Reading the drawing
Pale bells: flowers, each open one night
Gold threads: pollen a bat carried between trees
A gray ring: the tree’s own pollen, no fruit
The second tree is drawn closer than in life; flowers, bats and pods far larger. A night passes in about a minute and a half.
How it works
A tree that needs another tree.
Kapoks grow scattered through the forest, and a kapok makes little or no fruit from its own pollen. In tests in Costa Rica and the Amazon, flowers given only their own tree’s pollen set none. So nearly every pod began with a bat that had already fed at another tree. In Guanacaste most of that work is done by the pale spear-nosed bat.
The rule is not absolute. On Costa Rica’s Osa Peninsula, where no bats were seen at the flowers, genetic tests found that much of the kapoks’ seed came from their own pollen. In Guanacaste, where bats came all night, most seed came from another tree. A forest that keeps its bats keeps its kapoks mixing their genes.
Nearly every pod began with a bat flying in from another tree.
Where the facts come from
- Lobo et al. 2003, American Journal of BotanyWhen kapok flowers in Guanacaste and Chamela, and how many trees flower each year
- Rojas-Sandoval, Lobo & Quesada 2008, Revista Chilena de Historia NaturalFlowering and fruiting in Guanacaste dry forest
- Rojas-Sandoval et al. 2008, StapfiaOsa, Costa Rica: own-pollen flowers set no fruit; about one flower in ten becomes a pod; kinkajous at the flowers
- Stoner et al. 2007, in Harvey & Sáenz (eds.), INBioMore than 5,000 flowers a night; which bats visit in Guanacaste, and how often; own-pollen seed on the Osa Peninsula
- Gribel, Gibbs & Queiroz 1999, Journal of Tropical EcologyCentral Amazonia: nectar per flower and per season; own-pollen flowers set no fruit; early-morning pollinations fail
- Ward, Dick, Gribel & Lowe 2005, HeredityPollen carried 18.6 km by bats, the longest recorded for a tree
- PROTA, Ceiba pentandraOne night per flower; 80–100 days to a ripe pod; the hollow fiber that floats 20–30 times its weight
- World Agroforestry, Agroforestree DatabaseFlowers open soon after dark; pod size; bees at first light
- National Parks Board Singapore, Flora & Fauna WebFlower clusters and the sour-milk scent
- Nathan et al. 2005, Current ScienceFlowers opening near 7:30 p.m. and falling near 6:30 a.m. (India)
- Calderón-Capote et al. 2024, Biology LettersGreater spear-nosed bats commuting 15–25 km to feed
- Holden 1946, US Naval Institute ProceedingsKapok, milkweed and the Navy’s life preservers in the Second World War