Why butterflies, bees drink crocodile tears

In a rare image taken by aquatic ecologist Carlos de la Rosa, a Julia butterfly (Dryas iulia) and a bee (Centris sp.), drank the tears from a spectacled caiman (Caiman crocodilus) on Costa Rica’s Puerto Viejo River for more than 15 minutes.

Many insect species including moths, butterflies and bees tear-feed, usually on mammals, and are referred to as ‘lacryphagous’ from lacrima, the Latin word for ‘tear’. Tear-feeding on reptiles is less well documented, but in every case the insect seems to be in pursuit of nutrients and minerals — chiefly salt.

Butterflies often flutter around mud puddles, sipping their mineral-laden water, a behaviour known as “mud-puddling”. When minerals are rare in the soil, insects look for tears, sweat, urine, and even blood to scavenge the vital mineral.

Tear drinkers can target humans too. In parts of Thailand, where minerals can be rare in local soils, bees have been known to sip human tears.

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