Dobsonflies!

Last week we had an event at the museum, "Science in Action." It was a very busy

day for all of us, but it was great to see so many families interested in science, and encouraging their kids to learn more. We set out a beautiful display case of insects that were collected by a former curator. This display case got a LOT of attention - here, you can see it for yourself!

There are a lot of insects to examine here, but I noticed there was a particular kind that garnered a lot of intrigue. Let's look a little closer, and focus toward the bottom of the display:

Many people thought these looked positively ferocious, and everyone wanted to know what on earth these creatures are. These are a type of Megalopterans, in the family Corydalidae. These are commonly known as dobsonflies, and they tend to live near the water. These are males, and you can tell by their huge tusks on their head. While these tusks look like they could administer an unpleasant bite, they really can't do much harm to humans. The tusks are merely an attempt to show off for the female dobsonfly, and for holding her during mating once she's been suitably impressed.

When these Corydalidae are younger, they look like this:

If you fish, you might know these as hellgrammites, and you might also know that these can bite in their larval stage of life. You'll find these under rocks in cool, running water, and they're very common. They also throw quite a fit if, for instance, you try to collect them for your Aquatic Entomology class. I found one when we went on a collecting field trip, and this little insect would NOT let go of my net with its mouth. Once I finally managed to pull it off my net and drop it into my collection vial, it thrashed around and tore apart everything else in the vial. Several of us ended up with intact hellgrammites and a sad pile of other insect parts. These larvae definitely don't go down without a fight.

These larvae have gills, which you can see in the picture above - they look like tufts of fur. Most of Corydalidae's life is spent in the larval stage. When they become adults, however, they lose their gills and live on land. The adults also do not live long - only about a week or so. If you find a dobsonfly, it's near the end of its life, and is only interested in mating before it dies. As the weather warms up throughout this spring, see if you can find one!