Yesterday afternoon’s beautiful weather persuaded me to leave my useful-but-tedious work for an hour or two to ride to Aplin’s Weir, leave the bike under a tree and walk upstream between the bike path and the water (still on the Mundingburra side of the river). It’s quite a wide, rich zone in that stretch of Ross River’s parkland, with a broad backwater, swampy areas and an unmade walking track under mature trees – a bit of everything for the local wildlife and (therefore) for a casual naturalist/photographer like myself. I came home relaxed and with a good haul of photos. I have started with an insect so I will continue with invertebrates before getting to the birds. Continue reading “A riverside ramble”
The Palmetum is one ‘campus’ of Townsville’s Botanic Gardens, the other two being Queen’s Gardens in North Ward and Anderson Park near us in Mundingburra.
The Palmetum is beside Ross River just off the main road between town and the university/hospital area. Its speciality is, obviously, palms but that means a broad variety of habitats from arid to rainforest and swamp, with a correspondingly broad range of insects and birds. Here are four of the ten or more (I haven’t yet sorted them all out) species of dragonflies and damselflies I photographed in one slow walk around the lagoon yesterday.
Dragons and damsels are closely related, all grouped together in Odonata, but damselflies are mostly smaller than dragonflies so the last image you see here is all the pixels I’ve got, while clicking on any of the others will get you a bigger image.
Head north from Townsville looking for a pretty spot for a picnic and you might end up at Paluma; head south, and you get to Billabong Sanctuary or, just a little further on, Alligator Creek picnic and camping grounds. Turning inland from the highway takes you into Bowling Green Bay National Park (their photo is definitely a wet-season one) and, a couple of kilometres up a narrow road, a basic camping ground and picnic ground serving a popular swimming spot. (Alligator Creek is named after a boat which went aground at its mouth, not after scaly inhabitants, so the swimmers are safe enough so long as they are careful on the rocks.)
We hadn’t been there for years but it seemed like a good thing to do on a Sunday clear of other commitments. The picnic ground, like the bush around it, was very dry but the creek was still running – plenty of water in the pools for kids to splash around in, although you could easily step across the creek between the pools. It is a violent rocky torrent many metres wide in the Wet, so the picnic ground is well above the creek bed.
I rock-hopped my way upstream with my camera after lunch. Dragonflies and damselflies (see this post for similarities and differences) caught my attention immediately, especially one large, gorgeous bright blue variety that I hadn’t seen before. I was sure it was a dragon (big, and resting with wings outstretched) but found when I got home that it was a damsel, the Tropical Rockmaster, Diphlebia euphoeoides.
The early afternoon light among the rocks was very bright (brilliant? harsh? glary?), making the shadows correspondingly black. In this case the shadows could almost fool you into thinking the insect has eight wings, like this one I saw a few months ago.
I also photographed two more typical damsels (one here), a red-brown dragon and a blue-black one (both of which I know from Ross River and Anderson Park), a few spiders (one unfamiliar relative of our familiar St Andrew’s Cross spider and a couple of very skinny tetragnathids, here and here), some fish and tadpoles easily visible in the crystal-clear water, skinks on the rocks and, just before we left, a kangaroo flying through the picnic grounds as though it was being pursued by something with big snappy jaws. It wasn’t, or I might have run instead of picking up my camera:
I said a while ago that all the dragonflies had vanished from my garden with the onset of the dry season. I believed that the damselflies (their more delicate relations) had gone with them, but today I found this delicate creature perched in the shadows of the macadamia tree.
It would have been so easy to overlook this one, though, that I now wonder whether there have been a few around all the time. Their larvae need permanent water and the nearest I know of is two or three hundred metres away in Anderson Park in one direction or Ross River in the other. Perhaps the adults do constantly roam that far, or perhaps this one was just unlucky enough to be caught by a gust of wind.
Quite by coincidence, I saw on Flickr today a great photo of a dragonfly emerging from its larval shell. It may take a moment to make sense of it, however: the new, soft, adult is emerging with feet in the air, eyes very prominent at the upper right and wings still collapsed into creamy-white buds.
No, this is not a story of days of old – sorry. It’s about two groups of insects which had a wonderful time in our recent big Wet: damselflies and dragonflies. I saw far more this year than ever before, and an online friend from Exmouth, WA, says the same.
Damsels are (appropriately enough) generally smaller and more delicate than dragons but both families are aerial predators, hunting on the wing. The easiest way to tell them apart is that damsels fold their wings over their abdomens when resting, whereas dragons hold them outstretched or forwards and downwards. The two groups, Zygoptera and Anisoptera respectively, make up the order Odonata. There are some 320 species in Australia, mostly in the north.
They are an ancient order – every prehistoric-nature doco seems to mention the enormous dragonflies of the late Paleozoic, 300 million years ago, when greater oxygen content in the air allowed them to reach wingspans of 70 cm.
Adults lay eggs in fresh water, where the larvae (also carnivorous) develop through several moults before crawling up into the air to split open, much as cicadas do, to emerge as adults. Adults can roam far from water but must return to breed and the abundance of dragonflies is a good indicator of a healthy ecosystem. Their mating behaviour is complex and quite strange. Read about it here if you don’t want to wait until I can find time to write about it.
Dragons and damsels have no economic significance to us but are universally loved for their beauty and agility in the air.
More about damsels and dragons
This article first appeared in a slightly different form in Kapok, newsletter of Coastal Dry Tropics Landcare, Inc., in March 2011.