How to make an inexpensive plug to keep bugs out of your airplane
Buy a 100-pack of bright orange “fuzzy sticks.” Used to be commonly known as “pipe cleaners.” You can find them in the fabric and crafts section, or Amazon.
Fold each leg outward about halfway up. Stick the “V” end up in the hole in the fuel drain, gascolator, fuel vent, etc, with the legs sticking out to the side.
Example fuel drain and fuel vent are shown.
Remove before flight, but in theory air would be able to pass if you accidentally left them in the fuel vent.