"Smell" - what is it, definition of the term
The sensation known as «odor» arises when volatile molecules enter the nasal cavity, bind to specialized olfactory receptors, and generate electrical impulses that the brain interprets as distinct scents, forming the physiological basis of the olfactory system.
Detailed information
Olfactory perception in arthropods operates through specialized sensilla that convert volatile molecules into neural signals. These structures, typically located on antennae or mouthparts, contain receptor proteins tuned to specific chemical patterns.
Ticks locate hosts by detecting carbon dioxide, ammonia, and lactic acid emitted from skin and breath. The sensory apparatus includes Haller’s organ, a complex of chemoreceptors that discriminates among host species based on the composition of emitted odors.
Bugs utilize scent cues for multiple biological functions:
- Host identification: volatile fatty acids and aldehydes guide feeding behavior.
- Mate selection: pheromonal blends released by conspecifics trigger courtship responses.
- Habitat preference: plant-derived terpenes influence oviposition sites.
Lice demonstrate a strong preference for human odor profiles rich in sweat-derived compounds such as urea and isovaleric acid. Their mandibular sensilla detect these molecules, directing movement toward suitable hosts.
Fleas respond to a combination of heat and odor, particularly the presence of phenolic substances found in mammalian skin secretions. The antennae house olfactory receptors that are highly sensitive to these volatile markers, enabling rapid host attachment.
Collectively, chemical detection mechanisms enable these ectoparasites to locate, assess, and exploit suitable environments, ensuring survival and reproduction.