Deep in lockdown, Vilya Congreave watched a miracle of Nature unfold in the backyard. Photo: Martin Congreave By Vilya Congreave
IT ALL started with Costa, from Gardening Australia, telling us that moths were great pollinators. It prompted me to think of them with a new-found respect. With COVID 19 restrictions in place, there was more time to spend wandering the garden to inspect and marvel at what was growing and what needed to be attended to.
To my amazement I came across a “stick insect”, which most of us would remember finding as children and which prompted me to find some answers: What’s the correct terminology for a stick insect, what’s actually inside and how was this amazing portable home even made?
With thanks to the Queensland Museum, I found an article that created great excitement as it took me through the life span of the Saunders case moth.
IT ALL started with Costa, from Gardening Australia, telling us that moths were great pollinators. It prompted me to think of them with a new-found respect. With COVID 19 restrictions in place, there was more time to spend wandering the garden to inspect and marvel at what was growing and what needed to be attended to.
To my amazement I came across a “stick insect”, which most of us would remember finding as children and which prompted me to find some answers: What’s the correct terminology for a stick insect, what’s actually inside and how was this amazing portable home even made?
With thanks to the Queensland Museum, I found an article that created great excitement as it took me through the life span of the Saunders case moth.
So now we had a name and could follow “Saunders” on his daily travels. It was surprising to see the distance he could cover. From guava trunk to post, over grass and up the henhouse, to the rock wall and back to the guava which he seems to favour. With his head poking out, he would pull himself along, using three pairs of strong legs attached to his thorax.
This meant we had to be vigilant as to the possible direction he was heading. Many mornings we were at a loss, always concerned he may have been taken by a bird, or similar fate. A bit like finding that elusive missing piece to a jigsaw puzzle, a cry would go out “All good, I’ve found him!”
Just getting close, with no contact, could make him disappear back into the cocoon, closing up the opening quick smart. When we did touch, it was firmly in place and some force would have been needed to remove it.
This meant we had to be vigilant as to the possible direction he was heading. Many mornings we were at a loss, always concerned he may have been taken by a bird, or similar fate. A bit like finding that elusive missing piece to a jigsaw puzzle, a cry would go out “All good, I’ve found him!”
Just getting close, with no contact, could make him disappear back into the cocoon, closing up the opening quick smart. When we did touch, it was firmly in place and some force would have been needed to remove it.
Saunders case moth. Photo: Martin Congreave
The thorax spins out a strong silk to create a soft cocoon encasing. Detritus and sand grains adhere to develop a stronger casing. As the caterpillar grows it attaches twigs to the base, usually with one long twig protruding right at the base of the casing.
The next step is utterly amazing, for the head and thorax will come out and, using its jaws, the Saunders case moth will harvest a twig to the correct length and attach it with a few strands of silk. The caterpillar now goes back into the case and chews a hole big enough for its head and thorax to pass through. It then holds and bites the twig free from the outside, to pull it into the casing where it is attached firmly with more silk. This process can take up to two hours to complete.
This is then repeated over and over, creating a casing so strong it can withstand most conditions for several years.
I’m wondering if any readers have ever witnessed this incredible process?
We have been following Saunders now for almost a month and questions still remain. We call Saunders “him” but we don’t know yet whether he is male or female. What stage of his life cycle are we privy to?
The next step is utterly amazing, for the head and thorax will come out and, using its jaws, the Saunders case moth will harvest a twig to the correct length and attach it with a few strands of silk. The caterpillar now goes back into the case and chews a hole big enough for its head and thorax to pass through. It then holds and bites the twig free from the outside, to pull it into the casing where it is attached firmly with more silk. This process can take up to two hours to complete.
This is then repeated over and over, creating a casing so strong it can withstand most conditions for several years.
I’m wondering if any readers have ever witnessed this incredible process?
We have been following Saunders now for almost a month and questions still remain. We call Saunders “him” but we don’t know yet whether he is male or female. What stage of his life cycle are we privy to?
Male Saunders case moth. Photo: CSIRO I know that if Saunders turns out to be a male and is fully developed he will pupate to the bottom end of the case, emerge and immediately seek out female company. His head and thorax will be covered by solid, orange scales, with a dark abdomen and his wings will be brown with contrasting pale veins.
If he should turn out to be she, there will be no wings, much smaller, weaker legs and she will remain within the case, again at the lower end and await her male visitor. She will then lay up to a thousand eggs and will stoically provide herself as nourishment for the offspring.
The surviving eggs become tiny caterpillars and will go on their way to recreate the same process. Both parents are dead by this stage, but they know exactly what is required of them.
Certainly one of Nature’s miracles.
How long we will have this privilege of observing is anyone’s guess.
Saunders has reinforced the need to look more carefully when walking around the garden.
As the current restrictions are lifted, we may also feel as though we are emerging from our home-spun cocoons to spread our wings and reconnect with family and friends.
If he should turn out to be she, there will be no wings, much smaller, weaker legs and she will remain within the case, again at the lower end and await her male visitor. She will then lay up to a thousand eggs and will stoically provide herself as nourishment for the offspring.
The surviving eggs become tiny caterpillars and will go on their way to recreate the same process. Both parents are dead by this stage, but they know exactly what is required of them.
Certainly one of Nature’s miracles.
How long we will have this privilege of observing is anyone’s guess.
Saunders has reinforced the need to look more carefully when walking around the garden.
As the current restrictions are lifted, we may also feel as though we are emerging from our home-spun cocoons to spread our wings and reconnect with family and friends.