Greetings fellow Foxies,
                                     Recently I climbed Yilliminning rock in the evening which is a great time to gain an understanding of its formation. There is a great story in the rock itself if you look closely.
Most continents in the world consist mainly of granite (a light coloured quartz and feldspar rich rock that crystallised out from molten magma (igneous rock). The continents are separated by black dense crystalline rock (a bit like dolerite used for road building) that underlies ocean floors.
 I suspect that the granite here formed up to two thousand million years ago (your ancestral line may have been bacteria then) when two geological plates were colliding. As one slowly slid underneath the other it was forced into deep molten rock of the mantle and gradually melted.
Being lighter, large domes of molten granite gradually forced their way upwards. They moved upwards through solid rock by “cauldron subsidence”. Intense heat from dome magma causes rock above to fracture and fall into the magma, creating a chamber that the magma moves into. Fractured rock from top and sides is often incorporated into the dome as partially melted xenoliths.
If they reach the surface, volcanoes spew out a fine grained granite like rock called andesite. However most times the domes stop two kilometers (km) or more below the land surface and gradually solidify into granite. You can tell that it cooled slowly because granite has large evenly spaced crystals.
 
Just think about it. As you stand on the top of Yilliminning Rock, you are 2 km below an ancient land surface.
 
The diagram on left shows ocean crust melting in the hot mantle after it has collided with and been forced underneath a continent. Molten material separates into dense black gabbro and lighter granite that rises towards the surface of the continent by cauldron subsidence.

​Like most of the large granite outcrops in the wheatbelt, Yilliminning Rock is an inselberg (steep sided dome of bedrock that has been exposed above the surface as surrounding land eroded away).
If you wander over the surface you can see the relatively uniform speckled pale crystalline granite.
But look carefully, and you will see more.
Yilliminning rock contains lots of roughly north-west/south-east corrugations that are easily seen at dusk as shadows define them. Simplistically, I think that these could be due to slight differences in rock composition from

• Magma intruding cracks in the cooling rock.
• Changes in crystal size and possibly mineral composition that occurred due to temperature and pressure changes as the granite slowly cooled while still molten.

The huge sheets of rock are geologically a very recent, and form in a process called exfoliation. Basically, granite is a very poor conductor of heat, and hot-cold temperature variations cause onion skin type cracks.
In winter, cracks expands as water in them freezes. Voila, a great home for Ornate Dragon Lizards (Ctenophorus ornatus). Eventually gravity and vibration/ pressure from earth movements (or more commonly humans) causes these sheets to break off and move downslope (or be crushed or carted away by humans!)
 The image below shows granite structure in a broken sheet

​Images below show rock sheet on the northern side of the rock. If you sit quietly, the dragon lizards (mini dragons really!) will come out. Watch them bobbing up and down to warn off intruders and running around on their tippy toes (evolved to help them avoid heat from hot rocks

Here are some great references
Geology of Granite
Overview of Granite Outcrops in Western Australia

Greetings fellow Foxies,
Over the years I have reported on sucking insects such as lerps, psyllids, scale and mealybugs, many of which have formed an alliance with ants by secreting a sugary liquid that attracts them to keep predators away.
 
Recently I found a more active association on a brown mallet at Newman Block. I noticed what looked like a termite gallery creeping up the smooth mallet trunk and was intrigued that termites would attack intact sapwood. When I scratched open the gallery wall, I noticed that it was more like cardboard than clay and that ants rather than termites poured out. This was reinforced by ants running up my leg from their nest in a rotting branch at the base of the tree that I happened to be standing on.
Undaunted by this setback, I investigated further and noticed scale insects feeding on the bark under the cover.
I returned to the spot another three times to collect more samples to take photographs and samples  to show to various experts I had approached. Each time the damage had been repaired, and ants poured out again (sorry ants but science must progress). The last time I noticed that the repaired section consisted of grass seeds that were germinating in the humid conditions.
 
An answer to my queries come via the WAISS (Western Australian Insect Study Society).
Here is a copy of a reply from Dr Brian Heterick at the Western Australian Museum)
“The ant is in the genus Papyrius (Subfamily Dolichoderinae, the same family to which the meat ants belong). The species is not clear from the photograph, but the group needs revision; there are several named species.
Papyrius ants are known to tend butterfly larvae that produce sweet secretions, so their also tending scale insects that produce honeydew is no surprise. This genus of ants is also associated with trees, and their nests constructed of frass and plant fibres are readily identifiable. They also nest in soil, often around tree trunks. 
When at Curtin I received occasional reports of these ants nesting in ceiling spaces and frass falling down from the ceiling on to carpet, so they can be a (very minor) nuisance, especially in country areas. 
The scale insect looks as though it may be in the Family Coccidae (soft scales).”
 
So there you are, by providing a secure and moist ‘house’, the ant colony gets a free honeydew supply.
To see more images click here

The reference above to ants tending butterfly larvae is a dark example of deception of noble ants by devious butterflies. This was described in the August edition of the WAISS newsletter.
 
“Larvae of particular moth species begin life as parasites of homopterans (the sub-order Homoptera includes aphids, cicadas and leafhoppers).
Once the larva reaches a certain stage of growth, it leaves its homopteran hosts and awaits an encounter with a meat ant, Iridomyrmex purpureus. Upon discovery, the meat ant picks up the larva and takes it into the ant nest.
The larva spends the rest of its development in the galleries of the ant nest. For food, the moth larva eats the ant larvae, yet the adult ants don’t seem to object. 
As if in payment for their safe lodgings and all-you-can-eat buffet, the caterpillars produce a liquid from their rear ends that the adult ants find irresistible. The unfortunate ant, blinded by his partiality for liquor, overlooks the fact that it is produced entirely at the expense of his (her) own larvae devoured.
 
So these dreaded ant swarms that destroy picnics and climb into you undies also get their come-uppance.
 
For those wishing to join or know more about WAISS click here.

​Greetings Fellow Foxies,
A year ago I spotted a wandoo in Candy Reserve that had large strange pits in its trunk and didn’t think too much about it until I found another example in another reserve. In this case a large branch had fallen an affected tree many years ago, leaving beautifully patterned wood after the bark had fallen off.

​Pits on the living tree are like inverted oval cones, and the damage extends up the tree to the youngest branches.

​On close examination I could see the tree’s annual growth rings on the sides and a small hole in the heartwood at the base. The sapwood was clean and clear of fungi indicating that an insect was the primary cause.
When I cut a section trough a pit I found a small (about 3mm diameter) burrow leading from the base into a more extensive gallery system in the middle of the stem.

Enquiries have failed to produce an identification
There are similarities to wandoo crown decline as fungal canker was present in the heartwood but there are clear differences.

• This is very rare and hasn’t spread to any adjoining trees.
• The sapwood is healthy.
• I could see a ring of chew marks on the outermost sapwood layer surrounding pit which suggests that some insect comes out of the basal burrow to feed regularly.
• There must be successive generations of the insect, as indicated by the growth rings in the pits and the continuation of damage on the youngest branches

 Apart from cutting down a 200 year old tree or camping out by it and do nightly inspections, I can only ask if any of my readers can help solve this intriguing mystery
For more images click HERE

Greetings fellow Foxies,
I never cease to be amazed by the things one can learn by observing nature and asking questions.
 I photographed tiny pools of water containing dead insects on a gilled fungus and asked about it on the Western Australian Fungi Facebook Page.
I learnt that they are 6 legged fungi-eating Springtails (not insects!) on Cortinarius rotundidisporus (Elegant Blue Webcap). The group includes lucerne fleas, but are everywhere – even as innocuous residents in the house. As to the drowned ones, just read the extract from the Facebook site below.
 "Temporary rain pools are a kind of trap for small surface-active springtails. Once they jump into such a pool they cannot easily escape from it. Due to the meniscus of the pool surface water at the edges, they will always slide back to the center of the pool. Eventually they will aggregate and form a kind of floating mass of crawling bodies from which some specimens will be able to escape by jumping away.
"If and when a sufficient number of individuals of the same species of Hypogastruridae gather together by accident on such a pool, another thing might happen. Adult females will release a sex pheromone to attract males. Also other females will be attracted by the pheromone signal. The more individuals gather together, the stronger the pheromone signal and more individuals will be attracted from a greater distance. This may eventually result in the spectacular mass aggregations typical for Hypogastruridae. 100,000s of individuals may aggregate as such. The purpose of these mass aggregations is to reproduce.
The pool party then becomes in fact a sex party! ;-)
 
OMG I posted springtail pornography!