Dickinson’s second talk focuses on power.  Small insect wings must beat very rapidly – much more quickly than can be controlled by the release and uptake of Ca2+ that typically regulates muscle contraction.  Instead flies use two sets of stretch activated power muscles. The contraction of downstroke muscles stretches and stimulates upstroke muscles, and vice versa, allowing the insect to beat its wings very quickly. In addition to power muscles, insects have tiny steering muscles that connect directly to the wing and regulate wing deviation during the wing stroke. With a combination of high speed video and electrical recording, Dickinson demonstrates how these tiny muscles can change wing position and allow a fly to undergo its amazing aerial acrobatics.