<p>Force loss is an instantaneous consequence of wing damage and plays a leading role in determining the subsequent compensation strategies of the insect and insect-like flapping wing micro-air vehicles (FWMAVs). In this study, the aerodynamic force loss of the damaged wings was thoroughly studied numerically, with a focus on the differences caused by various damage forms. Five wing models were employed, including one intact wing and four damaged wings, which have different forms of damage but the same reduction in wing area. The results show that not only is the lift generated by the missing part lost, but the force behavior of the remaining part also changes significantly. This nonlinear force reduction is related to the changes in the flow structures of damaged wings, which are mainly caused by three effects, namely, the “leading-edge-vortex-attachment-weakening effect”, “trailing-edge-vortex-rolling-up effect”, and “chord-length-shortening effect”. More importantly, when the lost area is 20% of the intact wing and located in the wing tip region, the force loss of the damaged wing is always about 50% of the total lift of the intact wing, regardless of the form of damage. This finding implies that insects can adopt consistent coping strategies to deal with wing damage, providing a theoretical basis for the design of wing-damage coping strategies for FWMAVs.</p>