Hunting Dragons at White Memorial

Cyrano darner (Nasiaeschna pentacantha), a dragonfly

Ebony jewelwing (Claopteryx maculata), a damselfly

 
  In preparation for an upcoming odonata-themed mini BioBlitz, we've been visiting ponds, streams, and wetlands around the property, catching and identifying as many dragonfly and damselfly species as we can.  While several species of dragonflies and damselflies are generalists and can be found near most bodies of water on the property, others have specific habitat preferences and are much more difficult to find. Dragonflies and damselflies, especially specialist species, can help us better understand different habitat types, and it's possible that they can act as indicator species.  This means that changes in their abundance or in the assemblage of species at a given habitat can warn us of changes in that habitat, such as a shift in water quality.
 
     Dragonflies are most active when it's sunny.  Their speed and agility makes them almost impossible to catch in flight,so we generally waited until they paused to rest on vegetation.  Damselflies are smaller and some can be difficult to see, but they are active even when it's cloudy and are much easier to catch.  Some female damselflies resembled closely related species so much that a positive ID in the field was impossible.

Male variable dancer (Argia fumipennis), a damselfly

     Aside from improving our hand-eye coordination, catching dragonflies and damselflies has also given us practice working with a dichotomous key.  Dichotomous keys work by presenting you with two statements.  You choose whichever is true for your specimen and it will direct you to the next set of two statements.  For example, to identify the variable dancer (left) you would say his eyes are on separate sides of his head rather than his eyes are connected in the middle of his head.  This statement would lead you to another question that would help you determine whether you were holding a damselfly or a clubtail, which are the only dragonflies without connected eyes.  The next statements would further weed out species of damselflies until eventually you would be left with the variable dancer.  These statements help us hone in on what the distinguishing characteristics for dragonfly and damselfly species are.  In many cases, the last few statements in the key had us examining the last two segments of the insects' tails under magnifying glasses.  Attention to detail is crucial, but so is knowing which details are important.

     We sampled at fifteen locations (see map below), and positively identified 36 species from seven different families (see the link at the end of this post). We chose locations to represent different habitat types.  The species present will vary according to habitat type and time of year, with some species reaching their peak later in the year than the species we encountered. I'm in the process of uploading our findings to Odonata Central.  I encourage other odonata enthusiasts to do the same, and to join us on Saturday, July 9th (weather permitting), for our odonata mini BioBlitz!   Sunscreen, bugspray (but not on your hands!), long pants and waterproof boots are recommended, and butterfly nets are provided.      

Map of White Memorial with dragonfly sampling sites marked with red dragonflies

For a list of the species we encountered and the habitats in which they were found, click here.