Weekend Insects

While botanizing this past weekend, I ran into an array of interesting insects, including one yellow jacket that wasn't too happy to be stuck under my shirt sleeve. Below are some photos of the more docile and cooperative species that I saw.

This gorgeous fluorescent blue and black-striped damselfly is in the group called bluets. The best that I can tell, this is a Tule Bluet (Enallagma carunculata). As always, help with identification, if I'm wrong, is much appreciated. This individual was observed at Merry Lea Environmental Center, close to Bear Lake, in Noble County, Indiana. Take a gander at the look he is giving me in the photo below. I think he's had enough of me chasing him around.


At the pannes north of Miller Woods in Lake County, Indiana, I saw the female Eastern Amberwing (Perithemis tenera) pictured below. This small, orange-tinged dragonfly, which is typically less than an inch long, can be confused for a wasp because of its size and the way that it moves in flight. Males of this species don't have the spotted wing pattern that the females do, but instead have solid amber-colored wings. Eastern Amberwings are most often found over lakes and ponds.


Also in one of the pannes, I ran into this crazy creature...


Ever seen anything like it? I sure hadn't. This white and black-checkered member of the long-horned beetle family is a Cottonwood Borer (Plectrodera scalator). The pattern on this beetle reminds me of a Rorschach inkblot test. Cottonwood Borers have a body that is over an inch and a half long, with spiny antennae that alone exceed that length! As the name implies, this species relies on Eastern Cottonwood (Populus deltoides), willows (Salix spp.), and other members of the willow family (Salicaceae) for multiple stages of its life cycle. In the photos above and below, the adult Cottonwood Borer is feeding on Bayberry Willow (Salix myricoides).

Have a close look at those mandibles. It's amazing that they only eat leaves and young twigs! After mating, the female lays eggs in pits at the base of a Salicaceous tree. The larvae hatch and burrow further into the tree, feeding as they go. This process can take up to two years. The larva then pupates in a root below ground, metamorphizes into an adult, and digs its way out from the ground. Because it doesn't leave from the tree itself, it leaves no exit hole in the tree.

With colorful insects that have life cycles like this, it's amazing I am still able to focus on the plants!

A Dragon and Two Damsels

Until recently, I didn't have many photos of damselflies and dragonflies. Maybe it's just the fact that I've been in good habitat, but it really seems like these insects have been much more photogenic lately. Here are a few of the species I've seen in the past week.

While in the field in northwest Indiana along the Little Calumet River on July 9, 2009, I heard the familiar sound of a dragonfly drying its wings in preparation for flight. I turned around, expecting to see a very common species like a 12-Spotted Skimmer (Libellula pulchella), Common Whitetail (Libellula lydia), Widow Skimmer (Libellula luctuosa), or Common Green Darner (Anax junius). But when I found the insect, it was obviously none of those. Instead, it was what I believe to be a Cyrano Darner (Nasiaeschna pentacantha). According to the books that I have, this species is uncommon in Ohio and common in Indiana, but not known from the northwest Indiana counties near the lake, where I observed it.


A bit later, a damselfly landed on my pants. For the most part, you can distinguish a dragonfly from a damselfly by the orientation of their wings when they are resting. A dragonfly rests with its wings held perpendicular to the body, while a damselfly rests with its wings above and together. There are a few exceptions to this rule, including spreadwing damselflies and a few others, that rest with their wings out, but spread apart. Another difference between dragonflies and damselflies is that the hindwings of dragonflies are wider than the forewings, but in damselflies, the hindwings and forewings are similar in shape. Damselflies seem much more difficult to identify than dragonflies. Carl Strang of Nature Inquiries has identified the damselfly below as potentially a brown-form female Blue-fronted Dancer (Argia apicalis). See the comments below for Carl's justification of this identification.

Then, on July 11, 2009 in a wet prairie at Round Lake Nature Preserve in Starke County, Indiana, a spreadwing damselfly landed on a nearby stem and posed for me. You can see that, at rest, this damselfly has its wings spread apart, but the hindwings and forewings are of similar shape. I believe that this is a male Slender Spreadwing (Lestes rectangularis). A good field character for this species, which I think I see in my photo, is the pale edge of the wingtips. Slender Spreadwings are common and widespread in Ohio, but from what I can find are only known from 13 counties in Indiana. Most of those counties are in the northeastern part of the state, and it does not appear that the species was previously known from Starke County.

Please feel free to correct me if any of these identifications are incorrect.