MCR Monthly Newsletter

August 2025

A week ago, a hiker came into the MCR Visitors Center with a picture and asked if I could identify a strange large creature they encountered on the Orange Trail near upper Merrill Creek. It was a DOBSON FLY (Order Megaloptera).  These are some of the largest insects found in our area! The male has some extremely large mandibles but does not bite or pinch. These large mandibles are used primarily for show, to impress and attract the female. Below is a large male.

Male Dobsonfly

The female Dobsonfly has much shorter and stronger mandibles and can deliver a sharp pinch.

Female Dobsonfly

The larvae of dobsonflies are known as Hellgrammites. Hellgrammites are the aquatic larvae of the Dobsonflies and can be found in both upper and lower Merrill Creeks.  They are a favorite food of bass and trout. These aquatic larvae can also deliver a painful pinch.

Hellgrammite

Hellgrammites are also often found and plentiful in Merrill Creek along with the “lobster-like” crayfish which can be grow to over 6 inches long at MCR!

Crayfish

Both Hellgrammites and Crayfish are excellent indicators of good water quality because they are sensitive to pollution and their presence or absence can reveal the overall health of an aquatic ecosystem. Their ability to integrate water quality over time makes them more reliable than single water chemistry samples. 

The stewardship work we do here at MCR helps the Merrill Creek provide crucial habitat for many unique creatures that are not always obvious.

Remember take only memories and leave only footprints!

Thank You,

Ranger Rich