Danaus plexippus is in trouble. David Mizejewski raised one to demonstrate its life cycle, and explains what you can do to help them thriveRead the rest
This is Uraba lugens, a caterpillar that wears a bunch of its old heads on top of its current head like the world's most ridiculously macabre hat. The part of this photo where the otherwise horizontal caterpillar goes vertical? That's a pyramid of exoskeleton head capsules, stacked in descending order from smallest to largest.
The venerable Bug Girl has some better shots of this phenomenon at her blog, along with lots of great information explaining how the heck Uraba lugens ends up making this questionable fashion statement. She also offers this helpful advice:
If you do happen to see one of these, you should not touch it! Apparently these caterpillars are covered with highly itchy and irritating spines–which seems to make their chapeau of old heads a bit redundant.
What happens inside a caterpillar's cocoon? Scientists got to watch the whole process with the help of X-ray 3D scanning technology. In the video above, you can watch a caterpillar turn into a butterfly. Over the course of 16 days its breathing tubes (shown in blue) and its digestive system (shown in red) change shape and position within the body, while other structures grow from scratch.
Ed Yong has a great story to go with this, too. All about why it's important to actually watch the process happening in a single caterpillar, instead of just relying on the data scientists have collected from years of dissecting different caterpillars at different stages in the transformation.