Size did matter -- evidence of giant sperm found in microfossils
In the competition for a partner, males typically have to vie with each other – be it with a colorful plumage, a large set of antlers or a seductive courtship dance. The females of some species, however, copulate with several males, so that rivals even after mating are still not defeated. So their sperm become rivals. Because greater size can increase the chance of fertilization, in some species truly giant sperm cells have evolved – some grow to be even larger than the male that produced them. Now, an international group of researchers led by Dr. Renate Matzke-Karasz, Ludwig-Maximilians-Universität (LMU) in Munich, has indirectly detected signs of giant sperm in fossilized ostracods. Using synchrotron X-ray holotomography, a highly complex imaging technique developed at the European Synchrotron Radiation Facility, the researchers were able to look non-invasively deep inside these tiny crustaceans, which measure only one millimeter in length. "In these microfossils,...