Dragonflies and a Presentation in Winthrop

Betsy and I gave a dragonfly presentation last week at the Merc Playhouse in Twisp, near Winthrop, WA, for the Methow Conservancy. The presentation was well attended, and there were lots of good questions—it was a lot of fun. Thanks to all who came out on a smoky evening to learn more about dragonflies.

The next day, we led a field trip to Beaver Pond, near Sun Mountain Lodge. Later in the day we also stopped by Twin Lakes for a few additional species.

Here's a view of Beaver Pond from the wooden footbridge.

The view from the wooden footbridge at Beaver Pond near Sun Mountain Lodge in Winthrop, WA. This is a good place to see lots of dragonflies, and to watch for the splash-dunk/spin-dry behavior. We saw a few examples during our field trip.

This is the other end of Beaver Pond. Notice the darner flying by at the top of the photo.



We saw lots of darners flying back and forth over the water. A few meadowhawks were in the bushes along the shoreline, in addition to many damselflies.

We were also fortunate to see the splash-dunk/spin-dry behavior a couple times. The footbridge is a great place to see the behavior—in fact, the spin-dry at this location is performed at eye level, making it particularly easy to observe. We had a couple good views of this rare phenomenon.

Here's our species list for the field trip:

Damselflies
Spotted Spreadwing
Northern/Boreal Bluet
Tule Bluet
Pacific Forktail
Western Forktail

Dragonflies
Paddle-tailed Darner (Happy Face)
Canada Darner
Blue-eyed Darner
Variable Darner
Striped Meadowhawk
White-faced Meadowhawk
Black Meadowhawk
Cherry-faced Meadowhawk
Eight-spotted Skimmer

At the end of the trip we encountered an interesting situation at Twin Lakes. It was a female damselfly with the abdomen of a male attached to her. What likely happened is that a dragonfly at the lake captured a pair of damselflies flying together in tandem. It then snipped off the thorax of the male for a nice snack, dropping the rest of the pair into the vegetation. Here's a detailed discussion of a similar event observed at Cranberry Lake:

http://thedragonflywhisperer.blogspot.com/2012/09/15-damselflies-darner-predation-in.html

This was truly a damsel in distress, but one of our participants kindly removed the male's abdomen, freeing the female to continue her life unencumbered.

Here's the poster advertising the talk:

1.5 Damselflies – Darner Predation In Action

Strange things happen in nature – things you might never predict in advance.  No one predicted superconductivity, for example, even though it's a direct consequence of well-known physics.

Here's an example from biology.  Once in a while you look in the bushes and see something like the following:

1.5 dameslflies – a female Tule Bluet plus the abdomen of her former mate.

What's going on here?  At first it looks like some sort of strange creature with a weird body plan, but then you realize it's a female damselfly with the abdomen of a male attached behind her head.  That's strange alright, not something you might have predicted in advance, but then you ask yourself, "How did that come about?"

The first thought is generally that it's the result of a pair of damselflies in tandem being attacked by a bird that makes off with part of the male.  That's certainly reasonable, and probably happens a lot, though it does beg the question of why the bird doesn't finish off the job since the female with the attached abdomen is an easy catch.

The explanation is quite different in this case, however.  I was observing a male California Darner on the shore of Cranberry Lake – California Darners like to perch on the ground, as compared with Paddle-tailed Darners, Blue-eyed Darners, and Shadow Darners that prefer to perch in bushes about chest high.  In any case, the darner took off and I watched as it flew over the water.  In a second it attacked a pair of Tule Bluets that were flying in tandem.  The darner had quite a struggle on its hands, and it flew toward some bushes on the shore.  I followed, expecting it to land and process its catch.  Instead, something fell from the darner into the bushes, and it continued flying.  When I looked in the bush I saw the 1.5 damselfly pictured above.  The darner had snipped off the male at the base of its abdomen, and continued in flight to eat the nice, meaty thorax.

Since that time we've observed similar types of darner attacks a number of times.  One of the most common happens near the end of the season, when Paddle-tailed Darners and Autumn Meadowhawks are particularly numerous.  We've seen several instances of a darner grabbing a pair of Autumn Meadowhawks in tandem.  The darner sometimes snips off the abdomen of the male meadowhawk, eats the thorax, and leaves the female with an abdomen attached.  Sometimes the darner eats the entire male while it is still attached to the female.  When it gets most of the way through the abdomen the female is released, and she rests in the vegetation before flying off as the darner finishes its meal.

Yes, strange things happen in nature.