We have been growing a particular vine, for years, just for the Birdwing butterflies whose caterpillars depend on it. Just what the vine is called and which butterflies depend on it are, however, recurring questions – for us as well as for the many other people who love the butterflies. This post pulls together information from botanical and entomological books and websites to try to settle both questions.
Very briefly, all species of butterflies in one group of Swallowtail butterflies have specialised to feed exclusively on one group of closely related plants. The butterflies are the Troidini, a “tribe” (in scientific language that’s a level between “family” and “genus”) of Swallowtails (Papilionidae) and the plants are the Birthworts (Aristolochiaceae).
Our Troidini are the Clearwing Swallowtail (Cressida cressida), Red-bodied Swallowtail (Atrophaneura polydorus) and all of the Birdwings (Ornithoptera species). The Aristolochiaceae we’re interested in are in the genus Aristolochia, or used to be, and many of them are known as Dutchman’s Pipe vines.
A few weeks ago I received an enquiry from a reader: did I know what was happening with the Blue Tigers at Horseshoe Bay on Magnetic Island?
At that time all I knew was second-hand or worse but soon afterwards I saw a local ABC News report about thousands of them on the site of the old Horseshoe Bay school, which I was fortunate enough to visit with family and friends at the end of May. It was a magical experience.
A reader’s recent query grew into an interesting discussion and, with her permission, I have turned it into a blog post as I did with the Kookaburra story a year ago. The photos are hers, as is most of the text; I’ve just edited it lightly for clarity and continuity. My emails are in italics, while my introductory and linking text is formatted (illogically, I know) as quoted text like this.
Pat to Malcolm, 12 April
We live on the banks of the Barron River in Mareeba and I’m pretty sure these wasps are the yellow paper wasp you wrote about and put on line.
The initial nest was in a low lying branch in my front yard and I accidentally hit the branch or nest and out came wasps and I got stung. (I’m allergic, so a bit of a big deal.)
After a few days I noticed a swarm at my front porch, and although not wanting to poison them we had to encourage them to move on, and mostly they did. One tiny nest remained and my husband will remove it this evening.
But this morning on the big eucalyptus tree in our back area toward the river, the swarm looks like it is in the thousands, and building very different sort of ‘nests’ down the trunk of the white tree, a vertical row of individual pieces protruding off the tree. It doesn’t look like the usual nest but the nest in the bunya tree in our front yard (at least I think it’s a bunya – super straight, very tall and with cones) might be the same kind except that it’s about 50 feet up on the bunya.
A friend sent me a photo of a caterpillar ten days ago, with two implied questions:
This caterpillar is feeding off native Dutchmans Pipe.
Also, the Cairns Birdwing caterpillars of several people I have spoken to have died and butterflies are scarce even though there is a plentiful food source.
The first question was easy to answer: it was a caterpillar of the Clearwing Swallowtail, aka Big Greasy, butterfly (Cressida cressida), which shares Aristolochia tagala with the Cairns Birdwing.
They are quite distinctive at every stage of their little lives. The tiniest ones are orange; a little later they are maroon with white spines; and finally they are creamy-white with some maroon markings, as in this old post.
A mature St Andrew’s Cross spider (Argiope keyserlingi) has set up her web between two maidenhair ferns on our back patio and I noticed yesterday morning that she had caught and wrapped a substantial meal, perhaps a fly or a small moth.
Looking more closely after lunch (my lunch, that is, not hers), I saw a much smaller spider hanging around in the edge of her web.
The macro lens with a close-up filter was able to show that it was a Dewdrop Spider, Argyrodes antipodianus, and even that it was a male (those “boxing gloves”, really enlarged palps, are the giveaway).