Efficiency of subaquatic light traps

Abstract

Subaquatic light traps are often used for sampling of the aquatic insects; however, their efficiency has not been tested yet. Here, we describe the use of such traps, illustrate the design of a simple trap allowing standardised sampling, and present results of assessment of the light trap efficiency according to the different turbidity levels, as well as model insects’ escape rates. The effect of turbidity on the capture efficiency was not significant for Sigara lateralis (Leach, 1817), Notonecta glauca Linnaeus, 1758 and Corixa punctata (Illiger, 1807) and was marginally significant for Chaoborus sp. Escape rates were affected by the entrance size and daylight exposure time. Although subaquatic light traps are helpful for standardised sampling, their entrance should be adequate for the target species, and the traps should be removed soon after the dawn or the resulting specimen counts should be corrected for the daylight exposure time before the trap removal.