A butterfly and a bee were recently discovered drinking crocodile tears. One can encounter many strange sights on a boat tour down Costa Rica's Puerto Viejo River. This is definitely one of them. Last December boat passengers spotted and documented a butterfly and a bee drinking tears straight from a crocodile's eyes.
Apparently the encounter between the crocodile and the insects lasted fifteen minutes. The encounter involved a Julia Butterfly, a bee, and a Spectacled Caiman. The large reptile peacefully lounged in the sun as the insects drank their fill.
The group was led by Carlos De La Rosa, an aquatic ecologist and director of the La Selva Biological Station in San Pedro, Costa Rica. His findings have been reported and peer-reviewed in the May edition of Frontiers in Ecology and the Environment.
The scientific term for this phenomenon is lachryphagy, but it is commonly referred to as "tear-feeding." Several species of insect including moths, butterflies, and bees are known to tear-feed on mammals and in some cases even humans. Witnessing this event with a large reptile such as a crocodile is a much rarer occurrence.
The chief motivation by insects to tear-feed is the search for salt as De La Rosa explained to National Geographic, "Sodium and some of those other micronutrients are hard to find in nature. Butterflies and bees consume nectar, and nectar does not have a lot of salt. But they still need salt for egg production and for their metabolism."
Butterflies and other insect species have been known to employ a similar strategy called "mud-puddling." Insects gather around puddles containing mineral deposits and drink vital nutrients.
"You see the butterflies down on the ground, and they drink water, usually to gain salt," Jérôme Casas, an ecology professor at the University of Tours in France, explained to National Geographic, "The salt is either used for biological purposes or it's transmitted through the sperm as a gift to the female. So it's really a valuable item."
It is still under debate whether this relationship between insects and crocodiles should be considered symbiotic or parasitic. De la Rosa told National Geographic, "From my few observations, the caimans don't seem to be bothered at all by all this attention. The river turtles, however, are less tolerant to the bees buzzing close to their eyes. I've seen them shaking their heads at the bees and eventually even jumping back in the water."
Casas told National Geographic that the phenomenon could help shed light on "the surprising world of insect-vertebrate interactions. We always think about mosquitos biting us, but there is way more than that."