Creek dwelling creatures build themselves a protective house of stones with some of the stickiest tapes on the earth. The uniqueness about this house is that it remains intact inside the water and it’s a mobile house too. Scientists are struggling to make an adhesive tape that bonds while wet, but these creatures have no trouble constructing their outer stone case entirely underwater. They have been living close to human dwelling in Ladakh for ages yet we have never appreciated it. They have been helping us to live a healthy life too but, unfortunately, they are disappearing due to unsustainable human activities. No stonemason or architect can compete with them. You might be wondering what it could be and why have you failed to notice it? Yes, it’s not a monster or any creepy creature hiding from us but we often encounter it daily especially in villages.
Let me introduce you to nature’s most astounding yet underappreciated architect: The Caddisfly
What the heck is a caddisfly? It’s not a “fly” at all; it’s more closely related to a moth. I know you are still not able to figure out this creature. The easiest way to find caddisfly is to wade into shallows of a clear, fast-moving stream, pick up a stone, and turn them over. You will soon notice tiny piles or trails of sand grains that don’t wash or rub off but are affixed to the rock’s surface. Wait patiently, and a tiny, worm-like creature might emerge from one end, quietly yelling at you to put its rock back. Sometimes, you may have noticed an insect moving underwater with distinctive cylindrical-shaped cases from coarse sand, especially during the spring season in Ladakh when they begin to pupate. These marvellous edifices provide camouflage and protection from aquatic predators and a peaceful retreat from the rapids.
To protect themselves from predators, they gather up sand grains and other sediment and paste them all together with silk, forming a cone that holds their worm-like bodies. As they mature and elongate, they have to continuously add materials to the case- think of it like adding rooms to your home for the rest of your life.
Adult caddisflies resemble moths, but with their wings folded back along the body. Unlike moths, they have a fine set of hairs on their wings instead of scales. Adult caddisflies are terrestrial. They tend to be most active at night, hiding in cool, moist habitats during the daytime. The females mate as soon as possible as they only live about 5 days to a few weeks, during which time they lay about fifty eggs. The egg hatch in about 3 weeks. Whereas the larvae of most species live for one year, though some species live for two.
A caddisfly larvae passes through several growth phases, known as in stars before it makes a final shelter in which it can pupate. ( The pupa is the stage between larvae and adults.)
The adult female goes underwater to lay eggs; she can stay under for up to 30 minutes while she glues her eggs to submerged rocks and vegetation. She does this by using air that is trapped on her tiny hair for oxygen.
The name possibly arises from the ancient name for a travelling cloth salesman, who pinned samples of their wares to their coat. They were known as ‘Cadice men’ and it is possible the name ‘Caddis Fly’ is a reference to the cases many Caddisfly larvae build from bits of debris.
There are three broad classifications of Caddis larvae types: Primitive Caddis (aka free-living or free-ranging Caddis) that does not build a case or net. Instead, they cling to substrates, much like mayfly and stonefly nymphs: 2) Tube case makers that live in a case they build from bits of vegetation, sand, gravel, and debris: 3) Fixed-retreat Caddis that build similar shelters or nets. These types of Caddis feed outside their shelters but can retreat to them.
Caddisflies are one of the largest groups of aquatic insects with about 7,100 described species worldwide. It belongs to the Trichoptera group.
Caddisflies seem undervalued and under-appreciated by us, which is a bit of a conundrum.
You may wonder why this insect species matters to us. But caddisflies are critical actors in these ecosystems, and their diminishing habitats due to water pollution could well have consequences. Caddisfly larvae do an important job of hoovering up aquatic vegetation, keeping a river from getting overgrown. It is one of the most important bio-indicator of clean water. The presence of caddis larvae in stream water is an indication that water is clean and consumable. Most species are quite intolerant of polluted water; thus, their abundance is a reliable indicator of good water quality. What’s good for caddisflies is good for fish- and us.
During my recent visit to few villages in Nubra valley, I noticed the presence of caddisfly larvae in the main streams of all those villages, which indicates that drinking water sources in villages are not yet polluted for caddisfly to retreat. But the important question is, have you noticed Caddisfly larvae in your village? If not, it is the major cause of concern.
So, when you see caddisfly larvae in a stream from where you fetch drinking water, be happy and grateful to these astonishing architects of nature.
The writer is a Former Executive Director of Ladakh Ecological Development Group. You can send your views and comment at email@example.com