Images © Ivan & Marlies Sazima & © Marco Tschapka
Passion flowers Passiflora – Bat pollination
Different bats eat insects, small mammals, fish, lizards, frogs, fruit, pollen, nectar, blood & even other bats. The fruit, pollen & nectar eating bats are essential to the survival of the rain forests both with regard to pollination & seed dispersal. Plants & trees that bloom at night rely on bats & to a lesser extent moths & any cleared area of forest will depend largely on seed dispersed by bats to recover.
Many of the nectar eating bats are in sub family Glossophaginae, Glossophaga. They rely on sight & smell (perfumed flowers & nectar) to locate their food sources & so the night blooming flowers targeted, amongst others, would be Passiflora such as P. mucronata, P. ovalis, P. penduliflora & P. trisecta, all of which have very striking white flowers, except P. penduliflora which is lime green. These bats have long thin tongues like hummingbirds that can reach deep into the flower for the nectar. Carollia perspicillata (short-tailed leaf-nosed bats) have been observed pollinating P. mucronata in Southeastern Brazil by Marlies & Ivan Sazima. They are a short tongued bat however & as such are not nectar specialists.Their main diet is fruit such as bananas, wild figs, guavas and plantains. They can be destructive to crops & are seen as pests.
The specifically bat pollinated passion flowers include:- Passiflora candida, Passiflora galbana, Passiflora mucronata, Passiflora ovalis (& possibly another similar species), Passiflora penduliflora & Passiflora trisecta. There is also a very exciting new bat pollinated species from Ecuador, Passiflora unipetala. Bats are also thought to visit other Passiflora flowers more usually pollinated by hummingbirds. e.g. Passiflora ampullacea. They are also known to eat the fruit of a number of Passiflora species and so aid dispersal.
Bat pollinated Passiflora share particular characteristics:-
The flowers are white/green & either hang down or are held out on a stiff peduncle from the foliage of the plant for easy access bearing in mind the size of a bat. On the flowers that are held out, the anthers can clearly be seen to be angled down so that they will dust the head of the bat with pollen. The flowers open late afternoon to after midnight & close early morning to lunchtime the next day. In the case of P. mucronata the flowers open explosively by passion flower standards in about 15 seconds, with all flowers opening within about 20 minutes. The flowers & nectar, which is constantly topped up while the flower is open, give off a distinctive sweet or musty odour decribed in the case of P. mucronata by Marlies & Ivan Sazima as like pumpkin, fresh beans or lemon cake.
Most are visited by a surprising number of potential pollinators in the early evening or early morning, such as bees, butterflies, hummingbirds, moths & wasps. None of these however, with the possible exception of the hummingbirds, appear to get dusted with pollen or touch the stigma when drinking nectar as they are too small.
I have had reports that bats may be visiting more Passiflora than we realise. In the same way that some hummingbirds visit bat pollinated passiflora, some bats may visit flowers not ‘meant’ for them:-
Elma Kay has done some work on the pollination of P. penduliflora by the Greater Antillean Long-tongued Bat Monophyllus redmani.
Joe Trybyszewski notes that when staying with an English butterfly breeder in Cockscomb Jaguar Reserve, the Cayo district, Southern Belize, Central America, he saw numerous bats feeding off various species of Passiflora.
Dustin Janeke, Research Assistant, University of Guam advises that
”The Mariana Fruit Bat, Pteropus mariannus mariannus, is known to feed on the fruits of Passiflora suberosa, an invasive vine on Guam. He comments, ‘Here in Guam, Passiflora suberosa is a weedy vine that will grow up into and cover the canopies of forest trees species, especially in disturbed habitats. The bats feed on the fruit mostly, which I’ve tasted and its not tasty at all, but I wouldn’t dismiss the possibility of the bats eating the flowers as well. Feeding occurs mostly when the vines grow up in the tops of trees, so the bat lands in the tree to feed. Our bat is a large flying fox type, 300 to 500 grams roughly.”
The bats may also transfer pollen during their visits to eat P. suberosa fruit as ripe fruit & flowers can be close to each other.
Dr. Tatyana A. Lobova advises that the NYBG Database has a list of species of Passiflora that are pollinated and dispersed by bats in the New World. You need to select ‘Plant Search’ and type ‘Passiflora’ in the Genus field.