Airborne Gardeners of the Tropical Rain Forest

AS ANY gardener knows, successful cultivation depends on sowing seeds in the right place at the right time. Strange as it may seem, however, some of the most effective sowing in the rain forest is done at night​—and from the air. The airborne gardeners doing the sowing are Old World fruit bats​—some of which are known as flying foxes.a

Most fruit bats fly around at night, scouring the forest for trees that offer them tasty fruit or flowers rich in nectar. As they go about their aerial foraging, the bats digest fruit and expel undigested pulp and seeds. To complete their gardening work, they also pollinate flowers while sipping the nectar they enjoy so much.

Since fruit bats may cover long distances during the night, they can disperse seeds over a wide area. And because the bats pass some seeds through their digestive tract, they also provide “fertilizer” that encourages seed growth. Not surprisingly, a variety of plants in the rain forest depend on bats to pollinate their flowers or disperse their seeds.

Since they range far and wide, fruit bats have to have navigational skills and exceptional eyesight. In poor light, they can see better than humans. They can even distinguish some colors. And they are not at all averse to flying by day as well as by night.

The Samoan flying fox (Pteropus samoensis) species mates for life. As observed in some species, the female bat cares well for her offspring, carrying it with her for a few weeks and suckling it almost to adulthood. In the case of two species of fruit bat, the female may even get the services of a “midwife” to assist her during birth.

Sadly, many fruit bats are threatened with extinction, partly because of the destruction of their habitat. In the islands of the South Pacific, the disappearance of fruit bats would be catastrophic because some plant species of these islands seemingly cannot be pollinated without bats. Clearly, the work of these airborne gardeners should never be taken for granted.