All-Female Fish Army
Amazon mollies are an all-female species that 'steals' sperm from males of other species to trigger reproduction — but doesn't use any of the male's DNA.
The Amazon molly is one of nature's most remarkable reproductive cheats: an all-female species that has survived for thousands of generations without any males.
Here's how it works:
Amazon mollies reproduce through gynogenesis — a form of asexual reproduction that still requires sperm. Females mate with males from closely related species (sailfin mollies or Atlantic mollies), but the male's sperm only triggers egg development. His DNA is discarded entirely.
The result: all offspring are genetic clones of the mother.
This creates a bizarre situation: - Amazon mollies depend entirely on other species' males - Males gain nothing from mating with them - Yet males keep doing it
Why would males waste their sperm? Scientists believe: - They can't distinguish Amazon mollies from their own females - Amazon mollies may mimic the appearance of fertile females - Males are "programmed" to mate when opportunities arise - The energetic cost is low enough to not matter evolutionarily
This system has worked for an estimated 100,000-500,000 years — far longer than most all-female species survive. Amazon mollies have some genetic variation from occasional errors in cloning and rare incorporation of host DNA.
Named after the mythical Amazon warriors (not the river), these fish demonstrate that males aren't always necessary for successful reproduction.