Rearing Lepidoptera

I've added a "Rearing Lepidoptera" section to my web site. It's basically notes and photographs from some of my rearing projects. I still have a few more to add but unfortunately I have lost 29 lots of project notes on my computer. The missing ones are all Australian species I've reared over the last 2 years. I've checked back up discs etc but just can't figure out what I've done with them. Such is life. I'll just have to start again.

In the mean time, perhaps a few of you may find these of interest.

http://tasmoths.net/rearing.php

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Crexa Moth Caterpillars

..... Genduara punctigera

On the 26th October I posted a photo of a Crexa moth (Lasiocampidae)

The moth was put in a jar waiting to be released. Unfortunately the jar was put aside and overlooked until today. Fortunately I was in time to discover the 129 caterpillars which were climbing around on the inside of the jar. A few were already dead so I would say they would have hatched at least 24 hours ago. From that we can say the eggs would have taken about 17 days to hatch.

The caterpillars are only 5mm in length. If disturbed they drop and hang from a thread of silk.

#1 - Eggs - already hatched

#2 - First instar larva next to eggs - about 5mm in length

#3 - Lateral view of larva

#4 - Larva feeding on Native Cherry - Exocarpos cupressiformis

#5 - Mum - The adult female moth

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Caterpillar - Helena Gum Moth

You may remember the Helena Gum Moth I posted here recently. If not, then you can see the photos of the moth and it's eggs by clicking here. I have had a dozen or so of these moths in the backyard since then but all have been males except that first one. Fortunately I was able to get some eggs from her.

On the nights of the 19th and 20th October she laid 108 eggs. Most of these hatched 14 days later on the 2nd and 3rd of November. I had hoped to get a shot of them hatching but they seemed to do so overnight. Whether this is normal for them or just coincidence I cannot say. Certainly I've had eggs of many other species which have hatched during the day.

I've been feeding them on Eucalyptus pauciflora which is not a local species. At this stage they have shown a strong preference for young leaves.

The last time I tried to rear these I only got them to second instar before they succumbed to a fungal attack. This time I've put them in a larger rearing cage with better ventilation so hopefully I'll be successful this time round.

(Click on Photo to Enlarge)

Helena Gum Moth - Opodiphthera helena - 1st instar larvae

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Don't Count Your Chickens 'till They're Hatched

..... or your caterpillars

You may remember I posted a series of moth egg photographs. Well one of those photographs was of eggs which I only recently found in the backyard and some have begun to hatch. This poor fellow seems to have died (not unusual) and so it maid a good subject for the microscope. It's not the best picture but keep in mind it is less than 1mm in length. I also ended up with a posterior view so not the most aesthetically pleasing.

The shape of the eggs and the appearance of the caterpillar suggest to me that it may be a Noctuid but this is just a wild guess. The Shape of the eggs is very similar to the Gum leaf skeletoniser - Uraba lugens but they are laid in a different pattern.

My little microscope is not set up for photography. This was taken by hand holding a camera at the eye piece.

Click on it to see a bigger version

This first instar larva is less than 1mm in length.

The eggs were only 0.5mm in diameter

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Tree Lucerne Moth - Uresiphita ornithopteralis

• Class: Insecta
• Order: Lepidoptera
• Family: Crambidae
• Species: Uresiphita ornithopteralis (Guenee, 1854)

The imago

This is a very common moth locally, with a long flight period running from November to July. The larvae feed on various plants of the family Fabaceae including English and Spanish Broome, as well as some Acacias. We have a bit of a problem with the intoduced Broom, Genista monspessulana, on our block so it is a good species to have around. I have seen young broom plants completely defoliated by this caterpillar.

Larva

Batches of 10 -15 eggs are laid on the upper leaf surface of the host plant. These hatch after about 2 weeks. The larvae go though 4 instars over a period of 4 to 8 weeks reaching 18 - 30mm in length. after which they pupate on the ground within a finely woven, loose cocoon. Pupation can last anwhere from 9 to 114 days.

Larvae on Cape Broom -Genista monspessulana

These are fairly easy to rear from larvae. I have done so using just a chinese take-away container as you might be able to detect in the photo below. Just provide fresh food and keep the container clean and aired so as to avoid fungal attack.

Cocoon - the larva within has not yet pupated

The Tree Lucerne Moth is considered by some to be a subspecies of the Uresiphita gilvata (Fabricius, 1794).


References:

• Common Moths of the Adelaide Region - McQuillan & Forrest, 1985
• Moths of Australia - Common I.F.B, 1990

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BYO Beetles

BYO - Not "bring your own" but "breed your own" beetles. For anyone interested in learning more about invertebrates you may want to try rearing beetles and observing their life cycle. Oh and I know this is not specifically related to Tasmania but it is a convenient test for my first use of this blogging software.

Tenebrio molitor - (Mealworm beetle or Darkling Beetles)

• Order: Coleoptera
• Sub-order: Polyphaga
• Superfamily: Cucujoidea
• Family: Tenebrionidae

This Mealworm Beetle (Tenebrio molitor) is one of the largest Tenebrionids with adults at 12 and 20 mm. It is considered a commercial pest of stored grain and grain products. However, the larvae, or mealworms as they are known, are often bred and sold for feeding fish and wild birds. As they are readily available in many countries they are a great species to observe the beetle life cycle.

We ordered ours over the Net and they arrived safely packaged overnight. We kept them in a small plastic fish tank with a layer of oatmeal and bran for food. An apple cut in half an placed face down as seen in the photo, should provide enough moisture.

Obviously the apple will need replacing and the food topped up as needed. A fine mist spray could be used but be careful. Mealworms are built to tolerate very dry conditions. Too much moisture could lead to fungal infection.

All Coleoptera (Beetles) experience a complete metamorohisis, also called holometabolism, which includes four stages; the egg, larva, pupa, and imago(adult). When our mealworms arrived they were already well along in there larval development. As any arthropod grows it needs to moult or shed it's skin. The periods between each moult are known as instars and in the case of mealworms they go through about 15 instars.

Here is a photo of a mealworm:

..... and another which is in the process of moulting. When they first moult they appear white but within a day or so they take on the golden brown colouring.



A week after receiving the mealworms some were already passing through their final moult into the pupal stage. This next image shows the final larval moult.



....and here is a ventral view of the new pupa.


I removed the first four and kept them in a seperate container so that I could time their progression into adults. The next photo was take six days after pupation.

On day ten, the beetles emerged which was sooner than I had expected. The emergence process took about 20 minutes.


Notice the beetle has not yet attained its mature colouring. It is also still quite soft. This stage is described as the teneral imago.



Over the next couple of days they gradually darken and harden until reaching a dark brown, almost black, colouration.


Four days after emergence I've noticed the first interest in mating.

....and so the cycle continues.

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