Especially during product development, olfactometer tests are a helpful tool to identify the most promising candidates out of a broad range of active substances.
Biogents Y-tube olfactometers are an in-house development to investigate the level of attraction or repulsion of mosquitoes to volatile stimuli in choice experiments (Geier, M. & Boeck, J., 1999). Clean and conditioned air constantly flows through the apparatus towards the base leg where batches of host-seeking mosquito females are connected. During stimulus application, mosquitoes are released into the tube system to respond to the stimuli by choosing between a test chamber (with the stimuli) and a control chamber (with clean air).
- Repellents: The candidate material is dropped onto filter paper and introduced into the apparatus in combination with a human finger. The efficacy of the candidate material is compared to tests of the finger alone. In this way the repellent potential can be estimated through the test candidate’s ability to reduce the attraction to the finger.
- Attractants: Attractive chemical stimuli can be introduced into the apparatus with clean and pressurized air at different flowrates, or it can be evaporated from specific dispensers. Their efficacy can be compared to tests of a human finger in order to get an indication on the attracting potential of the artificial lure.
Biogents olfactometers were successfully used during the development of synthetic mosquito attractants (BG-Lure and BG-Sweetscent), and they played also an important role in identifying the potential of the repellent BayrepelTM (now Saltidin®, also known as KBR3023, Icardin or picaridine). Our testing facility owns a battery of four Y-tube olfactometers, identical in construction, which can be used for quick and efficient product screenings.