Brian is a founding member of the Palm Grove Ourimbah Creek Landcare group. Since 2000 the group of dedicated volunteers have been meeting twice weekly with a primary focus on restoring remnant rainforest along Ourimbah Creek. The area has become a haven and refuge for the local wildlife and is well known in the birdwatching community.

Large parts of this site were previously cleared for farming. More recently, since farming practices ceased, a range of weed species has established throughout the site. Small leaved privet (Ligustrum sinense) is the most common and problematic weed species across the site. Thanks to the many years of dedicated work from this group large areas of the site have now been restored.

The following article on cheese trees (Glochidion ferdinandi) was sent to us by Brian and with his permission we are happy to be able to share it with you. 

'Cheese trees are so called because they have a fruit that resembles a round of Dutch cheese, but much smaller. It’s a common tree on our site, and usually looks ragged. However, the fact that cheese trees look so moth-eaten means that they must be feeding our native fauna.

So many species rely on cheese trees that a case could be made for them being the most valuable trees we have. The fruits alone are food for Lewin’s honeyeaters, various pigeons, king parrots, and probably more. In turn, these birds spread cheese tree seeds far and wide in their droppings. The bit of red flesh that surrounds each seed presumably has some food value, although I don’t think it tastes of much. The seeds resist bird digestion and pass right through and get dispersed with a blob of fertilising poop. Biologists refer to this as mutualism - the cheese trees need the birds as much as the birds need the cheese trees.

Lots of insects too eat bits of cheese trees, especially the leaves. That accounts for their ragged look. And there’s another insect that every cheese tree is host to. It’s a maggot that eats the seeds as they develop in the fruit. Cheese trees have to live with a maggot that eats their developing babies!

This is not as bad for cheese trees as its sounds, without these little maggots cheese trees would very likely die out. That’s because the mother of the maggots is a tiny moth, and that moth is necessary to pollinate the cheese tree flowers. The moth is programmed genetically to perform pollination services, and so ensures that seeds develop. After that, it lays its eggs. The eggs hatch into grubs, and the grubs eat the seeds. But the grubs are also programmed genetically - they always leave some of the seeds uneaten. In this way, some seeds are left to be spread by birds and make more cheese trees. Again, the behaviour benefits both moth and tree - obligate pollination mutualism it’s called.

A similar relationship has evolved independently, far away in North America. It’s a completely different tree, a yucca, and an unrelated moth. The moth also carefully pollinates the yucca flower. It lays its eggs in the flower, the grubs eat the developing seeds, but always leave some to make future yuccas. Several, equally weird, pollination mutualisms between plants and insects have been described, and many more may be waiting to be.'