The St Andrew’s Cross spider, Argiope keyserlingi, is very common in our gardens and it is named for its trademark, an “x” cross built into its web, this being the symbol of the Scottish patron saint. (Why? Find out here.)
This mid-sized female, however, wasn’t going to stop with an “x” but had added half of a central vertical stroke and a hint of the other half when I saw her yesterday. Her web is the same today, so that must be how she likes it. Why? No-one knows. In fact, no-one knows why spiders add any of these decorations to their webs.
The decoration, whether it’s a cross (as this ought to be), a loose squiggle (like this, created by a juvenile of the same species, or this, created by an adult of a related species) or any other shape, is called a stabilimentum. The new Whyte & Anderson Field Guide says, “proposed functions have included providing camouflage, making the web more conspicuous to prevent destruction, or attracting insects by reflecting UV light.”
Other orb-weaving spiders add different kinds of solid-looking components to their webs. Cyclosa species, for instance, construct a bar of prey debris across the centre of their web, in which they very deliberately camouflage themselves, but there is no guarantee that this behaviour is related to the Argiope species’ construction of a stabilimentum.
There isn’t much insect activity in the garden at this (dry, cool) time of year but when I was ambling around it last week I saw a Green Ant which was too small – only about two thirds of the size of a normal Green Ant.
That was my first thought, anyway, but a closer look revealed that it wasn’t an ant at all but a very good mimic. It is a juvenile Pod-Sucking Bug (Riptortus sp., Alydidae, Hemiptera) and in fact is the same species I described here on Green Path four years ago. That post shows older juveniles, gradually less and less like the Green Ant; this very small one turns out to be the best mimic of all, other than being too small.
This second image clearly shows its proboscis or sucking tube, tucked away beneath its body until needed.
Our few days of rain last month, welcome as they were, seem to have been an aberration and we’re now enjoying a normal Townsville winter – cool nights, warm days, blue skies and humidity low enough that static electricity sparks off car door handles. Every second person you meet asks, “Isn’t this weather gorgeous?” and the answer is always some version of, “It sure is!”
I paused at Sandy Crossing quite early one morning last week for this photo. The dew was still on the grass and the birds were moving around the mangroves – Brown Honeyeaters making far more noise than their size seems to warrant, as they so often do; a Rainbow Bee-eater perching watchfully on the power line; and a little gathering of Woodswallows not far away.
This year’s Eco-Fiesta, a few days ago, was much like those of previous years: a lovely day in the park with all sorts of loosely ‘greenie’ and ‘alternative’ people and organisations. I wrote enough about the 2014 and 2013 events that I shouldn’t need to present an overview this time, so I will dive straight in to the things which caught my attention.
Wildlife Queensland had a well-staffed stall featuring a great gallery of flying fox photos. These animals get a bad press and need all the support they can get.
North Queensland Regional Plan had a very boring stall (I’m sorry, but it’s true!) which tried to engage visitors in planning for our region, the local government areas of Charters Towers, Burdekin Shire, Hinchinbrook Shire and Townsville. It’s a state government initiative and welcomes online input here. I told them about our declining rainfall. What’s your concern?
As regular readers will be aware, I like spiders as well as butterflies and birds. I was very pleased when I heard the first hints that a new guide to them might be on the way, the more so since the author-to-be was my regular mentor in all things arachnological through his site Arachne.org and the Spiders of Australia flickr group. When he asked whether he could use a couple of my photos Continue reading “A Field Guide to Spiders of Australia”
My third visit to Wallaman Falls was a day trip with Wildlife Queensland. A full report will appear on their blog in due course but I thought I might quickly share this photo and mention my previous posts – from almost exactly one year ago and two years ago, as it happens. (This is a good time of year for camping and bushwalking, since everything is still quite green after the Wet but the weather is reliably fine and not too hot.)
I have added the spider and insect photos from this trip to my existing Wallaman Falls album on flickr.
Five years ago I wrote a post celebrating our backyard bananas and lamenting the vulnerability of the commercial crop. Several more posts since then have touched on the dangerous lack of genetic diversity of the endlessly-cloned Cavendish (especially Wild bananas) and a book I picked up in our Balinese guesthouse recently refocused my attention on the issue.