image: Female freshwater ostracods store the giant sperm in two so-called seminal receptacles until they use the sperm cells to fertilize their eggs. When filled, these receptacles make up more than a third of the female's body length. This picture shows a light microscopical view of an artificially stained receptacle of a Eucypris virens, filled to about half of its maximum capacity with sperm cells (receptacle length approx. 0.6 mm, sperm length approximately 1.8 mm). This image relates to an article that appeared in the June 19, 2009, issue of Science, published by AAAS. The study, by Dr. Renate Matzke-Karasz of Ludwig-Maximilians-Universitaet and colleagues was titled, "Sexual Intercourse Involving Giant Sperm in Cretaceous Ostracode." view more
Credit: Image courtesy of Renate Matzke-Karasz