Mosguitos and Car Exhaust

We had an unusual experience at a KOA on Pine Island Florida. We had backed into our camp site and were setting things up when a swarm of mosquitos attacted us -- fortunely we had some Off and were able to proceed. About 20 minutes after setting up and relaxing in the TM, I went outside -- there wasn't a mosquito around -- what happend to them? Apparently they were attracted by the carbon monoxide (or is it dioxide) from our truck engine -- since our dog has still in the truck while we were setting up in the 90 degree heat, we had left the truck engine running until we were set up.

Isn't it true that mosquitos are attracted by carbon monoxide?