What’s around – mid August 2012

mating craneflies
A mating pair of Tiger Craneflies, Nephrotoma australasiae. Legs everywhere!
The sexes are very similar but the female (at top of this picture) is more heavily built.

The total rainfall since my previous mid-month summary is exactly zero, and the relative humidity has been very low, too: below 20% at 3pm every day for the last two weeks, for instance. Temperatures have consistently swung between 8 – 10C overnight and the mid twenties during the day. Cool and dry is not what the bugs like and I’m beginning to think of them as being in ‘maintenance mode’, just ticking over and waiting for some warmth and moisture.

The paperbark is flowering, as I mentioned a few days ago, and so is the mango tree. The Macadamia is almost ready to follow suit, and so is the Poplar Gum. Each of these trees attracts its own group of nectar-feeders. The birds love the paperbark (as I mentioned in my previous post) and the poplar gum, but are not particularly fond of the other two. The honey bees don’t seem to care for the mango blossom but love the other three, so that pretty much leaves the mango to the butterflies, the flies (mainly hoverflies), wasps and native bees.

large hoverfly on mango blossom
Hoverfly on mango blossom

I’m seeing …

    • Quite a lot of little orb-weaving spiders – Silver Orb-weavers (Leucauge granulata), Spiny Orb-weavers ( which I now believe to be Gasteracantha sacerdotalis rather than Austracantha) and St Andrew’s Cross spiders; also quite a lot of jumping spiders (Salticidae), some Lynx, and a few flower spiders.
    • Hoppers and their nymphs, which often become food for the above.
    • Butterflies: reasonable numbers of Junonia and Eurema and grass moths; very small numbers of everything else but including Migrants, Skippers, Melanitis leda and recently one visiting Orchard Swallowtail.
Giant grasshopper on variegated leaves
Giant grasshopper on giant variegated lily
  • Diptera (Flies): Long-legged flies (see bottom of this page), Hoverflies (see at left) and Blowflies, with occasional soldier flies and craneflies (above) and – still – mosquitoes.
  • Hymenoptera (wasps, bees and ants): occasional little wasps including paper wasps (though no nests that I’m aware of) and a very few mud-daubers; some native bees again recently after a gap of a few months; the usual small ants and a slowly-growing green-ant colony.
  • Others: a few Giant Grasshoppers; a healthy population of cockroaches in the compost bin; but no mantises (although saying that usually ensures I will see one in the next day or so).

Same time a year ago

Crane flies

Crane fly on mango blossom
Tiger Crane Fly, Nephrotoma australasiae, on mango blossom

Tiger Crane Flies are common in my garden all year round, their staggering flight from leaf to leaf distinctive enough that they are rarely confused with wasps even at a distance. Close up, of course, their extraordinarily long legs are unmistakeable.

But I had never really thought about what they live on – and the fact that they are flies doesn’t tell me a thing, since flies (Diptera) have diversified to live on nearly anything you can think of (and a few things we would usually rather not think of, for that matter). I have seen one apparently drinking from a drop of water on a leaf (see below) and this one on our mango blossom does seem to be drinking nectar, but almost every time I see them they are either in flight or simply resting on a leaf.

Wikipedia to the rescue: ‘Adult crane flies feed on nectar or they do not feed at all; once they become adults, most crane fly species exist as adults only to mate and die.’ (That must explain why I so often see them mating. Here is a picture of a mating pair.)

Wikipedia continues: ‘Female abdomens contain eggs, and as a result appear swollen in comparison to those of males. The female abdomen also ends in a pointed ovipositor that may look somewhat like a stinger, but is in fact completely harmless. Their larvae, called “leatherjackets”, “leatherbacks”, or “leatherjacket slugs” because of the way they move, consume roots of turf grass and other vegetation, in some cases causing damage to plants.’

Cranefly drinking from water droplet on leaf
Cranefly drinking water from the surface of a leaf