Monday, 1 December 2008

Thistle do me

Given that I'm still tethered to the computer — and probably will be until the end of the year — I've had to confine my nature study to the garden. And that's rapidly turning into a monoculture of sow thistle. I could blame the constant seeding from the laneway and vacant block next door but it might also ... possibly ... have its origins in the disgraceful tangle of weeds along the fence.

I was standing on the back step, looking at the appalling mess and considering taking action against the invasion, when I noticed just how many visitors were dropping in on the weeds. The paperbark in the street might be loaded with blossoms but the insects ignored it in favour of the little yellow flowers on the thistles. Maybe it was the difference in pollen production. Maybe it was the army of wattlebirds in the tree. Whatever the reason, the thistles were attracting all sorts of insects and the tree wasn't.

Of course, the moment I got out the camera a) the wind picked up and whipped the plants around and b) every insect fluttered for cover. I could regale you with tales of the Ones That Got Away but you'd never believe them. So here's what I did catch.

From idle observation, I think at least three species of hoverfly pop into the garden. Although adults are mostly pollen and nectar feeders, larvae are predators of aphids and other small insects. Normally, the thistles are covered in juicy little aphids. (Swarms of them cluster on the stems just below the leaves.) But the plants are completely aphid-free. Not an aphid in sight. Surely the hoverfly larvae haven't cleaned up every last one of them? Is it worth keeping a thistle patch to see whether the aphids and hoverflies return?

Other flies enjoy the pollen. I'm not sure what type of fly this is — other than an unco-ordinated one. It did love roaming around the stamens.

Native bees gather pollen from the flowers. (This isn't bad photography, by the way. They are naturally out of focus. Rather like the hoverflies.) Halictids tuck their pollen haul away under their tummies. You might be able to make out a rim of gold along the abdomen of this bee.

And there's always room for one more thrips.

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