A three-dimensional imaging technique makes it possible to watch butterfly pupae mature within the chrysalis.
In most studies of developing insects, seeing means destroying. Researchers must dissect a number of specimens at different time points rather than following the maturation of a single individual. Russell Garwood and Tristan Lowe at the University of Manchester, UK, and their colleagues used high-resolution X-ray computed tomography to peer into living pupae of painted lady butterflies (Vanessa cardui). The authors took several scans over the insects' approximately 16-day development and produced detailed models (pictured) of external and internal anatomy. The technique showed that butterfly breathing apparatus forms surprisingly early, and promises to allow quantitative developmental studies of a range of insects.