Scaling up

Recent hot weather sent garden ants scurrying indoors. Workers from the colony near the back door had kept their distance for months but when the temperature exceeded 40C, they rethought their strategy.

Although the kitchen sink offers many morsels, the choicest pickings are in the laundry. That's where I keep a small collection of native figs. One of the plants — a Port Jackson fig (Ficus rubiginosa) — is infested with soft brown scale (Coccus hesperidum). So well are the scale insects doing that they have already produced several generations. The tiny mobile nymphs are distributed over the stems and leaves, trying to find unoccupied spaces to settle.

While the scale insects feed on plant sap, the ants are crazy for the honeydew exuded from the scales' rear ends. Despite the large number of photographs I've taken, I do not have a soft spot for either the scale insects or the ants. They'll soon be relocated, possibly with extreme prejudice. Until then, I will marvel at the ants' industry, the scale insects' sloth and the exquisite morphology of both species. (Without having any deep fondness for them, you understand.)

The corella tree

I'd heard them fly over but hadn't seen the flock of long-billed corellas that has moved into the neighbourhood. Late this evening, as the setting sun was struggling through the smoky air, they landed in a neighbour's tree and started to dine. Apart from some intraflock squabbling, they were pleasant and talkative guests.

Long-billed corellas are common in the 'burbs and now seem to be shifting into the urbs, following crested pigeons and galahs. The pigeons and galahs are now a common sight here in Footscray. The corellas will probably settle in too.

If you love frogs …

… you'll love David Nelson's blog about his travels up the east coast. It's the (very) wet season in the tropics and the frogs are out and about.

In fact, you might say that North Queensland is a Frogger's Paradise. The reptiles are pretty cool too. And he's also seen some charismatic slimofauna.

In the Wild is a good place to get lost for a while.

Stuff happens

A combination of drought and high winds took a toll on this tree today. Fortunately, it didn't do much damage to the house and the occupants were surprised but not injured. The State Emergency Service turned up promptly, armed with chain saws and a variety of slicing and dicing implements.

Although it was only across the road from my place (that's my twee fence in the foreground), I didn't hear the crack above the roar of the wind. Not until the chainsaws started up did I take a peek.

The Crabs' Revolution

A short animated film with lessons for us all.

In the murky waters of the Gironde estuary, between the tar-ridden rocks and the muddy sand that harbours the best oysters, no one is aware of the tragedy that has befallen our kind. We are the Pachygrapsus marmoratus, commonly known as the "chancroids" or "depressed crabs". You know, the ugly square ones; the poor blighters that kids love pulling the legs off; the ones that make you ill. In short, a species that never asked to be put on earth.

HT to Jussi and Lulu Stader

I and the Bird #93

The latest edition is up at Vicki Henderson's Art Blog.

Hottest day on record in Melbourne

The temperature reached 46.4C (115.5F) before dropping to a more tolerable 30C (86F) by early evening. With the heat came strong northerly winds. Authorities issued warnings that the conditions today would be similar to those on Ash Wednesday, 1983, when huge fires burned out of control across Victoria and South Australia, killing 75 people and destroying thousands of buildings. They were right.

Dozens of bushfires started today, many of which are still burning out of control. Some fires cover thousands of hectares. According to the people on the front lines, it's likely that there'll be a major loss of property. My friend Chuckie has posted photos of the fires near him at Kinglake.

ABC News has excellent coverage, including extraordinary pictures of the fires.

Map of major fires in Victoria (Department of Sustainability and Environment)

Smoke from bushfires picked up by Bureau of Meteorology radar

Meanwhile, at the other end of the continent, the town of Ingham (home to Tyto Tony … and about 13,000 other people) is experiencing its worst floods ever.

Incredible Spineless

Christopher Taylor of Catalogue of Organisms wants your nominations for 'the most incredible organisms of all time'.

If you're stuck for ideas, check out the blog carnival without a backbone*, Circus of the Spineless at The Other 95%. All the most incredible organisms are invertebrates. What? I thought you knew that.

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* In a good way

Wasp ways

My garden is full of wasps of all stripes*. They are mostly solitary species, looking for a little something to feed to the youngsters. Many spend their formative days inside other insects, dining on the victim's internal organs while it is still alive. Eventually the wasps emerge, killing their hosts. Because of these deadly consequences, such wasps are termed parasitoids — their life cycles are similar in many ways to that of parasites but the outcome for the host is significantly different. True parasites usually don't kill their host; true parasitoids do.

Depending on the species, wasps either lay their eggs on or in another insect while it goes about its daily activity or relocate the victim to a nest. In the second case, the soon-to-be-larval-larder isn't always encountered in a convenient spot. The wasp has first to disable the victim and then lug around the large and awkward lump, sometimes over many metres. Life isn't easy for a parasitoid.

The emerald cockroach wasp (Ampulex compressa) avoids the problem of heavy lifting by making the take-away take itself away. Instead of paralysing the victim, Ampulex modifies its behaviour to make it compliant. The doomed cockroach can still move, but is acquiescent. All the wasp as to do is lead it away. It's one step away from the Dish of the Day.

The elements of the Ampulex life cycle follow the typical parasitoid pattern. An egg laid on the host hatches after a few days. The larvae spends time on the outside, feeding on haemolymph (insect 'blood') through the cockroach's body wall. As it grows, it chews its way in, spending the rest of its larval life feeding on the host's viscera. When it metamorphoses into an adult wasp, the inevitable happens. The host finally expires. And it may well be grateful for an end to that gnawing feeling.

The truly remarkable part of the life cycle is the way in which Ampulex alters the cockroach's behaviour. It's a two part process. First, the wasp temporarily paralyses the victim's front legs. It achieves this by inserting the sting into the prothoracic ganglion and injecting a venom — a mixture of the neurotransmitter GABA, taurine and β-alanine — that blocks nerve impulses to the first pair of legs. The paralysis only lasts for a couple of minutes, but that gives the wasp enough time to perform the next bit of surgery.

Now Ampulex injects its venom directly into the brain and the suboesophageal ganglion. The sting goes in from the underside, which is not as heavily armoured as the top of the cockroach's head. The venom induces a progressive change in behaviour. On being stung in the brain, the cockroach first grooms itself for about 20 minutes. (This could explain those makeover shows on television.) Then the venom permanently blocks its escape response by inhibiting the associated nerves. The victim no longer receives 'danger, run away!' signals from the antennae or the sensitive hairs on the cerci. (Those pointy bits sticking out of the posterior of a cockroach are covered in fine hairs that detect the slightest air movement. Each hair has its own nerve. When a nerve is triggered, the cockroach goes into scuttle mode. That's why the little beggars are so difficult to approach.)

The wasp grabs hold of an antenna with its jaws and leads the cockroach to a burrow. Once the victim is in place, the wasp lays an egg and then seals the burrow entrance with pebbles. A month or so later, a new wasp emerges and all that remains is a hole in the ground filled with the husk of a cockroach.

Not surprisingly, Ampulex compressa is used as a biological control for cockroaches. It is not as effective as other wasps, which target cockroach eggs, but it has a certain élan, wouldn't you say?

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* Except European wasps, for some reason. Perhaps the drought has hit them hard? Not that I'm complaining.

Too good to last

I've just been speaking to the builders who'll be responsible for the work on the vacant block next door. They're about to start on a two-storey house. So, that's the end of my peace and quiet for the next five months.

Of course, I couldn't expect it to last. But that's even more incentive to move.

Bugger!

Tim Minchin: 'Storm'

Australian comedian Tim Minchin's beat poem on the conflict between science and woo.

Throughout history
Every mystery
Ever solved
Has turned out to be
Not magic

Mountain Devil (Lambertia formosa)

The stunning Mountain Devil (Lambertia formosa) of New South Wales was among the first Australian plants to be brought into cultivation. James Lee and Lewis Kennedy grew it in their Vineyard Nursery, Hammersmith, for sale to wealthy European plant-lovers. The Empress Josephine was a client. Her Jardin de la Malmaison held one of the world's finest collections of Australian species. I photographed this specimen at the more modest Karwarra Gardens near Olinda in the Dandenong Ranges.

Of all the plants yet introduced from New Holland, that have hitherto flowered with us, this unquestionably takes the lead for beauty, considering the plant altogether. It is a hardy greenhouse plant, growing to the height of six or eight feet before it flowers; when the blossoms break from the ends of almost every branch. The seeds of this plant were among the first which arrived from Botany Bay, in the year 1788; when two varieties of it were raised by Messrs. Lee and Kennedy, at their nursery, who were fortunate enough to procure all the seeds which came home that season. This fine genus has received its title, (under the sanction of Dr. Smith, see the Linn. Trans. page 214, vol. 3.) from Aylmer Bourke Lambert, Esq. Fellow of the Royal and Linnæan Societies; a gentleman whose zeal for the advancement of the science is unbounded, and whose labours to that end, as well as his endeavours to render botany of universal benefit, by combining the useful with the pleasing (witness his work on the Cinchonas, or Jesuits' Barks) do him the greatest credit.

Henry Andrews (1797)
The Botanist's Repository for New and Rare Plants

Wasp's going on here?

While I was relocating a very excitable huntsman spider from the kitchen to the garden, a black flower wasp (Scolia sp.) dropped in to see what was happening. Of course, I didn't have my camera so I had to rush back into the house, find it and then track down the wasp. Luckily, they're not that difficult to spot, given that they're 3 – 4 cm long and their wings have an eye-catching iridescent blue sheen.



To make things trickier, I had the macro lens on, so I had to get close to this mighty buzzer to take the photo. Even though they're not aggressive wasps, I still gave it breathing space.

The newly-liberated hunstman was reasonably safe from the attentions of this species. Unlike the orange-and-black pompiliids, which lay their eggs on live but paralysed spiders, the black flower wasp prefers curl grubs and other scarab larvae as hosts for their young. Without lawn, my garden is probably scarab free, so there are slim pickings here for these wonderful wasps. At least I got a close look before it moved on.

Episode IV: A New Hope

In just a few weeks, I'll be willingly and willfully unemployed. Yes, yes, it's not the most sensible decision in the world, given current economic conditions, but sometimes you just have to take a chance.

I am but mad north-north-west

… because that's the direction of the hot winds in southeastern Australia. We've just been through a scorcher of a week, with maxima in the mid-40s and minima not far below that. Over three consecutive days, the temperature inside my house did not drop below 35C. The worst is over in Melbourne and other coastal areas of Victoria, with sea breezes pushing backing the blast furnace northerlies but folk on the other side of the range are still suffering.

With the heat comes bushfires. Some of those burning in South Gippsland were deliberately lit last week by an arsonist, whereas the others appear to have been started by lightning strikes. The Delburn Complex fires have already destroyed more than two dozen houses. Fortunately, no one has been killed. Once again, I'm endlessly impressed by everyone fighting these fires, especially the Country Fire Authority.



The consequences of the heatwave have been rather trivial at my place. I went troppo*, the kitchen filled with heat affected earwigs and many of the garden plants cooked to a crisp. I'm keeping my fingers crossed that they'll survive. All we need now is some rain. Tony, can you send us some?

Fronds of a cabbage palm (Livistona australis) dried by the sun

Even the kurrajong (Brachychiton discolor) couldn't resist the heat.

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* So what exactly is odd about suggesting that a hollowed out watermelon would make a useful hat for keeping your head cool? When the wind is southerly I know a hawk from a handsaw.