Rearing the Crexa Moth from Egg to Adult - Genduara punctigera (Full Life Cycle - Twenty Photographs)

If you enjoy learning about the mini beasts that inhabit your backyard then you'd probably enjoy rearing moths (or other insects) from eggs or larvae. It's certainly something that I enjoy. However, due to a hard drive failure, I lost my records for literally dozens of rearing projects. I later found that some of my notes survived on a backup disk. Below is one such project, which I undertook back in 2008 / 2009. I've spent many hours today going through my photos and matching them up with the notes. By posting it here I will at least have a good backup :-) In the weeks ahead I hope to post few more rearing projects. Hopefully some of you will find them of interest.

For the photographers, the photos below were taken with a Canon 300D and Canon EF 100mm f/2.8L Macro lens.

_{( All photos, videos, and text on this blog are by @mostly.nature )}

Rearing the Crexa Moth - Genduara punctigera (Family: Lasiocampidae)

26th October 2008

A female Crexa Moth, Genduara punctigera, which had come to the moth trap was photographed, and then placed in a jar awaiting release. What I hadn't realised is that the moth proceeded to lay her eggs in the jar before being released.

_{Female Genduara punctigera}

13th Nov 2008

When I examined the jar on the 13th November, it contained 129 caterpillars. A few of the larvae were already dead and others were still feeding on the eggs shells, so I would say they had hatched at least 24 hours previously. From this I would estimate the eggs had taken about 17 days to hatch. The larvae are only 5mm in length. If disturbed they drop and hang from a thread of silk.

Initially the larvae were kept in a rectangular plastic box (Chinese takeaway container). They were fed on Native Cherry - Exocarpos cupressiformis.

_{Eggs - already hatched}

_{1st instar larva eating egg shells}

_{Hanging by silk thread}

18th November 2008

The caterpillars in the photo below are six days old.

_{Larvae on Native Cherry}

20th November 2008

The caterpillars are now eight days old.

_{Eight days old}

12th December 2008

The caterpillars are 30 days old and some are now up to 45mm in length. I moved them into a large rearing cage with larger sprigs of the food plant, as they will soon be ready to pupate.

_{Rearing cage with food plant}

_{Thirty days old. (forty seven days since eggs were laid)}

16th December 2008

Now 34 days old. The larvae are quite variable in size, ranging from 28 - 45mm. One has made the first cocoon between the cage frame and some foliage. The cocoon measures 25mm in length. The larva within has not yet pupated.

Since moving the larvae into a larger rearing cage, it has also become more clear that they are primarily feeding at night. By day, most are congregating in small groups in the corners of the cages frame.

_{Specimen A makes the first cocoon - 34 days from hatching}

_{Small groups resting by day.}

18th December 2008

I've been away for two days, but on return I noticed a second larva (Specimen B) has made a cocoon and the previous one (Specimen A) has actually pupated.

24th December 2008

Pupae were removed from their cocoons so that I could measure them. (Perfectly safe for them as there are no predators in the cage)

_{Specimen A (left) - First pupa 19mm - Specimen B (right) -Second pupa 19.5mm}

3rd January 2009

The first pupa above (Specimen A) emerged on the 3rd January 2009. It was a male and rather small, with a forewing length of 12mm. The males have a semitransparent area on the wings, which has not shown up well in the photographs.

_{Specimen A: Male imago. Forewing 12mm}

_{Another shot of Specimen A}

5th January 2009

On the morning of the 5th January 2009 another moth had emerged. This was from the second pupa (specimen B) shown above. It was also a male, but slightly larger with a forewing length of 13.5 mm. In this photo you can see the semitransparent areas on the wings. In both cases it they have emerged 18 days after completing their cocoon.

Notice too, the brown fluid in the next photo. This is the pupal fluid or meconium. It is the waste and dead cells that were produced during metamorphosis. It is ejected shortly after the moth emerges.

_{Specimen B: Male imago. Forewing 13.5mm}

There are 7 pupae remaining. I've labeled these C through to I, and they appear in the photo below arranged left to right. For these I have no dates recorded as to when pupation occurred. Their lengths are:

• C: 21mm
• D: 20mm
• E: 18mm
• F: 17.5mm
• G: 17.5mm
• H: 17mm
• I: 16mm

_{Remaining pupae ranging from 16mm to 21mm}

9th January 2009

Specimen D emerged on 9th January 2009.

_{Specimen D: Female imago. Forewing 17mm}

13th January 2009

Specimen C emerged on 13th January 2009.

_{Specimen C: Female imago. Forewing 17mm}

14th January 2009

Specimen F emerged on 14th January 2009. Placed with specimen C for mating.

_{Specimen F: Male imago. Forewing 13mm}

15th January 2009

Specimen H emerged on 15th January 2009.

_{Specimen H: Male imago. Forewing 11mm}

Meanwhile, specimen C, having been less than 24 hours with the male specimen F, has laid eggs. There are 24 eggs in 4 small groups of 3, 4, 8 and 9. The eggs measure about 1mm x 1.2mm.

_{Eggs from Specimens C & F - 1mm X 1.2mm}

...and so life goes on.

Summary

All up, 80 days passed from the eggs being laid until the first eggs of the second generation were laid. The size of the pupae ranged from 16mm to 21mm. Emergence was spread over at least twelve days. Adult females were larger, with an average forewing length of 17mm. Male forewing length averaged 12.5mm.

Further Reading:

• Enjoying Moths – Roy Leverton (2001) – Poyser Natural History Books
• Breeding Butterflies and Moths - Ekkehard Friedrich (1986) - Harley Books

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