Lerps abundantly fall to the ground at my place during autumn. They collect on my car and get stuck in the windscreen wipers and bonnet air intake area. I have driven kilometres away to have Noisy Miners and butcherbirds land on my bonnet and eat the lerps. They clearly value this sweet treat so much that they work their way back and forth along the windscreen, even while I am sitting in my car

Australia is still revealing its sweet secrets to its new human inhabitants. Indigenous peoples have known about, valued and celebrated its sugary delights for thousands of years. In pre-sugar farming times, sweet food was prized. Today, sugar filled food is hard to avoid.

The Australian environment produces a range of sugary sweets including lerps, honeydew, nectar, fruit, manna and honey. All are found here in south-east Queensland. This article focusses on just one of these sweet treats – lerps. Early European settlers documented the widespread use and efficient collection techniques of lerp by Indigenous people. Many settlers also valued and collected this free sweet resource.

In autumn, I find the ground and my car covered in lerps fallen from the Gum-topped Box (Eucalyptus moluccana) trees above. I scoop them up in my palm, check to see that my neighbours are not watching, and then eat the lot. Why I am embarrassed to eat nature’s nectar? In writing this, I am changing my attitude to proudly value this country’s gifts more.

When people outside of the environment industry ask, what are lerps, and I tell them that they are sugary insect excretions, they look at me sideways. Except for honey, I guess we don’t eat many insect excretions. And I should probably choose a different word than ‘excretions’ if I am going to win people over to lerp-eating.
Despite the fact that fruits and seeds are the by-product of insect pollination, and arguably all food is the result of insect-derived soil formation, we don’t eat many insects or their by-products directly, except for honey. Let me introduce you to lerps.

Lerps are basically pure starch with some proteins and fats. They are white in colour, about 5mm in size and look like round, pointy hats. They are created by psyllids. Psyllids are tiny sap-sucking insects. Like many insects, adult female psyllids lay eggs, which hatch into nymphs, which transition through various nymphal stages before emerging as adults. An adult psyllid is about 4mm in size. Psyllids build lerps, which act like tents, to protect them from predators and drying winds.

Psyllids draw sap out of leaves and create their hut-like homes (lerps) to live in. Unfortunately for psyllids, their homes taste sweet (containing more starch than cane sugar) and are prized food of birds, mammals and opportunistic humans. The level of sweetness fluctuates depending on the season, weather and the species of psyllid. Yes, there are over 300 species of psyllid in Australia. Some are associated with only one species of tree, whereas other psyllid species can live on several plant species.

Lerp is a highly valued resource in the Australian environment. It is eaten by flying foxes, possums, gliders and a variety of birds such as pardalotes, honeyeaters, friarbirds, whistlers, silvereyes and thornbills. Some birds such as pardalotes, weebills and small honeyeaters virtually live off lerps in some seasons.

When psyllids imbibe tree sap their gut absorbs the amino acids and nutrients, but they quickly excrete the water (as honeydew) and sugar (as lerp). I can certainly remember standing, camping or parking my car under trees that are raining down honeydew. This sticky sweet substance can make a mess of objects left under these trees. This honeydew is difficult to collect, and I was unable to find much literature on it. Whereas lerps are relatively easy to collect and have been slightly better researched – although it would seem we still have lots to learn about their valuable role in Australian ecology.

Tim Low’s book, Where Song Began, draws a wonderful link between Australia’s nutrient poor soils, sugary excretions such as lerp and our wildlife. He also writes about how lerps on plantation eucalypts, derived from Australia, have created a whole new sugary bounty for wildlife in other continents.
As with all topics in nature, this story about lerps is just the tip of the iceberg. I hope it helps raise some awareness of just one of Australia’s natural sweet treats and gives us all the confidence to enjoy this bountiful product when we can.

Article and photos by Deborah Metters
Land for Wildlife Regional Coordinator

Share

Leave a Reply

Your email address will not be published. Required fields are marked *