Females live for up to two years, compared to the three to four month lifespan of a male. Keeping dead dads' sperm on tap could allow females to give birth to a blast from the past male color pattern that will have all the other guppy girls going gaga. Female guppies are attracted to males with unusual patterns.
"In addition to learning about sperm storage, this is the first time we are learning about the huge differences in lifespan between males and females," Reznick said. "If we were to use males to estimate generation time, then these differences mean that lucky females live for three generations. A human equivalent would be for us to have women around who were 90 years old and still very fertile."
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Reznick noted that although long-term sperm storage seems rare in vertebrates, it may be that scientists simply haven't observed it before. His team's guppy observations span multiple generations and involve marking and recapturing the fish, as well as analyzing their genetic signatures. Guppy fathers from beyond the grave was an unexpected discovery from this extensive data gathering.