Firefly Nuptial Gift (image) Tufts University Caption These male fireflies give a nuptial gift -- sperm wrapped in a nutritious, high-protein package -- to females during mating. New research led by Tufts University biologists shows that some fireflies have evolved to have wingless females, and their males forego gift-giving to these "stay-at-home" mates. Credit Tufts University Usage Restrictions Use only with appropriate caption and photo credit. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.