I am still surprised every time I see this tree. There are three individual Crescentia Alatas that I know well but this one is my favorite. Actually, it is a pair of very old trees growing in the middle of granite boulders that are the home of a family of black iguanas. The fruit growing from the branches seems the work of a glue gun rather than evolution. The leaves also look somehow glued together and they grow lining the taller branches like armies of small people walking upward toward the sun. Even though the tree blooms throughout the year I have seen explosions of blooms after very heavy rains.
Cauliflory is the growth of flowers from tree trunks and main branches rather than the tips of the small branches at the top of the tree. This placement allows smaller trees to compete with the taller ones by attracting non-flying or low flying pollinators to flowers that are also accessible to crawling insects and small terrestrial mammals. In terms of echolocation, a large flower stands out from a relatively smooth trunk much more than small flowers on the end of small branches.
I imagine that the internal system of nutrient delivery must be quite different in cauliflorous plants than in conventional angiosperms. Another cauliflorous tree with is the Therabroma Cacao, which has small flowers and is pollinated by mites and beetles, the trees that target small mammals as pollinators have evolved larger flowers with more nectar to appeal to these mammals’ larger appetites.
Bats ability to fly gave them an advantage over these terrestrial mammals, although the bats that feed from the Crescentia Alata must not only fly but also be able to hover like hummingbirds. Bats that pollinate cacti and agave must land on the plant in order to feed. But hovering takes a lot of energy, so these bats have evolved long tongues with erectile hairs on their tips that plump up when dipped in nectar to maximize nectar volume intake.
What does the plant gain from catering exclusively to bats?
Bats carry more pollen than insects can on the special hairs of their head and face. The pollen is also more varied because bats travel so far between trees to feed. This trap line way of feeding carries the pollen further afield. Bats are the champions of tropical reforestation yet the fragmentation of tropical habitats puts nectar-feeding bats at the highest risk for extinction of all bat species.