What element is often used as bait in light traps for mosquito collection?

The use of carbon dioxide (CO2) as bait in light traps for mosquito collection is highly effective because CO2 is a significant attractant for many mosquito species. Mosquitoes have sensory receptors that can detect CO2 from a distance, as it signals the presence of potential hosts—typically warm-blooded animals or humans. When light traps combine CO2 with the emitted light, they simulate a more natural environment that can significantly increase the capture rate of mosquitoes.

Heat is also attractive to mosquitoes, mimicking the warmth of a host, but it is not the primary bait used in these traps. While water may attract some species due to standing water being a breeding ground, it does not act as bait in the same context as CO2. Light primarily serves to attract insects and can operate without the presence of other attractants, but CO2 enhances the effectiveness of light traps specifically targeting mosquito capture.