Biotech Updates

Why Small Squids Have Big Sperm

August 12, 2011

Researchers from London and Japan discovered that smaller male squids have larger sperms than the large male squids, as reported in a research paper published by BMC Evolutionary Biology.

Large male squids usually court the females through flashy skin color-change displays. Once the female lays her eggs, small "sneaker" males immediately mates with her and put packages of sperm by the female's mouth to have a chance of fertilizing the eggs as they leave the female's body. Aside from this tactic, they have evolved to have larger sperms to have higher chances of passing their genes than the larger males.

Dr. Yoko Iwata from University of Tokyo said, "Sperm size is likely to be an adaptation to fertilization environment, either inside the female or externally, rather than competition between sperm, because the fertility and motility of sneaker and consort sperm were the same."

Read the research paper at http://www.biomedcentral.com/1471-2148/11/236/abstract.