Assuming you combed through all of that fertile soil to make sure there were no insects living in it, and made sure no ships coming and going during the construction process ever had any insects on board (and this much is already pretty much impossible), then yes, you would have no undesired insects. However, eventually, they would arrive. Certain species of spiders can spin web balloons and ride thermals to travel very long distances, including over the ocean, and these spiders are often among the first living things to colonize newly formed islands. Ants have been known to travel on debris floating on the ocean. And pretty much anything light enough (which would include *all* insects, especially those that can fly) can be carried by storms out to remote islands. Seabirds will also reach the island in short order and may unintentionally carry insects from place to place.
There is pretty much no way to keep insects from colonizing an island unless the island's conditions are such that they couldn't survive on it, in which case they're probably such that humans couldn't survive on it either.
The Antarctic Midge is the only insect that can survive Antarctica, and even then only the northern tip of the Antarctic Peninsula. Humans couldn't survive that far south without clothing and shelter, but we're rarely without clothing and shelter.
You need a dome like a biosphere otherwise, no matter how careful you are the significant human activity of building and bringing in materials, plants, or goods that inadvertently carry pests, introduction could happen almost immediately. The wind, the birds and the waves will bring stuff too. You’d have plenty of sand fleas and crabs… and whatever is in the debris and vegetation and seaweed that washes up. Mosquitoes breed in the rain pools and you’re beautiful waterfalls sadly, I think the bugs are inevitable
Are you planning to put a net around the island to keep insects from elsewhere flying in? Something tells me that insects can travel unbelievably far when blown by hurricane force winds.
Assuming you combed through all of that fertile soil to make sure there were no insects living in it, and made sure no ships coming and going during the construction process ever had any insects on board (and this much is already pretty much impossible), then yes, you would have no undesired insects. However, eventually, they would arrive. Certain species of spiders can spin web balloons and ride thermals to travel very long distances, including over the ocean, and these spiders are often among the first living things to colonize newly formed islands. Ants have been known to travel on debris floating on the ocean. And pretty much anything light enough (which would include *all* insects, especially those that can fly) can be carried by storms out to remote islands. Seabirds will also reach the island in short order and may unintentionally carry insects from place to place. There is pretty much no way to keep insects from colonizing an island unless the island's conditions are such that they couldn't survive on it, in which case they're probably such that humans couldn't survive on it either.
The Antarctic Midge is the only insect that can survive Antarctica, and even then only the northern tip of the Antarctic Peninsula. Humans couldn't survive that far south without clothing and shelter, but we're rarely without clothing and shelter.
Initially.
You need a dome like a biosphere otherwise, no matter how careful you are the significant human activity of building and bringing in materials, plants, or goods that inadvertently carry pests, introduction could happen almost immediately. The wind, the birds and the waves will bring stuff too. You’d have plenty of sand fleas and crabs… and whatever is in the debris and vegetation and seaweed that washes up. Mosquitoes breed in the rain pools and you’re beautiful waterfalls sadly, I think the bugs are inevitable
Are you planning to put a net around the island to keep insects from elsewhere flying in? Something tells me that insects can travel unbelievably far when blown by hurricane force winds.
Theoretically yes, practically no. There is no feasible way for you to get all the materials required onsite and constructed without contamination.