Showing posts with label damselfly. Show all posts
Showing posts with label damselfly. Show all posts

Tuesday, October 2, 2007

What Happened to the Dragonflies?


Now that summer is over, I’ve been thinking about bugs. More specifically, I’ve been thinking about one of my favorite bugs, the dragonfly and wondering why we had so few in the yard this past summer.

For as many years as I can remember, we have been fortunate to have great numbers of dragonflies. Late afternoon would find the front yard or the little pond out back swarming with dragonflies, flying back and forth in what looked like a massive swarm of chaos. There were so many, I often wondered that they didn’t bump into each other. Often while drinking my morning coffee on the deck, a dragonfly would land on the table or even on my hand and stay for a brief time. They were all sizes and colors. Beautiful!

This past year was different. The numbers swarming in the late afternoon had been sparse. Rather than looking as though they would crash into each other, the swarm reminded me of animations I’ve seen of the Universe – vast spaces between the stars, the emptiness ever expanding. My morning coffee time was seldom interrupted by the delightful presence of these wonderful creatures. I missed them!

My observation of other critters gave me some clues as to why there had been so few dragonflies. My research supported my observations. Early spring brought our few eastern phoebes to the yard to nest, just as it had for years. As the season went on, I realized we had more than a few phoebes in the yard. I was surprised to see them in all parts of the yard and across the street since they are not known to flock together. I guessed each had enough of its own space. Phoebes are one of the species that catch insects in flight. During the course of the summer, I often spotted a phoebe swoop down through the air and return to perch on the telephone wire or fence with a dragonfly in its beak.

Still, it seemed to me that the phoebes and other birds that catch insects in flight couldn’t be responsible for such a drastic reduction of dragonflies. Then I realized I needed to research the developmental stages of the dragonfly. Dragonfly larvae live in water! My attention turned to the little pond out back. We had salamanders, turtles and a bumper crop of frogs all of which eat larvae. Since we don’t use pesticides, my hunch is that the pond residents gobbled up the dragonfly larvae resulting in a small adult population. To further exacerbate the problem, dragonflies eat mosquito larvae, which would be a good thing except that the larvae is in the pond shared by the frogs that eat adult dragonflies as well as their larvae. Oh, the circle of life is sometimes sad.

Since we do not use pesticides, this seemed like a good explanation for the small dragonfly population - until I thought about the damselflies. Damselfly eggs are laid on vegetation in the water, they hatch into nymphs that live in the water and as adults they live near the water, even skimming over it during mating season. This past summer the damselfly population was huge, greater than I had ever seen it. Perhaps the pond critters only had a yen for dragonflies? Oh, the circle of life is sometimes very mysterious!