Both Nikon L31 and Panasonic FH8 have 16.0 MP resolution sensors but Nikon L31's sensor is 1/2.3' (6.17 x 4.55 mm ) and Panasonic FH8's sensor is 1/2.3-inch (6.08 x 4.56 mm ).
Since Nikon L31's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Panasonic FH8.
Below you can see the L31 and FH8 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon L31 and Panasonic FH8 Cameras
Nikon L31 and Panasonic FH8 have almost the same sensor size so none of them has any significant advantage over other in providing control over depth of field when used with same focal length and aperture.