Emperor Moth

(Saturnia pavonia)

both pictures: April 2001
On the left a male sits on my hand, on the right is a newly hatched female.
Males have orange hind wings and are a little smaller than the females. 
Both sexes possess the beautifully painted eye-markings on each of the four wings. 
In German they get their name from this: "Night-Peacock".

Emperor Moths are rarely seen, even though they are native to Switzerland. The reason for this lies in their somewhat strange way of living:

The females are active at night and spend the day sitting motionless in a bush on a twig near the ground.  They are not completely inactive though: from a gland in their abdomen they send out a scent (pheromone) in order to attract the day-flying males. The males spend their days flying low above the ground searching for traces of the female's pheromones in the air. Their flight is fast and abrupt and it's likely the moth has already been and gone before you've properly noticed it was here... With their feathered antennae (better seen in the pictures below) they are able to detect a scent trail from more than 1 km away! 
Emperor Moths don't eat anything during their short lifespan of 14 days at most (they have neither mouths nor stomachs).

Thanks to the fact that I was able to attract a male from the wild population with one of "my" females in April 2002, I ended up with eggs and after 10 days little caterpillars. The mating of the two moths went on for about 2 hours, then the male wanted to be let out of the cage again and flew off (presumable in search of the next scenting female). The female continued sitting there quietly. In the following two nights it laid approx 80 eggs onto bramble twigs I had put in the cage for this purpose. Unfortunately the females died the next night, but that is apparently the norm for Emperor Moths! 10 days later tiny black caterpillars hatched from most of the eggs. After wandering aimlessly around the foodplant for a few hours they gathered together in a few big groups and only then started feeding (and I breathed a sigh of relief! ;)). Just as stated in my butterfly book they began to eat each leaf from the rim towards the center leaving just the tough skeleton. 
The 2 pictures below were taken in the time after the first, resp. second molting:    

The picture on the right shows a caterpillar shortly after its second molting. After a molting the caterpillars look a lot peltier than before. 

Caterpillars after second molting.

Caterpillar before third molting

Caterpillars after third molting.

Left caterpillar before its fourth molting, right caterpillar afterwards 
with the typical orange-yellow warts

Adult caterpillars, inclusive rolled-up fright position

The caterpillars started weaving their cocoons from June 1, 2002. The cocoons are pearshaped and have an exit funnel inbuilt at the top end. Next spring the emerging moth will crawl to freedom through this funnel. Inside these artfully constructed cocoons is the actual pupa. The outer cocoon-shell is incredibly tough and offers good protection for the metamorphosis from caterpillar to moth with takes 10 months or more! From the different sizes of the cocoons it's already possible to guess which ones will produce females and which ones males.
The newly finished cocoons are white, later they turn brown:

Just finished cocoons, 
the emerging funnels are pointing upwards

Cocoon that's already darkened, the exit funnel is on the left

So we're back at the beginning, that is I'm eagerly awaiting the next spring and the roughly 40 Emperor Moths which will hopefully hatch then on my balcony! The males I'll let fly off, with the females I'll be trying to attract a male from the native population (this is necessrary because sibling moths will not mate with each other to prevent inbreeding), achieve a mating and collect some eggs. Then the little caterpillars will hatch and - it's an endless spiral! ;))) 

April 5, 2003: It worked beautifully, all but 2 have hatched, 13 matings occured and I have already some 100 eggs!

Here are another four pictures of Emperor Moths on my balcony from April 2001 and 2002. Which are males and which are females should be clear now, no?;))

Link back to the main Swiss page in German: Der Schwalbenschwanz
Link back to the English main page: Home