October Gold and Blue

White oaks shine against a cloudless October sky.

Bur oaks (Quercus macrocarpa) shine against a cloudless October sky.

The fleeting season of gold and blue arrived in central Minnesota last week. The golden hues of bitternut hickory, bur oak, aspen and ash glow against a sky the color of a newly opened morning glory — a shade unique to autumn. Along the Snake River, the steely blue-gray wings of a great blue heron swoop over the sparkling water.

A great blue heron (Ardea herodias) swoops over the Snake River in east central Minnesota.

A great blue heron (Ardea herodias) swoops over the Snake River in east central Minnesota.

Sky blue morning glories continue to bloom in October.

Heavenly blue (Ipomea purpurea) morning glories continue to bloom in October.

Closer to the ground, the last of the powder-blue bottle gentians and asters — some with center disks as bold as the sun — bloom among the grasses. Fallen aspen leaves accent walkways, and the heart-shaped leaves of the carrion flower vine wind their tendrils skyward. In a few days, this lovely combination will dampen down to more muted tones, the gentle softness that insulates the earth for winter’s palette of black and white.

Bottle gentian blooms (Gentiana andrewsii) turn dark and dry out as their seeds mature.

Bottle gentian blooms (Gentiana andrewsii) turn dark and dry out as their seeds mature.

Asters (Symphyotrichum novi-begii) provide nectar to these hoverflies and many other autumn insects.

Asters (Symphyotrichum novi-belgii) provide nectar to these hoverflies, or syrphids, and many other autumn insects.

Aspen leaves and moss decorate a walkway at our cabin.

Quaking aspen leaves (Populus tremuloides) and moss decorate a walkway at our cabin.

The heart-shaped leaves of the carrion flower (Smilax herbacea) add light and color to the October woods.

The heart-shaped leaves of the carrion flower vine (Smilax herbacea) add light and color to the October woods.

 

Metallic Green Bees

A metallic green bee (agapostemon) drinks nectar from a Helenium flower.

A metallic green bee (Agapostemon) drinks nectar from a Helenium flower.

A female green metallic bee searches for nectar in a woodland sunflower.

A female metallic green bee searches for nectar in a Jerusalem Artichoke (Helianthus tuberosus L.).

Bees of many kinds visit our backyard garden on sunny autumn afternoons — and not all are black and yellow!  I think one of the prettiest is the metallic green bee, which is a type of tiny sweat bee in the (family Halictidae).  The female bee’s body is usually a beautiful iridescent green.  The male bee has a bright green head and thorax, but in contrast to the female, he sports a vibrantly striped abdomen — black with yellow or white stripes.

Native asters are a favorite of metallic green bees.

Native heath asters (Symphyotrichum ericoides) are a favorite of metallic green bees.

Metallic green bees, typically just a few eighths of an inch in size, are small in comparison to many backyard bees, such as bumble bees and honey bees.  They are short-tongued bees, so they prefer to drink nectar from flowers that have a more shallow, open structure. In our yard they prefer Helenium and asters.

Unlike colonial bees that live in hives, each adult female green bee creates her own underground nesting chamber in which she lays her eggs. Sometimes, several females construct individual nests near each other, but they remain solitary.

When cold weather arrives in late October, the male green bees die. Fertilized females survive because they form a layer of insulating fat and burrow into the ground to overwinter. Next spring, they will lay eggs in new underground nests and continue the life cycle. Most years, green bees should be visiting your garden by the end of April.

A green bee catches the warmth of the late afternoon sun.

A male green bee catches the warmth of the late afternoon sun on an aster (Symphyotrichum novi-belgii).