Insect olfaction
Insect olfaction refers to the function of chemical receptors that enable insects to detect and identify (airborne) scents and odors for foraging, navigation or finding mating partners (via pheromones). Insect repellents mimic adverse stimuli that signal danger to the insect.
Insects have been used as a model system to study mammal and especially human olfaction. Insects use primarily their antennae for detecting odors. The majority of olfactory receptor neurons typically resides on the antenna. Much like in vertebrates, axons from the sensory neurons converge into glomeruli in the antennal lobe.[1]
Sensory neurons in the antenna generate odor-specific electrical signals called spikes (action potentials) in response to binding of odors to cell surface proteins like the insect pheromone-binding protein. The sensory neurons send this information via their axons to the antennal lobe, where they synapse with other neurons in semidelineated (with membrane boundaries) structures called glomeruli. The antennal lobes have two kinds of neurons, projection neurons (mostly excitatory) and local neurons (inhibitory, and some excitatory). The projection neurons send their axon terminals to mushroom bodies and the lateral horn (both of which are part of the protocerebrum of the insects). Recordings from projection neurons show in some insects strong specialization and discrimination for the odors presented (especially for the projection neurons of the macroglomeruli, a specialized complex of glomeruli responsible for the pheromones detection). Olfaction is essential for hunting in many species of wasps, including Polybia sericea.
References
- ↑ Wilson, Rachel I (2013). "Early olfactory processing in Drosophila: mechanisms and principles". Annual Review of Neuroscience 36: 217–41. doi:10.1146/annurev-neuro-062111-150533. PMID 23841839.