Noah was commanded to take into the ark all the animals on land in whose nostrils was the breath of life (Genesis 6:17, 7:14-15, 22). There is no reason to believe that all the varieties of insects were on the ark because they breathe through their skin and do not have nostrils. They could have survived on floating matter or by burrowing in the mud. Some of the insects may have been on the ark in the fur of the animals or in nooks and crannies of the ark. The Bible does not teach that they had to be on board.