Photo of the Day
Five caterpillars emitting a blue-green glow under ultraviolet light.
Glow in the Light
Hornworms fluorescing under ultraviolet light during a nocturnal field survey at Yasuní National Park, Ecuador. Their blue-green glow is likely produced by fluorescent compounds in the cuticle or epidermis that absorb UV and re-emit visible wavelengths. The adaptive function of this fluorescence is still uncertain, with hypotheses including enhanced shelter or host-plant detection, intraspecific communication, or predator deterrence via unexpected visual cues.
