There are 5,500 known species in North America. Dragonflies are our oldest known insects, having been on earth for 300 million years! They are also a major insect predator, as adults and as larvae, making them very beneficial to humans. Of the 27 families, there are 6 families in Wisconsin. They overwinter as eggs or larva.
Dragonflies and damselflies are great indicators of good water quality, so I am especially happy to find them hanging around our property. My hope is that our prairies will make the downhill streams cleaner since native plants are the best filtering systems for water runoff! Some resources say they are indicators of pristine habitat – really makes me feel doubly good about our restoration efforts!
The difference between dragonflies and damselflies is how they hold their wings. Dragonflies hold them flat; damselflies hold theirs upright over their body. Another difference is in how they hunt. Dragonflies hunt while flying, catching their prey in flight as well; damselflies will hunt from perches, snatching their prey from plant surfaces.
Dragonflies are the best fliers among insects, some flying upwards of 35-45mph. Another amazing aspect to these insects is their eyes, which make up the majority of their head. They have over 30,000 lenses and can see in all directions except behind them. They see colors including ultra-violet light and polarized light. Can you imagine a world with this much visual stimuli? With this fabulous eyesight they have no need for hearing.
Leglers and Westover’s guide has a page with diagrams on how to ID the 6 different families. This is just one aspect of this guide but I mention it because it’s unique.
For more info:
Wisconsin Odonata Survey
Calopterygidae (Broad-winged Damselflies)
Calopteryx maculata – Ebony Jewelwing
Coenagrionidae (Narrow-winged Damselflies)
Argia apicalis – Blue-fronted Dancer
Argia fumipennis – Variable Dancer
Libellula luctuosa – Widow Skimmer
Pachydiplax longipennis – Blue Dasher
Plathemis lydia – Common Whitetail
Sympetrum sp – Meadowhawk