Tips for Rearing Larvae

Being a novice at this lark, and I'm sure there are others in a similar position of ignorance, any helpful info relating to the rearing of caterpillars etc would be most welcome. A start has been made here (these comments now reprinted below)

Latest "Reared from larval stage:"



Wow, Tony! You should have taken the credit! Thank you very much for this.

Delete this note if it stands in your way to edit or add to the above.

-- Beetledude

Not a problem

As curator I can update historical stuff: when I do I always leave a note to the effect, otherwise it just causes mayhem (esp. if it corrects a mistake pointed out below).

gee whizz

homework time

Go for it, Tuli!

Suggest that you put all the info in the content section (copy and paste should do the trick).

re print of Marion Maclean comment

Firstly: Very well done on rearing your first moth! It is always great excitement :-)

Secondly: Photographing the moths:
* as you have discovered, moths are more docile in the morning, and when they're cold
* rearing boxes that are clear, flat-sided and of thin glass/perspex are best for taking photos through. A couple of us have found that the Ferrero Rocher boxes are super for this. And aquaria are also good.
* I have made the mistake of having two species in one box (coz I ran out of boxes), and having a moth emerge and not knowing which pillar it belongs to. If mixed collections are unavoidable, then these pointers might help -

make sure the pillars are from different moth families (e.g. Geometridae (loopers) and Noctuidae (non-loopers)).
some moths have a fast generation time and others go for the long haul. What that means is that some pillars appear in, say, September, pupate, and moths appear within a month or two, whereas others pupate in September and the moth emerges the following September.
sometimes you don't get a moth at all, but wasps or flies, so keep a look out.
I have been astonished at how many moths pupate in the soil! So if your pillar disappears, it may well have burrowed for pupating, i.e. don't throw the box out (and have soil in the bottom of your container for this purpose).

Magriet will be able to give you many more useful pointers too!

Tritonia Gallery

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one year to emerge!!

I perceive a permanent marker pen and a wee notebook would be invaluable assets


re print of Roy Goff comment

Did your moths ever suffer a food shortage because this can be the cause of dwarfism which is very common in reared specimens. The quality of the food is also important, ie wilted.

Another potential reason is overcrowding if you collected many larvae.

Another is sex related. The males are frequently smaller and pupate that little bit quicker having reached full size quicker than the females.

they probably did.
I also noticed that if I didn't place them in a sunny position in the morning they were inactive and didn't eat so much - too cold?

moisture regime for larvae

Can anyone shed light on suitable moisture regimes for munching 'pillars and for pupating larvae?

Moisture regime

I have never had a moisture or temperature problem (of which I am aware!) when rearing leps indoors, at room temperature and ambient atmospheric moisture. Mind you -- that is in Pretoria, which is moderate in both those variables. Things may be different in Gaborone, Montagu, Kleinmond and Scottburgh.

However, when it is hot and dry outside, I like to give my insects some "rain" -- a few squirts of water vapour from one of those squirty bottles sold in nursery shops, tuned to a fine mist spray. I do not know whether I fool myself or whether my animals actually like their rain.

Where moisture is a serious problem is in sealed containers -- never use these. You will get condensation of moisture, and fungus is sure to follow.

-- Beetledude

artificial weather

I was thinking that within a canopy the surrounding leaves would be transpiring and maintaining a reasonable level of humidity but in a container this could easily fall, I guess keeping up with a good supply of fresh feed should help. I like the idea of your little rain showers.
What about pupae though, if they are hanging around or buried in a little shallow soil in a container for an extended period aren't they prone to fatal dessication? Do you provide them with periodic squally weather?

Artificial winter drought

Tuli, I have a suggestion of something I admit I have not been conscientious myself. Simply this: if it rains outside, give some artificial rain to your pillars and pupae. But if it is dry outside, like the winters in Pretoria and Gaborone, likewise keep the pupae (and pillars?) as dry as it is outside. Because that drought is what the animals would have been experiencing outside in Nature. They may even require dry conditions for successful pupation, although I have no hard data for this.

Something that has been adequately recorded in the literature, is that many pupae require the cold shock of winter chills for successful development. But that's easy to do: (1) I don't think Gabs ever has any cold snaps (?); (2) When keeping your insects at room temperature, that excludes rooms heated by whatever means.

-- Beetledude

actually both Gabs and the Tuli Block can get quite cold

a few years back we recorded -7C on and off over a two week period in Gabs; the orange trees all went brown on top, that was exceptional of course, often it goes down to -2 or -3C but also we have years when the temperature just reaches zero but not below.

Freezing nights are often recognized by the brown wilted sensitive plants in the morning rather than by obvious white frost as the air lacks sufficient moisture to condense.

I can see mimicking external weather conditions makes sense apart from those nasty little twists that temporarily knock down a species

very rare cold snaps of vital significance

Richard Brooke told of a cold snap that affected the Savannas of Zimbabwe (I think in the 1960s): a severe cold front was followed by severe frost that killed all growth below a few metres (depending on position in landscape), killing all plants and saplings below that height. The landscape took many years to recover.

I dont know if this is documented anywhere.
Another example is the hypothesis that the "savanna" we come to think of as True Africa is purely the result of the Rinderpest Epidemic of the late 1800s. With the ungulates all killed off, the trees were able to establish, and grow tall enough to escape browsing by the time the animals recovered. Previous to this the savanna would have been a grassland with very few, very scattered trees. And with time trees should become rarer and rarer, until the next epidemic.


last paragraph re-edited from a single sentence to reduce fog index.

Microclimate more important than weather

Larvae will rest in very different places to their feeding sites and if these are within a rootstock etc, then humidity and temperature are likely to be greater than outside.

Also many feed at night when these conditions are also very different from the daytime weather we observe, and take notice of.

Many larvae will drink dew which may only exist briefly and go un-noticed.

Humidity is very important at different times for example when a larvae sheds its skin it needs to be humid or the shedding can experience difficulties causing the death of the larvae.

A regular LIGHT spray of water every day is usually beneficial but it needs to be combined with a good air flow to prevent disease.

winter cold?

I may be getting the wrong end of the stick because you are in the Southern Hemishpere but to reproduce winter conditions I have used two very different methods in the UK

Firstly rear on growing pots of foodplant with a mesh tent to retain your moths and keep out predators. Don't tidy the pots leave rotting leaves etc and the larvae find a place that suits them and then just place the pot outside for the cold season with just a minimal extra protection, (ensure the holes at the bottom of the pot are also meshed)

Secondly, small plastic boxes, without air holes, and put them in the fridge, (the salad compartments are ideal for this), give a very light misting every week or two. This is also useful if there is a late spring and foodplants are slow but also you can bring on a foodplant with a greenhouse or a warm room and then add your larvae when you are ready for them.

The authority of experience

Thank you very much for all this, Roy. You are certainly right that microclimate is more important than weather.

A general message is that a captive insect's home should mimic its home in nature at the scale that the insect interacts with its environment. Quite beside this truism, I have had success (sometimes unintentionally so!) in rearing insects in what would seem like the most inappropriate conditions -- but don't push your luck!

-- Beetledude

Thanks Roy

It seems to me that the main aim is to produce healthy adults so providing them with 'ideal' conditions to suite the particular species would be the best bet, IF one happened to know what constituted ideal.

I think imitating what one would guess is the natural microenvironment, is the next best option. Dehydration still concerns me so
I've started dampening the soil just on one side of the container to hopefully provide a gradient of moisture for the larvae to choose their own comfort zone - my current containers are big enough for this (which makes them too big for placing in the fridge for photo sessions as suggested above). My containers are also well ventilated so condensation and fungi shouldn't cause a problem - time will tell.

When my hawkmoth 'pillars started ignoring food and walking round and round I added some bark pieces to the soil surface which seemed to satisfy the fellows as they disappeared shortly thereafter.

be careful of cowding

When big larvae such as hawkmoths burrow they can still move around a lot and sometimes they all choose the same spot in a container. If one has just shed and has not properly hardened they will get damaged by the new one. (This can actually happen with just two larvae in a bucket size container!)
What I used to do with these is use a margarine size tub and fill it with scrumpled up tissue and add just one larva as soon as it stated to walk. Most of the time this worked very well even for burrowing larvae. It also has the advantage that when each one has hardened they can be removed to a single container for storage, especially if they are going to take months to pupate, but be aware that a larvae can lie up for a week before it pupates.

now thats what I call useful info

Is there any rule to how long pupation is likely to take. I suppose if one doesn't know the species ID at that juncture then it's just wait and see.

I like the idea of captive living environments

great for herbaceous vegetation, if you've got green fingers; a bit of a problem for arboreal leaf eaters perhaps!

look out for aliens

I have discovered that new food items should be carefully inspected for existing diners before being introduced to boxes.

I now have an extra box of tiny spiny larvae but I imagine the inadvertent introduction of a hungry spider could be disastrous.

Alien predators

Makes sense to me.

-- Beetledude

older forum

There was a forum already:

which just goes to show the importance of subject titles!


for the pointer to this thread Tony. Great info thanks all!

Occasional Hungarian princess who believes: Indigenous plants have every aspect covered

Great thread going on here

Thanks for all the tips and links guys, this is fantastic.

I'm finding it fascinating how different climates play a massive role, of course it is obvious but still not something I often think about. In seaside Kleinmond I would never dream of giving my pillars a rainy treat as they would instantly succumb to mold, but in the rest of Southern Africa it is probably vital. Even so I have had pupas dry out on me (or maybe just plain old die), sometimes even while mold is growing on the leaves they're buried in.

Incidentally, a tip I heard for checking on a slow pupa's health is to carefully submerge it in a bit of water. If it floats it is most likely to be dead, if it sinks it is alive. I got this from a very active new caterpillar rearing group on Facebook, started by Hermann our very own mothman among others.


I see the site has poached a few of our regulars. Curse that Mark Zucchiniburger.

not poached ; shared perhaps

While your guys are the specialists it might be hoped that iSpotters will be more generalists, more broad-minded and not restrict themselves to the Lepidoptera. Then we can all smile in our little niches.

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