Few years ago, we had been to Aralam wildlife sanctuary, Kerala. It is a moist deciduous, semi evergreen/ evergreen forest. Our attention was caught by the appearance of an endemic Butterfly – Southern Birdwing Troides minos which is known to be the largest butterfly of western ghats with a wing span of nearly 190 mm. It is a beautiful insect, black and yellow in colour. Its caterpillar host plant is Thottea siliqousa, an endemic climber of Arstolochiaceae in addition to commoners Aristolochia indica, and Aristolochia tagala . The butterfly is always in search of these particular plant on the leaves of which the adult lays the eggs. The caterpillar on hatching from the eggs eagerly munches the leaves and after a few days becomes pupa.
Fig: Southern bird-wing
Fig: Southern Birdwing caterpillar (Troides minos) on Aristolochia tagala Fig: Thottea siliquosa
The butterfly usually flies at a great height of nearly 90-100 ft above apparently detect the climber even from such a great height. We started guessing how the butterfly could sense the presence of this particular climber. It is possible that the plant was releasing the particular chemical into the air in small quantities, perhaps few molecules at a time. The butterfly after sensing the plant from such a height slowly starts descending and as it came closer to the plant, it is possible that concentration of molecules detected will be high. The butterfly was evidently joyful that the particular plant was the desired one. The butterfly did not stop at that it came closer and closer and almost touched the plant and evidently confirmed the identity of the plant. Just as we human beings sense the presence of perfume plants like jasmine or champaka confirming its identity. It is a classical living instance of nano technology in practice. Once the butterfly is sure of the climber’s identity, it descended further and started laying eggs. This whole instance simply amazed us. The butterfly apparently is an example of expert taxonomist!
All the while Ms. Vijayalaxmi was happily recording the whole sequence photographically. After finishing its task the butterfly flew away perhaps looking out for another Thottea plant ahead. The whole instance indicates the amazing ways of nature. Nature is always so. It never fails to amaze us, if we observe it closer and deeper. Such instances could happen in your own garden. Amazing are the ways of Mother Nature! Do observe and document it.
Author: KB Sadananda
Photo courtesy: M Sahana & Rubin Nair