Article by Mike Moore
As a Lepidopterist one of the activities that you can engage in is the raising of butterflies and moths at home.
There are probably three reasons for doing this –
What happens is that you end up with a whole host of plants in pots just on the off chance that you will collect an egg or caterpillar.
Most butterflies can be raised in jars and I will be talking more about that in a moment. Skippers however because of their long life cycle, most of it spent as a caterpillar, are a bigger and more difficult problem.
Raising Butterflies in Jars
The technique is very simple.
Collect a Screw Top Jar.
I find appropriate coffee jars, vegemite jars and pasta sauce bottles good to use. The latter have the advantage of being square and hence do not roll when placed on their side.
I do not use pressure seal jars. Caterpillars are hydrostatic organisms (full of fluid) and could be affected by the pressure changes in opening and shutting the sealing lid.
Some collectors do not like using plastic containers. I have not had any problems with plastic containers but then again I invariably use glass containers anyway. Some plastics release hormone like chemicals and these may upset the caterpillars’ development.
When hatching caterpillars from eggs I usually start with a small jar. Using a small jar has pluses and minuses. On the plus side is that because you only put a small amount of plant material in the jar you can find the tiny caterpillar when it comes time to clean the jar and/ or replace the food. On the minus side however, because you only have a small amount of plant material in the jar it tends to dry out quickly meaning more regular replacement. This regular replacement is critical during the time the egg is developing and no caterpillar is present so that when the egg hatches the hatchling has something good to eat.
I usually lay my jars on their side
The Paper Bed
Cut a piece of paper to lie flat in the jar. I usually use kitchen paper towel but toilet paper will do.
Cut it to fit. (I usually cut it slightly undersize)
If it is too big it provides enticing nooks and crannies for caterpillars to crawl into meaning that at cleaning time they might be damaged by unsuspected rough handling.
The paper is valuable for the following reasons.
When cleaning the jar or replacing the food you can carefully grab the paper with tweezers and pull everything out more easily. When doing this CARE must be taken. Many caterpillars love to hide under the paper meaning that careless handling again could damage them. I always look under the paper from outside of the jar before I remove it to make sure I know where the caterpillars are or are not located.
A Piece of Bark
If the butterfly species lives on or near the bark of tree or shrub I always make sure I put a piece of bark in the jar.
Remember butterflies have very specific food requirements and so you must have the correct food on hand. Some butterflies can be transferred onto other food plants but this is usually the exception rather than the rule.
If at all possible what-ever plant species they were collected on I try to maintain them on.
For young caterpillars I try to provide young shoots. Many plants have within them toxins to stop animals predating upon them. Young leaves have less toxins and are probably more palatable for smaller caterpillars.
Provide enough food so that moisture levels in the jar are sufficient to keep all of the plant material moist. Caterpillars cannot eat dry leaves.
This can be provided by placing a wet but squeezed wad of absorbent paper or cotton wool in the jar. If I do this and I only do it irregularly I trap the wad in the lid. Remember caterpillars do not handle wetness at all well so you do not want liquid water free in your breeding chamber.
Replacing The Food.
Ideally this would be done every second or third day.
Cleaning The Jars
Some people clean the jars, ie wash and dry them regularly. I do not usually do this. I find that as long as the frass is cleaned out completely each time you add new food you do not need to clean the jars. If however the frass starts to go mouldy (usually through too infrequent cleaning) then you will need to clean the jars thoroughly.
Ideally the jars should placed in a location where they can be easily and regularly accessed by you. They must not ever be in direct sunlight but placed in a location where the natural rhythms of light and dark are present. Unless you have a dedicated study that you regularly use or such, this is difficult to achieve in a household.
I have taken to placing a tea towel over the jars, keeping them permanently shaded but still able to detect the normal diurnal cycles.
Handling The Caterpillars.
Caterpillars are rather fragile so try to avoid touching, or prodding or poking the caterpillars. If you feel you need to clean them or move them along use a paint brush to very gently brush away what is annoying you or them. That is why you need to be careful locating them before you add new food. If when maintaining the jars the caterpillars are located on the food I cut the leaf or twig or piece of paper bedding off the old plant or bed and place it back in the jar and add new food around it.
When shedding their skin caterpillars will often sit motionless for days. It is imperative that they are not disturbed during this time, so cut off the substrate (leaf, twig or occasionally paper bedding) and place it carefully back in the jar after maintenance. If they are ecdysing on the bark all the better.
How Many Caterpillars?
Firstly the smaller the jar the fewer the caterpillars. The larger the caterpillars the larger the jar! Some Lycaenid (Blues) species can be carnivorous, but in my experience that has related to the amount of fresh food available. Perhaps in a medium sized Vegamite jar two small caterpillars. Pasta sauce three small, two larger?
Keeping the numbers down in the jar also helps if any of them have/get diseased. If a caterpillar becomes diseased it inevitably dies, and will probably take any others in the jar with it. If this happens makes sure you do not transfer the disease to the other caterpillars
It is always a relief when the caterpillars pupate. Although disaster can still strike the task of feeding them and cleaning them is over. Clean out the jar. Make sure you have a paper bed in place. Position the pupae such that it is easy for the adults to emerge. Some species produce hanging pupae (often on the lid) and these need to be placed in a larger space. When the adults emerge they are going to need to have enough room to pump up their wings so pupation might be a good time to change the jar to a larger one. A small aquarium or a hatching chamber?
DO NOT TOUCH THE PUPA.
In the past I have also
The only problems I have encountered is to do is usually with the nature of the food plant
Wanderer butterflies use Milkweed as their food plant. This plant has a sticky white sap which seems to exude non-stop from the cut end of the branches. If this is placed in a jar the jar become sticky with the sap, the caterpillars also produce vast amounts of poo and the whole jar becomes a putrid sticky mass in which the caterpillars can become stuck. This is one of those species where it is better to place a cut stem in water make sure to cover the top of the vase or jar with paper, and pierce through it with the plant cutting, otherwise the caterpillars will inevitably fall into the water. Because the butterflies are exposed be very careful with any sprays used around the house. Fly spray also kills caterpillars.
Placing a plant piece in water can prolong its longevity but of course you can’t do that in jars. My friend Lindsay Hunt used to use this technique for Candalides species that live on a thin soft climbing parasitic plant called Dodder.
The nettles that Australian Admirals use also present their own problems. As they die off they contract and dry whilst the caterpillar is trying to make a shelter out of silk and cut leaf. All this can make quite a mess in the jar particularly if the caterpillars are small. What I have done in the past is to let the eggs hatch on the plant in the garden and collected caterpillars when they are larger and easier to see and manage.
This was, I thought, to be a short piece but have got quite carried away. I hope you have enjoyed reading it and enthused to try; All you need are eggs or caterpillars.
The Cabbage White butterflies are a good species to begin with.