Cover image: Pictured is a scanning electron micrograph, in false color, of the front end of a larva of the drosophilid fly Chymomyza costata, displaying mouth hooks, and olfactory and gustatory sense organs. The larva survives temperatures of −196 °C in liquid nitrogen despite containing body fluids that can freeze into potentially lethal ice crystals. Vladimír Koštál et al. report that high amounts of the amino acid proline in the larval body help confer freeze tolerance by inducing the transformation of body fluids into a glass-like state. The authors found that feeding the larvae proline-augmented diets increased their freeze tolerance, suggesting that proline might serve as a cryoprotectant for biomedical applications. See the article by Koštál et al. on pages 13041–13046. Image courtesy of Jana Nebesářová and Jiří Vaněček (Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic).