Borers that tunnel through dying wattles are a valuable resource for the table or fish hook, writes MARTYN ROBINSON
Wattles are lovely but tend to be short-lived. Some grow to the height of a small tree and look great for a while, but within a year or two of achieving maturity they start to look sick. If you see sawdust emerging from holes in the trunk, it’s easy to think that borers are killing the tree. In fact, the tree was already dying of old age, and the borers are just salvaging the remains for their own use. This also presents an opportunity, as they are delicious!
The most common borer of large acacias in eastern Australia is the larva of the poinciana longicorn beetle (Agrianome spinicollis). This big beetle is able to detect damaged or dying trees of a number of species, including wattles and poinciana (Delonix regia), and lays its eggs in them. The eggs hatch into creamy-white grubs that feed on the tree as they tunnel through the trunk, and before they emerge as adult beetles.
These are the most commonly used of what are loosely grouped as witchetty grubs in bush food cuisine. Bush food restaurants often pay their suppliers several dollars apiece. Being large, they can be cooked up in a variety of ways, or eaten raw if you can’t wait. Also, freshwater anglers hoping to catch a nice big golden perch or Murray cod regard these as superior bait, so tackle shops often stock them. Grubs stay plump and healthy for a couple of weeks when they are stored in containers of sawdust from the dying tree you found them in, and kept in a cool place.
So if you need to remove a dying wattle tree, be careful how you cut it up so you can save the grubs for dinner, or a fishing trip!
Martyn gardens mainly on Sydney’s Northern Beaches Have you found something interesting in your garden? Send us a photo and Martyn will ID it. Email firstname.lastname@example.org with ‘Creature’ in the subject line.