For today’s Macroinvertebrate post I present to you the Feathermouth Caddisfly (Ptilostomis sp.), from the Giant Casemaker (Phyrganeidae) family. There are at least four described species of Ptilostomis. Ptilostomis means “feathermouth,” referring to the fine filaments in their mouth as larvae.
Ptilostomis in its long case made of shredded leaves and grasses
The larvae of these species use various organic material to construct their large case(s). They are most often found in wetlands, swamps, lakes, and slack/slow-water areas of rivers and streams.
Ptilostomis profile view showing the large dorsal hump/horn
Some of their defining characteristics are long, filamentous gills and a large dorsal hump/horn. To see these features, delicately remove the larvae from its case.
Ptilostomis individual highlighting the long, filamentous gills they use to breath
The larvae of Ptilostomis can reside underwater for 1-2 years before emerging as adults. Here in the Midwest, the main emergence occurs around May and June. Caddisflies (Trichoptera) as an order are the largest and most diverse group of the EPT water quality indicator aquatic insects. Our Ptilostomis here have a tolerance value of around 5, making them moderately intolerant to water quality and pollution.
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