"As usual", the moulting process is a little faster than what I had expected. The fourth instar lasted between 3 to 7 days. 3 days is quite incredulous, that is counted from the 1st 4th instar moult to the 1st 5th instar moult.
in the video above, you can see it consuming the exuvia, with the wax bits floating down like snow.
by this time, the caterpillars get to about 5cm.
On day 12 from hatching, we observe another round of molting, which will bring the atlas moth caterpillars into the fourth instar. this is only 3-4 days from the first observation of moulting into third instar. It is rather shockingly surprising to witness such a fast turnaround for the moulting phases.
Day 12 photos when the first moulting to fourth instar is observed.
Today is day 9 from hatching, and while I was doing a quick glance check, I noticed one of the catty butt seem to have some loose skin. Because it is only day 4 from the last moult, i didnt think it was moulting. But I stopped to check for a while anyway.
To my surprise, it really was moulting. I quickly took my handphone to take a video before it is about to be fully shedded.
According to one of the source that I was using as reference (NUS Wiki - link here) the second instar was supposed to last for 8-10 days. But here, it has only been four days. Even if we might have missed some early moulting, it would have been at best 5 days only. Is it because the weather has been hot? Checking on a few more caterpillars, it appear that more than one might have moulted into third instar, as we see at least three head capsules on the tank floor.
The caterpillars now measure an approximate 2-2.5cm in length. The third instar is supposed to be 13-14 days. Will continue to observe and document if that is true in these specimens.
It is a lot easier to find out about butterfly life history and development than it is to find for moth species. For many moth species, it is difficult to find out detailed information on its recorded host plants, egg incubation duration, each instar stage duration and characteristics, pupa duration and eclosion.
Thankfully, Atlas moth being how interesting and eye catching it is, is a little better documented. Some effort is still required to hunt down the information and use whatever that is useful.
I have put the links I have read (again and again) together in this post, hopefully it will be useful to those reading it.
The first series of information I read on Atlas moths were from ButterflyCircle. It helped a lot with reading it as a story form with its developments
https://butterflycircle.blogspot.com/2012/08/the-atlas-moth-chronicles-episode-1.html
https://butterflycircle.blogspot.com/2012/08/the-atlas-moth-chronicles-episode-2.html
https://butterflycircle.blogspot.com/2012/09/the-atlas-moth-chronicles-episode-3.html?m=0
This link was useful in knowing what are the possible host plants for the Atlas moth. I experimented with a few but am very likely to stick with Ardisia elliptica (which interestingly, isn't on this list athough another Ardesia species is listed) which was the host plant that we found the eggs on.
https://breedingbutterflies.com/attacus-atlas-data/
Even harder to find were instar information, which the ButterflyCircle blog posts did not quire mention as well. Scrolling past the trivia, somewhere in the middle of the post below, you would be able to find the instar information, which was useful to anticipate and confirm instar duration and appearances.
https://wiki.nus.edu.sg/display/TAX/Attacus+atlas+-+Atlas+Moth
Lastly, the post below briefly mention about the cocoon requirements, which i find it useful. the rest of the information are generic and appeared in most other articles.
https://www.keepinginsects.com/butterfly/species/atlas-moth/
The early second instar caterpillars measure approximately 1cm to 1.2cm, with its head capsule in a deep orange colour, with similar coloured markings on its top and sides.
After three days following the discovery of the Atlas moth eggs, they started to hatch one by one. Of the 17 eggs, 1 did not hatch which was among those passed to a friend. As mentioned previously, this blog is recording the development progress of the 9 hatchlings that remain in our care. Estimated length: 4mm
Any caterpillar hobbyist, who rears the caterpillar to observe the growth and development to pupation and eclosion, would have a sort of wish list. There would be certain species that is likely to make it onto most hobbyists's wishlist, even if it may not be on the top of the list.
Most hobbyists look for butterfly caterpillars and shun moth types. However there are certain moth caterpillars that are also attractive and sought after. If it is rare, or have beautiful markings, or extraordinary development stages, you can bet the caterpillar hobbyist would be looking for it. one such moth would be the Attacus Atlas, the Atlas Moth. It isnt that easy to find it in Singapore, and most of the sightings that we could read about, is in the far north in Yishun, Kranji, Woodlands etc.
At a friend's gathering in April 2021, we chatted about my new hobby during this covid period, which is caterpillar rearing. A friend mentioned she saw the biggest caterpillar of her life and continued to gesture what looks like an arm length. While I calmly said no caterpillar reaches that kind of size, she was insistent and showed me a video of the below screenshot. Even before she showed the video, I already asked, is it white and green?
True enough, she had seen the caterpillars of the Atlas moth, and looked like they were in the last instar. of course they were not an arm's length but probably the shock of seeing 12-15cm caterpillars for the first time was a shock and magnified the impression. There were three of them from her memory. I immediately asked for the location, and how long ago. She had seen it exactly 7 days ago, in the west. We quickly changed our plans for the day and headed to the location to check it out, even though we knew the chances were little, given the gap in seven days, they would have likely wandered off in pupation or eaten by predators.
We managed to locate the site and combed it thoroughly plus expanded the search site. Unfortunately, after 2 hours, we couldn't find anything, not even possible cocoons. We took pics of the host plant and left. We subsequently identified the plant as Ardisia elliptica.
Fast forward five weeks later, we went back to the same location, in search of another host plant, but decided to check out the site again. While we didn't see sightings of the humongous caterpillars, some eggs on the topside of a leaf caught my eye. I was a little doubtful as they were not sticking to the leaves, and my understanding is the behaviour is to lay the eggs on the underside. But sure enough, with some flipping around, we found more eggs and laid in the classical fashion of Atlas moth.
It feels like a prayer answered! To finally found Atlas Moth and from egg stage! In this blog, we will document the process of rearing 9 Atlas Moth caterpillars from eggs, to the best of our layman ability.
