Yep!

They use propane just to burn it and put of carbon dioxide to attract the little buggers!

Heat, Carbon dioxide, and the attractant used those things are affective but $$ for good sized ones

i have noticed that in a group, non-smokers have more problems than smokers. working on the levee last year (mosquito heaven! lots of stagnant water) i had very little issue i.e. i smoke. my co-workers got eaten alive. i got tired of their whining, so i hiked back to my truck, retrieved my deet spray. (i use for deep woods, had not thought to use) and still had to listen to it all over again. i have found that smoke repels most insects. maybe its just me, other smokers argue with me that they have insect problems, dunno.