A honey bee has two pairs of membranous wings on each side: a larger forewing and a smaller hindwing. In flight, a row of tiny hooks on the hindwing's leading edge — the hamuli — clip onto a fold on the forewing's trailing edge, zipping the two into one stiff aerodynamic surface. Muscles in the thorax don't pull the wings directly; they distort the thorax box itself, and the wing hinges convert that distortion into a rapid flapping stroke combined with a twisting rotation that changes the angle of attack every half-stroke.
A honey bee has about 17–28 hamuli per hindwing. Losing the coupling — from wear, disease or an injury — measurably increases the metabolic cost of flight because the bee must beat its wings harder and less efficiently to make up the lost lift.
A honey bee's forewing and hindwing hook together via rows of tiny hamuli to beat as one blade, twisting through each stroke to generate lift that must outweigh the bee's body and nectar load.
Lift scales with wingbeat frequency and angle of attack, but collapses if the hamuli disengage — the hindwing then lags out of phase and contributes far less usable wing area, forcing the bee to sink.
Adjust wingbeat frequency, angle of attack and nectar load, then unhook the hamuli to watch the hindwing flutter independently. Watch the lift arrow and hover height respond in real time.
A honey bee's hindwing carries roughly 17–28 microscopic hooks along its leading edge — the hamuli — that clip onto a fold in the forewing every time the wings unfold for flight.