Final answer:
Male silk moths have large antennae designed to detect female pheromones for mating purposes. These antennae are extremely sensitive, enabling the moth to sense minimal concentrations of pheromones across substantial distances.
Step-by-step explanation:
Male silk moths have huge antennae for the purpose of detecting pheromones released by female moths. These pheromones are chemical signals essential for communication, especially for the purpose of mating. The antennae of male moths are highly sensitive and can detect these chemical cues over remarkably long distances, sometimes spanning several miles. In fact, a male moth may respond to the female's pheromones with as few as a hundred molecules of the substance per millilitre of air being enough to elicit a reaction. Moreover, such sensitive chemical communication is found in a wide range of insects and is particularly well developed within social insects.
This advanced level of detection aids in ensuring that males and females find each other to mate, which is critical for the survival and propagation of their species. These specialized antennae highlight the incredible adaptations of insects, like the male silk moth, with regards to their sensory capabilities, such as 'smelling' and 'tasting' chemicals, which often go well beyond human abilities.