Mosquitoes ignore repellent Deet after first exposure

Repellent Deet appears to be losing its effectiveness against mosquitoes. Mosquitoes are first deterred by the substance but then later ignore it.  By knowing the cause of this the researchers attached electrodes to the insects antenna and after that they could saw that the mosquitoes were no longer as sensitive to the chemical so they weren’t picking it up as well.

I know that some repellent aren’t effective. Sometimes I use it but after an hour or two mosquitoes appear again so it doesn’t work. Always mosquitoes bit me but I didn’t do nothing because after a days the bit didn’t hurt me.

http://www.bbc.co.uk/news/science-environment-21519998