Chapter 2 Insect Record Caddisia

I put some small aquatic animals called caddis worms into my glass pond.To be precise, they are the larvae of the caddis moth, which are usually cleverly hidden in small sheaths made of dead branches. Caddis worms originally grew in reeds in mire swamps.In many cases, it is attached to the broken branches of reeds and drifts in the water with the reeds.The small sheath is its mobile house, or it can be said to be a simple house it takes with it when traveling. This movable house can actually be regarded as a very delicate woven artwork. Its material is composed of the root bark of the plant that has been eroded and fallen off after being soaked in water.When building a nest, the caddis silkworm uses its teeth to tear the root bark into fibers of appropriate thickness, and then skillfully weaves these fibers into a small sheath of appropriate size so that its body can fit inside.Sometimes it also uses very small shells to piece together a small sheath, just like a small panacea; sometimes, it is also piled up with rice grains.Arranged in a nest of ivory towers, this is its most splendid dwelling.

mob attack The small sheath of the caddisworm is not only its shelter, but also its defense.I have seen an interesting battle scene in my glass pond, which vividly confirms the role of that humble little sheath. There was a dozen water beetles lurking in the water of the glass pond, and the way they swam piqued my interest.One day, I unintentionally dropped two handfuls of caddis worms, and the water beetles lurking next to the stone just saw them. They immediately swam to the surface of the water and quickly grabbed the small sheath of caddis worms. The caddis worms inside felt this The attack was ferocious and it was not easy to resist, so he came up with a clever plan for the golden cicada to escape its shell, slipped out of the sheath unhurriedly, and escaped without a trace in the blink of an eye.

The savage water beetle continued to tear at the small sheath viciously, until it realized that it had lost the food it wanted and was deceived by the caddisworm, and then it showed an expression of remorse and frustration, nostalgia and helplessly dropped the empty sheath , went elsewhere for food. Poor water beetle!They'll never know that the clever caddis has long since escaped to the bottom of the rock, rebuilt its new sheath, and is ready for your next attack. Submarine - Caddisiac Relying on their small sheaths, caddis worms swim freely in the water. They are like a team of submarines, ascending for a while, descending for a while, and staying in the middle of the water magically for a while.They can also freely control the direction of sailing by the swing of the rudder.

I couldn't help but think of rafts. Does the small sheath of the caddis worms have a structure like a raft, or is there a device similar to the function of a floating bag to keep them from sinking? I stripped off the small sheaths of the caddis worms and placed them separately on the water.As a result, both the small sheath and the caddiskworm sank.Why is this? It turned out that when the caddisworm was resting at the bottom of the water, it stuffed its whole body into the small sheath.When it wants to float to the surface, it first climbs up the reed stem with its small sheath, and then sticks its front body out of the sheath.At this time, there is a gap at the back of the small sheath, and the caddisworm can float up smoothly by relying on this gap.It's as if a piston is installed, and when it is pulled out, it is the same as the air column in the syringe.This section of sheath filled with air is like a life buoy on a ship, relying on the buoyancy inside to keep the caddisworm from sinking.Therefore, the caddiskworm does not need to be firmly attached to the reed branches or aquatic plants. It can float to the surface of the water to be exposed to sunlight, and it can also swim freely at the bottom of the water.

However, the caddisworm is not a very good swimmer, and its movements of turning or turning seem clumsy.This is because it only relies on the part of the body stretched out of the sheath as the rudder oar, and there are no other auxiliary tools. When it enjoys enough sunlight, it retracts to the front body, exhausts the air, and gradually sinks fell. We humans have submarines, and the caddisworm also has such a small submarine.They can rise and fall freely, or stay in the middle of the water - that's when they are slowly expelling the air from their sheaths.Although they don't understand the extensive and profound physics of human beings, the perfection and ingenuity of this little sheath are all due to their instincts.Everything dominated by nature is always so ingenious and harmonious.