Movie 4
Opening reaction of the inner valve lids of the metathoracic spiracle on a visual stimulus. (filter plate and filter flap removed). The opening is much quicker than the closing.
Structure of the thoracic spiracular valves and their contribution to unidirectional gas exchange in flying blowflies Calliphora vicina
Journal of Experimental Biology 2017. 220:208-219; doi: 10.1242/jeb.149013