Ficus padana illustration from Naturalis.

Herbarium photos and Chinese translations kindly supplied by Shuai LIAO

Ficus padana is endemic to  Java and Sumatra.   F. padana is one of 29 species of figs in Section Eriosycea distributed from NE India  and South China south to SE Asia and New Guinea. The center of diversity is in Borneo with 21 species most of them endemics.

The majority of these figs are small trees of secondary forest with large hairy leaves and twigs. The figs are more or less very hairy  both externally and internally. The figs are generally too hairy to be swallowed by birds.

Based  the food preferences of the Sumatran Rhinos at the BORA Rhino compound at Tabin in Sabah it appears that these hairy figs evolved to be dispersed primarily by rhinos.  The scientific rationale  is based on Daniel Janzen’s

Foliage as fruit hypothesis

Were Rhinos Important Disperses of hairy  Section Eriosycea Figs ?

Large browsers such as elephants and rhinos need to consume very large amounts of vegetation each day.  As fruits are relatively scarce in Bornean forests, Section Eriosycea figs have evolved leaves which are attractive to large browsers. When eating the leaves the rhinos and elephants also consume the ripe fruits thereby dispersing the seeds in their dung.

All Section Eriosycea figs are dioecious i.e. each fig tree is either male or female and produces only male or female figs respectively. In general male figs usually contain either unpalatable toxins or  deterrent substances which deter animals from eating them. This is because the male figs act as brood chambers  for pollinating fig wasps and so it is beneficial to the fig tree if male figs are not eaten but that female figs remain attractive to animal dispersers.

If  Janzen’s  “Foliage as fruit” hypothesis is correct one would expect that not only the figs but also the leaves of female trees would be attractive to large browsers but both the  leaves  and the figs of male trees would be unattractive to large browsers. However this hypothesis has yet to be  tested.

See this article Ficus aurata and rhino dispersal

The two herbarium collections below have Chinese National Herbarium numbers 01724703 and 07124704. They were collected in Sumatra in June 1960 as part of a project to study the food preferences of Sumatran rhinos. Unfortunately there is no indication if the trees were male or female.

01 Ficus padana sp.—Indonesia—1960-s.coll., #s.n.—PE01724703 - Copy

Ficus padana 02 sp.—Indonesia—1960-s.coll., #s.n.—PE01724703

Ficus sp.—padana 04 Indonesia—1960-s.coll., #s.n.—PE01724704 -

Ficus padana 03 sp.—Indonesia—1960-s.coll., #s.n.—PE01724704