Light measurement for entomology in the field and laboratory

ABSTRACT. Light units weighted for human vision (e.g. lux) are unsuitable for work on insects which have good sensitivity in the blue and UV. We have built and calibrated two light meters - a portable field unit and a mains operated laboratory device-which measure illumination in physical units over a wavelength range suitable for insect vision. Both meters share a single photocell, so field and laboratory measurements are strictly comparable. The field meter covers a range from starlight to tropical sunlight on a single scale, and can be used in conditions when the operator has no effective vision. The laboratory meter is linear over five decade ranges, of which the most sensitive has a full-scale deflection of 1 mW m^-2.