Seed dispersal by monkey spitting in Scadoxus (Amaryllidaceae): Fruit selection, dispersal distances and effects on seed germination

Fleshy fruits are usually associated with ingestion of seeds but can also serve as a reward to animals that discard seeds without ingesting them. We investigated the seed dispersal systems of two South African Scadoxus lilies. Like those in some other genera in Amaryllidaceae tribe Haemantheae, seeds of Scadoxus are non-orthodox, reputedly poisonous and enclosed within fleshy fruits. The bright red ripe Scadoxus fruits attract monkeys, which consume the fleshy fruit and spit out the seeds. Depulping increases the rate of seed germination. Monkeys spit some seeds out in the immediate vicinity of the plant and carry others further away in their cheek pouches (84% of S. multiflorus subsp katherinae seeds and 78% of S. puniceus seeds were dispersed further than 1 m away from the parent plant). Both species occur in very specific spatially restricted habitats; S. multiflorus subspecies katherinae is confined to patches of swamp within forests, while S. puniceus is confined to small bush clumps in a grassland mosaic. Monkey-mediated seed dispersal may be advantageous for these two Scadoxus species as it ensures that some seeds are spat out in the immediate spatially restricted habitats of the parent plants, while others are carried through cheek-pouching to more distant habitat patches.

Automated summary

This study investigated the seed dispersal systems of two South African Scadoxus lilies and found that monkeys are attracted to the ripe fleshy fruits, consuming the flesh and spitting out the seeds. This form of seed dispersal allows seeds to be deposited near the parent plant or carried to distant habitats by monkeys.