Maple-leaf Viburnum

Maple-leaf (or Maple-leaved) Viburnum (Vibernum acerifolium) is spectacular this fall, with colors ranging from pale pink to deep magenta,

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum (Vibernum acerifolium)

often with washes of blue and purple.

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum (Vibernum acerifolium)

The combination of decreasing hours of daylight, the increasing length of darkness, and cool nighttime temperatures is nature’s signal that it’s time to prepare for winter. Plants gradually stop producing chlorophyll, which is responsible for the green color visible in the leaves during the growing season. The absence of chlorophyll reveals the colors of other chemical compounds present, like the yellows of xanthophylls, oranges of carotenes, and browns of tannins.

Many days this fall have been warm and sunny.  Nights have been cool with temperatures often in the low to mid 40s (4 – 8°C).  These conditions enable deciduous trees and shrubs to continue to produce sugars in their leaves during the day.  Some of the sugars combine with minerals obtained from the soil to manufacture anthocyanins, the chemicals that cause the red, blue and purple colors in the leaves.  The decreasing number of daylight hours combined with the cool temperatures signal the plant to stop nutrients from moving into the trees’ circulatory system as the leaves prepare to detach from the plant.  These chemical compounds are trapped in the leaves, resulting in the colorful fall display.

Maple-Leaved Viburnum (Viburnum acerifolium) with fruit

Maple-Leaved Viburnum (Viburnum acerifolium) with fruit

Fleshy, dark blue, berry-like fruits called drupes accompany the colorful leaves. Each drupe contains a single seed enclosed by a stony casing or pit, like a peach.  For many birds and other animals, the fleshy fruit is an enticement to dine in the coming weeks.   Maple-leaf Viburnum and many other plants have evolved to produce such fruits in order to enlist animals as partners in dispersing their seeds.  The animal consumes the fruit, passing the seed through its digestive system, and depositing the seed accompanied by other nutrients.  White-throated Sparrows,

White-throated Sparrow

White-throated Sparrow

Cardinals,

Northern Cardinal

Northern Cardinal

and Hermit Thrush, as well as chipmunks and squirrels are among those who consume the fruits and disperse the seeds.

In early summer, Spring or Summer Azure butterflies may lay eggs on the flower buds of this and many species of viburnums, dogwoods and other shrubs.

Summer Azure

Summer Azure

After hatching from the eggs, the butterfly’s caterpillars feed on the flower buds. That is, they do if they manage to avoid being eaten by a predator like a bird, a spider, an ant or other parasitic insect.

Maple-leaf Viburnum (Vibernum acerifolium) in bud.  Can you spot the two spiders waiting patiently for an unsuspecting caterpillar or other victim?

Maple-leaf Viburnum (Vibernum acerifolium) in bud. Can you spot the two spiders waiting patiently for an unsuspecting caterpillar or other victim?

Plenty of flowers survive the feeding frenzy to provide a beautiful summer display. Several species of native bees, flies and other insects visit the flowers for nectar, providing essential pollination services that result in the fall fruits.

Maple-leaf Viburnum (Vibernum acerifolium) in flower.  Look for the ants who are visiting the flowers for nectar.  They would also be happy to find a caterpillar.

Maple-leaf Viburnum (Vibernum acerifolium) in flower. Look for the ants who are visiting the flowers for nectar. They would also be happy to find a caterpillar.

Maple-leaf Viburnum is a great alternative to the non-native, invasive Burning Bush (Euonymus alatus), which is often planted in formal landscapes for its fall foliage.  Maple-leaf Viburnum offers an equally attractive, and more nuanced display.  More importantly, it provides food and shelter for the insects, birds and other animals that share its territory.

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum is a woodland understory shrub native to the eastern United States, and Quebec and Ontario provinces. If you live within it’s natural range, go for a walk in the woods near you to see if you can spot it.  Then think about adding it to your own landscape to guarantee a view of this gorgeous shrub.

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum (Vibernum acerifolium)

For more information on fall foliage colors, see Nutritious Fall Foliage: What Makes Fall Leaves So Colorful?

Resources

Capon, Brian. Botany for Gardeners.  2005

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

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

Illinois Wildflowers

 

A Butterfly with Unusual Eating Habits: The Harvester

We often think of butterflies as relying on nectar from flowers as their primary source of food for adult butterflies, and many species do.

Clouded Sulphur and Honey Bee on Aster

Clouded Sulphur and Honey Bee on Aster

But there are others who feed mainly on minerals, often from mud or dung, or who consume both nectar and mineral sources.

Red-spotted Purple feeding on minerals in mud

Red-spotted Purple feeding on minerals in mud

One species that has more unusual eating habits is the Harvester (Feniseca tarquinius).

Harvester (Feniseca tarquinius)

Harvester (Feniseca tarquinius)

 

This butterfly rejects flower nectar in favor of honeydew, the sugary secretion produced by aphids. Harvesters also feed on mineral sources such as dung, sap and mud.  In the photo below, the butterfly is feeding on a mushroom.

Harvester (Feniseca tarquinius)

Harvester (Feniseca tarquinius)

The Harvester’s eating habits explain its habitat preference, wet woodlands or along streams, especially where alders are found.

Smooth Alder (Alnus serrulata)

Smooth Alder (Alnus serrulata)

Alders are hosts to the Woolly Alder Aphid (Prociphilus tessellatus), a favorite honeydew source for Harvesters.

Woolly Alder Aphids on Smooth Alder (Alnus serrulata)

Woolly Alder Aphids on Smooth Alder (Alnus serrulata)

Even more important for the Harvester, these aphids are a favorite diet source of its caterpillars. The Harvester is the only butterfly species in North America whose caterpillars are strictly carnivorous.   They feed primarily on several species of woolly aphids, often the Woolly Alder Aphid, but also the Woolly Beech Aphid, as well as others.  The caterpillars will sometimes disguise themselves from predators by using their silk to tie to their bodies the remains of the aphids they consume.  This is especially effective as protection from ants that may be tending the aphids for their honeydew.  The Harvester caterpillars share some of the chemical signature of their aphid diet, which also may give them protection from predatory ants.

So wooly aphids feed both the Harvester butterfly and its caterpillars.  Because of its habitat and food preferences, the Harvester is not commonly seen. So consider yourself lucky if you encounter one!

Harvester

Harvester

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

Featured Creatures – University of Florida

Butterflies and Moths of North America

 

Red-banded Hairstreaks Need Sumacs and Leaf Mulch

If you need any evidence to convince yourself of the nutritional value of leaf mulch, look to the Red-banded Hairstreak’s eating habits for confirmation. This small but showy butterfly, named for the wide slash of red across its wings, has a preference for leaf mulch as the food source for its caterpillars.

Red-banded Hairstreak nectaring on Short-toothed Mountain Mint

Red-banded Hairstreak nectaring on Short-toothed Mountain Mint

By leaf mulch I mean naturally fallen, decomposing leaves. It is often referred to as leaf litter or detritus, terms that sound like something we should clean up or remove.  Leaf mulch is such a valuable source of nutrients for both plants and animals, and such a good habitat for so many beneficial insects, that I’ve decide it needs a positive public relations campaign to make it socially acceptable to use naturally fallen leaves as a garden mulch.  So I’m calling it what it is – leaf mulch.  Join the movement!

Adult Red-banded Hairstreaks nectar on a variety of flowers, including Mountain Mints (Pycnanthemum species), Goldenrods (Solidago species), Green-headed (or Cutleaf) and other coneflowers (Rudbeckia laciniata, Rudbeckia species), and even the flowers of sumac (Rhus species) trees.

Red-banded Hairstreak and friend nectaring on Green-headed or Cutleaf Coneflower

Red-banded Hairstreak and friend nectaring on Green-headed or Cutleaf Coneflower

Red-banded Hairstreak caterpillars are reported to eat the fallen leaves of Wax Myrtle (Myrica cerifera) and other trees including oaks (Quercus species), but fallen sumac leaves are thought to be the favored hosts for this butterfly’s caterpillars.

When laying their eggs (ovipositing) female Red-banded Hairstreaks walk on the ground, usually depositing eggs on the underside of fallen leaves. After they hatch, the caterpillars feed on the leaves.  Red-banded Hairstreaks spend the winter as fourth instar caterpillars, likely in the shelter of this naturally fallen leaf mulch.

Winged Sumac (Rhus copallinum) is a favorite food source for Red-banded Hairstreak caterpillars.  It’s also a good choice as an ornamental shrub, because it has glossy deep green compound leaves with a ‘winged’ midrib that gives this species its name.

Winged Sumac flowers

Winged Sumac flowers

Its large pyramid-shaped clusters of yellowish flowers bloom in mid to late summer.  They are attractive to many insect pollinators, including butterflies.

Orange Sulphur nectaring on Winged Sumac flowers

Orange Sulphur nectaring on Winged Sumac flowers

Juniper Hairstreak nectaring on Winged Sumac flowers

Juniper Hairstreak nectaring on Winged Sumac flowers

Successfully pollinated flowers yield bright red fruit that is complemented by dark red foliage in fall.  Winged Sumac grows to a maximum height of about 10 feet (3 meters), and prefers sunny locations.

Winged Sumac in fall

Winged Sumac in fall

Fragrant Sumac (Rhus aromatica) is another attractive shrub that grows to a height of about 8 feet (2.5 meters) with glossy blue-green three-parted leaves that are somewhat aromatic.  It blooms in spring before or concurrently with its leaves unfurling, has brightly colored fall foliage, and red fruit.  It can tolerate sun to part shade.

Fragrant Sumac in fall

Fragrant Sumac in fall

Staghorn Sumac is (Rhus typhina) taller, with a maximum height of about 25-33 feet (7.5-10 meters), beautiful fall color that begins to show in late summer, and bright red fruit clusters.  It has large clusters of yellowish flowers that generally bloom in June.

Staghorn Sumac in fall

Staghorn Sumac in fall

With sumacs, male and female flowers are usually, although not always, on separate plants, so to get fruit make sure you have a male as well as females. According to the USDA, several mammals and over 300 species of birds eat the fruit, although usually not until late in the winter, so you’ll be able to see their luscious bright red color for a long time.

Staghorn Sumac fruit

Staghorn Sumac fruit

Among the birds I’ve seen eating the fruits are Chickadees, Downy and Pileated Woodpeckers.

Carolina Chickadee

Carolina Chickadee

When established, sumacs may also spread through their underground root system. If you are considering a plant screening or hedgerow, consider Winged Sumac.  It spreads quickly, and is quite lovely.

Are you thinking, “Sumacs? Won’t I get a rash from them?  Aren’t they poison?”  No!  Only the related species, Poison Sumac (Toxicodendron vernix), has the chemical composition to give you a rash.  Poison Sumac is actually more closely related to Poison Ivy (Toxicodendron radicans) than it is to the other sumacs.  Even these two ‘poison’ plants have wildlife value in the food offered by their flowers and fruits!  But they’re usually not recommended as garden plants.

Let’s get back to leaf mulch for a minute, because it’s the best fertilizer you can offer your plants. There may be more scenarios than those below, but let’s consider some of our options:

  1. Rake or blow leaves from planting beds, prepare them for municipal pick up, buy composted leaf mulch and apply it to beds;
  2. Rake or blow leaves from planting beds, compost or chop them, apply composted or chopped leaves to beds;
  3. Let the naturally fallen leaves stay in the planting beds.

I like option 3. What about you?   To entice Red-banded Hairstreaks to take up residency with you, consider adding sumacs to your landscape.  For a healthy garden, use leaf mulch. To enable Red-banded Hairstreaks to successfully reproduce and survive the winter, let the naturally fallen leaves be your mulch.

Red-banded Hairstreak on goldenrod flower buds

Red-banded Hairstreak on goldenrod flower buds

Note:  This post was adapted from an article that appeared in the Fall 2013 issue of Butterfly Gardener, a publication of the North American Butterfly Association.

References

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

Lady Bird Johson Wildflower Center Native Plant Database

USDA Plants Database

 

‘Will Work for Food’ – Extrafloral Nectaries

Wild Senna (Senna hebecarpa, S. marylandica) has so many stories to tell!  This tall, herbaceous plant has flowers that are unusual for a member of the Pea (Fabaceae) family.  Rather than curling to form the banner, wings and keel that are common Pea family characteristics,

Everlasting Pea (Lathyrus latifolius) with skipper

Everlasting Pea (Lathyrus latifolius) with skipper

Wild Senna’s petals are open and distinct.

Wild Senna (Senna hebecarpa) with Bumble Bee. Note the pollen on her rear legs.

Wild Senna (Senna hebecarpa) with Bumble Bee. Note the pollen on her rear legs.

Wild Senna’s flowers have another somewhat unusual feature, or more accurately, they lack a feature, nectaries, that many flowers have.  Many plant species have evolved to entice pollinators to their flowers by providing a reward of nectar in exchange for their visits. In spite of the lack of nectar, Wild Senna is pollinated by bees, primarily Bumble Bees but also Sweat Bees (Halictid species).  They visit the flowers for their pollen, a highly nutritious food that contains protein, carbohydrates, fats, vitamins and minerals; plenty of incentive for a bee to visit even without nectar.  Alerted to the possibility of food by the colorful yellow flowers, the adult bees come to dine on pollen and to harvest some to bring back to their nests for their larvae.

Many plant species have evolved to produce chemical compounds whose primary purpose is to protect the plant from being eaten by making it bitter, distasteful or even toxic to potential consumers.  Wild Senna is a species that has adapted to use this defense.  Both the leaves and fruits (seed pods) contain anthraquinones, which are powerful laxatives.  Often people take advantage of the protective chemicals that plants produce by finding medicinal uses for them. In the case of the Senna species, the laxative is used for treating constipation.

These chemicals are a very effective deterrent to many animal species that eat plants (herbivores).  Even in areas where there is severe deer pressure, it’s unusual to see Wild Senna browsed.  But this strategy is not effective against all potential herbivores.  There are some butterflies and moths, including the Cloudless Sulphur,

Cloudless Sulphur caterpillar on Wild Senna (Senna hebecarpa)

Cloudless Sulphur caterpillar on Wild Senna (Senna hebecarpa)

Sleepy Orange,

Sleepy Orange butterfly

Sleepy Orange butterfly

and the Common Tan Wave, whose caterpillars are able to eat the leaves or other parts of Wild Senna.  These insects have evolved to specialize on these and other closely related plants, without being harmed by the chemicals that are toxic to other species.

Which brings us to an interesting back-up strategy Wild Senna employs for protection.  Wild Senna has extrafloral nectaries, a nectar source separate from the flowers. They are positioned on the leaf petioles (stems) near their attachment to the primary plant stem and adjacent to the flower buds.  Why would a plant species offer nectar if it’s not a lure for pollinators?  It takes energy and resources to produce nectar.  What’s in it for the plant to provide this service?  Who feeds here?

The egg-shaped bump is an extrafloral nectary on a leaf stem of Wild Senna (Senna hebecarpa)

The egg-shaped bump is an extrafloral nectary on a leaf stem of Wild Senna (Senna hebecarpa)

Wild Senna’s extrafloral nectaries attract a variety of visitors, many of them beneficial members of the ecosystem.  The Sweat Bee below may have stopped here before or after visiting Wild Senna flowers for their pollen.

Sweat Bee feeding at an extrafloral nectary on Wild Senna (Senna hebecarpa)

Sweat Bee feeding at an extrafloral nectary on Wild Senna (Senna hebecarpa)

Many lady beetle species, including the Seven-spotted Lady Beetle pictured here, help to keep the aphid population in check.

Seven-spotted Lady Beetle feeding at an extrafloral nectary on Wild Senna (Senna hebecarpa)

Seven-spotted Lady Beetle feeding at an extrafloral nectary on Wild Senna (Senna hebecarpa)

This jewel-like creature is a Perilampid wasp, one of several parasitic wasps that specialize on various insect species as their prey, including some other parasitites.

Perilampid wasp feeding at an extrafloral nectary on Wild Senna (Senna hebecarpa)

Perilampid wasp feeding at an extrafloral nectary on Wild Senna (Senna hebecarpa)

For Wild Senna, ants are probably the most beneficial visitor to this nutritious food source.

Ant feeding at an extrafloral nectary on Wild Senna (Senna hebecarpa)

Ant feeding at an extrafloral nectary on Wild Senna (Senna hebecarpa)

Sugary substances like nectar are important food for ants.  But protein and other nutrients available from insects (including caterpillars) are also an essential part of the diet of most ant species.  Ants that are enticed to visit Wild Senna for its nectar can also hunt for and eat the insects that may be consuming the leaves or buds of the plant.  The placement of the nectaries between the leaf blade and flower buds is an advantageous location for protecting both plant parts.

Ant with caterpillar prey

Ant with caterpillar prey

You might think of the ants as an army of mercenaries paid in nectar to guard the plant, with as many caterpillars and other herbivores as they can catch as a bonus.  Ants will work for food!

Resources

USDA NRCS Plant Database http://www.plants.usda.gov/factsheet/pdf/fs_sehe3.pdf

Illinois Wildflowers http://www.illinoiswildflowers.info/savanna/plants/wild_senna.htm

Marshall, Stephen A.  Insects Their Natural History and Diversity.  2006.

Waldbauer, Gilbert.  What Good Are Bugs?.  2003.

Feasting on Green-headed Coneflower

How many flowers do you see in the photo below?

Gray Hairstreak on Green-headed Coneflower (Rudbeckia laciniata)

Gray Hairstreak on Green-headed Coneflower (Rudbeckia laciniata)

If you said one, that’s the answer I was looking for. However, it’s not correct!

The plant pictured here is Green-headed Coneflower (Rudbeckia laciniata), also sometimes called Cut-leaf Coneflower in deference to its deeply lobed leaves.  Green-headed Coneflower is a member of the Aster, or ‘Composite’ family, a name that’s pretty descriptive of their typical flower clusters (inflorescences). What our brains think is a single flower is actually a cluster (or composite) of tiny flowers, often of two different types, ray flowers and disc flowers. The petal-like parts of the flower cluster are each an individual ray flower with a single petal. In the center there are dozens of tiny tubular flowers called disk flowers, in reference to the disk-like shape of the flower cluster.  In the picture above, just a few of the disk flowers are blooming.

Some Aster family members just have ray flowers, like Dandelions.

Eastern-Tailed Blue nectaring on a Dandelion

Eastern-Tailed Blue nectaring on a Dandelion

Some have just disk flowers, like New York Ironweed.

Bumble Bee on New York Ironweed

Bumble Bee on New York Ironweed

Many, like Green-headed Coneflower, have both types of flowers. When both ray flowers and disk flowers are present, the ray flowers are often sterile, in which case their primary purpose is to act as nectar guides, alerting pollinators to the availability of nectar and pollen in the many disk flowers at the center of the flower cluster.

A Silver-spotted Skipper is nectaring on the disk flowers that are in bloom on this Green-headed Coneflower.  The lowest disk flowers have finished blooming, while those at the top of the flower cluster are still in bud.

A Silver-spotted Skipper is nectaring on the disk flowers that are in bloom on this Green-headed Coneflower. The lowest disk flowers have finished blooming, while those at the top of the flower cluster are still in bud.

The disk flowers bloom gradually over a period of a few weeks, maximizing the plant’s chances for pollination with the assistance of insect partners. In the case of Green-headed Coneflower, the disk flowers bloom gradually from the bottom, or outside ring, to the top, or center, of the flower cluster.

A Red-banded Hairstreak is drinking nectar from the last few blooming flowers of this Green-headed Coneflower inflorescence.

A Red-banded Hairstreak is drinking nectar from the last few blooming flowers of this Green-headed Coneflower inflorescence.

Because of the number and size of its disk flowers, Green-headed Coneflower is able to attract many insects as potential pollinators. Often multiple insects can be found feeding simultaneously on different flowers in the same flower cluster.

This Green-headed Coneflower offers enough flowers with nectar to feed both an American Copper and a Honey Bee.

This Green-headed Coneflower offers enough flowers with nectar to feed both an American Copper and a Honey Bee.

Green-headed Coneflower’s disk flowers are large enough to accommodate small to medium sized butterflies like those pictured here.  They may rub against some pollen and transfer it to another plant, assisting with pollination.

Summer Azure with Green-headed Coneflower (Rudbeckia laciniata)

Summer Azure with Green-headed Coneflower (Rudbeckia laciniata)

Common Buckeye and Bumble Bee feeding on Green-headed Coneflower (Rudbeckia laciniata)

Common Buckeye and Bumble Bee feeding on Green-headed Coneflower (Rudbeckia laciniata)

Beneficial predators like the thread-waisted wasps (a species of Sphecid wasp) pictured below also benefit from the abundant nectar, giving them the energy they need to reproduce.  (I often see this species mating and nectaring at the same time, as they are doing here. A level of skill and coordination to which humans can only aspire!)  Their anatomy makes it more likely that they will help with pollination than butterflies, since more of their bodies are likely to come in contact with pollen.  The female wasps of this species (Eremnophila aureonotata) hunt caterpillars to feed their larvae.

Green-headed Coneflower with mating Wasps (Eremnophila aureonotata)

Green-headed Coneflower with mating Wasps (Eremnophila aureonotata)

But bees are the most likely to be successful pollinators, because they are the best anatomical match for gathering pollen, and it’s more likely to stick to the branched hair on their bodies and be carried away to be deposited on another flower.

Bumble Bee and American Copper nectaring on Green-headed Coneflower (Rudbeckia laciniata)

Bumble Bee and American Copper nectaring on Green-headed Coneflower (Rudbeckia laciniata)

Sweat Bee on Green-headed Coneflower (Rudbeckia laciniata)

Sweat Bee on Green-headed Coneflower (Rudbeckia laciniata)

The Sweat Bee below is gathering pollen on her hind legs to take back to feed her larvae.  Only female bees gather pollen this way.

Sweat Bee (Lasioglossum species) on Green-headed Coneflower (Rudbeckia laciniata)

Sweat Bee (Lasioglossum species) on Green-headed Coneflower (Rudbeckia laciniata)

Dining on Green-headed Coneflower is not without danger, as this Bumble Bee found out when it fell victim to a Wheel Bug, a type of assassin bug.  Sometimes the diner becomes the dinner.

Wheel Bug (Arilus cristatus) consuming a Bumble Bee smoothie

Wheel Bug (Arilus cristatus) consuming a Bumble Bee smoothie

If the flowers are successfully pollinated, you’re likely to see Goldfinches and other birds feeding on the seeds later in the season and throughout fall.

Goldfinch eating Green-Headed Coneflower seeds

Goldfinch eating Green-Headed Coneflower seeds

The Aster family is the second largest family of flowering plants in terms of its number of species, second only to the Orchid family.  In late summer and fall the Aster family represents a high percentage of what’s in bloom.  For information on a few other Aster family members, see Asters Yield a Treasure Trove! and Fall Allergies?  Don’t Blame Goldenrod!

Resources

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

Elpel, Thomas J.  Botany in a Day.  2006.