Dragonflies of the arch

This is a follow-up to the post, “Dragonflies and damselflies”.  We were on vacation at a small lake on the Frontenac Arch, an area known for its rocky hills and lakes, beautiful forests, biodiversity and the presence of rare/endangered species. While I’m from a nearby community, I didn’t know about its geographical significance until more recently. The arch is an extension of the Canadian Shield that connects habitats from central/northern Ontario to those of the Adirondack Mountains.

White-faced Meadowhawk (female)

There were so many different kinds of dragons at the lake, much more than at our farmhouse, even though it’s fairly close to Lake Ontario. Of course, not all of my photos turned out, or it was impossible to get a clear shot at times. So, for reference sake, I saw Slaty Skimmers, Widow Skimmers, Common Whitetails, Eastern Pondhawks, a Variable Darner, White-faced Meadowhawks, Cherry-faced Meadowhawks, Blue Dashers and Halloween Pennants.

Widow Skimmer (male)

I didn’t notice the little red bumps under this dragonfly’s wing, in the photo below, until I was looking at the image on my computer. After searching on Bugguide.net and Whatsthatbug.com, I think they are parasitic, larval water mites (family Arrenuridae, genus Arrenurus).

White-faced Meadowhawk (with larval water mites attached)

An article by Kari Kirschbaum (2007) notes that these larval mites stay on the dragonfly for 2-3 weeks, feeding on its blood, and returning to the water for their adult stage. The dragonflies are not normally harmed by the parasites, however the article indicates that if a dragonfly is carrying a very large number of them, the mites can decrease egg production and cause deformities.

Widow Skimmer and Slaty Skimmer (both males)

White-faced Meadowhawk (female)

Eastern Pondhawk (female)

This Eastern Pondhawk was eating a fly, but I also saw one eat a damselfly, which means being relatives offers no protection at all!

Blue Dasher (male)

It’s not a yoga pose, it’s called “obelisking” and is one way that dragonflies regulate their body temperature. Cynthia Berger and Amelia Hansen (2004) note that dragonflies do this headstand, of sorts,  in order to maximize or minimize their exposure to the sun depending on whether they’re too cold or too hot. However, they point out that dragonflies in this posture are not always obelisking, as the pose can also be territorial in nature – used to threaten other males. Only a handful of dragonflies have been found to use obelisking, the Blue Dasher among them (Berger and Hansen, 2004).

Even relaxing and swimming all day long can be tiring for some!

Sources:

Berger, C. and Hansen, A. (2004). Dragonflies. Mechanicsburg, PA: Stackpole Books.

BugGuide: http://bugguide.net/node/view/125870

Kirschbaum, K. 2007. “Anisoptera” (On-line), Animal Diversity Web. Accessed July 31, 2011: http://animaldiversity.ummz.umich.edu/site/accounts/information/Anisoptera.html

What’s That Bug?: http://www.whatsthatbug.com/2004/08/07/not-locust-mites-but-larval-water-mites-on-dragonfly/

Note: The owners of referenced or linked-to materials do not endorse me or this site.

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Comments
18 Responses to “Dragonflies of the arch”
  1. I appreciate these detailed pictures of dragonflies as well as the information you’ve included about them. I’d read that dragonflies and damselflies are carnivorous, but it took a few years before I finally saw one chomping away on another insect. I also originally assumed that the little thingies attached to dragonflies and damselflies were eggs, but then someone told me about the parasitic mites. Your information will help viewers/readers learn these things more quickly than I did.

    Steve Schwartzman
    http://portraitsofwildflowers.wordpress.com

  2. Sybil says:

    Oh wow those photos are wonderful. Being able to see the mites is amazing.

    Thanks for the pics and the fascinating info.

    • Thanks for reading, Sybil, it was interesting to find out what they were. I’ve been by your site and tried to leave comments a couple of times, but they never appear. I’ll keep trying!

  3. Montucky says:

    I love dragons and your photos are outstanding! Very enjoyable to see!

  4. Meanderer says:

    Stunning detailed photographs. It’s wonderful to be able to see these beauties so close. Thank you for the information too.

  5. Lisa says:

    The larval mite are amazing – they look almost like berries. It’s sad to think that something so beautiful can be potentially harmful to the dragonfly.
    Also: That is a fantastic picture of your dog!

  6. Barbara Rodgers says:

    These are amazing and wonderfully colorful shots, Cait! Each one just as riveting as the previous one. The wings on the female Eastern Pondhawk are transparent and so intricately detailed! I appreciate the natural history you shared as well. I’m going to link this post to my post as well. 🙂 Beautiful!

  7. donald says:

    love the shots and all the interesting information. who would have thought that they were parasites. and what a beautiful dog!

  8. Sue J says:

    The pup makes me smile. Thanks for that! 🙂

  9. sandy says:

    More great shots, and what colors! I haven’t seen a green one yet this year, but did get shot several years ago.

    I love that purple one!!

    Thanks for the mite info. I saw a meadowhawk like that last year, and wondered about it.

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