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
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.
