[Someone]

The search term “insect counting device” gave me many hits, for example https://link.springer.com/article/10.1007/s00340-019-7361-2:

“We have constructed two optical sensing systems for insects based on light attenuation and light backscattering, respectively. The systems, which were tested with the potentially dangerous Aedes albopictus and Culex pipiens, were able to extract the wing-beat frequency, when they passed impinging light, derived from light-emitting diodes. We could achieve distinction between the sexes of A. albopictus and C. pipiens based on the wing-beat frequency”

https://www.hindawi.com/journals/js/2018/3949415/:

“We present a novel bimodal optoelectronic sensor based on Fresnel lenses and the associated stereo-recording device that records the wingbeat event of an insect in flight as backscattered and extinction light. We investigate the complementary information of these two sources of biometric evidence and we finally embed part of this technology in an electronic e-trap for fruit flies. The e-trap examines the spectral content of the wingbeat of the insect flying in and reports wirelessly counts and species identity“

I also would think the number of insect deaths by scientist-placed insect traps would be dwarfed by both that of traps placed just to kill insects and ‘traps’ formed by the area of car wind shields being swiped through the world.