Cairns Birdwing butterflies emerging

Three weeks ago I wrote about the collection of Cairns Birdwing chrysalises we found on our bottlebrush tree and observed that we should be seeing the adults emerging “around the end of the month.” They have been appearing for a few days now, so it seems that some of the chrysalises were a bit older than we thought.

Normal courtship involves the hopeful male flying close below and behind the larger, darker female as seen here and doing aerobatic tricks around her; if she is impressed enough, she will allow mating to begin.

However, males have no compunction whatever about taking advantage of a female who is still waiting for her wings to stretch and dry after squeezing out of her chrysalis, and that is what has happened in the photo above.

(How do I know the male is older? Simple: when you look closely, you will see that his wings are quite battered.)

As her strength increased, she fluttered and crawled higher in the foliage, dragging him with her.

This happened late yesterday afternoon and was the second emergence we saw during the day. Meanwhile, we still have half-grown caterpillars in the garden, and others full-grown and beginning pupation.

I checked on the seasonality of the species and Braby’s huge, authoritative Butterflies of Australia said that adults appear all year round but chrysalises can lie dormant for some months in the dry season. That makes sense, since there is no point emerging as an adult when the caterpillars’ food plants are not growing well.

Don Herbison-Evans’ page about the species lists their food plants and provides links to information about them.

Our caterpillars have been eating the bark of the main stems of our largest surviving vine and (once again) we would love to hear from people who have more Aristolochia. I’m sure that if we gave away all the caterpillars we could find we would still have more than we can feed.