Aristolochias are also popularly known as Birthworts besides many other names given to them. The family is represented by about 500 species world over. Most birthworts are creepers and several species with very showy flowers are grown in gardens as ornamentals. In India, we have a few species belonging to this family of plants.
These plants use a very interesting strategy to effect pollination of their flowers. The pollinators are perhaps attracted to the flowers owing to their colour and smell. The flowers have downward pointing hairs on the inside wall leading from the mouth to the bulb at the base. These hairs facilitate the downward movement of the pollinator. When the insect is in the bulb part of the flower, pollination is effected. Subsequently, the hairs wither allowing the pollinators to fly out.
Aristolochias also have interesting fruits. Several winged seeds are packed inside each fruit. When the fruit is mature, it breaks open and releases the flat winged seeds. At this stage the fruit looks like a little inverted parachute.
Recently, I saw an Aristolochia indica creeper entwined completely on a thorny shrub. When I saw the plant my eyes automatically started searching for the larvae of the Crimson Rose butterfly. At first, I saw a small caterpillar sitting on a flower.
Subsequently, I saw one that was feeding on the fruit of the plant.
There was also one large caterpillar resting on the main stem of the creeper. I quickly set about photographing various aspects of the flower and the larvae.
It is interesting to note that the Crimson Rose butterfly lays eggs selectively on the Aristolochia indica vines.
For that matter, all female butterflies are very particular about the plant on which they lay eggs. They will not lay eggs on every other plant they come across – they are host-specific. This is yet another example of how things in nature are inter-related.