Laying eggs is a sign that your betta is in a healthy and safe environment, with or without a male present. Bettas are considered spawning fish. This means that a female first lays the eggs and then a male fertilizes them. Because of this, a male is not needed for a female to lay eggs, though those eggs will be empty. Whether you are breeding your bettas or just have females for pets, you may want to look for signs that your female will lay eggs.
Notice if your betta's belly looks full and bloated.
Look at the underside of your betta's belly for a white dot or small white stripe. These indicate that your betta is carrying eggs.
Watch the male betta, if you have one. You will notice him lightly squeeze the female until she expels the eggs. He will take them into his mouth and create a bubble nest. A female betta will occasionally expel eggs without a male present, but the eggs will not be fertile.