May 25th, 2026 at 1:26PM we gathered waders, D-nets, glass vials, aspirators, and a bucket with a transparent bottom. Then we piled into a van. From there we headed East from Au Sable to the Manestee River headwaters. Upon parking along the side of the road we carefully crossed the street and headed down a few stair steps to the edge of the Manestee River.
View from where we entered the Manistee River
When looking for aquatic insects, there are a few places that one would look primarily. That includes muddy banks, especially with overhangs, dead trees, and places with dense plants or rocks. These habitats provide space for organisms to hide and places for them to cling onto.
My personal goal for this trip was to find a Trichoptera, more commonly known as a caddisfly. But unlike butterflies where you tend to look for the adults, I wanted to find a caddisfly larvae. I wanted to find this particular insect because just a few days before we did a stream survey and that was the first time I had seen a caddisfly in real life and I had awed. These larvae are unique in that they use their silk to bind together twigs and small rocks to create a casing for themselves. And it is fascinating.
After donning our waders, we entered the water with the D-nets and the bucket. Almost immediately, an adult caddisfly landed on my D-net, so I put it in a jar. But it wasn't what I was looking for. Dr. Hoekman explained to us that the purpose of the bucket was to press it into the water to look closer at the bottom of the stream. And this is where the first surprise came.
Upon looking through the bucket, I could see tiny organisms clinging for their lives to blades of grass and bits of gravel as they fought the current. The current wasn’t terribly strong, but when looking at the little creatures you would have thought they were in a hurricane, and yet, they held on defiantly. But their presence wasn’t the surprise, the surprise was that these were caddisfly larva. I had initially thought they were snails with long straight shells. But no, they were definitly caddisflies. Though they shared the name caddisflies, they were much smaller than the ones I was used to and their casing was much simpler. I unfortunately didn’t collect a specimen, so I wasn’t able to fully identify it, but it certainly was not the Trichoptera I had been looking for.
After admiring these creatures for a while, I turned my attention to finding the bigger caddisflies, which I later found out are called Longhorn-case caddisflies, in the family Leptoceridae (BNHM).
After I crossed the stream and began sampling the muddy overhang, Dr. Hoekman called out that he had found a bunch of caddisflies under a dead tree, but he was on the other side of the river and farther downstream, so I decided to find a dead tree closer to me.
I found one, but had no luck. I wasn’t finding much of anything besides bits of mud, tree litter, and a mayfly here and there. So I decided to try the mud bank again and after draining the water and searching through the muck, I finally caught a glimpse of the tell-tail caddisfly case. It is interesting to me that each species has the same case layout as the others in it's species. In this case (no pun intended), Leptoceridae tend to have a few broken twig bits or pieces of pine needles extending from the back and a few bits of gravel and sand at the front. I made sure there was actually a larvae inside this case by letting it sit in the water to see it crawl out and, once comfirmed, I put it into a vial.
As I mentioned before these caddisflies were bigger and can be found attached to dead trees or in the mud. Since they are found closer to shore, then they have more protection and have the luxury of creating a more elaborate case. However, they still need something to cling to or else they will be swept away by the current just like everything else.
As time progressed, I kept sampling different habitats beyond just muck and dead trees. There were sandy patches and a gravel portion under a nearby bridge. And every once in a while a few people would float by on their kayaks.
The bridge and tree stump we sampled under and around
On my way back from the bridge, there were some massive tree stumps which seemed to act almost like little islands. Besides catching a toad there, I found yet another species of caddisfly. This one had no casing at all. I had scraped it off the underside of some of the dead tree's roots. When I showed it to Dr. Hoekman, he said that it was a caddisfly. I was befuddled. It didn't have a case, how could it be a caddisfly? Wasn't that there staple? And so, I was surprised yet again.
Hydropsychidae under a microscope
Apparently, these caddisflies still have silk, but instead of using it to create a protective shell around themselves, they use it to build weblike structures to capture small particles for them to eat (Stroud). This particular net-building caddisfly is the common netspinner, in the family Hydropsychidae, because all of its thoracic segments are hardened and it has hairs extending from its anal prolegs (BNHM). I even saw it try to use some of it's silk to hang onto the top of the vial I put it in.
It turns out that the result of this trip to the Manistee River wasn't just about finding more insects for my collection, but it was discovering first hand that there are in fact different species of caddisflies. For some reason, I never really put it together that Trichoptera was an order just like Lepidoptera or Coleoptera. I always just thought caddisflies were caddisflies, but evidently, there is so much more to them than just that.
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