Is this a caddis fly? alder fly? stone fly? something else!? - Ask Extension
Hell!
I saw this insect in the 'lower' Kinnickinnic River yesterday.
Can you tell what sort of insect it is from this photograph?
Many thanks...
Knowledgebase
Is this a caddis fly? alder fly? stone fly? something else!? #860773
Asked March 07, 2024, 9:07 AM EST
Hell!
I saw this insect in the 'lower' Kinnickinnic River yesterday.
Can you tell what sort of insect it is from this photograph?
Many thanks!
Charles Phelps
Hennepin County Minnesota
Expert Response
It appears to be a species of stone fly.
https://www.canr.msu.edu/resources/stoneflies
https://www.canr.msu.edu/resources/stoneflies
Thank you for the very speedy reply!
What is it in the images that makes it clear to you that it is not an alder fly nor a cadis fly?
I'm trying to get smarter! ;)
Best,
Charles
I didn't check those other possibilities. I used an app called Picture Insect. It said Stone Fly and then I did an online search for Stone Fly and it appeared to match up. The apps are not always accurate so checking a second source is always a good idea.
With all due respect, please forward this to someone who's willing to tell me what the differences are between the Stonefly, the Alderfly, and the Caddisfly.
I don't say that rudely. I just want to keep learning!!!
...I think they all look similar and I am curious as to what it is about the fly in my images that make it look different than Alder flies and Caddis flies.
Many thanks,
Charles
done, to UMN Insect instructor.
Hi Charles,
I can't quite tell if this is a stonefly or alderfly based on these pictures.
Marissa Schuh
Horticulture Integrated Pest Management Extension Educator
University of Minnesota Extension
I can't quite tell if this is a stonefly or alderfly based on these pictures.
- Caddisflies have scales on their wings, giving them a moth-like appearance. These wings don't look scale-y to me.
- Stoneflies have a pair of appendages that come off their rear called cerci. They almost looks like another pair of antennae. Can't see them in your pictures, but they could be there. They also rest their wings closely on their bodies in an almost flat fashion.
- Alderflies have dark-veined wings held over their back in an angled, roof-like fashion. They also don't have ocelli (small bonus eyes that sit between their large, complex eyes). The pictures has some blurry glares on the insects head that might be ocelli, can't tell with the picture quality.
Marissa Schuh
Horticulture Integrated Pest Management Extension Educator
University of Minnesota Extension
Many thanks Marissa! Thank you for your speedy and thorough reply.
...Do either of these images (closeups) make it more obvious to you?
Best, Charles Phelps
P.S. I won't interrupt you again!
These pictures aren’t any clearer for the identification needed. Photo is not close enough to see any cerci because the rear is not pictured. Photo is not close enough to see the front eyes and ocelli. Also photos can flatten features like tented roof like wings.
