Maupiti has only one pass where all boats have to enter the lagoon. This pass, however, is very narrow and known as dangerous especially at rough sea. This often forces boats to wait for the right time to go through it or to renounce entering the lagoon.
Whether you want it or not, you will encounter the "nono", especially on the motus. This is a minuscule "no-see-um" sand fly with a nasty sting. They are most common at daybreak and late in the afternoon, when they come to chew on your ankles. You might not even know you've been bitten until hours later, when the itching starts.
Do not scratch it, however, as that will only aggrevate the pain and cause an infected sore.
The only way to keep these little buggers away is to slather yourself in oil.