In July 2019,  Following  a Sabah wide drought in March and April 2019 there was a mass fruiting  (masting) of many of the forest trees at the Rainforest Discovery Centre at Sepilok.

Artocarpus and Dipterocarpus  fruit were especially prominent  but trees of many different species and families produced fruit simultaneously.

Wild Fruits Artocarpus anisophyllus .png

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You can download the excellent slideshow produced  by the Sabah Forest Department   by clicking the link below;

Wild Fruits & Some Iconic Trees of RDC, Sepilok, Sabah

Why do different rain forest tree species in Borneo fruit together in one big bang (masting) ?   There are 2 main theories  and probably both are important.

  • The Need for Pollination:   Borneo’s rainforest  has some of the most diverse rainforest in the world due to species specific  fungal attack  on different trees. This means that young trees survive best the further away they grow from the parent tree. The result is very diverse forest with trees of the same species often very widely separated. Regardless of whether pollination is carried out by insect , bird or wind, if the whole population of a certain tree species flowers simultaneously the greater the chance of successful pollination.
  • To Escape Seed Predation via Predator Satiation: There are many seed eaters living in Borneo’s forests. These seed predators include weevils  (beetles)  fungi, bacteria, birds such as green pigeons and pheasants and mammals such as rats, pigs, porcupines, langurs and orangutans. Most of these seed predators are generalists and will eat all types of seeds. By fruiting simultaneously in one big bang  trees produce so many seeds  that the seed predators are temporarily satiated  enabling some seeds to escape predation and grow into saplings.

Figs Do Not Mast ! Studies show that figs do not mast and either produce crops of figs at random intervals through the year (most stranglers  eg Ficus subgelderi )  or fruit almost continuously eg , Ficus auriculata.

Wild Fruits of Sepilok Ficus subgelderi .png

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Fig seeds are so small they pass intact through the guts of most birds and mammals  so they are dispersed rather than predated if eaten by most rats. Figs also have their own unique pollination system based on fig wasps which can travel very long distances between isolated trees. Figs are more likely to be eaten if they fruit when  other forest trees were not fruiting thus the random fruiting  strategy of figs  helps to feed forest wildlife in the gaps between mass fruiting, big bangs.

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