Wing deformation during flight affects insect’s aerodynamic force production and energetic efficiency. However, measuring wing deformation in flying insects is challenging as many points must be tracked over the wing’s surface to resolve its instantaneous shape. Some insects have mechano-receptors in their wings which detect wing strain and strain time histories. This strain feedback is believed to be used to realize closed-loop altitude control. Inspired by these sensing mechanisms, we propose a novel method to resolve instantaneous wing shape using a low number of measurements. We use a physics-based reconstruction technique called System Equivalent Reduction Expansion Process with sparse strain measurements to estimate the full field strain and deformation of the wing. Sensor placement is informed by the Weighted Normalized Displacement Method. The method positions the sensors at locations where the strain contributions of different modes are distinguishable and where the strain signal is high, thereby reducing the influence of noise. The method is validated by flapping a paper wing with three mounted strain sensors and using two of the measurements to estimate the third. We then extend to a more realistic insect wing in numerical simulation. The work demonstrates that full field displacement can be estimated from sparse strain or displacement measurement, and it is shown that additional sensors spatially average measurement noise to improve reconstruction accuracy. This research provides a technique to overcome some challenges of measuring full-field dynamics in flying insects, and it offers a framework for strain-based sensing that may be advantageous for the design of insect-inspired flapping robots.