The silk web serves as a physical barrier that protects social insects from external stressors. This study demonstrated that the physical barrier provided by the silk web effectively reduced the efficacy of β-cypermethrin in controlling Hyphantria cunea larvae. Removal of the silk web increased larval exposure to β-cypermethrin. The enhanced physiological disturbance under β-cypermethrin, resulting from the absence of the silk web, was the primary factor contributing to the increased larval mortality. Furthermore, the silk web acts as a key thermal buffer in high-temperature environments, significantly alleviating heat stress on larvae. The antioxidant defense ability of the H. cunea larvae against high-temperature stress was weakened after the removal of the silk web, leading to the accumulation of reactive oxygen species and the intensification of cell apoptosis. These findings provide a novel perspective for understanding the ecological adaptation strategies of temporary social insects.