One example system for insect detection includes a block of material defining a transit opening and a sensing opening, the transit opening defined along a first axis in a first direction, and the sensing opening defined to provide a light path to traverse a cross-section of the transit opening； a light emitter positioned at a first end of the sensing opening and oriented to project light through the sensing opening and across the transit opening； and a plurality of light detectors positioned at a second end of the sensing opening and oriented to receive the projected light and to output detector signals based on an amount of detected light.
