How does a butterfly feel and know about its surroundings? Like all other insects, the butterfly has a pair of feelers on its head. These are slender jointed finger like structures. They are called Antenna (Antennae: pleural).
The butterfly antenna is specially designed to understand the scents in the air, wind currents and the smell of nectar. These functions are essential for the butterfly, when it is flying in search of food. Though butterflies can see the flowers with their eyes, they locate them first by sensing the smell. Flowers attract insects through their color and smell.
For a nectar feeder like the butterfly, the antenna serves three basic functions:
- Locate the right kind of flowers
- navigate the butterfly to the flowers and
- Assess the nectar availability.
The butterfly antenna has a knob at its tip. The knob contains thousands of “sensilae”or pore plates. These serve as ‘noses’. The butterfly has similar ‘noses’ on its legs too. When the butterfly lands on a flower, the feet of the legs perceive the smell of the substances on the flower. If these substances are bad, the butterfly will immediately reject the flower and fly away. If the substances are accepted by the feet, the brain of the butterfly gives a signal to go about exploring the flower and extend its proboscis into the nectar chamber. The proboscis also has sensory structures which can feel the taste of the nectar.
An excellent coordination of functions from the antenna, legs and proboscis enable the butterfly to enjoy its meal.
The antenna also has special sensory cells which locate molecules of chemical substances released by the fellow butterflies. For example, a female butterfly can attract a male through the release of certain chemical substances called Pheromones which help in mating.
Several insect activities like, mutual attraction, grouping, and flying together are the result of chemical perception.
The butterfly feelers or the Antennae thus are so essential, that the very survival of the butterfly depends on their accuracy of function.
Butterfly A thing of Beauty