It’s called sweet rain, and if you were walking through a Brazilian rain forest during the dry season, you might experience it.
Sweet rain is actually excess nectar produced by the flowers of the tall Jatoba (Hymenacaea cangaceira) tree. So much nectar is manufactured that the flowers drip nectar, which might make it feel like a light rain to anyone walking under a flowering Jatoba tree – a very important tree that has been used medicinally by indigenous people for centuries.
Research into the sweet rain phenomena has revealed an interesting symbiotic relationship between the Jatoba tree and bats.
Nectar bats swarm these trees consuming the abundant, drippy nectar. In return the bats help in the procreation of more Jatoba trees by delivering a high-quality pollination service.
Nectar bats have one of the highest energy demands among pollinators and can carry pollen over long distances.
The enigma in all this: In order to produce so much nectar, Jatoba trees must manufacture a lot of water and sugar at a time in the year when the environment is harsh and dry due to months without rain. However, it would appear that the risky business of dripping away so much water is worth it in order to catch the attention of the nectar bats.
In fact, the importance of this quid pro quo relationship with the bats is further emphasized with yet another strategy: A Jatoba tree creates a kind of “attraction field” around itself because the oozing nectar has a fragrant, musty odor that serves as a long-distance cue to attract the flower-visiting bats.
The sweet rain phenomenon has been observed in a few other species, but H. cangaceira is remarkable for the copious amounts of nectar (multiple liters) produced in a single tree in just one night.
The Jatoba tree (known as guapinol in Central America) produces a large seed pod with an edible pulp inside that smells like cheese and has the consistency of wet sawdust. Local people have used the pulp for thousands of years as a natural medicine for many remedies including promoting prostate health.
The bark is also used medicinally. Different parts of the Jatoba tree are used for arthritis, asthma, beriberi, blenorrhagia, bronchitis, bruises, catarrh, cystitis, diarrhea, dyspepsia, emphysema, fractures, headaches, laryngitis, lungs, malaria, nephritis, rheumatism, sore, spasms, stomatitis, ulcers and venereal disease.
(Source: globalsouthbats.org)