flowers and fruit unless it goes through a sufficient period of dormancy induced by day length change and cold temperatures.  To successfully break dormancy, the plants must experience a cumulative number of ‘chill hours’, usually defined as temperatures between 32 and 45 °F (0 – 7.2 °C), during the winter months.  A study done by University of Wisconsin researchers found that 1500 chill hours seemed to be in the optimal range for successful bloom of cranberry flowers.  As the climate changes and night time temperatures warm, the geographic range where these optimal conditions can be met may shrink.

Enjoy those cranberry dishes while you can!

Manoff’s Apple Cranberry Chutney!

Related Posts

The Buzz about Shooting Star

Love Blueberries?  Thank a Native bee

Resources

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Eastman, John.  The Book of Swamp and Bog.  1995.

Eaton, Eric R.; Kauffman, Ken.  Kaufman Field Guide to Insects of North America.  2007.

Foster, Steven; Duke, James A.  A Field Guide to Medicinal Plants and Herbs of Eastern and Central North America.  2000.

Hoffmann, David.  Medical Herbalism.  2003.

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Biobest Sustainable crop Management

Illinois Wildflowers

https://illinoiswildflowers.info/plant_insects/plants/vaccinium_macrocarpum.html

http://www.illinoiswildflowers.info/flower_insects/plants/lg_cranberry.htm

Lady Bird Johnson Wildflower Center Plant Database

The Canadian Encyclopedia

University of Wisconsin Extension; Cranberry Crop Management Journal

University of Massachusetts, Natural History of the American Cranberry (Vaccinium macrocarpon)

USDA NRCS Plants Database

USDA REEIS Cranberry Cold Hardiness in Relation to Dormancy and Bud Development; Source: University of Wisconsin

United States Department of Agriculture National Agricultural Statistics Service New Jersey Field Office – Cranberry Highlights

US Forest Service – What is a Fen?

 

 

WisCONTEXT: Pollinators Provide Extra Buzz To Wisconsin’s Cranberry Crop

https://www.wiscontext.org/pollinators-provide-extra-buzz-wisconsins-cranberry-crop

 

Another Migrating Butterfly, and the Plants that Sustain It

Common Buckeyes have been, well, really common this year.

Common Buckeye drinking nectar from Short-toothed Mountain Mint (Pycnanthemum muticum)

That isn’t the case every year in the areas I frequent near the Delaware River in central New Jersey and eastern Pennsylvania.  Common Buckeyes are not year-round residents this far north. They migrate south in late fall to spend the winter in warmer territories, often as far south as Florida.  In migration they can sometimes be seen in large numbers, often moving along the coast in the eastern United States, or sometimes following river valleys.  They migrate north in spring and early summer, sometimes reaching as far north as southern Canada.  Their numbers vary from year to year in these northern locations, becoming increasingly rare the further north they go.

On warm sunny days even in late October, I am still seeing Common Buckeyes often drinking nectar, mostly from flowers that are members of the Aster family.  This family of plants, which includes asters, goldenrods, sunflowers, bonesets, beggar-ticks, and more are typically the most abundant plants blooming in late summer through the end of the growing season.

Common Buckeye nectaring on Aromatic Aster (Symphyotrichum oblongifolium)

Common Buckeyes can also be found basking at ground level, catching the low rays from the late season sun.

Common Buckeye basking

Common Buckeyes frequent open fields, roadsides, gardens, and even beaches, especially where nectar plants are available.

Common Buckeye drinking nectar from goldenrod flowers along the sandy beach at Cape May, New Jersey

Common Buckeyes have a fairly broad geographic range, and have evolved to use a variety of plants as food for their caterpillars, including plantains, figworts,

Lanceleaf Figwort (Scrophularia lanceolata), a caterpillar food plant for Common Buckeye butterflies

gerardia,

Purple Gerardia or Purple False Foxglove (Agalinis purpurea), a caterpillar food plant for Common Buckeye butterflies

Monkey Flower,

Allegheny Monkey Flower (Mimulus ringens), a caterpillar food plant for Common Buckeye butterflies

and Wild Petunia.

Fringeleaf Wild Petunia (Ruellia humilis) a caterpillar food plant for Common Buckeye butterflies

The coloration of the Common Buckeye’s outside hind wing early in the season is mostly tan, with prominent eye spots.

Common Buckeye drinking nectar from Short-toothed Mountain Mint (Pycnanthemum muticum). Note the tan color and eyespots of the hind wing.

The wing color can be quite different in late summer and fall, taking on a rosy hue.  This may be an adaptation that helps Common Buckeyes blend in with the changing color of the surrounding foliage.

Common Buckeye in autumn. Note the rosy color of the hind wing.

Keep an eye out for Common Buckeyes on these last warm days of fall!

Common Buckeyes on goldenrod

 

Resources

Brock, Jim P.; Kauffman, Ken.  Kaufman Field Guide to Butterflies of North America.  2003.

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Glassberg, Jeffrey.  A Swift Guide to Butterflies of North America.  2012.

Glassberg, Jeffrey.  Butterflies through Binoculars A Field Guide to Butterflies in the Boston-New York-Washington Region.  1993.

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Wagner, David L.;  Caterpillars of Eastern North America, 2005.

Canadian Biodiversity Information Facility: Butterflies of Canada

Butterflies and Moths of North America

 

 

Wingstem

There are still pockets of Wingstem (Verbesina alternifolia) in bloom along the Delaware and Raritan Canal in central New Jersey.  This species has been flowering in nearby locations since August.

Wingstem (Verbesina alternifolia) along the Delware and Raritan Canal in central New Jersey

Like so many other plants that bloom in late summer and fall, Wingstem is a member of the prolific Aster (Asteraceae) family, which consists of more than 23,600 species.

Aster family members have a floral display that is a composite of multiple flowers, called a flower head, inflorescence, or capitulum.  What our brain wants to interpret as a single flower is really a group of many flowers, all attached to the same platform, or receptacle.

There are two types of flowers that may be present in the flower head of an aster family member, ray flowers and disk flowers.  Each ‘petal’ we see is an individual ray flower that consists of a single petal.  The other type of flower is a disk flower, whose petals have fused to form a narrow tube.  Many Aster family members have a classic look with both ray and disk flowers, while some have evolved to produce just ray flowers, and others just disk flowers.

Aromatic Aster (Symphyotrichum oblongifolium) is a classic aster family member with both ray and disk flowers. A pair of mating Flower (Syrphid) Flies is visiting.

For many species that produce both ray and disk flowers, the ray flowers are sterile; they don’t have functioning reproductive parts.  Their role is just to look pretty, to be part of an appealing advertisement that attracts pollinators to the disk flowers in the center of the flower head.  It’s the disk flowers that produce pollen and nectar, and where the business of reproduction is carried out.

Wingstem is a species that has sterile ray flowers and fertile disk flowers, all attached to a rounded receptacle.  The disk flowers are large and distinct; it’s easy to see each individual flower, especially when insects are foraging for food.

Wingstem (Verbesina alternifolia) flowers with foraging bees. Notice the large but narrow tubular disk flowers projecting from the round recepticle, with the petal-like ray flowers below.

Like its relatives, Wingstem is a great source of food for late season pollinators. The ray flowers open first as a signal to pollinators that the flower head is open for business.  The disk flowers bloom a few at a time, starting with those closest to the ray flowers, then over many days gradually working towards the center of the head.  In each disk flower, the male reproductive parts (stamens) mature first, opening their anthers to make pollen available. Later the female reproductive parts (pistils) replace the stamens, the stigmas at the tips of the pistils becoming receptive to pollen.  At any time while in bloom there may be some flowers in a head that are in the male phase, others in the female phase.

Wingstem (Verbesina alternifolia) with foraging Bumble Bee. Note the distinct disk flowers. Those with a straight brown projection (the anthers) emerging are in the male phase. The disk flowers with yellow curliques (the stigmas) are in the female phase.

It’s easy to see how the pollen-covered Bumble Bee in the photo below would be an effective pollination partner for Wingstem.

Wingstem (Verbesina alternifolia) with foraging Bumble Bee

Not all pollen is destined to be used for pollination, however, since it’s an importance source of food for bees and flies.  Bees and flies drink nectar, but they also eat pollen.  Female bees also collect pollen to bring back to their nests to feed their larvae.  The female below already has a good quantity of food to bring to her offspring, packed onto the bristly hairs on her hind legs.

Female Bumble Bee on Wingstem (Verbesina alternifolia) foraging for food for herself and her offspring. The orange blob on her hind leg is pollen and nectar that she has already gathered to bring back to her nest. Note the long hairs on that leg, perfectly suited to transporting this food.

Sweat Bees and Small Carpenter Bees also visit Wingstem flowers for the nectar and pollen banquet they provide.

Wingstem (Verbesina alternifolia) with visiting Sweat Bee

Small Carpenter Bee on Wingstem (Verbesina alternifolia)

This Toxomerous geminatus, a Flower Fly, may not have a tongue long enough to reach the nectar, but it can still consume pollen from these abundant flowers.

Toxomerous geminatus, a Flower Fly, eating pollen from a Wingstem (Verbesina alternifolia) disk flower

Wingstem nectar is a welcome offering for butterflies.

Summer Azure butterfly drinking nectar from a Wingstem (Verbesina alternifolia) disk flower

Even this thread-waisted wasp is doing her best to get into the flowers to drink nectar.

Mating Thread-waisted Wasps, with female attempting to drink nectar from Wingstem (Verbesina alternifolia) flowers

If these insects assist in transporting pollen to help achieve successful pollination, the disk flowers will produce dry, winged fruits (achenes) that will take the place of the flowers on the globe-shaped receptacle.  The fruits may drop in place, be scattered by wind, or dispersed with the assistance of a passing animal hooked by the pointy bristles on each achene.

Wingstem (Verbesina alternifolia) with fruit still attached to the round recepticle

Deer and other mammals avoid eating Wingstem because of its bitter taste. But there are some insects that happily get nourishment from this species.  The caterpillars of Silvery Checkerspot butterflies and some moths eat Wingstem leaves.

A Yellow Bear moth caterpillar taking refuge in a Wingstem (Verbesina alternifolia) leaf

The aphids in the photo below are feeding on Wingstem sap, while the ants are drinking the aphids’ honeydew (excrement).  The ants will protect the aphids in exchange for this treat.

Aphids on Wingstem (Verbesina alternifolia) flower head, being tended by ants

Wingstem is an herbaceous perennial that often grows to a height of 5-6 feet (1.5-2 meters), but can reach eight feet (2.5 meters) tall.  It can tolerate full sun to part shade, average to moist soil.  This plant’s name describes its appearance, providing clues to its identification.  ‘Wingstem’ refers to the leafy wing-like appendages along the sides of the main stem of the plant.  ‘Verbesina’ means that its foliage is similar to that of verbena, and ‘alternifolia’ tells us that the leaves are alternate, not opposite each other where they attach to the stem.

Note the alternate leaves. The leafy appendages along the sides of the stem, giving this plant its common name, ‘Wingstem’

Wingstem is native in the United States in Massachusetts, Rhode Island, and from New York west to Nebraska, south as far as northeastern Texas and the Florida panhandle.  In Canada, it can be found in Ontario province.  Wingstem is less common in the northern and southernmost parts of its range.

Look for Wingstem and its visitors in late summer and fall.

Wingstem (Verbesina alternifolia) with Bumble Bees

Related Posts

Bountiful Blue Wood Aster

New England Asters – A Hotbed of Activity!

Asters Yield a Treasure Trove

Fall Allergies?  Don’t Blame Goldenrod!

‘Will Work for Food’ – Extra-floral Nectaries

Milkweed – It’s Not Just for Monarchs

Resources

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Eaton, Eric R.; Kauffman, Ken.  Kaufman Field Guide to Insects of North America.  2007.

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Stearn, William T. Stearn’s Dictionary of Plant Names.  1996

Wagner, David L.;  Caterpillars of Eastern North America, 2005.

Illinois Wildflowers

Missouri Botanical Garden

USDA NRCS Plant Database

 

 

Love Blueberries? Thank a Native Bee!

It’s blueberry season in New Jersey!  There are plenty of delicious deep blue orbs ripening for use on cereal, in pancakes, pies, crisps, cobblers, muffins, or just for snacking.  The blue color reflects the presence of anthocyanins, antioxidants with anti-inflammatory, anti-viral, and anti-cancer properties. Blueberries are not only tasty, but good for you.

A Bowl of Blueberries

For anyone who loves blueberries, you should know that some of our native bees are the most effective pollinators of this flavorsome fruit.

Blueberries are the fruit of deciduous shrubs that generally bloom in spring.  Most commercial blueberries in this region are cultivars of native blueberry species, usually Highbush Blueberry (Vaccinium corymbosum).  Lowbush Blueberry (Vaccinium angustifolium) is a species whose fruit is commonly harvested and sold in New England.  If the flowers are pollinated, the fruit ripens in mid to late summer, depending on their growing conditions.

Lowbush Blueberry (Vaccinium angustifolium)

An essential partner in the production of blueberries are the bees that are the primary pollinators for blueberry flowers.  While commercial growers may use Honey Bees to pollinate their crops, there are several species of native bees that are much more efficient blueberry pollinators.

How could that be?  Honey Bees pollinate flowers for a living.  Many are shipped from farm to farm specifically to pollinate crops.  (I think of them as the migrant workers of the insect world.)  How could there be bees that are more efficient pollinators?

Flowers come in all shapes and sizes, and they store and dispense their nectar (if they produce any) and pollen in many different ways.  Blueberry flowers are bell-shaped, with a narrow opening that allows access to the flowers’ nectar from the bottom of the hanging blossom.

Highbush Blueberry (Vaccinium corymbosum) Flowers

Lowbush Blueberry (Vaccinium angustifolium) Flowers

The pollen is most efficiently dispensed from the flowers’ anthers through a process called sonication, or ‘buzz’ pollination.  Buzz pollination is a process of releasing pollen by which the pollinator clings to the flower and vibrates its wing muscles without moving its wings.  This sets up enough of a vibration for the anthers to discharge a dusting of pollen on the flower visitor.  The wing vibration makes a buzzing sound, which gives this technique its name.  (Buzz pollination is the bee equivalent of ventriloquism!.)  Some of the pollen will be carried from flower to flower to enable pollination, while the rest is a pay-off for this service, and will be eaten by the bee and her larvae.  Bees drink nectar, but pollen is also a very important food source for them.

Honey Bees are not capable of buzz pollination, but several families of native bees are, including bumble bees, large carpenter bees, mining (Andrenid) bees, many sweat bees, some mason (Osmia) bees and Melitta bees.  Highbush and Lowbush Blueberry shrubs evolved with these bees who are native to the same region and habitats.  These native bees are able to handle the flowers more quickly and dispense and carry more pollen than the Honey Bees who lack this athletic skill.  Mason bees generally are very swift and efficient pollinators, able to process flowers many times more quickly than Honey Bees.

Mining Bee (Andrenid) visiting Lowbush Blueberry (Vaccinium angustifolium) Flower

Some of the native bees who are able to buzz pollinate specialize on visiting the flowers of blueberries; they and their larvae can only digest pollen from blueberry plants.  This is a great benefit to the blueberries, since these bees spend all of their foraging time visiting blueberry flowers, and there is no risk of pollen being dropped off on the wrong species.  It’s a risk for the bees, however.  If no blueberry flowers are available when the bees are active, the bees have no back-up plan; they could starve.  On the other hand, if blueberry flowers are available, it’s like assembly line processing. The bees know how to handle the flowers very efficiently to get the nectar and pollen they need to survive.

Mason Bee (Osmia) visiting Lowbush Blueberry (Vaccinium angustifolium) Flower

Blueberries are not the only crop that is most efficiently pollinated through sonication.  Cranberries, tomatoes, tomatillos, potatoes, peppers and eggplant are some of the other crops that have a higher rate of pollination when native bees with this skill are available to help pollinate their flowers.

A love of blueberries is not exclusive to people. Many other mammals and birds also enjoy the tasty fruit. Black bears are probably second to humans as consumers of blueberries, but fox, rabbits, raccoons, mice and many more eat their share, too.

Red Fox are among the animals that love blueberries.

Ruffed and Spruce Grouse relish the bounty blueberries provide,

Spruce Grouse

as do many other birds including Bluebirds, Catbirds, Scarlet Tanagers, Tufted Titmice, Veeries, Robins, and Brown Thrashers.

Eastern Bluebirds love blueberries

Veery in Fringtree (Chionanthus virginicus) Veeries are among the many birds who eat blueberries.

Butterflies and moths depend on blueberries, too, but in a completely different way.  Many species use the leaves and flowers as their caterpillar food.  The Natural History Museum’s Database of the World’s Lepidopteran Hostplants (HOSTS) lists 32 species that use Highbush Blueberry as caterpillar food, 42 that use Lowbush Blueberry.

Spring Azure butterfly. Highbush and Lowbush Blueberry shrubs are a caterpillar food plant for Spring Azures.

Saddleback moth caterpillar. Highbush and Lowbush Blueberry shrubs are a caterpillar food plant for Saddlebacks.

Caterpillars are an important part of the diet of many birds and other animals, so feeding caterpillars means that these other species will have the food they need, too.

Female Common Yellowthroat with Caterpillar

Blueberries are great landscape plants.  Not only do they provide food for our many animal neighbors (and us, if we’re quick!), but they are beautiful throughout the seasons, with their spring flowers, summer fruit, fabulous fall color and winter architectural structure and slightly shredding bark.  Why would anyone plant the non-native, invasive Burning Bush (Euonymus alatus) for its brief flash of color, when they could have blueberries instead?

Lowbush Blueberry (Vaccinium angustifolium) with Lichen in Fall

Highbush Blueberry is native primarily in the eastern third of the United States and Canada, but also in Washington state and British Columbia.  It is common in dry to wet woods, in thickets and on stream banks.  It can grow to a height of about 13 feet (4 meters).  Lowbush Blueberry is native from Manitoba to Newfoundland and Labrador provinces in Canada, and south as far as Tennessee and North Carolina (except Kentucky) in the United States. It can be found in dry woods and barrens, where its partnership with mycorrhizal fungi helps it to get the nutrients it needs from the soil.  It is a low growing plant, usually to a maximum height of about 2.5 feet (.75 meters).

The USDA NRCS Plant Database lists 25 species of blueberries that are native in different regions in North America.  Find one that’s native where you live, and add it to your landscape to enjoy its beauty and bounty.

A Bowl of Blueberries

A Bowl of Blueberries

Related Posts

Nutritious Fall Foliage – What Makes Leaves So Colorful?

The Buzz About Shooting Star

Partridge Pea Puzzles

Resources

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Eastman, John.  The Book of Forest and Thicket.  1992.

Eastman, John.  The Book of Field and Roadside.  2003.

Holm, Heather.  Bees An Identification and Native Plant Forage Guide.  2017.

Mader, Eric; Shepherd, Matthew; Vaughan, Mace; Black, Scott Hoffman; LeBuhn, Gretchen.  Attracting Native Pollinators: Protecting North America’s Bees and Butterflies.  2011.

Martin, Alexander C.;  Zim, Herbert S.; Nelson, Arnold L.  American Wildlife & Plants A Guide to Wildlife Food Habits.  1951.

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Tallamy, Douglas W.  Bringing Nature Home.  2007

Wagner, David L.;  Caterpillars of Eastern North America, 2005.

Wilson, Joseph S.; Carril, Olivia Messinger.  The Bees in Your Backyard. 2016.

Illinois Wildflowers

Natural History Museum’s Database of the World’s Lepidopteran Hostplants – Vaccinium corymbosum

Natural History Museum’s Database of the World’s Lepidopteran Hostplants – Vaccinium angustifolium

 

Hackberry, Butterflies and Birds

Common Hackberry (Celtis occidentalis) is a tree whose ridged, warty bark makes it easy to recognize in any season.  It may be easiest to spot in winter, since there are fewer leaves to distract from Hackberry’s distinctive outerwear.

Common Hackberry (Celtis occidentalis)

Look for Hackberry on a winter day that’s a little warmer than normal, and you might be rewarded with a glimpse of one of the butterflies that are among Hackberry’s known associates, the Mourning Cloak and the Question Mark.

Mourning Cloak butterfly

Question Mark butterfly. It is named for the white markings on its wing.

Both of these butterflies survive the winter as adults, spending most of the time sheltering in dry accommodations such as under loose bark, in a woodpile, or in a crevice or hole in a tree.  The butterflies are able to produce an anti-freeze-like substance that keeps them from succumbing to the winter cold.  They are mostly inactive during the winter; they rarely eat and don’t reproduce.  But they may venture out on a warmish winter day to look for a snack of minerals from rotting fruit, dung, sap or mud puddles.  When you are a butterfly that wakes up from a winter nap in northern latitudes, you have to have a flexible diet.  Not many flowers are blooming to offer nectar during the cold winter months.

While these butterflies may be found anywhere in the woods, in the warmer months when reproduction is on their mind, they are known to associate with Hackberry trees because they are one of the species whose leaves the caterpillars of both these butterflies can eat.  In addition to Hackberries, Mourning Cloak caterpillars use the leaves of a variety of trees, including willows, elms, birch, cottonwoods and aspen.  Question Mark caterpillars can also eat elm tree and nettle leaves.

Question Mark caterpillar on Hackberry leaves

In the spring and summer months, you may see additional butterflies whose caterpillars specialize on Hackberry leaves.  These species depend solely on Hackberries for their survival.  They include the curious looking and aptly named American Snout, the Tawny Emperor, and Hackberry Emperor.

American Snout butterfly drinking nectar from Short-toothed Mountain Mint (Pycnanthemum muticum)

The American Snout drinks nectar in addition to seeking out minerals.  Its long ‘nose’ is thought to have evolved to look like the stem of a leaf, which together with the cryptic coloration of its wings helps this butterfly to hide in plain sight, disguised as a dead leaf.

Tawny Emperor

Hackberry Emperor

Because Tawny and Hackberry Emperors rarely nectar, you are most likely to encounter them in or near wooded areas where their caterpillar food is present.  Their diet of minerals from mud, sap, and rotting materials such as fruit and dung is similar to that of the Mourning Cloak and Question Mark.  Hackberry Emperors also find human sweat to be a good nutritional source.  It is the species of butterfly I have most often seen landing on people to get a quick snack!

Hackberry Emperor getting minerals from soil and rocks.

Hackberry Emperor getting minerals from the sweat on someone’s shirt!

Hackberry Emperor getting minerals from the hood of a car. Is it the paint or the dirt?

Not every caterpillar will live to become an adult butterfly, since there are many predators to elude first.  The Hackberry Emperor caterpillar in the photo below has fallen victim to a parasitic wasp. Her larva will develop inside the caterpillar, consuming its insides until the wasp is mature enough to emerge.  As you might expect, the caterpillar is unlikely to survive.

Hackberry Emperor caterpillar, with a predatory wasp.

Several moth species including the IO Moth, and White-marked and Banded Tussock Moths also use Hackberries, among other woody species, as food for their caterpillars.

White-marked Tussock Moth

Banded Tussock Moth

The round growths on the leaves in the photo below are galls called Hackberry Nipple Galls.  They are caused by a type of true bug in a group called psyllids, or less appealingly, jumping plant lice.  The insects develop inside the galls and emerge when they mature.

Common Hackberry with ripening fruit and Hackberry Nipple Galls, caused by Pachypsylla celtidismamma.

Many of these insects are a potential bounty of food for birds.  I watched the young Tufted Titmouse below and its nest mates forage for food and play among the branches of a mature Hackberry.

Tufted Titmouse in Hackberry

Hackberry’s somewhat inconspicuous flowers are pollinated by the wind, blooming at the same time that the leaves are beginning to emerge.  Hackberries are monoecious; they have some flowers with just male reproductive parts, others with just female flowers, with both types of flowers on the same trees.  In the photo below, both male and female flowers are present.  The female flowers have two stigma-tipped styles that are spread in a ‘v’ shape projecting from the flower. (They look like forceps, or they also remind me of the arcade games where you have to use a similar looking tool to retrieve a toy from a glass enclosure.)  The male flowers have five or six anther-tipped stamens that barely project beyond the enclosing sepals.  A tree may even have some flowers with both male and female parts.  Pollen is carried by the wind from the anthers and deposited on the stigmas.

Common Hackberry (Celtis occidentalis) flowers. The female flowers have 2 styles spread in a ‘v’ shape. The male flowers each have 5-6 dark-colored anthers.

If the flowers are pollinated, a fruit called a drupe is produced.  A drupe is a fleshy fruit that has a stony enclosure around the seed inside, like a peach.  The fruit ripens in fall, but may persist into winter. Birds as diverse as Mockingbirds,

Mockingbird

Pileated Woodpeckers,

Pileated Woodpecker

and Wood Ducks eat Hackberry fruit.

A pair of Wood Ducks

Raccoons and squirrels are among the small mammals who eat the fruit.

A raccoon peaking out from its home.

Common Hackberry’s natural habitat includes wooded floodplains and hillsides, and can grow to a height of about 115 feet (35 meters).  It is native in Manitoba, Ontario and Quebec provinces in Canada and most of the United States, from New Hampshire to Montana in the north, south through Utah, New Mexico and east to Florida, except Louisiana, although it is less common in the southern part of its range.   It is also often used as a street tree.

There is a related species, Sugarberry (C. laevigata) that is native in the southern half of the United States and in the western states.  Dwarf Hackberry (Celtis pumila) is native in Ontario, Michigan, and from New Jersey west to Kansas, and south from Texas to Florida.  The butterflies that specialize on Hackberries use these species, too!

Common Hackberry (Celtis occidentalis)

Resources

Allen, Thomas J.; Brock, Jim P.; Glassberg, Jeffrey. Caterpillars in the Field and Garden. 2005.

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Eastman, John.  The Book of Forest and Thicket.  1992.

Eaton, Eric R.; Kauffman, Ken.  Kaufman Field Guide to Insects of North America.  2007.

Eiseman, Charley; Charney, Noah.  Tracks & Sign of Insects and Other Invertebrates.  2010.

Martin, Alexander C.;  Zim, Herbert S.; Nelson, Arnold L.  American Wildlife & Plants A Guide to Wildlife Food Habits.  1951.

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Tallamy, Douglas W.  Bringing Nature Home.  2007

Wagner, David L.;  Caterpillars of Eastern North America, 2005.

Illinois Wildflowers
http://www.illinoiswildflowers.info/trees/plants/hackberry.html
http://www.illinoiswildflowers.info/trees/tables/table153.html

USDA NRCS Plant Database
https://plants.usda.gov/core/profile?symbol=CEOC
https://plants.usda.gov/plantguide/pdf/pg_ceoc.pdf

USDA US Forest Service

Oregon State University College of Agricultural Sciences Department of Horticulture Landscape Plants