The photo shows the interior of a male fig filled with gall flowers. The exit holes in some of the gall flowers shows that the fig wasps  obviously started to emerge from the gall flowers but then halted and the majority died inside the gall flowers.

HOW TO IDENTIFY THE SEX OF DIOECIOUS FIGS

This is best done by cutting a section through a mature fruit and examining the contents . The photos in this article are of Ficus cumingii figs collected and photographed by Chun Xing Wong of 1Stop Borneo Wildlife at Tawau in Sabah.

Two thirds of Borneo’s wild figs are dioecious. This means that male trees and female trees grow separately.

Male figs contain gall flowers which act as brood chambers for fig wasps plus pollen bearing anthers. Male figs do not contain seeds.

Female figs  contain female flowers which produce seeds. Female flowers never contain fig wasps.

Below are some links to photos of dioecious male figs where the male anthers can be seen more clearly;

Ficus lepicarpa male

Ficus treubii male

Ficus fistulosa male and female figs compared

Ficus satterthwaitei male

WHY WOULD ANYONE WANT TO KNOW THE SEX  OF A WILD SPECIES OF BORNEAN FIG ?

Because it is very important to understanding and manipulating fig ecology !

In ecological terms male figs produce edible insects but not edible fruit. Female figs produce edible fruit and seeds but not insects.

With wild fig trees the the numbers of each sex are usually roughly equal. We can assume then that the seeds from any fig will contain equal numbers of male and female seeds and any fig seed collection will be roughly half male and half female. As far as we are aware there are no external differences between male and female seeds

Imagine however that you have spent many years  developing a Ficus research orchard or a plant nursery for reforestation. Your stock has come from a variety of sources but you have  used cuttings or marcots (not seeds)  to increase your stock. Marcots and cuttings are clones of the parent plant. Therefore if the marcot came from a male plant all the offspring will be male. With rare figs all your stock might be a clone of a single plant. Assume that  you have planted 100 clones from one rare male fig plant.

Ten years later your rare fig trees start producing figs but if there is no female fig of the same species within wasp dispersal distance,  all your figs will be barren. Not only can your male  figs not breed, they are  useless ecologically  and will not even produce fig wasps.

(The need for species specific fig wasps to travel back and forth between the two sexes for pollination in order to establish a viable population is an additional complication which will be detailed in a separate article).