"Carnivore urine was significantly more attractive to puddling butterflies than herbivore or omnivore urine," according to the article's abstract. "This study was unable to determine if puddling butterflies were capable of seeking out sand with a specific sodium content or if amino acids and/or volatiles influenced their choice."
Bodri concluded that butterflies are attracted by smell "cues unique to nitrogen and/or sodium rather than visual cues."
He had observed puddling on many occasions, particularly in the tropics.
"They puddle at lots of things most often for (presumably) sodium. How they know it is there is still a mystery," Bodri said. "I was just curious if they can discern between urine from different types of mammals based upon the diet."
Bait stations demonstrated that butterflies can not only detect but can distinguish between urine from mammals of different feeding classifications, according to his research.
The research was reported on by Discover magazine.
