Even though the larvae of the insects are safeguarded to some extent by the exoskeleton covering their bodies, it is necessary for them to camouflage themselves to hide from the sight of their predators.
Since the fly’s larvae are protein-rich and nutritious snacks for many creatures such as fish, amphibians, arachnids, insects, birds and even some mammals, it is necessary for the creatures to come up with different ways and means to protect themselves; of which camouflaging their bodies to fit perfectly with their surroundings is the best way to achieve safety easily. While some members choose the colours suiting to their environments and even the shapes, some tend to make use of the tools to safeguard them.
If the thought is now aligned about humans using the sand and stones around them to build shelters, stop for a moment; there are several creatures of nature that also perform such acts. It’s not just the spiders that build their homes, but also larvae of some flies that execute this safety mechanism for protection.
The caddis-fly larvae tend to make use of the tiny pebbles, mud, dust, dirt and even twigs to build a log cabin around themselves, which they attach to their bodies using the sticky silk that they produce. The process of sticking one twig would take about 15 to 20 minutes or even up to an hour, if the conditions are not favourable, but the caddis-worm (as the larva is called) has all the patience in the world to execute this act.
Step 1: Check if the twig would suit the purpose. It should neither be rough nor thorny. It should be smooth, light and yet strong.
Step 2: Once the twig is fixed, go to the free end of it.
Step 3: Turn around and move towards the tethered end until the length of the twig matches with the length of the body.
Step 4: Fix the existing shell to the twig and chop the twig to free the length that is selected as required.
Step 5: Hold the twig with the six legs and apply silk, which is the glue that would adhere the twig with the body and other twigs that may exist already. The mouth applies glue, while legs hold the twig. Hey, but won’t the larva fall off. It will not, since the log cabin’s top end is already fixed to the static part of the twig.
Step 6: Apply glue throughout the twig, since it has to be parallel to the body and other logs.
Step 7: Allow the twig to dry for about a minute to ensure that the silk would stick for the rest of the life of the larva, until it is ready to pupate and emerge as a fly. Pull back the head and legs inside the log cabin until drying happens. The new log would not fly or drop off since the silk would retain it safely.
Step 8: Align the twig to be parallel to the body. To achieve this, the caddis-worm would even re-emerge in the side of the cylinder and fix the position properly.
Once enough twigs that are neither too less to be camouflaged nor too many to be carried around by the light caddis-worm, he starts to gobble up and fatten until ready for pupation.