Whether in spray or candle form, bug repellant seems to be a necessity in the humid days of summer. But what exactly are those chemicals that give the spray its distinctive smell, and how do they work to keep bugs away?
Most bug sprays are made
from synthetic chemicals, such as DEET, the most common
ingredient in bug repellant. Originally
developed by the U.S. Army for jungle warfare, and tested as a
pesticide on farms, DEET offers protection against tick and
mosquito bites. Scientists don’t yet know exactly how DEET works, but the prevailing theory is that it disrupts insects’ ability to detect the natural chemicals - carbon dioxide, lacticacid, and a compound called 1-octen-3-ol – that would otherwise lead them to humans.
Essentially, the bug spray masks your scent, keeping the mosquitoes away. This "blindness" is achieved by DEET interfering with the function of specific odorant receptors that work with a smell co-receptor called Or83b. This receptor is needed for mosquitoes to detect 1-octen-3-ol and other odors in sweat, but not for them to detect carbon dioxide. So DEET works by blocking parts of the olfactory system, not all of it.
However, some tests show that DEET can be harmful when used often and in high concentrations. While DEET can possibly cause seizures, the seizure rate is about one per 100 million users, and therefore generally considered safe. However, some people prefer to use natural bug repellent, not just for safety reasons, but because of DEET’s strong smell. Citronella oil has been used as an insect repellent for over 60 years, and now most of us know it from bug-repelling candles. Most essential oil-based repellents are not as effective as DEET, but oils with high levels of effectiveness include eucalyptus and lemongrass.
Many people claim that eating certain foods, particularly bananas, will make you more likely to be bitten by mosquitoes . This, unfortunately, has remained inconclusive, and some people even claim that bananas will keep mosquitoes away. So don’t change your diet in hopes of surviving mosquito season.
You can, however, change your hair color. Mosquitoes have been shown to be more attracted to blondes and redheads , though only because these hair colors stand out in a crowd. Research has also shown that the bugs prefer ovulating women and people with smelly feet. But no matter what you’ve eaten, what your hair color is, or what time of the month it is, DEET is the way to go in bug protection.
Erica Hersh is an editorial intern and writer for Under The Microscope.