Abstract

Lisotrigona cacciae, L. furva and Pariotrigona klossi (Meliponini, Apidae) workers drank lachrymation (tears) from human eyes in more than 262 naturally-occurred cases at 10 sites in N and S Thailand during all months of the year. A few visits were also seen to eyes of zebu and dog, indicating a probable broad mammalian host range. On man the bees were relatively gentle visitors, mostly landing on the lower eyelashes from where they imbibed tears for 0.5–2.5 min, often singly but occasionally in congregations of 5–7 specimens per eye. Less typically, they also took sweat, a behavior found in 11 other species of anthropophilous meliponines which are not lachryphagous. Nine further meliponine species were not anthropophilous. Lachryphagy in bees is compared to lepidopterous tear drinking and related feeding strategies such as puddling by various insects, mostly for salt requirements but in other cases proteins are sought. We propose that L. cacciae, L. furva and P. klossi drink tears for their high content in proteins in addition to, or in lieu of pollen, rather than only for salts and water. Few reports of flower visitation, rare presence of only minor amounts of pollen on legs, reduced pilosity, absence of resin on body and legs, presence of a strongly extensible metasoma for fluid transport, are all interpreted as possible indications of an adaptation to lachryphagy for proteins. The potential hazard of pathogen transmission by eye-visiting bees is discussed.