What is the primary function of monomolecular surface films in mosquito control?

Monomolecular surface films play a crucial role in mosquito control by lowering the surface tension of water. When applied to water bodies, these films spread out to form a thin layer on the surface. This alteration of surface tension leads to the disruption of the water's natural properties, which can adversely affect mosquito larvae. They may be unable to effectively break the surface to obtain oxygen, leading to increased mortality rates among the larvae.

This effect is specific to the way that these films interact with water and the biology of mosquito larvae. As the surface tension is reduced, larvae cannot maintain their buoyancy, making it difficult for them to swim to the surface for air. The other options, while they touch on various aspects of pest control or mosquito development, do not describe the mechanism of action that is characteristic of monomolecular surface films in achieving control over mosquito populations.