I had planned write about an unique moth pupa which uses its caterpillars hairs to build a cage like structure around it , but when I looked up for the id I found that it belonged to the family of moths that specialized in jamming bat signals and that these were also called as lichen moths. Lichen moth are good indicators of environmental health . Fascinated by the interconnections here is a post which is a bit long one though ,Please read on and let me know .
This year we decided to spend the diwali weekend at Valparai. It was wonderful to wake up to the song of Malabar Whistling Thrush, instead of the firecrackers! Valparai is a plantation town, a hill station, a biodiversity hotspot and a tropical rain forest. Located in the Anamalai range of the Western Ghats, this is one of the most pristine spots in Tamil Nadu. I first heard about Amazonian rain forests in my geography lessons in school. More recently I helped my daughter for her assignment on rain forests. I stumbled upon very interesting facts about these forests in the book by Sandesh Kadur – Sahyadris,the book which was a part of the submission that helped convince UNESCO to name the Western Ghats a World Heritage site.
Some interesting facts about rain forests below
- More than half of the world’s species of plants and animals are found in the rainforest.
- Rainforests support a very broad array of fauna, including mammals, reptiles, birds and invertebrates.
- Tropical rainforests have been called the “Earth’s lungs”, 40 % of the oxygen on earth is released by the rainforests.
- 200 species of trees can be found in one hecctare of rainforest.
- Trees with height of 150 feet are found in the emergent layer.
- Researchers found 950 species of beetle on one rain tree .
- 70 % of the anticancer plants identified so far come from rainforests.
Forests were cleared to make way for tea plantations in Valparai. But conservation efforts by NCF seems to have made an impact in reviving the rain forests around the region. Native trees have been planted in vacant plots and abandoned estates. More important, for me it was fascinating to see Orchids and lichens in Valparai.
Orchids are sensitive to even slightest disturbances to their habitats and with the tremendous pressure on natural resources, particularly forest resources, orchids and their habitat are continuously under threat. The major threats for orchid population in nature are habitat destruction and over collection. Well, Orchids will have to wait for one more blog – I am dwelling on the fascinating Lichens and some special moths. Read on!
Lichens are often important components of natural habitats, providing nutrients and preventing erosion, and lichen moths may provide a means of measuring environmental health. Lichen moths may also be good environmental indicators of pollution. Pollutants such as acid rain and heavy metals often kill lichens, and absence, or reduced diversity of lichen moth species in affected areas may indicate that damage to the lichen community has occurred.
We found an interesting moth pupa which looked as if it was in a cage. My friend Chandu had posted a link about this interesting pupa few days ago. On browsing further they were identified as moth pupa of the Cyana genus (Arctiinae) – a lichen moth, which makes an elaborate open mesh cocoon with the pupa suspended in the middle. While pupating, the caterpillar attaches pairs of hairs and uses these to make the sides of the cage. The pupa is suspended in the middle of the cage, equidistant from the sides. The caterpillar even manages to push its final larval skin outside the mesh cage while forming its pupa. When the moth emerges, it appears to exit the cage without damaging it.
The most distinctive feature of the family is a tymbal organ on the metathorax. This organ has membranes which are vibrated to produce ultrasonic sounds. Analysis of the clicks produced by some arctiid moths shows that their acoustic characteristics are remarkably similar to those of frequency-modulated echolocation calls produced by many bats as they close on their prey. Scientists suspect that the clicks are initially processed as echoes by the auditory systems of these bats and function by interfering with information processing by the bat. So the bats signal is jammed and it fails to locate the moth!
It is really amazing to learn about creatures which have designed smart protection mechanisms.