Tuesday, June 30, 2015

The Dragonflies of Somme

Photos by Lisa Culp

Said to be the world’s fastest insects, they “can reach 19 to 38 mph.”

The twelve species shown below are the commonest ones at Somme. 

Dragonflies are among our most ancient animals. Fossils showing dragonflies much like ours go back 300 million years, predating the dinosaurs by 100 million. Evolving over all this time, they have become very good at what they do. Somme is proud to be a living home to such treasures.

Just take a walk and look.
Binoculars that can focus close up are a great help, while they’re sitting still. On the wing, they’re so fast, you need pure eyes to follow them.

Just relax. Be happy. Let your eyes do what they want to do. Marvel.

Green Darner
These often perch low in the grass on trail edges. Look about 10 feet ahead to see them before they take off.
Their transparent wings take on an amber tone as they grow older. Some migrate “thousands of kilometers.”
“To begin mating, a male usually just grabs a female, but the female chooses whether to actually mate.” (http://www.biokids.umich.edu/critters/Anax_junius/)
Shown here perching on last year's bush clover and this year's prairie clover. 

Eastern amber wing - female.
Just an inch long. One of our smallest dragonflies. Said to fly in ways that make them 
appear to be wasps, thereby scaring away some possible predators. 
Shown here perching on prairie Indian plantain.

Eastern Amber Wing - male
In this species the male patrols a good egg-laying territory and waits for the females to come to him. 
Shown here perching on Dudley's rush.   

Ruby Meadowhawk - male
Eat deer flies and mosquitoes. Thus – the more meadowhawks, the better. Somme Prairie Grove has vastly fewer mosquitoes than Somme Woods. Is that because we have so many more dragonflies?

Ruby Meadowhawk - female (or young male) 
Meadowhawks are “sit and wait” hunters. When they see prey, they dart out and grab it; 
then they return to their perch to eat. 
See: https://www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/meadowhawks.cfm

White faced meadowhawk
Hunt flying insects from perches – often long arching blades of grass.

It takes a while for these dragonflies to develop their white faces, and they look like ruby meadowhawks until they do.
I’ve often shown people that if I put my finger in front of a ruby meadowhawk, it will often climb on my finger and stay put while I show other people a closer look. Or I put my finger above their perch when they fly out to hunt and find that they return and land on my finger - for as long as I'm patient to hold it there – unless another mosquito comes by. 
But “the internet” says that the white-face is the one most likely to do this. This research suggests that perhaps I was giving credit to the wrong bug?

Four-spotted Skimmer
An aggressive hunter, often catches and eats other dragonflies its size and smaller.
Circumpolar in the northern hemisphere, found in Europe, Asia, 
and Japan (a good place to be a dragonfly, as this elegant insect is much appreciated there).
Often sits on perches with a good view and tilts head back and forth while scanning its territory for flying insects (to catch and eat) or other dragonflies (to chase out of its territory) (or catch and eat).

Halloween Pennant
Lays its eggs in ponds or marshes (like most dragonflies) – or even in holes in trees that fill with water. 
Males and females fly around, attached, and the female is lowered underwater to lay eggs (where she can breathe through air that is trapped by hairs on her legs). Note: Insects often breathe through parts of their bodies other than their mouths.
Adults eat flying insects – mosquitoes, flies, gnats and sometimes other dragonflies.
The larvae live under water and are predators of, among other things, mosquito larvae. Yes!
Shown here perching on rough blazing star buds. 

Common Whitetail - male
The aquatic larvae feed on smaller insect larvae, small crayfish, and even tadpoles or minnows.
These are not one of the dragonflies which when mating and laying eggs fly around attached to each other for long periods. Whitetail mating takes about three seconds. Hunts on the wing, rather than from a perch.

Great Blue Skimmer
This big beauty likes shaded pools, where it often perches for long periods and is very tame.
More a savanna and woodland species than the others shown here - all of which seem to like our savanna
but would also be at home on the open prairie.  

Black Saddlebags
Spend most of their time flying. Use their wide back wings to glide.
Adults may congregate in swarms and may migrate.
Lisa finds that they typically perch down low in the grasses.
Shown here perching low in rattlesnake master. 

Widow skimmer - female
Large and slow, making them easy to study.
In many dragonfly species the male guards the female as she lays her eggs. 
In contrast, the males of this species “widow” the female after sex.

Widow skimmer - male
Also large and slow. 
The male defends a large territory and spends a lot of time chasing other (large and slow) males back from the edges.

Twelve-spotted Skimmer - male
Each wing has three dark brown spots. The males also have ten white spots.

Twelve-spotted Skimmer - young male 
A National Park Service website advises: 
“Approach this dragonfly slowly, but if it flies off, move closer to its vacant perch quickly, and then stop. 
Often the twelve-spotted will return, providing the careful stalker great views of its behavior.” 
What a gorgeous creature. What a fine photo. 
Shown here on a fresh stem of big blue-stem.
This photo was originally labelled "female." John and Jane Balaban wrote to point out that "12 spot female looks rather to be a young male. Female is heavier bodied without long claspers and without white spots on the wings." 
Lisa responds, "I would totally agree with what J&J say. They have way more experience than I do."
There's a lot to learn to be an expert. But we novices can contribute too. 

Lance-tipped Darner
The large adults eat almost any soft-bodied flying insects 
including mosquitos, flies, butterflies, moths, and mayflies. 

Yes, dragonflies also eat the beauty of butterflies. If I were a delicate butterfly, would I rather be eaten by a dragonfly, a bird, or a spider? I think my last choice would be the spider. I don’t like the injection. But perhaps it would be less violent? Tough decisions. The world of nature is glorious and marvelous, but it's not "The Peaceable Kingdom.” Lots to ponder. 

Photos by Lisa Culp
(We who love the Somme preserves deeply appreciate her Great Dedication and Skill.)

The info in these notes came from Lisa’s experiences and, mostly, random places on the Internet. If you know dragonfly ecology or other tidbits, please educate us by leaving comments here.


Mark said...

I looked forward to seeing this since the Facebook post. Lovely photos from Lisa, as usual. I was interested to "compare and contrast" with Ted Stone, where the top twelve would include the Eastern Pondhawk and Calico Pennant, in place of the Lance-Tipped Darner and, surprisingly, the Blue Dasher, which seems to be common just about everywhere else - including the retention pond at my office complex. It is seen at Ted, just not in the numbers of the other species.

Stephen Packard said...

Mark, that's interesting. Since the blue dasher is one of the ones that tolerates polluted water, could it be that the Ted Stone preserve doesn't have much polluted water nearby? Could it be that dragonflies of high-quality habitats mostly out-compete all others in those habitats? If so, that would be a parallel to how competition works among plants.

Mark said...

Interesting thoughts, Steve. The creek that runs through Ted Stone drains Lake Ida, a man-made lake dug for fill to build the Southwest (Stevenson) Expressway. Some runoff from heavily-used LaGrange Road also ends up in the creek. But with the herb layer in the woods along the moraine slowly recovering, maybe not that much pollution is reaching the creek these days. I recently saw a bullfrog in the creek for the first time in years. The dragonflies near the creek are dominated by common whitetails, pondhawks, twelve-spotted skimmers, widow skimmers, and darners - all larger species than the dasher. I have only seen a handful of blue dashers this year near ephemeral ponds, but the green darners and skimmers dominate the ponds.

Stephen Packard said...

Ooops. We appear to have misidentified our blue dragonfly. According to John and Jane Balaban, it looks more like a great blue skimmer. Please subtract all the thoughts about polluted water. The great blue skimmer is more typical of savannas and woodlands. There's a lot to learn.

Mark said...
This comment has been removed by the author.
Mark said...

The thoughts about polluted water remain valid, and the speculation about "conservative" dragonflies is intriguing. I think I saw a GBS at Ted a week or so ago, but it didn't perch. It was certainly much larger than a Blue Dasher. Dragonflies of Indiana says, "Flooded wooded areas and marshes with standing dead trees are a favorite habitat of the Great Blue Skimmer." With the Great Ash Die-Off, Ted has that habitat. I'll keep looking.

James McGee said...

My most interesting observation about dragonflies and restoration is, like birds, dragonflies require certain habitat structure. However, unlike birds, the habitat with a certain structure that is able to attract and retain many dragonfly species does not have to be large. A small corner of a typical suburban yard planted into native grasses and sedges is sufficient to create an area where dragonflies will roost. The homeowner then benefits by having dragonflies around to eat mosquitoes.

In contrast, the typical yard with hedges of shrubbery along the property line is about the worst possible habitat configuration if mosquito control is desired. Shrubbery provides cover and wind protection for the mosquitoes. A lack of the vertical structure in the form of native grasses and sedges creates the result of having no good roosting habitat for dragonflies. The design of our suburban ecosystem has unintentionally created excellent conditions for the mosquitoes.