End of summer signals new faces in insect world

Summer’s nightly music festival began a few weeks ago. As daylight dims, I enjoy sitting on the back porch waiting for the concert to begin.

Male katydids sing from early evening well into the night. The song is harsh and burry and sounds something like “Ch-ch” or “Ch-ch-ch” or “ch-ch-ch-ch.” The phrases are repeated about once a second, and the rhythm suggests the insect’s name: Ka-ty, ka-ty-did or kay-ty-did-did.

Sometimes when I listen to individuals, their matching songs merge into a single chorus.

Another familiar voice will soon join the late summer nocturne. Snowy tree crickets generate a seemingly endless series of high-pitched melodic chirps. During the day, they feed quietly amidst the foliage of trees and shrubs. Thanks to their small size and cryptic pale green color, they blend in with their surroundings.

At night, their song is ventriloquistic. Shine a light where you think the tree cricket must be, and sure enough, it’s not.

Katydids and snowy tree crickets are just two common insects associated with late summer. Some we welcome; some we don’t.

Among other favorite summer insects are monarch butterflies and hummingbird moths.

Majestic monarchs

Like many birds, orange and black monarch butterflies migrate south for the winter. Mark and recapture studies show that monarchs travel as far as 1,800 miles in just four months. They fly by day at a leisurely pace of 5 to 18 mph.

Not only do monarchs travel great distances, they do so with unerring accuracy. Year after year, they return to the same winter areas, even the same trees, in just a handful of isolated mountaintops in central Mexico.

What makes the monarch migration even more amazing is that each butterfly makes the trip only once. Monarchs that fly to Mexico are from the last brood of the summer, usually hatched in August or early September. When monarchs depart their winter haven, females lay eggs on milkweed plants as they move northward. Then these females, which have lived as long as eight months, die. The eggs they leave behind become the next generation.

As adults, this new generation continues northward, laying eggs as it goes, until several generations later, adult monarchs reach the northern limits of milkweed distribution.

Hummer wannabes

Hummingbird moths mimic hummingbirds; every summer readers send me detailed descriptions of strange hummingbird-like creature. Most report a fuzzy, bee-like creature with antenna, and a long beak.

Such detailed reports, coupled with a habit of hovering above flowers while feeding, make identification easy.

The “beak” is actually a long, flexible tube (the proboscis) that stays coiled under the head when the moth is not feeding.

Clearwing hummingbird moths are among the smallest of these fascinating insects. They first appear in June and are active at mid-day.

The bad guys cometh, too

Yellow jackets and bald-faced hornets top the list of least favorite summer insects. When provoked or disturbed, they attack and sting aggressively. Yellow jackets are active all summer long, yet unless a lawn mower runs over a nesting burrow, they’re rarely aggressive.

But on warm late summer and fall days, they get mean. The simple explanation is that the social structure of the colony breaks down, and they get hungry.

Yellow jackets build their nests underground in abandoned rodent burrows. A yellow jacket nest is much like the nest of the bald faced hornet, except that the yellow jacket nest is built underground while a hornet nest hangs in a tree.

After the queen lays her first clutch of eggs, she collects food for the soon-to-hatch larva. Yellow jackets are predators, and any small insect is fair game. She deposits some food with each egg. Upon hatching, the larvae consume the awaiting food and grow rapidly.

After the first generation of yellow jackets matures, it continues expanding the size of the nest and collecting food for subsequent generations of larva. The queen then becomes an egg-laying machine and probably never again leaves the nest.

Bald-faced hornet nests become conspicuous in the fall. As leaves drop from trees, basketball-sized hornet nests become obvious hanging from tree branches. Hornets are essentially large yellow jackets, and their life cycle mirrors the yellow jacket’s, except where they build their nests.

As summer winds down, insect activity peaks. Enjoy and beware.