Odonata Update

by Carl Strang

This has been a remarkable spring for damselflies and dragonflies at Mayslake Forest Preserve. Carolina saddlebags have been present in unusual numbers for weeks, outnumbering black saddlebags by a wide margin.

This one posed on June 3, and they keep on coming.

This one posed on June 3, and they keep on coming.

Spring is also the time when the lakes host two baskettail species.

Common baskettails won’t be around for long. Good luck finding one perched.

Common baskettails won’t be around for long. Good luck finding one perched.

This is one of the few times I have seen a prince baskettail perched. I wonder if it needed a break in the midday sun. It seems to be semi-obelisking here.

This is one of the few times I have seen a prince baskettail perched. I wonder if it needed a break in the midday sun. It seems to be semi-obelisking here.

Friday was a remarkable damselfly day. First came the following two individuals, striking with a metallic sheen on their abdomens. I don’t think they were teneral spreadwings, however.

This one best matches the female orange bluet.

This one best matches the female orange bluet.

Nearby was this one, which I believe was an immature male orange bluet.

Nearby was this one, which I believe was an immature male orange bluet.

The best was yet to come, however. Up in the meadow surrounding the temporary off-leash dog area at the former friary site, two bluets appeared that I don’t believe I have ever seen before. The first was a blue-type bluet that was just too small to be a familiar bluet.

Ta-da! A double-striped bluet!

Ta-da! A double-striped bluet!

In a more shaded area were two foraging damselflies which proved to be male and female of another species new to my experience.

Check out the enormous eyespots and the large blue area at the tip of the abdomen. This is a male azure bluet.

Check out the enormous eyespots and the large blue area at the tip of the abdomen. This is a male azure bluet.

A female azure bluet was nearby.

A female azure bluet was nearby.

The female was using an interesting foraging technique, reminiscent of a hover-gleaning bird, slowly flying up and down and briefly hovering to scan each leaf of an erect goldenrod plant, visually hunting for resting prey. As the photo shows, she was successful.

Odonata Appearances

by Carl Strang

Additional insect species continue to make their first appearances of the year at Mayslake Forest Preserve. Last week brought the first widow skimmer.

This is a teneral, or newly emerged, individual. Note the faint undeveloped dark wing areas.

I remember learning to recognize these years ago, finally releasing my focus on wing pattern as I discovered the suspenders-like yellow body striping.

I still haven’t internalized the differences among spreadwing damselflies, and try to photograph every one I see.

Females like this slender spreadwing I find particularly challenging. The pale wingtip veins are a big help here.

One fun photographic challenge is to get pictures of dragonflies in flight.

Some, like the prince baskettail, never seem to land, so flight photos are the only choice most of the time.

Though insects continue to appear early, there are plenty still to emerge as the season is yet young.

More Insects Emerge

by Carl Strang

Phenology, the timing of natural history events, is an easy area of study that adults or schoolchildren can pursue. I have been sharing my phenology observations at Mayslake Forest Preserve for first flowers, first fruits, and spring arrivals of migrant birds. Today I would like to look at results comparing 2009 and 2010 spring first sighting dates of insects. Insects are small and easy to overlook. Their numbers can vary a lot between years. Consequently I am not going to place too much weight on small differences between years for individual species. A case in point is the hobomok skipper.

I have seen few of these at Mayslake. Nevertheless, last year’s first date of 5 June is very close to this year’s June 9. Similarly, the first prince baskettail dragonfly appeared on June 1 last year, June 10 this year.

They seldom land, so I’m resorting to a UFO photo here. The difference in dates for Peck’s skipper is large enough to suggest a brood difference. I saw this one on May 25 this year.

The first date last year was August 24. This represents last year’s second generation, and I did not see a first generation representative. I don’t see many of these butterflies, so this is not a surprising result. I also haven’t seen many lyre-tipped spreadwings

Thus I am not willing to put much emphasis on the between year difference in first sightings of 13 July 2009 vs. 10 June 2010 for this damselfly.

So much for individual species. I was interested in looking for patterns among seasonal groups of species. In March this year I had only 2 species to compare to 2009, with a median difference of 5 days earlier than last year. April numbers were 9 species, median 17 days earlier than 2009. The 12 May species had a similar 16.5 days earlier median. To date in June, 9 species are a median 4 days earlier. These results suggest that the warmer spring this year is producing emergence patterns in insects that are similar both in direction and amount to those of first flower dates in plants.

Mayslake Odonata Update

by Carl Strang

The weather has been rainy, gloomy and cool on many recent days, but when the sun appeared so did the insects. At Mayslake Forest Preserve I have been able to add new species and observations that provide a foundation for future study. Eastern forktail damselflies already have been busy laying eggs in May’s Lake.

Eastern forktails laying eggs b

Meanwhile, other damselflies are emerging. The next two photos are, I believe, of common spreadwings, a male

Common spreadwing b

and a female.

Common spreadwing female 3b

Having newly emerged, they are holding their wings together more than usual. Another spreadwing species is the slender spreadwing.

Slender spreadwing 1b

Note the contrasting pale veins of the wingtips. Another, blurry photo established that the abdomen has the characteristic length, twice that of the wings. I have seen orange bluets at both of the preserve’s lakes.

Orange bluet b

Familiar bluets also have begun to appear.

Familiar bluet b

The year’s first blue-fronted dancer was a female.

Blue-fronted dancer female b

Its abdomen is dark, including the sides of the tip, and has only a very narrow pale line down the top. Shifting now to dragonflies, I’ll start with a 12-spotted skimmer that began patrolling the stream corridor marsh in June. I expect the species to be common there. This one I photographed elsewhere in 2004.

12-spotted skimmer b

Blue dashers have been active out in the fields, and soon will be appearing at lakes and marshes.

Blue dasher female 1b

A jade clubtail has staked out a piece of the May’s Lake shore.

Jade clubtail b

Cruising farther out are the prince baskettails. Here is a UFO-ish shot of one.

Prince baskettail UFO b

And here is a common baskettail  showing the basal wingspots that are visible on some, but not all individuals.

Common baskettail spot b

A final, cautionary photo:

Eastern forktail new female b

This is not an orange bluet, but a newly emerged female eastern forktail. Note the absence of the orange at the abdomen tip plus the expanded orange area at the base of the abdomen.

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