Clemant State Forest straddles the Bruce Highway between Bluewater and Rollingstone. Its inland section really is ‘forest’ but its coastal section, the location of a Native Plants Queensland excursion last weekend, is a patchwork of low-lying dry scrub and swampy paperbark woodland (see map).
We drove down a rough track which leads to the beach (and a bush camping area) north of Toomulla, stopping to poke around in several areas along the way. I’m gradually learning more about plants, thanks to these trips, but my main interest is still insects and spiders. There were plenty of both.
Ant Plants
The most interesting plant we saw was the Ant Plant, Myrmecodia beccarii, a wonderful example of symbiosis.
Ant Plants grow on a suitable tree, a paperbark in this case, preferring a location high in the canopy where they form a large gall-like base (this one is in two sections, grapefruit- or coconut-sized) which is actually an enlarged stem. They are epiphytic rather than parasitic, i.e., they use the tree for support but not for nutrition.
A particular species of ant (Iridomyrmex cordatus) takes up residence in the natural hollows of this stem and protects the plant by consuming leaf-eating bugs. The chamber walls then act as roots, absorbing nutrients from ant excreta and dead ants.
Meanwhile, the Apollo Jewel butterfly (Hypochrysops apollo) lays eggs on the leaves; the ants carry them into their nest, where the caterpillars hatch, grow and pupate before emerging to fly off and repeat the life cycle. What do the caterpillars eat? Food begged or stolen from the ants, or perhaps ant larvae or both.
Further intricate adaptations are detailed on Wikipedia’s Myrmecodia page. Symbiotic arrangements as complex as this are inherently vulnerable to disruption because the decline or loss of any one species affects all of them. That’s true, actually, of our whole biosphere; symbiosis is just a particularly close relationship.