Mayslake Bugs

by Carl Strang

The warming weather has produced the first wave of insects at Mayslake Forest Preserve. These early-season adults overwintered in that form or in the stage just prior, or in some cases, migrated from the South.

The Carolina saddlebags is one such likely migrant.

The Carolina saddlebags is one such likely migrant.

This individual gave me a rare opportunity to photograph it in such a way as to show off its diagnostic purple forehead. The slender legs have the strength to hold the dragonfly to its perch.

Though I think of the eastern tailed-blue as a late-summer butterfly, that is the second generation of the year. Here is one of the early-season firsters.

Though I think of the eastern tailed-blue as a late-summer butterfly, that is the second generation of the year. Here is one of the early-season firsters.

Wild indigo dusky wings frequently may be encountered at Mayslake early in the season.

Wild indigo dusky wings frequently may be encountered at Mayslake early in the season.

The preserve harbors two host plants for the caterpillars: white wild indigo, a desired native prairie species, and the unwanted crown vetch, an introduced invasive.

Mayslake Insect Update

by Carl Strang

The past couple of months have provided new insects to add to the site list at Mayslake Forest Preserve. The great golden digger, a solitary wasp species in which the females dig tunnels in the soil where they provision their young with paralyzed grasshoppers, katydids and crickets, appeared at Mayslake’s flowers in small numbers beginning mid-summer.

Striking in its yellow, red and black colors, this wasp is not aggressive toward people.

Another addition was this tiger moth caterpillar humping its way across the parking lot one mid-day.

As in a cartoon sheepdog, it’s hard to tell which end is which in a static photo.

This is the yellow woolly bear or Virginian tiger moth. Probably pretty common, it nevertheless will be an addition to the Forest Preserve District’s county species list.

I was pleased to get the opportunity to photograph a live lyric cicada.

Usually these are too high in the trees to see easily.

The black collar and large chestnut patches on the pronotum (top of the thorax) are distinctive.

Lately there have been a lot of eastern tailed-blues.

These tiny butterflies don’t seem to land very often, and then seldom show the dorsal sides of their wings.

Autumn advances, and soon these colorful insects will be out of sight, wintering as eggs or other dormant forms.

Butterfly News

by Carl Strang

Butterflies continue to be diverse and abundant this spring, and last week brought some news to share from Mayslake Forest Preserve. Earlier I commented that question mark butterflies had a surprisingly delayed appearance, showing up in numbers on May 4 but not earlier as one would expect from overwintering individuals. I found a reference indicating that, like red admirals and some others we’ve been seeing this spring, question marks can migrate north in spring.

They looked fresh and clean in early May, like this one from a previous year, but last week I noticed that they now appear worn and tattered.

The butterfly highlight last week was an addition to the preserve species list.

This is the first gray hairstreak I have seen at Mayslake.

Also remarkable was an early-season eastern tailed-blue.

This relative of the hairstreaks usually doesn’t appear in noticeable numbers until mid-summer or so.

I made a mental note that I need to take a close look at all these little blue butterflies. Obviously I can no longer assume they are all spring azures.

August Insect Phenology

by Carl Strang

I was able to accumulate first-of-the-year sightings for 11 insect species at Mayslake Forest Preserve in August that could be compared to last year’s dates. These ranged from 44 days earlier to 77 days later, with a median of 11 days earlier. The extremes in range are greater than I see in plants, and usually reflect either different generations of insects within a season (I missed spotting representatives of an earlier or later generation in one year or the other), or uncommon species.

I also added 13 new species to the preserve’s list. Some of these I have mentioned in earlier posts (straight-lanced meadow katydid, citrine forktail, and fork-tailed bush katydid). Others were the black blister beetle,

meadow fritillary,

common buckeye,

ailanthus webworm,

fiery skipper,

and green cloverworm moth.

The fiery skipper is a southern species that moves north in considerable numbers in some years. The green cloverworm moth is distinctive enough that the blurry photo is sufficient to identify it, a common species whose presence is expected. The remaining new species were eastern tailed-blue, common true katydid, jumping bush cricket, and swamp cicada. As mentioned in an earlier post, I have been alert for the presence of the swamp cicada in DuPage County, and was pleased to hear single individuals singing on three different days at Mayslake in August.

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