We examine the effect of different wavelength spectra in the performance of our optical penetration-based silkworm
pupa sex identification system. With available low-cost light emitting diodes (LEDs), each emitting different wavelength
spectra at 468 nm, 565 nm, 639 nm, 940 nm, and broad white light, we find that the body of the silkworm pupa can block
blue and near infrared light while allowing green and red light pass through. In particular, the red light can clearly
highlight an important organ called “chitin gland” of the female, leading to high accuracy of silkworm gender
identification. In our experiment with 120 silkworm pupae, measured high average 92.8% and lower average 87.5%
accuracies in identifying silkworm gender are obtained under red and white light LEDs, respectively.