About us: We own the Wild Birds Unlimited nature shop in East Lansing, Michigan,
a store that provides a wide variety of supplies to help you enjoy the birdwatching hobby.

This blog was created to answer frequently asked questions & to share nature stories and photographs.
To contribute, email me at bloubird@gmail.com.

Wednesday, August 6, 2014

Photo Share: Common parasites attacking dragonflies

I was taking pictures of a dragonfly today; I was particularly curious about what the round things on its thorax were (parasitized?).  Every once in a while it would leave its perch briefly, and then return a moment later.  One time it came back with a mosquito and proceeded to munch it down, and, while my focus wasn't the best, I did manage to get pictures.

I have read that dragonflies prey on mosquitoes, and dragonfly nymphs prey on mosquito wigglers, but this is the first time I've ever seen it for myself. - Lynn

You are a very patient photographer. A single dragonfly can eat 30 to hundreds of mosquitoes per day.

Those tiny orbs are probably larval water mites, external parasites. Arrenurus mites hatch from eggs in the water and attach themselves to larval dragonflies right before they emerge from the water. The mites crawl onto the just emerged adult, and pierce a feeding tube into the abdomen of a dragonfly while the exoskeleton is still soft. Then the mites drop off over water to continue their life-cycle once they have engorged sufficiently. 

Limnochares, a second genus of water mites climb onto dragonflies as they perch on vegetation. These mites climb onto hosts at different times and may show variations in size based on how long they have been feeding and riding along the host.

This information is from the book: Dragonflies and Damselflies:Model Organisms for Ecological and Evolutionary Research

Thank you Lynn for sharing your photos and observations!
Related Articles:
- Mosquito hawks http://goo.gl/f8ojiF
- Why Do Mosquitoes Bite Some People More Than Others?: http://bit.ly/nMo9uV
- A Very Tiny Hummingbird (Moth)?: http://bit.ly/qtrAaV
- Why did I take a picture of bird poop?: http://bit.ly/o9APHb
- First winged insects: Dragonflies http://goo.gl/JZt4YV