From the point of view of the beetle, he's not walking upside down. Physical forces attract him to the "ground" (the underside of the water surfaces) and he ju

From the point of view of the beetle, he's not walking upside down. Physical forces attract him to the "ground" (the underside of the water surfaces) and he just walks normally, as if he was affected by gravity instead of buoyancy. The snail is definitely "upside down", for the physical force (gravity) wants to separate her from the "ceiling" on which she clings.