[You must be registered and logged in to see this image.]Mid-January is not a great time for a bug nut. If you're bit of a bug nut yourself you'll probably understand that feeling of wishing there were more beetles, bugs, moths and butterflies about. Spring is a few weeks off yet, but there's still a few things you can do to satisfy your inner entomologist.
For starters you can grab yourself a gardening hand trowel and go chrysalis hunting. Most moths spend the winter in the crysalis, or pupal stage, and you can usually find some by digging down in to the soil at the base of trees and shrubs.
Oaks, Limes, and Poplars are always worth rootling around under. The caterpillars rarely travel far from their foodplant, and if you dig just a few centimeters (an inch or two in old money) below the surface you can often find some buried treasures like those shown above.
My top 3 tips for this are:
1. Always check the north side of the tree first. It's usually the best.
2. Don't dig more than a foot away from the base of the tree.
3. Keep away from those trees which attract a lot of canine activity
Hand Rearing Moths
When people find hawk-moth caterpillars (or moth pupae) they often ask us what's the best way to rear them into adult moths. Ideally, the process is best handled by nature, but if you really want to witness the process in captivity then here's a few tips...
Growing the Caterpillar
The caterpillar should be placed in an airy container and given the correct food plant. Depending on the species it's usually best to line the base of the container with a layer of potting compost and some dry leaves.
It's really important to make sure that your caterpillar always has plenty of fresh food. This needs to be picked daily. The stems of the food plant not only provide food, but also give the insect something to climb on and a place to hide itself. Stand the stems inside in a jar of water inside the container. Place some sponge or cotton wool or kitchen tissue in the neck of the jar to prevent the caterpillars falling in and drowning.
Caterpillars are eating machines, and while a lot of food goes in the front end of the caterpillar, a similar volume of matter comes out of the back end, so you'll need to clean the base of the container daily.
The Pupation Stage
When the caterpillar is fully grown, it will very often turn a darker colour, lose interest in eating, and start running around looking for somewhere to pupate. When it does, the pupa should be placed on a layer of earth in a small sealed (but well ventilated) container.
The container should be kept in a cool but frost-free place until next spring. If you keep it indoors the heat will make it emerge too early and (depending on the species) it'll likely die. Winter = no flowers = no nectar = starvation.
Hatching the Pupa
In spring the pupa should be placed between the grooves of a sheet of corrugated cardboard. It should be misted with water occasionally to produce a humid atmosphere and to induce the emergence of the adult moth. Avoid over-spraying as too much moisture can promote the growth of mould which could kill the developing insect. I know, I know - too much water - bad, too little water - also bad - nobody said it would be easy.
When the adult is about to emerge place a number of twigs and stems in the emergence tank. The twigs are required by the moth to climb up before expanding and drying its wings. If no suitable supports are provided then your moth will have deformed wings and be unable to fly.
You should release the emerged adult in the same area as you collected the caterpillar. When releasing the moth during the day make sure its in secluded area so it won't immediately be eaten by a bird.
Sat Jan 12, 2013 9:06 am
