Another Migrating Butterfly, and the Plants that Sustain It

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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

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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

 

 

Shrubby St. Johnswort

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For about eight weeks during the summer, Shrubby St. Johnswort (Hypericum prolificum) is decorated with flowers, like ornaments on a holiday tree in mid-summer.

Shrubby St. Johnswort (Hypericum prolificum)

Each bright yellow blossom has five petals that provide a backdrop to a sphere-shaped burst of stamens, the male reproductive parts of the flowers.  Reaching out for a pollen deposit from the very center of the flowers are their female reproductive parts, called pistils.

Shrubby St. Johnswort (Hypericum prolificum) flower

This gaudy display is attractive to me, but more importantly, it’s a very effective lure for potential pollinators.  Bumble Bees are among the most likely visitors and effective pollinators.  While they climb around the stamens, eating and harvesting pollen from the anthers at their tips, they also pick up quite a bit of pollen on their hairy bodies.  As they forage, pollen on their bodies may be brushed off on the stigma at the tip of a flower’s pistil, setting the wheels in motion for pollination to occur.

Female Bumble Bee (Bombus impatiens) foraging on Shrubby St. Johnswort flowers

Female bees eat pollen themselves, and they also collect pollen to bring back to their nests to feed their larvae.  In the photo below, you can see the ‘bee bread’ this female has collected on her hind legs.  Quite a haul!

Female Bumble Bee (Bombus impatiens) harvesting pollen from Shrubby St. Johnswort flower

Other bees, like Sweat Bees, also visit the flowers for their pollen.

Female Sweat Bee (Lassioglossum species) harvesting pollen from Shrubby St. Johnswort flower

Female Sweat Bee (Lassioglossum species) eating pollen from Shrubby St. Johnswort flower. Notice the pollen on her back leg that she has harvested to take back to provision her nest for her larvae.

Flies are also consumers of pollen.  Flower Flies (also called Syrphid flies or Hover flies) are among those attracted to this pollen banquet.  They may also help with the pollination process, although their bodies are not as hairy as many of the bees.

Flower Fly or Syrphid Fly (Toxomerus geminatus) on Shrubby St. Johnswort flower

This bounty of pollen is so successful in enticing insects for whom pollen is an important part of their diet, primarily bees and flies, that Shrubby St. Johnswort doesn’t expend any energy producing nectar, finding it unnecessary to do so.

If the inadvertent pollination activities of these insects provide the expected payoff, this shrub lives up to the designation ‘prolificum’ in its scientific name, becoming ‘very fruitful’.  Fruit capsules replace the flowers, eventually opening to release their seeds for dispersal by gravity, or by hitching a ride on a passing animal. These dry fruits are visible throughout winter and into the following spring.

Shrubby St. Johnswort (Hypericum prolificum) fruit capsules

Shrubby St. Johnswort is related to the more well-known Common St. Johnswort (Hypericum perforatum), which is used for many medicinal purposes.  Shrubby St. Johnswort shares at least one chemical compound, hypericin, with its more famous relative.  Hypericin has a photosensitizing effect on its consumers, that is, it makes the skin of the animal that eats it especially sensitive to the sun, and exposure to sunlight after consumption results in rashes.  Producing hypericin evolved as an effective deterrent to animals that might otherwise be tempted to eat this plant, including deer.

Shrubby St. Johnswort is a relatively compact deciduous shrub that can grow to a height of about 6.5 feet (2 meters).  It does well in a variety of soils, from dry and rocky to moist, and can tolerate full sun to part shade.  Shrubby St. Johnswort is native in the eastern half of the United States, and in the province of Ontario in Canada.

Shrubby St. Johnswort (Hypericum prolificum)

 

Resources

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

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

Hoffmann, David.  Medical Herbalism.  2003.

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

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

Illinois Wildflowers

USDA NRCS Plants database

Missouri Botanical Garden

 

Love Blueberries? Thank a Native Bee!

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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

 

Trilliums, Flies and Ants

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For a few brief weeks in spring, Painted Trillium (Trillium undulatum) opens for business, the business of surviving as an individual plant and reproducing to ensure the continuation of the species.

Painted Trillium (Trillium undulatum)

Trilliums get their name from their structure.  Their leaves and flower parts are in threes or multiples of three.  Each plant has a whorl of three leaves below a single flower that has three petals, three sepals, six anthers, and a three-celled ovary.  ‘Undulatum’ refers to the wavy edges of the flower petals.

Painted Trillium’s three leaves act like solar panels to gather energy from the sun, enabling this plant to produce the carbohydrates it needs to grow and thrive, and to produce flowers that will enable reproduction if the flowers are pollinated.

Painted Trillium (Trillium undulatum)

Painted Trillium flowers have three bright white petals with paint-splatter-like dark red splotches at their base, bleeding into the petal’s veins.  This color contrast is an advertisement designed to attract potential pollinators to visit the flowers, implying that there is nectar and pollen available for a hungry insect to eat.  Painted Trillium offers these rewards because it needs help from a courier to move its pollen to another plant if it is to successfully reproduce through cross pollination.

Fly investigating Painted Trillium (Trillium undulatum), attracted by the dark red nectar guides

There is not a lot of documentation about the likely pollinators for Painted Trillium, but on more than one occasion, I have seen flies visiting the flowers.  The showy display works!  But the flies’ motivation is not to help with pollination.  They have their own needs to meet, mainly finding food.  They may visit the anthers to eat some nutritious pollen,

Fly harvesting pollen from Painted Trillium (Trillium undulatum)

and follow the colorful guides at the throat of the flower, diving deep to look for nectar.

Fly looking for nectar in a Painted Trillium (Trillium undulatum) flower

While foraging on the flower for food, the fly will likely rub its body or legs against the stigmas at the tips of the flower’s female reproductive parts, depositing pollen she may have brought on her body from a previous visit to a Painted Trillium flower.

Fly foraging on a Painted Trillium (Trillium undulatum) flower, with the underside of its abdomen brushing against the stigmas at the tips of the female reproductive parts of the flower. If this Painted Trillium is lucky, the fly will be depositing pollen picked up from another flower.

Fly foraging on a Painted Trillium (Trillium undulatum) flower, with its legs grasping the stigmas at the tips of the female reproductive parts of the flower.

It will also likely rub against the anthers of this flower, picking up pollen to take with it to deposit on the next Painted Trillium flower it visits.

Fly on a Painted Trillium (Trillium undulatum) flower, with its legs brushing against the anthers, from which pollen is dispensed.

Fly on a Painted Trillium (Trillium undulatum) flower, with the underside of its abdomen brushing against the anthers, hopefully picking up some pollen to take to another flower.

This inadvertent pollen transport is what Painted Trillium is counting on.  It has evolved to attract these unwitting pollination partners, and is willing to pay the energy price to reward them in exchange for their assistance with cross-pollination.

Several Trillium species with dark red flowers have evolved to attract flies as their pollinators.  The dark red flower color is often accompanied by a somewhat rank aroma. Together these features are meant to mimic dead rotting flesh (ok, carrion) or other decomposing matter.  Several fly species seek out this kind of material to lay their eggs.  When the larvae emerge from the eggs, they eat the decaying matter, breaking it down and add the result to the soil layer after it passes through the larva’s body.  These insects help crime scene investigators estimate time of death for a corpse, based on the stage and rate of development of the insect in the decaying body.  Many fly species are attracted to the flowers that use this strategy, only to be disappointed when there is no suitable place to lay their eggs.  At least the flies can console themselves with a pollen snack.

Trillium species that use this deceptive strategy include Red Trillium (Trillium erectum), and Toadshade (Trillium sessile, T. cuneatum).

Red Trillium (Trillium erectum)

Red Trillium has many aliases.  It is also known as Purple Trillium, Wake-robin and Stinking Benjamin, this last name a nod to the flowers’ scent, Wake-robin because it blooms at about the same time Robins returned from their wintering grounds, back when they used to migrate more.

Toadshade gets its name from stories of toads taking refuge under the umbrella-like leaves of the plant.

Toadshade (Trillium cuneatum, T.sessile)

In the photo below, a fly is investigating one of the anthers, the source of the flower’s pollen.

Toadshade with fly

If the flower is successfully pollinated, a fruit develops and ripens later in the summer.  The fruit is a berry that splits open when ripe, making its many seeds available for dispersal.  Each seed has an elaiosome attached, a nutritious food packet whose chemical content mimics that of an insect.  This mechanism has evolved to attract ants to disperse the seeds.  It works because ants are omnivorous; they eat some plant material and enjoy sweet treats such as nectar, but insect protein is an important part of their diet.  The ants are attracted to the seeds because of the elaiosome.  They take the seeds back to their homes, eat the elaiosome, and toss the seed on their compost heap, effectively planting the seed in a fertile, protected location.  This evolutionary strategy, known as myrmecochory, is shared by many spring blooming wildflowers.

If you need proof that other insects are important ant food, you’ll find some evidence in the photo below.  I watched while this ant worked tirelessly to drag to its home the moth it’s grasping, working its way across the trail, letting no obstacles like sticks, leaves or rocks deter it from its mission!

Insects are an important source of food for ants. This ant worked tirelessly to drag the moth back to its home.

The elaiosome strategy works in much the same way that fleshy fruits attract birds and other animals to eat their fruits and ‘disperse’ the seeds complete with fertilizer after the seeds pass through the animal’s digestive system, a trait used by many plants that bloom later in the season.

Trilliums typically grow in moist woods.  Painted Trillium is native from Ontario and Quebec south through northern New Jersey and much of Pennsylvania, from there south through the Appalachian mountains to northern Georgia and South Carolina.  It is also present in parts of Michigan.  Red Trillium’s range is a bit broader, from Ontario, Quebec and Michigan, south through northern Alabama, Georgia and South Carolina, with some presence in Indiana and Illinois.  Trillium sessile can be found from western New York state west to Illinois, Missouri and western Kansas, south from Oklahoma to north Carolina.  Trillium cuneatum is native in Pennsylvania, Maryland and Virginia, west to southern Illinois and south from Mississippi to Georgia.

These lovely Trilliums depend on flies and ants for their continued survival.

Painted Trillium (Trillium undulatum)

Related Posts

A Carpet of Spring Beauty, Woven by … Ants!

Resources 

Gracie, Carol.  Spring Wildflowers of the Northeast. 2012.

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

Marshall, Stephen A.  Flies The Natural History and Diversity of Diptera.  2012.

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

Michigan Natural Features Inventory, Trillium undulatum. Willdenow. 2004.

USDA NRCS Plants Database

https://plants.usda.gov/core/profile?symbol=TRUN

https://plants.usda.gov/core/profile?symbol=TRER3

https://plants.usda.gov/core/profile?symbol=TRSE2

https://plants.usda.gov/core/profile?symbol=TRCU

USDA Forest Service Plant of the Week, Painted Trillium (Trillium undulatum), Larry Stritch