Was it a micro moth? a gall? an egg?
As Halloween approaches, I always find myself noticing the stranger side of nature. Autumn may signal the end of the insect season, but if you look closely enough, there are still plenty of surprises waiting among the fading leaves.
This is the story of one such surprise, from many many years ago.
The days are drawing shorter and the nights colder, the season for most insects has already passed and the number of species of hoverflies spotted is reducing quickly in number. There are still a few on the flowering Ivy and Michaelmas daisies, so on a sunny day both can be full of pollinators.
At this time of year, I spend less time watching flowers and more time inspecting leaves. Autumn can reveal all sorts of hidden treasures, from strange plant galls to the winding tunnels of leaf miners hidden inside a leaf.
So, it was a mild autumn afternoon, I spotted what looked like nothing more than a tiny speck of dirt, on a leaf. It was so small I almost ignored it. My first thoughts were it was going to be a micro moth, a gall, or an egg - it turned out to be none of them.
Many micro-moths are incredibly small, their pupa even smaller. Some adult micro-moths resemble bird droppings, using white markings as camouflage to convince predators they’re not worth eating. They live inside the leaf as caterpillars protected from predators outside, feeding on the inner leaf spongy tissue. But eventually they must leave their mine and pupate, mostly this is done on the underside of the leaf.
This mystery object looked like it could be something similar.
But then it moved.
It moved.
I paused for a moment.
It was a breezy day, so perhaps the wind had caught it. Then it moved again.
This time it was travelling up the leaf. Defying the laws of gravity.
Now I was paying attention.
I watched for another minute as the tiny piece of debris continued its journey across the leaf surface, sideways.
Fortunately, I had a magnifying glass in my pocket. A closer inspection revealed the truth. Beneath the pile of debris was a tiny insect larva carrying what looked like skins, legs, and dirt on its back.
Why was this insect carrying them?
At the time I had no idea what it was.
As usual, I took a few notes, snapped some photographs with my phone, even a short video..
Perhaps it sensed my presence and decided that hiding was now it’s the safest option.
Apologies the footage isn’t the best quality, but it does show the little creature moving from one side on the leaf before it disappeared to find cover.
Once home, I investigated discovery further, using books and internet - not far did I have to look before I found it was a creature called a ‘junk bug’.
I must admit I didn’t see any aphids on the leaf, so it was doing an excellent job of clearing them up. What I hadn’t expected was that the detritus on its back was the indigestible remains from all its prey. Not the cases from previous instars which I first suspected. Yuk! A clever way of using rubbish to protect and fool would be predators. A mobile camouflage suit???
So, what is a Junk Bug…..
Nature's Master of Disguise
A Junk Bug is the larval stage of a lacewing. These tiny predators specialise in hunting aphids and other small insects.
What makes them remarkable is their habit of collecting debris and carrying it on their backs. The “junk” can include plant material, shed skins, and, rather gruesomely, the indigestible remains of their prey.
Yes, some of that moving debris was effectively yesterday’s lunch. Yuk!.
Imagine carrying your lunch leftovers around on your back wherever you went. Sandwich crusts, potato peelings and chicken bones, that’s essentially what a 'junk bug' is doing.
The disguise helps conceal the larva from predators while allowing it to move unnoticed among its unsuspecting prey. Just as it did me.
Growing Up
Every larva eventually grows up.
This rather scruffy little predator transforms into something altogether more elegant: the beautiful Green Lacewing (Chrysoperla carnea).
With its delicate green colouring, golden eyes and intricate wings, it’s hard to believe that such a beautiful adult begins life hidden beneath a backpack of insect remains.
Yet another reminder that some of nature’s most remarkable creatures are often hidden in plain sight.
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| Photo by Tao Yuan on Unsplash |
Next Steps
Maybe you will explore your local haunts for 'junk bugs', let me know if you find any.
Look out for squiggles on the leaves, evidence of hidden leaf miners.
Look out for more autumnal adventures in the coming weeks.
In the meantime, you might like to read the folklore of the Death Head fly. Click here
Oh and Don’t forget Tip or Treat! 🎃 💀 🦇
All proceeds kindly donated will be used to explore naturalist themed activities.
Happy Halloween all! 🕷️ 🕷️ 🕷️
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