Movie 1.

Flooding and position changes or oxygen-sampling behavior. The clip shows an A. callidryas embryo at 3 days inside a custom-made glass cup used in hypoxia-cued hatching tests, as it is submerged under boiled, degassed water and changes positions. The video was recorded using a Canon DSLR and MPE-65 mm macro lens and plays first in real time and then at 5x speed.