Bronze Corydora

I found small clumps of eggs against the glass of my tank over the weekend while cleaning it. The only fish in the tank that I suspect could have laid the eggs are the Bronze Corydora. There are eight of them, and I have not determined if they are all female or male. Would the females lay eggs even if there are no male corydoras in the tank like angelfish do, or do they only lay eggs if males are present.

 

Normally the females will lay 200 or 300 eggs.
The only way to tell female from male is size. The female is larger than the male.