Saturday, 22 October 2011

By the light of the silvery Moon (Moth)

A.selene male
Earlier this year we started showing a new species of silkmoth, in addition to the Giant Atlas Moths Attacus atlas and the Rothschild’s Atlas Moth Rothschildea jacobeae. These are the beautiful lime green Indian Moon Moth, Actias selene.Although we do not currently have adults on show, we have larvae growing off-show and should have the adults again in a few months.

I have a personal interest in these, as earlier this year I obtained some of the eggs of this species from a supplier and raised them myself at home. The larvae feed on many different plants, but I raised mine on hawthorn (Crataegus). They will also feed on the leaves of apple, evergreen oak, even rhododendron, and in their native habitat will feed on numerous forest trees.

A.luna female

Various species of moon moth can be found throughout Asia, and one species, Actias luna, the American Moon moth, has colonised North America from Quebec south to northern Mexico. They are usually fairly large moths, mostly green or yellow although the long tails on the hind wings are often pink. Males and females are often fairly distinct, with males having longer tails than the females.

Graellsia isabellae
There are perhaps over 20 different species of Actias described, and some species have several subspecies that should probably be treated as distinct. In addition, two other genera of moon moths exist, and seem to form a clade with Actias – the Spanish Moon Moth Graellsia isabellae, and the four species of African/Madagascan Argema. The latter genus contains one of the most magnificent of all moths, the Madagascan Moon Moth or Comet Moth Argema mittrei, which has a 20cm wingspan and tails 15cm long.

Argema mittrei
Although they will eat a variety of food plants in captivity, the moon moths in the wild often specialise in plants that protect themselves with resin against injury. American Moon Moths will feed on Liquidambar, Argema species feed on Eugenia, and Graellsia feeds on pine. Some Actias species will also feed on pine, such as the Chinese Moon Moth Actias dubernardii.
A.dubernardii male
As most of these moths are fairly easy to breed in captivity, and many species are subtropical or temperate zone moths rather than full rainforest species, they are widely bred on butterfly farms. Even the Madagascan moon moth can be bred in captivity, if with more difficulty than some others, as the larvae will take Eucalyptus as a substitute for the wild food plant. If you have access to the appropriate foodplants, anyone can raise the easier species such as A.selene or A.luna, so they make a fun project for children to try raising at home - the eggs are easily available mail order.

A. selene 5th instar larva
Most species will last out the winter or dry season as pupae inside fairly loosely woven cocoons. The “decision” to go into diapause rather than develop immediately depends on the larvae, especially the light regime and temperature as they develop. The adult moths emerge in early morning, and as with all Satuniids they do not feed, surviving on the fat reserves they built up as larvae. Depending on temperature, the adults live for around a week. They pair after dark, females attracting males with pheremones.

And what of the ones I raised I hear you ask? I only got one female emerge, but I had a successful pairing and the next generation of caterpillars hatched successfully. I have a thankful of second instar larvae now, feeding on raspberry and hawthorn. If I get these through to pupation, the next generation of moths should emerge in the spring.

(images from wikipedia)

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