Abstract
Insects have ability to discriminate a wide diversity of odorants in the natural environment as well as to detect species-specific pheromones with high sensitivity and specificity. Olfactory signals are mediated by odorant or pheromone receptors expressed in olfactory receptor neurons in the olfactory sensilla of antennae. The signals are transmitted to the first olfactory processing center, the antennal lobe (AL), then, further processed at higher centers (mushroom body and lateral protocerebrum) to elicit specific behavior in animals. In recent years, remarkable progress has been made in our knowledge of molecular mechanisms underlying odor discrimination and pheromone perception, mainly due to the identification of odorant and sex pheromone receptor genes in insects. At the same time, extensive studies in the AL have provided many insights into neural basis of odor discrimination in the insect brain. Understanding how insects detect and discriminate the olfactory information will tell us how nervous systems process the complicated environmental information, and ultimately translate it into meaningful behaviors.