Insects

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Annual Cicadas

The dog days of summer are here, and along with them, the annual cicadas.  They’re brown and green, look a bit intimidating and punctuate the hot, heavy August air with loud, raspy buzzing.  Usually present beginning in mid-July, annual cicadas were sparse in our garden until the heat and humidity arrived last weekend.  Now the air vibrates with their whining buzzes, and in the late evening, is accented with cricket song and the weet-weet-weet call of a male cardinal.  Cicadas “sing” from the branches of our apple, ash and spruce trees.  In the sultry dusk, a large cicada takes off from the apple tree buzzing loudly; a small bat pursues it across the backyard and out of sight.

Annual cicada sitting among plants and needles beneath our spruce tree.

Annual cicada sitting among plants and needles beneath our spruce tree.

Between one and two inches long, the adult annual cicada (Tibicen canicularis) has a blunt, thick body and large wings tinged with apple-green.  Cicadas live just a few days as adults singing in the trees, mating, and laying eggs for the next generation.  Females cut a slit in a tree branch and deposit their eggs.  When a nymph hatches, it burrows down into the soil beneath the tree where it spends 2-to-5 years sucking juices from the tree’s roots.  When it is ready, the nymph leaves the soil and climbs up the tree, splits open its exoskeleton and emerges as an adult.

A molted exoskeleton, or hard outer casing of an annual cicada nymph, attached to the bark of our apple tree.

A molted exoskeleton, or hard outer casing of an annual cicada nymph, attached to the bark of our apple tree.

Only the male cicada calls.  Males have two membranes called tymbals located underneath the abdomen.  They contract and relax muscles attached to the tymbals to vibrate them and produce a loud, raspy whine.  To listen to the songs of annual cicadas, follow this link to InsectSingers.com: cicadas/songs

The annual cicada is also called the dog-day cicada because it is most plentiful and vocal during the steamy days of late August.  Sirius, the brightest star in the sky (excluding our sun), is the largest star in the constellation Canis Major, or Greater Dog, and so is known as the “dog star”.  At this time of year, Sirius rises in the southeast just before dawn. The ancient Egyptians and Romans thought that the star added its heat to our sun’s, making late summer the hottest part of the year in the northern hemisphere, and called it “the dog days of summer”.

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On the Banks of the Snake River (St. Croix Basin)

It’s a breezy, clear, mid-August morning at the Snake River in east central Minnesota.  An old silver maple creeks in the wind and a pileated woodpecker’s call rings through the woods.  Trees, thickets and river grasses show lush shades of green.  I am so glad to see no hint of autumn in them yet. But, other plants tell a different story.  The berries of false Solomon’s seal grow red, chokecherries and currants ripen to purple, and hawthorne fruit and wild rose hips begin to blush.  Hickory and hazelnuts are plump and the fragrant basswood flowers of a few weeks ago are now little round nutlets.

False Solomon's Seal Berries

False Solomon’s Seal Berries

Flowers are changing too.  Turk’s-cap lilies, meadow rue and vetches have been replaced by woodland sunflowers and lesser purple fringed orchids.  The first goldenrod buds are turning yellow, and harebells and heal-all continue to bloom.

Woodland sunflower

Woodland sunflower

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Lesser purple fringed orchid

The woods are much quieter than in July.  Most birds have finished breeding and their babies have grown, putting an end to the feeding frenzy.  I miss the morning and evening chorus — especially the ethereal vespers sung by the wood thrushes.  Fortunately, the last few mornings, a family of five blue jays visited our hazelnut thicket.  They call softly to each other as they pluck the nuts, hold them against a tree branch and peck open the husk.  These jays are more elusive than the jays in our city yard.  They retreat deeper into the woods when I sit outside and try to photograph them.

In the late afternoon, a lone cicada buzzes.  Grasshoppers and crickets trill softly and are joined by snowy crickets and katydids in the evening.  Their night music, though simpler than birdsong, complements the burble of river water over rocks and gently soothes as darkness falls.

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Common Milkweed

Monarch butterflies are rare this summer.  I’ve seen just one in our St. Paul, MN, garden, even as monarda, swamp milkweed, common milkweed, black-eyed Susan’s, Joe-Pye weed, phlox and a blend of other native plants and garden perennials bloom.  However, we have no shortage of milkweed to nurture monarch caterpillars if they were present.  A lush patch of common milkweed (Asclepia syriaca) grows in our yard, possibly the best-ever since I spotted the first plant shooting up in the middle of a juniper hedge 15 years ago.  The first milkweed blossom opened on July 7 and  most of the plants were flowering by July 17.

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Milkweed buds and blossom.

Though monarchs are absent, red milkweed beetles, bumble bees and ruby-throated hummingbirds frequent our patch.

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Red milkweed beetle on swamp milkweed.

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Ruby-throated hummingbird sips milkweed nectar.

On July 22, I noticed the first seed pods.  New pods continue to form and the earliest pods have plumped-up in the past week.

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Newly formed milkweed seed pods.

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Striped Hairstreak Butterfly

Butterfly sightings have been rare this summer.  Last Sunday I found a hairstreak butterfly resting on a milkweed plant in the right-of-way near our cabin in Pine County.  Though not positive of the species, based on the dark bands bordered by white on just one side, and the orange cap of color on the blue patch near the tail, I think it may be a striped hairstreak.

striped hairstreak