One animal’s refuse is another animal’s resource. The yellow-spined bamboo locust, Ceracris kiangsu, has been observed drinking from puddles of human urine. Human urine contains nitrogen waste in the form of urea and excess salts. The locusts drink the urine to obtain nitrogen and salt. However, the locusts are unable to use urea as a source and urea is repellent. Why do the locusts drink urine?
When the urine is heated by sunlight on hot summer days, the urea is converted to ammonium bicarbonate with the help of microorganisms. The locusts are able to use ammonium bicarbonate to synthesize amino acids and ammonium bicarbonate has proved to be an attractant. Thus, the locusts will not drink fresh urine. They only drink after it is baked in the sun and the urea converted to ammonium bicarbonate.