Mayslake Insects Update

by Carl Strang

We’re at the edge of summer, and bees and butterflies and Odonata are center stage. Skippers have been appearing at flowers.

Earlier in the season there were wild indigo dusky wings. This is one of the skippers that typically rest with wings open.

Earlier in the season there were wild indigo dusky wings. This is one of the skippers that typically rest with wings open.

This week a new skipper appeared in Mayslake’s main prairie. This is one that closes the wings at least part way, and had practically no detail beneath.

This week a new skipper appeared in Mayslake’s main prairie. This is one that closes the wings at least part way, and had practically no detail beneath.

With the wings partly open there clearly is some color on the leading edge of the forewing, and small groups of dots. It appears to be a tawny-edged skipper.

With the wings partly open there clearly is some color on the leading edge of the forewing, and small groups of dots. It appears to be a tawny-edged skipper.

Carolina saddlebags have been one of our more consistent early season dragonflies.

The violet forehead is just visible in this back-lit individual.

The violet forehead is just visible in this back-lit individual.

So far the only spreadwing damselflies I have seen have been slender spreadwings.

Slender spreadwings continue to be common this week.

Slender spreadwings continue to be common this week.

In the past few days a number of dragonflies have made their first appearances of the season.

One of the recent species is the eastern amberwing. I like the way the light projects a distorted image of this male’s wings onto the rock.

One of the recent species is the eastern amberwing. I like the way the light projects a distorted image of this male’s wings onto the rock.

Early bumblebee colonies have begun sending out workers.

This bee was diving into the foxglove beard tongue flowers so quickly upon landing that flight photos were needed to show sufficient detail for identification. The black basal abdominal segment followed by two yellow ones is one clue. The trace of yellow on the back half of the dorsal thorax is another.

This bee was diving into the foxglove beard tongue flowers so quickly upon landing that flight photos were needed to show sufficient detail for identification. The black basal abdominal segment followed by two yellow ones is one clue. The trace of yellow on the back half of the dorsal thorax is another.

The other details are consistent with an identification of Bombus auricomus.

The other details are consistent with an identification of Bombus auricomus.

New insects will be emerging frequently for the next couple of months.

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Recent Maylake Insects

by Carl Strang

Today’s post accomplishes some catch-up on insect observations at Mayslake Forest Preserve. Familiar species have returned. Eastern amberwings have been especially abundant this year.

The male is well named, his wings a solid amber color.

Less abundant but always a welcome sight is the dogbane beetle.

The jewel-like iridescence makes this species stand out.

Earlier in the season I found some LeConte’s haploas in the stream corridor prairies.

This is the second member of its genus to appear at Mayslake, the other being the reversed haploa.

Another species commonly visiting flowers proved to be easy to identify.

Archytas apicifer has a shining blue-black abdomen and a striped olive or gray thorax. It has been an abundant flower feeder this year.

This fly is a parasite of caterpillars, laying its eggs especially on those of the noctuid family.

Dragonfly Notes

by Carl Strang

Today I want to share some observations of dragonflies from last week. It was, as you know, stinking hot all week, reaching 100F on Thursday and Friday. In the late morning on Friday, with the temperature in the mid-90’s, I was taking an early lunchtime walk along the May’s Lake shore. I noticed that the black saddlebags all were flying in an unusual position.

All had this peculiar abdomen dip, which they held as they flew.

It was reminiscent of the obelisk posture, shown by a perched dragonfly pointing its abdomen up at the sun. This is thought to reduce overheating in the insect’s body. I wonder if the saddlebags, in that extreme heat, likewise were reducing the size of their abdomens’ exposure profile. They were among the largest dragonflies I saw that day, which further might increase their danger of overheating.

Earlier in the week I was walking through one of Mayslake Forest Preserve’s prairies when I saw a common pondhawk carrying a relatively large prey to a perch.

It had caught a smaller dragonfly, a female eastern amberwing.

Female and immature male pondhawks have such perfect grass-green camouflage that they are practically invisible when perched in prairies and meadows. They are sit-and-wait predators, zooming out to catch passing insects. This predation on another dragonfly is not so rare. I once saw one catch a calico pennant, a dragonfly larger than the amberwing.

Kayak at Last

by Carl Strang

I was beginning to wonder if I would get the opportunity to put a paddle in the water this year, but circumstances allowed me to run my dragonfly monitoring route on the Des Plaines River at Waterfall Glen Forest Preserve this past weekend. Of course, in the context of this blog the monitoring is the main thing, but on a personal level it’s been hard to go almost a year without paddling. My sea kayak has taken me through north Georgian Bay.

It’s given me sights like this, Devil’s Island in the Apostles of Lake Superior.

On Sunday afternoon the sea kayak Water Strider was my vehicle yet again. I found no new species, but was interested to find that the counts for various species fell between the values for last year’s August 2 and September 3 counts, despite other measures of phenology generally placing this year earlier than last. Common whitetail and eastern amberwing dragonflies were closer to the August 2 count, though both exceeded any of last year’s counts for those species. Powdered dancers and stream bluets fell between the counts of last year’s dates. Familiar bluets were closer to the September 3 count. Many, like those in the following photo, were ovipositing.

Skimming bluets showed a significant increase, with 10 counted on this trip against 1 for the entire 2009 season. In contrast, jade clubtails were missing this time, and orange bluets were few. I wonder if their seasons are done for this year.

Back to the River

by Carl Strang

Last week I made my fourth dragonfly monitoring excursion of the season by kayak on the Des Plaines River (last updated here ). It was a pleasant, early autumn day. Practically nothing was happening over the center of the river, but there was more action near shore. I found only two dragonfly species. Eastern amberwings remained common, and I also saw a few jade clubtails. Here is one of the latter.

Jade clubtail 3SEb

September 3 is a late date for that species. Damselflies were common, and in general were the same species I had seen on the previous outing in early August. The only new species was a tiny skimming bluet, which perched for a time on my deck line.

Skimming bluet 3SEb

Otherwise, highlights included patches of halberd-leaved rose mallows,

Halberd-leaved rose mallow b

and the best surprise of all, a single sandhill crane hunting in one of Waterfall Glen’s marsh streams.

Sandhill crane 2b

I hope to get on that river at least one more time this year.

Dragonfly Monitoring Update

by Carl Strang

Earlier I described  my first venture into dragonfly and damselfly monitoring by kayak. I have been out on the Des Plaines River twice since then. There has been some variation in the count of species and individuals each time, but most seems unremarkable. I’ll focus on a couple high points. The biggest surprise was a transition in the damselflies. The slender bluet was the common black type bluet my first time around.

Slender bluet 5JL 1b

Bluets are a group of small to medium sized damselflies. Black type bluets are so called because their abdomens are nearly all black as viewed from above. On my second and third outings, the slender bluets were replaced by stream bluets as the common black type bluets. Here is one of the latter I rescued from the water.

Stream bluet 23JL09 1b

Note that, in contrast to the slender bluet in the top photo, the stream bluet has a slender blue shoulder stripe with a wider black stripe below it. “Eye spots” on the back of the head are smaller in the stream bluet, and there is less blue in the abdomen tip. Stream bluets were largely in tandem pairs and actively laying eggs on floating vegetation during both recent outings.

Stream bluets tandem b

The other surprise is the relatively large number of orange bluets. Here is one sharing a photo with a stream bluet.

Orange and stream bluet b

I’m not saying that the river is swarming with them, but in my experience a count of 13 orange bluets in a 2-hour outing is a lot. A final note is that eastern amberwings have become the most abundant dragonflies, despite my seeing none on the first outing. Here is a photo of one from 2007.

Eastern amberwing male 2b

I have decided to limit my monitoring to the stretch of river that bounds Waterfall Glen Forest Preserve. This gives me a span of stream between the launch ramp and the preserve in which I can practice another type of inquiry, to be featured tomorrow.

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