New England Asters – A Hotbed of Activity!

As the temperatures cool and the changing color of the leaves intensifies, plants in the Aster (Asteraceae) family continue to offer a bright display and food for flower visitors.

New England Asters (Symphyotrichum novae-angliae) with a flower fly (Eristalis transversa) and sweat bee (Agapostemom species)

New England Asters (Symphyotrichum novae-angliae) with a flower fly (Eristalis transversa) and sweat bee (Agapostemom species)

The Aster family is also called the composite family, because of the arrangement of their flowers. What looks to us like a single flower is actually a cluster of many flowers, often of two different types: ray flowers, which look like petals, and small tubular disk flowers in the center of the display.

Tricolored Bumble Bee (Bombus ternarius) feeding on New England Asters (Symphyotrichum novae-angliae)

Tricolored Bumble Bee (Bombus ternarius) feeding on New England Asters (Symphyotrichum novae-angliae)

Some aster family members, like dandelions (Taraxacum species), only have ray flowers.

Eastern-Tailed Blue butterfly drinking nectar from dandelion

Eastern-Tailed Blue butterfly drinking nectar from dandelion

Others have only disk flowers, like Mistflower (Conoclinium coelestinum).

Zabulon Skipper nectaring from Mistflower (Conoclinium coelestinum)

Zabulon Skipper nectaring from Mistflower (Conoclinium coelestinum)

In the case of New England Asters (Symphyotrichum novae-angliae), the ray flowers’ function is primarily to add to the attraction of the floral display to entice potential pollinators to visit the flowers.  It’s the tiny disk flowers at the center of each flower cluster that offer the reward of nectar and pollen.

Tricolored Bumble Bee (Bombus ternarius) feeding on New England Asters (Symphyotrichum novae-angliae)

Tricolored Bumble Bee (Bombus ternarius) feeding on New England Asters (Symphyotrichum novae-angliae)

Even on cool, blustery days, Bumble Bees, like the Tricolored Bumble Bee (Bombus ternarius) in the photo above, forage for food. The hair on their bodies helps to keep them warm, and is a good vehicle to pick up pollen from one flower and transfer it to another.

Sweat Bees are still active in autumn, fueled by the nectar aster family members offer.

Sweat bee (Halictid family)

Sweat bee (Halictid family)

Sweat bee (Agapostemom species) feeding from New England Aster (Symphyotrichum novae-angliae)

Sweat bee (Agapostemom species) feeding from New England Aster (Symphyotrichum novae-angliae)

Sweat bee (Agapostemom species) feeding from New England Aster (Symphyotrichum novae-angliae)

Sweat bee (Agapostemom species) feeding from New England Aster (Symphyotrichum novae-angliae)

Bees are not the only flower visitors at this time of year. Flies are second only to bees in their importance as pollinators.  Some species can be seen throughout fall.

Flower fly (Eristalis transversa) feeding from New England Aster (Symphyotrichum novae-angliae)

Flower fly (Eristalis transversa) feeding from New England Aster (Symphyotrichum novae-angliae)

Many fly species have evolved to look like bees or wasps in an effort to frighten off potential predators, but if you look carefully you can see the short antennae and very large eyes that almost meet in the center of their faces that are typical of flies.

Flower fly (Eristalis arbustorum) feeding from New England Aster (Symphyotrichum novae-angliae)

Flower fly (Eristalis arbustorum) feeding from New England Aster (Symphyotrichum novae-angliae)

The fly below is masquerading as a small wasp, hoping to elude predators.  It’s larvae consume aphids, another benefit from this diminutive creature!

Flower fly (Sphaerophoria contigua) on New England Aster (Symphyotrichum novae-angliae)

Flower fly (Sphaerophoria contigua) on New England Aster (Symphyotrichum novae-angliae)

Flower fly (Sphaerophoria contigua) on New England Aster (Symphyotrichum novae-angliae)

Flower fly (Sphaerophoria contigua) on New England Aster (Symphyotrichum novae-angliae)

Moths and butterflies also use New England Aster flowers as a convenient energy drink.

Common Looper Moth (Autographa precationis) feeding on New England Aster (Symphyotrichum novae-angliae)

Common Looper Moth (Autographa precationis) feeding on New England Aster (Symphyotrichum novae-angliae)

Despite their name, New England Asters are native throughout much of the United States and several Canadian provinces. They grow along roadsides and in meadows, and make a great addition to a sunny garden with average to moist soil, even tolerating clay soil.

Take a look at the New England Asters in the photo below. How many visitors can you find on these flowers?

New England Asters (Symphyotrichum novae-angliae) with flower visitors. How many can you find?

New England Asters (Symphyotrichum novae-angliae) with flower visitors. How many can you find?

 

Related posts

Asters Yield a Treasure Trove

Resources

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

USDA Plant Database

Missouri Botanical Garden

Illinois Wildflowers

 

Asters Yield A Treasure Trove!

Orange Sulphur on New England Aster (Symphyotrichum novae-angliae)

Orange Sulphur on New England Aster (Symphyotrichum novae-angliae)

A few days ago the weather was beautiful, with temperatures in the mid-60s, cloudless blue skies and a bit of a breeze, so we went for a walk at a wildlife management area in West Amwell, New Jersey.  We were looking for birds, fall fruit and foliage, and any other interesting critters that happened to present themselves.

We didn’t expect to see a lot in the way of butterflies because of the cool temperatures, and because it’s so late in the season.  We didn’t see many butterflies, but those we did see were pretty spectacular.  Orange Sulphurs were out and about, which was to be expected, since they are among the species that stay active as late as November in this area.  But the surprises were a Fiery Skipper and an American Snout, both of which are fairly rare in New Jersey, especially in late October.  All were nectaring on various species of asters, or other aster family members, the goldenrods.

American Snout

American Snout

Fiery Skipper on New England Aster (Symphyotrichum novae-angliae)

Fiery Skipper on New England Aster (Symphyotrichum novae-angliae)

Asters family members are the primary source of food for late season pollinators.  They are prolific in their long bloom period, often continuing into November.  Their flowering structure reflects a very clever strategy, and suggests this plant family’s alternate name, ‘composite’.  What looks to us like a single flower is actually a cluster of tiny flowers, potentially of two different types, ray flowers and disk flowers.

Blue Wood Aster (Symphyotrichum cordifolium)

Blue Wood Aster (Symphyotrichum cordifolium)

The photograph above of Blue Wood Aster (Symphyotrichum cordifolium) shows the classic flower heads of the Aster family:  a circle of ray flowers that look like petals, pale blue in this species, surrounding a cluster of tiny tubular disk flowers in the center of the head.  If you look carefully at the disk flowers in this photo, you can see that the outer rows are open and blooming, while those in the center of the cluster are still in bud.  This gradual bloom habit supports a long period of flowering, offering nectar to fall pollinators for many weeks.  The disk flowers of this plant are a pale yellow in bud and when they first open, then turning pink or magenta as they age.  This color change is thought to be a signal to pollinators, directing them to the receptive yellow flowers which are not yet pollinated and that will reward them with nectar, and steering them away from those blossoms that are already satisfactorily pollinated.  (Plants are so clever!)  Notice the pink and magenta disk flowers in some of the flower heads in this photo.

As soon as the temperature gets into the low 50s on these crisp late October mornings, the Bumble Bees begin foraging on billowing clouds of luminous Blue Wood Asters outside my windows, soon joined by other tiny bees and flies.  Large dense clusters of bright pale blue flowers top the heart-leaved covered stalks of this woodland beauty.  The shape of the leaves is reflected in the species name, cordifolium, and also gives this plant another commonly used name, Heart-leaved Aster.  Pair Blue Wood Aster with White Wood Aster (Eurybia divaricata) and Wreath (Bluestem) Goldenrod (Solidago caesia) or Zigzag Goldenrod (Solidago flexicaulis) for a spectacular late season shade garden display.

New England Aster (Symphyotrichum novae-angliae)

New England Aster (Symphyotrichum novae-angliae)

Favorites for a sunny garden or meadow include New England Aster (Symphyotrichum novae-angliae), which is also seen blooming in many spots along roadsides, and Aromatic Aster (Symphyotrichum oblongifolium), whose intense blue flowers are irresistible to insects and humans alike.

Following are more asters and their visitors.  You never know what treasures asters will yield!

Flower or Hover Fly, Helophilus sp, on Aromatic Aster (Symphyotrichum oblongifolium)

Flower or Hover Fly, Helophilus sp, on Aromatic Aster (Symphyotrichum oblongifolium)

Orange Sulphur on Aromatic Aster (Symphyotrichum oblongifolium)

Orange Sulphur on Aromatic Aster (Symphyotrichum oblongifolium)

Orange Sulphur on Awl Aster (Symphyotrichum pilosum)

Orange Sulphur on Awl Aster (Symphyotrichum pilosum)

Hover or Flower Fly, likely Toxomerus geminatus, on Aromatic Aster (Symphyotrichum oblongifolium)

Hover or Flower Fly, likely Toxomerus geminatus, on Aromatic Aster (Symphyotrichum oblongifolium)

Blue Wood Aster (Symphyotrichum cordifolium) with Bumble Bee

Blue Wood Aster (Symphyotrichum cordifolium) with Bumble Bee

Aromatic Aster (Symphyotrichum oblongifolium) with Common Buckeye

Aromatic Aster (Symphyotrichum oblongifolium) with Common Buckeye

Common Checkered Skipper on Aster

Common Checkered Skipper on Aster

Mating Bees on Aromatic Aster (Symphyotrichum oblongifolium)

Mating Bees on Aromatic Aster (Symphyotrichum oblongifolium)