2. Some grow.
Most eggs stay the same size once they leave the mother’s body, but one giant water bug, Lethocerus medius, lays eggs that grow! When they are laid, they are about 3 millimetres long and weigh 6 milligrams. Six days later, they are 5 millimetres long and weigh 14 milligrams. What’s more, the father rests on top of them, protecting them.