We're by the Gulf for most of the winter with our rig. I did exactly what you're talking about, otherwise I was dumping 2-3 gallons every 24 hours.
No problems with bugs. If you're really concern then put an ever so slight rise in the hose prior to going out side. This will fill with water an act as a stop. Drill the whole the size of the hose and if you have carpet that should be plenty good.
When I pull the hose out, I use some electrician clay to plug the hole in the floor. This hole is in the slide out portion so when the slide is in, I don't even need to do that.