Many of us may have noticed a little brown speck of ‘dirt’ stuck to the walls in our homes. It looks like a blot on an otherwise clean wall or should I say on our house-keeping skills? Often, it is promptly removed and disposed. If you were the procrastinating type perhaps you noticed that the speck has moved and it is no longer in the same place on the wall. If you happen to be curious, you would have figured out just what that moving brown speck of is!
We are talking about what is popularly referred to as bagworms. What are bagworms? They are a small family of moths belonging to family Psychidae. This family comprises of over 1300 species of the 1.3 lakh species or so moths in the world.
There is something unique about this family of moths. The larva, soon after emerging from the egg, builds a little case. For this purpose it uses the silk that it produces and material available in their environment – could be lichen, tree bark, twigs, sand, leaves etc. It can be seen with just a bit of its body protruding out when it is moving about.
Once its growth as a larva is complete, it will pupate within the ‘bag’ it had built as a larva. The males of most species have wings like other moths and will fly away. However, the adult females often lack wings and look like the larva itself! The males are very short lived. They even lack mouthparts and don’t eat as adults. So the males have to locate females as soon as they can and mate with one. They do this by following the pheromones produced by the females. Eventually, they mate and the females lay eggs within the ‘bag’ and die. The females too live just long enough to mate and lay eggs. Like the males, the females do not eat as adults. And, this entire process continues generation after generation.
In the outdoors, one can find a variety of ‘bags’ built by these little creatures. Some of them are really amazing feats of engineering, while some others look clumsy to help them camouflage beautifully with their environment. Below are some such ‘bags’.
So, the next time you see one of these aggregations of material – be it twigs, leaves, bark, etc., – give it another look. Lo and behold you may have discovered another beautiful piece of engineering – a bagworm!
See more images of Bagworms