Marvelous Macroinvertebrates: Caddisfly edition


If you have slept in a sleeping bag before, or at least know what one is, you may be able to relate to the Caddisfly. Now, imagine for a moment that instead of soft down material, your sleeping bag is made of dozens of tiny stones, and by the way, you made the sleeping bag yourself. This is a glimpse into the life of a Trichoptera, or caddisfly, larvae. The incredible Caddisfly family, aka Trichopterans are known as “case-makers,” due to their trademark protective cases they create out of various natural materials. The caddisfly pictured above chose to use small stones, however, it is common to see cases made of small twigs, pine needles, sand, and even living or dead plant parts.

Now you may wondering, what is the glue that holds this all together? In short, it is spit. Well, actually, it is silk produced by the salivary glands of the caddisfly. Not unlike the silk worms of Asia, caddisfly larvae have the ability to create a sinewy material in there mouths that acts as the perfect mortar for their respective cases (Ivanov et al., 2002). Crazy, right? What is crazier still, is that scientists can use the type of case the caddisfly creates to identify the species.

In their aquatic habitats, caddisflies feed mostly on periphyton, which is a layer of algae that collects on rocks and substrate. The caddisfly case protects the larvae undergoes complete metamorphosis in the form of four stages: egg, larva, pupa, and adult (Stewart and Wang, 2010).  Now, you may be asking, how do they breathe in their natural sleeping bags? Well, caddisfly larvae undulate, or twist, their bodies inside their cases to ensure the flow of the oxygenated water through their thin silken cocoons inside their hardened cases.

The trichopteran family is composed of more than 12,000 living species across the world (de Moor, 2008). Trichopterans are important bioindicators of water quality, as they are sensitive to any changes in the structure of aquatic environments (Spies et al., 2006). Therefore, here in Vesper Meadow and in Oregon, it is good news that surveys discovered these marvelous macros!


Works Cited

  1. de Moor, F. C. & Ivanov, V. D. (2008). Global diversity of caddisflies (Trichoptera: Insecta) in freshwater. Hydrobiologia 595, 393–407

  2. Ivanov, V. D. & Sukatsheva (2002) I. D. in History of Insects (eds. Rasnitsyn, A. P. & Quicke, L. J.) 199–220 Kluwer Academic Publishers, Dodrecht, Boston, London

  3. Stewart, R. J. & Wang, C. S. (2010) Adaptation of caddisfly larval silks to aquatic habitats by phosphorylation of H-fibroin serines. Biomacromolecules 11, 969–974.

  4. Spies M.R., Froehlich C.G. and Kotzian C.B., 2006. Composition and diversity of Trichoptera (Insecta) larvae communities in the middle section of the Jacuı´ river and some tributaries, state of Rio Grande do Sul, Brazil. Iheringia, Se´r. Zool., 96, 389–983