28 September 2008

Unexpected Darner

On Saturday, 9/27, I made a late afternoon trip over to Lenawee County to search for a couple of late season darners (Aeshna sp.) that would be new for the county. Onsted State Game Area near Cambridge Junction seemed like a good location since it includes several lakes and the River Raisin.

I initially stopped at the boat launch on the east shore of Grassy Lake and immediately saw a darner flying over the water. A 2nd one flew over my head and with a quick swing of the net, I found myself with an unusual male darner. The claspers were not wedge-shaped, but were fairly straight and there was a bump on the dorsal surface of abdominal segment 10. I initially thought of Canada Darner (Aeshna canadensis), that is, until I looked at the thorax. The mottled pattern clearly was that of a Mottled Darner (Aeshna clepsydra). A new species for me and the first for the county.

Searches of the adjacent lakes including One Mile Lake and Cleveland Lake didn't turn up any other darners so I returned to the original location for another hour.

There were ~4 males patrolling the shoreline and methodically searching the vegetation, just inches above the water of Grassy Lake.

At one point, one individual was checking me out, flying around me, checking out my face, then actually landing on my hat. I found this species to be very unwary and actually had a couple more instances of individuals fly near/around me while checking for prey.

Periodically individuals would land on tree trunks and, luckily, allowed a close approach.

Another darner landed in a dead tree, almost beyond the reach of my net. However, there were branches in the way so I fished my net up to the trunk. Surprisingly, the darner didn't fly and I was able to slowly position my net next to this dragonfly and get it to move onto the hoop. I was able to move the net out from the branches, and capture it with a quick flick of the wrist.

Surprise, another Mottled Darner (A. clepsydra).

Here's a closeup of the thoracic pattern.

...and the claspers

25 September 2008

Dragonflies of September

I both like and dislike September for odes. This month includes the last weeks of most dragonflies in southeast Michigan, but it includes the peak of some of my favorites such hanging clubtails (Stylurus sp.) and mosaic darners (Aeshna sp.).

While searching for Monarchs as noted in the previous post, I was also keeping an eye out for late season insects.

Knowing that we didn't have a good late date for Russet-tipped Clubtail (Stylurus plagiatus), I headed for the most reliable location in the refuge for this species. Almost immediately a female flew up from a waist-high dogwood and landed a few meters away. This individual extended the late date for Michigan by more than 2 weeks.

Several minutes later I found this 2nd female about 40m away. Thus, she is technically the late date S. plagiatus.

While wandering the fields of Tall Boneset looking for butterflies, this pair of Shadow Darners (Aeshna umbrosa) would repeatedly fly by, perch, then fly around a bit more and land again. For more than 30-40 minutes this pair was in the wheel.

At one point a male clubtail (Stylurus sp.) landed high up in a tree which was not a Russet-tipped. In past years, I've thought I may have seen Arrow Clubtails (S. spiniceps), but once again this individual was not in a position to make an ID. Thus, this species is still unconfirmed for this site.

While checking nearby trees, I did find a female clubtail which turned out to be an Elusive Clubtail (S. notatus). This was the 3rd or 4th time to see one in this area and only one of a couple dozen sightings for MI.

...and here's a closeup

22 September 2008

Smoky Rubyspot: New county record

One of our tasks this summer was to tag Monarch butterflies at the Detroit River International Wildlife Refuge, mostly the Humbug unit but other Detroit River habitats. Since Point Pelee is such an important migratory stopover for Monarchs, we thought this would be a worthwhile project for the U.S. side of the river. As luck would have it, this has been a spectacularly dismal year for Monarchs. We optimistically ordered two hundred tags, but have only tagged TWO butterflies so far!

Our consolation prize was found at Humbug on Saturday. Stylurus caught this old female damselfly. At first, we weren't sure what it was, although the little white pseudostigma pointed to a broad-winged damsel (Calopterygidae).

It was too dull and narrow-winged to be a jewelwing, leaving us with a rubyspot. We came to the conclusion it was a Smoky Rubyspot, Hetaerina titia, a species with only about 7 other state records, none for our county. I gave it a careful exam, since this is a species we had little experience with. Her thoracic pattern matched, her legs were dark, as was her ovipositor. These characteristics help separate it from the much more common American Rubyspot, H. americana. And the clincher is the spine on the dorsal surface of segment 10, shown in this shot.

Nice scans that help show these featuers can be found online: Smoky Rubyspot here, and American Rubyspot here.

Smoky seems to prefer larger rivers and streams than American. The similarity of the females of both species, and the later flight period of Smoky might indicate they are overlooked in Michigan, but this is probably fairly close to the northern limit of its range. Considering we have never recorded American Rubyspot at Humbug, or any location along the Detroit River, this Smoky Rubyspot was an unexpected find!

06 September 2008

In the River Raisin

Today I took advantage of low water levels due to the lack of rain this summer and visited one of my favorite rivers in southeast Michigan. The River Raisin flows through Indian Crossing Trails Park in Tecumseh and has great access for dragonflies. The low water level makes it easy to access much of the river in the park.

I was hoping for dragonflies that haven't been recorded or confirmed in Lenawee County such as clubtails, darners, or river cruisers. I wasn't disappointed.

As soon as I scanned the first sunny stretch of river, a dragonfly landed near my feet with prey. This was a female Black-shouldered Spinyleg (Dromogomphus spinosus). The photo below illustrates the reasons for its name.

I found a couple more individuals along the river such as this female resting on a downed tree.

I walked a good distance (~3/4 mile) downstream and found several Fawn Darners (Boyeria vinosa) along the way.
Here's a male:

and a female:

At one point, I was able to witness a male couple with a female, then fly up to a tree in a wheel.

Then a bit later, I found a female laying eggs along the river. The female is in the middle of the picture on the smaller diameter branch.

One location in the river had the greatest variety of odonata. This bend in the river had a sand, gravel, shaded tree roots, a downed tree, and most importantly, sun.

Individuals of all of the species pictured in this post were seen at this location, plus a few damselfly species.
One interesting find was a female Band-winged Meadowhawk (Sympetrum semicinctum). Typically, we tend to find these near small, overgrown streams.

One of the targets for the day was to find Stylurus species. Earlier in the morning I believed I had seen one flying between the sun and shade, but then convinced myself that I had mistaken a spinylegs. While checking one last sunlit area, a Stylurus flew past. Waiting patiently, I was eventually able to snag him during one of his many passes up and down the river. This was a male Arrow Clubtail (Stylurus spiniceps) and a new species for the county.

Upon returning to my car, I did a quick scan of the pond for darners or river cruisers and spotted some green eyes over the water. This river cruiser looked liked it may have been an Illinois River Cruiser (Macromia illinoiensis), but I'll never know for sure since it was too far out to catch for an examination. Regardless of the Macromia species, this would have been new for the county too.

It was great to confirm the first Stylurus for the Lenawee County, but there are more late season odes to be found. However, these will have to wait until next year since I may not make it over there again this month.