spanningtree

spanningtree

Collection of interesting natural things

I took the picture above to see if I could get a good shot of the ocelli - three secondary eyes between the big ones. They are just about visible. Why spanning tree? It's a routing term, from each user's perspective the network looks like a spanning tree - with no loops and only one route to any place. Every user's spanning tree is unique.

Common carder bee

SciencePosted by Jay Fri, April 20, 2012 15:24:52
Difficult to capture on camera, a common carder bee Bombus pascuorum



Beetle tracks

SciencePosted by Jay Mon, April 16, 2012 20:14:51
Ash Bark Beetle - Leperisinus varius

http://www.eakringbirds.com/eakringbirds4/insectinfocusleperisinusvarius.htm

I guess, although I didn't catch any, I'll have a closer look. In ash log, felled 2 years ago. How do they avoid other tunnels? Side to side as well as end on?



King Alfred

SciencePosted by Jay Mon, April 16, 2012 19:47:37
His cakes

About 8 cm across...

and here are a few others...


All coming out of the cambium, and while we are at interesting fungi...



Rose chafer beetle

SciencePosted by Jay Sun, March 25, 2012 17:40:53
Here's a rose chafer I found today. Cetonia aurata - had a few hot days in a row.


Interesting antennae which she can totally suck into little slots in front of the eyes...
I think the little things emerging from near the mouth are its palps. Apparently they fly quite quickly and live for two years.

Summer branch fall

SciencePosted by Jay Sun, March 25, 2012 15:30:08

Guest posting from http://www.sydneytreecare.com.au/ - interesting natural phenomena I have seen recently. Two weeks ago (10th March 2012) a very large Gum tree branch failed and hit a house in Vaucluse in the Eastern Suburbs of Sydney. I was one of the first to attend the site and while I was there the team leader of the State Emergency Service arrived and we had a brief conversation of what he was able to do as a first response. In this conversation he mentioned that he had two other branch failures in the same or nearby suburbs to attend to that same morning. I thought that was strange. I was chatting to a friend about this and he relayed that that same night he was aware of another branch failure in his suburb of Engadine (30kms to the south). This seemed stranger. Particularly when considering that this was a very still and quiet night after some very wet and windy weather.

I am aware of the syndrome 'Summer Branch Drop', where, the syndrome goes, that while leaf size is at its maximum and fruit size at its maximum, this is most likely when failure will occur in a branch, particularly so after heavy dew-fall or wet and windy weather, which adds load to the branch. But this circumstance in Sydney two weeks ago does not meet those criteria. Dew falls after sun-down, so a mid-night break would seem strange. Also, the weather had been pretty awful up to a day before, but not that day and night when it was quite still. The branch failure was very counter-intuitive. Especially so endemically.

I think it maybe it could be a post-stress syndrome, maybe a bit like work-hardening in metals, when after a big viable load, it is the release of that load and inactivity that triggers the failure, perhaps brought on by a large difference in diurnal temperature. Seems a bit weird. I would welcome comment on this, as branch failure is a big deal when the tree is next to a house. (I am a consultant arboriculturalist working in Sydney.)

Pineal in tuna

SciencePosted by Jay Thu, March 22, 2012 13:59:30
I have been meaning to consider the pineal apparatus in tuna in more detail. In tuna the structures around this instrument are well developed.

Here is an MRI scan that the people at Hobart Hospital were kind enough to do for me. I'll just post these here for interest while I go off and do something else. The pineal window is the oval white structure in the middle - just in front of the brain. A picture from the side may be better to see the detail. The side picture shows much more interesting stuff...


You can see the heart in the 'throat' and the oil filled holes along the backbone - these should be familiar from cans of salmon - where they are often preserved as little round disks. Anyhow, the brain and the pineal window are all quite clear from this picture an it can be seen that light from above can illuminate the semi-spherical nodule at the front of the brain. I suspect this is related to navigation. We wrote a paper about it...

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