Image of the Day: Self-Insemination
Image of the Day: Self-Insemination

Image of the Day: Self-Insemination

Videos reveal how a female squid fertilizes her eggs—one at a time and without spilling much stored sperm.

Carolyn Wilke
Feb 1, 2019

ABOVE: Spawning Japanese pygmy squid attaching eggs to a blade of seagrass
EIJI FUJIWARA

Reproductive biologists can have a hard time figuring out how sperm reach eggs when females of some species store the sperm for later use. Now, researchers have caught a female Japanese pygmy squid (Idiosepius paradoxus) in the act. The squid inseminates her eggs one at a time using very little sperm. She cradles an egg in the arm crown from which her arms extend and attaches the egg to a surface, such as seagrass, then fertilizes it by placing her sperm-storage organ over it. The scientists published their observations in Current Biology on January 21. 

EIJI FUJIWARA
EIJI FUJIWARA

Y. Iwata et...

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