Sunday, 7 August 2016

An inordinate fondness for beetles

Ground beetles, in the garden pitfall trap during a seven day period (nb these are not to scale). There were other kinds of beetles in the trap - several species of Rove beetles for example these are just the Carabidae - Ground Beetles

The biologist J.B.S. Haldane is reputed to have been asked what could be concluded about the nature of god from a study of his creation -  his reply was that he has -  "An inordinate fondness for beetles."

Yes there are a lot of beetle species - nature has got beetles coming out of its ears. I had my own taste of this during my week long 'beetle drive' (fans of pointless stuff your parents used to do should check out the beetle drive). I put a pitfall trap in the garden - this being a glass jar placed into a hole in the ground. Beetles stumble into the trap and can't get out - simple, yet...erm...simple.

Almost every time I inspected the trap - I would see one or two ground beetles scurrying around and bumping into each other like tiny dogem cars. Black and shiny and all the same - until closer inspection revealed them to be mostly different species  - an inordinate fondness indeed.

There are are around 400,000 described species of beetles (and probably over a million in total), compared to 5,487 species of mammal, for example.

Why are there so many species?

A number of suggestions have been put forward:
  • Many beetles are plant feeders and plants provide a large number of ecological niches.
  • As they go through metamorphosis the different stages are able to exploit a range of habitats.
  • As they have a hard exoskeleton they are able to withstand extreme conditions. 
  • Some groups are innately good at speciation.
It has also been suggested that, as beetles are a relatively old group they have had longer to diversify than newer groups such as mammals. There are, however, other orders of a similar vintage which are nowhere near as diverse as beetles.

Recent studies of the fossil record indicate that the key factor is that beetles tend to be extinction proof.  So while they're good at producing new species they're even better at not going extinct - and clearly didn't pass on any tips to the dinosaurs.

Very few beetle families have ever gone extinct through their evolutionary history.

This begs further questions however - why are beetles resistant to extinction? Why are there so many insects per se, and indeed why are there so many species of anything?

In common with the reggae song by Johnny Nash this blog has 'more questions than answers'.
Ruptela maculata
Phyllobius glaucus
Athous haemorrhoidalis
Gastrophysa viridula

Black Sexton Beetle (Nicrophorus humator)

I quite often catch beetles in the moth trap and particularly the carrion eating sexton beetles - these have a fascinating mutual relationship with mites.

Mites of the genus Poecilochirus produce nymphs that crawl on the beetles and are transported to carrion. Once they arrive at the carrion the mites leave the beetle and proceed to feed on nearby fly eggs and immature larvae.

Mites help sexton beetles reduce the amount of competitors on carrion. With less competition the beetles' larvae have a better chance of maturing to adults."

It's win-win - the mites get free transport to sources of carrion - the beetle larvae get more food - hoorah!

Rosemary beetle (Chrysolina americana)

This beetle originates from southern Europe and has been found in Britain since the mid-1990s. It feeds on Rosemary and Lavenda and is now considered a pest

It's a bit of a beauty though!

Scarlet lily beetle (Lilioceris lilii)

Sometimes wildlife should come with a Parental Guidance warning!

Carabus nitens

My blog rule is that I only include wildlife from the patch - I've made an exception for this jewel of a beetle however found in the Bowland Area

Monday, 1 August 2016

Arthur C. Barnett's Mysterious World

There are mysteries around every corner. Anyone who tells you otherwise is a fool, a charlatan and/or Ezra Pound, without an ounce of poetry in their soul (I personally have 3.02 grams of poetry in my soul).

With this in mind, I embarked on a patch expedition to get to the heart, of the kernel, of the crux of these riddles, that have puzzled precisely no-one since the dawn of time. Camera grasped to my sweaty palm like a diseased sailor (nonsensical similes ahoy) I embarked on the Odyssey of a Lunchtime, armed only with my ‘weak lemon drink’…and some clothes…and shoes…and the aforementioned camera.

'Giants Back-Alley'

The first port of call was the conundrum, not known in these parts as ‘Giant's Back Alley’ (also ‘Large Person’s Lego’). These ‘building bricks’ were on a truly gargantuan scale, with a girth and breadth of...oh…easily…..that much.

Did celebrity giant, Fin Mctool use this site as a dry run for his later piece – the famous ‘Causeway’. Is it performance art? Is there a sense in which it works on several levels? Will it ever be finished?

A more prosaic explanation is that these are the stones that previously belonged to some kind of ‘building’ as it were – who can say...perhaps we’ll never know.

Mystery one – nailed it.

'The Fire Trees of Doom'

Buoyed by having definitely solved my first mystery I strode on with the confidence of a small anteater. I felt like some latterday ‘Richard Dawkins’, debunking sloppy thinking left, right and centre, one god delusion at a time - whilst getting really annoyed at religious fanatics and totally loving the evolution.

The next stop in my patch puzzle pilgrimage was the breathtaking ‘Fire Trees of Doom’.

Dude, this really is an all-time top eight mystery! It’s a cornucopia of confusement and a plethora of perplexitude. This is also ’something like a phenomenon’, which only happens at certain times of the day – nearly always in the morning – a fact that only deepens the mystery.

Certain fir trees appear to glow! Yes that's right you heard correctly - hold off the ear syringing for the moment. They are backlit with an eerie radiance, looking for all the world like a star (or a kind of ‘sun’, if you will) rising up in the background!

Is this a magical transmission from a sparkly netherworld of sprites and spirits? …or maybe celestial yobbos starting a fire for no reason??...or maybe these are glowworms on a truly industrial scale??

The answer…it’s definitely a magical transmission from a sparkly netherworld of sprites and spirits.

Mystery 2 - cracked! 

The Hatch (also of Doom)

Warming to my task, like an underwater salesman, I proceeded to the best, boldest and baddest of all possible enigmas - The Hatch!!! This is also of course 'of doom'.  Viewers of the long-running reality series, ‘Lost’ will be well aware of the significance of a hatch.

What we learnt from the well-researched and easy-to-follow documentary was that ALL hatches lead down to a chamber, in which sits a little Scotsman, preventing a global catastrophe by the simple expedient of pressing a button.

This hatch was, of course, no exception - I shouted down to the Jailed Jock –‘don’t bother pressing the button, it’s just a poorly explained psychological experiment – no disastrous consequences will ensue if you don’t do it”. He shouted back ‘oh, ok’.

Mystery 3 Solved!

And so I returned home, tired but happy in the knowledge that the final pieces in the jigsaw of time had fallen at my feet.

Bestriding the mysteries of the patch like a bloomin’, big colossus? – job done! where's me breaky.

Tuesday, 12 July 2016

'Minimal Wildlife' - quiz

When doing my blog post on camouflage I was messing about with a couple of moth designs in photoshop. I found that I could simplify the design a lot and it would still suggest the moth.

So I thought what's the minimum amount of information, that's needed to suggest a certain species? I've tried to use just geometric shapes. I've also tried to get as far away as possible from any kind of representation of the species and still have it be in some way recognisable.

I also quite like these as wildlife art - I'm going to hang them on my wall!

What do you think these are? They could be birds, mammals, insects, flowers or fungi.

I was asked by a local RSPB group to do these additional images - as fun / educational resources for Children

Friday, 1 July 2016

Moths are messing with your mind

Buff Arches - it's moth masterpiece, it also exhibits a very convincing optical illusion.

I think the Buff Arches is my favourite moth - it's a moth masterpiece! Even though you know you're looking at a flat wing, the optical illusion is so convincing that you can't help but see it as two surfaces.

I like the way that evolution has provided it with a drop shadow, to give the illusion of depth, of the kind you'd produce if you were using photoshop. To see how closely I could mimic the effect I produced the image on the right.

Why would coloration like this evolve? It seems clear that breaking up the outline is the 'objective' here. But what about the other markings? Why is it that colour? Why does it have the looped markings, why does it have the line along the wings' trailing edge? Is it possible to ever know?

It's sometimes contended that every single marking on a moth or butterfly's wing, every tiny line and dot, must have an adaptive benefit. This may seem hard to believe - surely some of it is purely random?..isn't it?

To attempt to mimic the illusion I added an  area of uniform colour to the wings then added a drop shadow. The illusion is enhanced by the contrasting white line around the shadow.
The illusion is even stronger from the side.

The Buff-tip a very striking example of mimicry in moths - not only does it closely resemble a twig, but a broken twig and a silver Birch, broken twig at that

Moths are messing with your mind...well actually birds' minds.

They've got a problem.  In order to avoid daytime predators most are active at night. They are less conspicuous during the day as they are inactive, however they still have to avoid detection – that’s the problem.

Birds - and it’s mostly birds – eat moths (by day).  Birds will find it more difficult to detect well concealed moths - these will have a better chance of producing offspring. Birds are, therefore, exerting a continual selection pressure on moths.

So predators and their prey are in a contstant ‘arms race’ with each other – as the moths improve ways of avoiding being detected so birds improve their moth detection skills.

Evolution has come up with a bewildering array of different solutions - a host of designs – some subtle in their sombre beauty, others mesmerisingly showy. These designs are aimed directly at influencing the brains of birds – or more often avoid influencing them.

Burnished Brass - one of several species I catch, which have patches of metallic colouration. Having contrasting light  absorbing areas and the light reflecting areas very effectively break up the moth's outline - disruptive colouration.

Predators have a ‘search image’ – a mental template of a prey item's form. When an object in the field of view matches this search image it triggers a series of ‘prey’ responses  - identification, capture, handling, ingestion.

So adaptions which allow the moth to avoid conforming to the search image will be selected for. By far the commonest means of achieving this is camouflage.

When we look at camouflaged animals it’s easy to forget that the patterns aren’t usually ‘for us’. The pattern on a zebra for example seems conspicuous – but we have colour vision, lions only see in black and white – hence the zebra’s monochrome stripes.

While I would have thought it impossible to find an adaptive reason for each and every one of these lines and dots, even if one exists, it is maybe possible to, at least, list some of the factors that may be at play. So, here goes...

The moth itself
Phylogeny - features 'handed down' by the species' evolution
Behaviour - 'lifestyle'
Morphology - size and shape
Cost - metabolic cost of producing a given feature
Background specificity - is camouflage targetting a specific or a range of backgrounds
Method of concealment - pigment, reflection, hairs
Day-time versus night-time factors

Seasonality - what part of the year is the adult's flight period - how long
Other strategies - fall back strategies such as startling patterns

Functions other than predator avoidance, e.g sexual selection, heat retention - there  may be trade-offs between these and the dictates of predator avoidance (and visa-versa)

Other moths
Frequency - if other moths of the same species are plentiful the predator's search image will be reinforced
Appearance - if there is little variation the search image will be reinforced
Competition - for 'camouflage space', spatially and ecologically
Other species - which similar ones are present - where moths (and other groups) are plentiful moth predators will be plentiful

Backgrounds - what backgrounds are available
Mimicable objects - which are available
Availability - of raw materials, pigments for example
Lighting conditions 
Seasonality - how does it change through the year
Homogeneity of background - may influence background matching versus disruption

The Predator
Behaviour - compare the foraging behaviour of the Treecreeper and Robin for example
Morphology - size, shape
'Gullibility' - how easily is it fooled
Cognition  for example how good is it at spotting a moth
Search image - how specific, how accurate

Background Matching The moth's pattern resembles a random sample of the background it rests on. The 'goal' is to reduce the contrast between the moth and the background. This kind of camouflage is background specific.  Marbled Beauty
Disruptive Colouration The moth's colouration obscures its outline. This kind of camouflage is effective against a variety of backgrounds (even when the pattern cotains colours that are pesent in the background1). Clouded border
The Clouded border's pattern allows it to diverge from a typical moth shape and therefore helps to avoid conforming to the predator's search image. Edge detection plays a big part in the visual processing responsible for shape recognition - hence the role of camouflage in disrupting it.
Most moths that have background matching patterns, also exhibit some disruptive markings, especially near the wing edges.1   Green Arches
Mimicry Here the object is not to avoid detection, but following detection, to be perceived as an irrelevant object - often a twig or leaf or distasteful object such as, in this case, a bird dropping. Bird droppings make a good 'target object' for micro moths to evolve a likeness to. They occur commonly, they are on a similar scale and they are distasteful. Plum tortrix
The Angle shades folds its wings in a way that enhances the similarity to a dead leaf, as well as having disruptive markings.

This list of factors is possibly just scratching the surface, but I think it's clear that there will be a whole web of interconnecting factors determining the moth's appearance. These factors will be in flux, some will be traded off against others.

Take one example of a factor -  the moth's 'lifestyle' - how it feeds, how it moves about, its larval foodplants - these will directly influence the moth's morphology - its size and shape. This will in turn influence which backgrounds it's possible to match, which objects it's possible to mimic (there won't be an unlimited range of backgrounds and objects available) this will, further, be determined by the the moth's habitat.

It's fascinating to speculate how there could be effects in the opposite direction - that's to say the kind of camouflage strategy the moth adopts could influence the moth's behaviour - a feedback loop.

The eye is often brought up as an example of something that seems too difficult for evolution to arrive at 'by chance'.  Or in the case of the Buff-tip, how do you get from a Buff-tip ancestor to something that not only mimics a broken twig but a silver birch broken twig?

The answer is - you don't get from one to the other in a 'great leap forward' but incrementally, bit by bit.  So you come to look more and more like the thing you're imitating.

"That wouldn't work as you'd have to have intermediates that only look a bit like a stick", is a possible objection.

In the same way that having some vision, with an intermediate form of eye, is better than having no vision at all, looking a bit like a stick is better than not looking at all like a stick. The benefits might only be marginal, but they're benefits all the same. When your competitors have no vision at all, or no form of camouflage you're in evolution's pole position.

In the land of the blind the one eyed man is king, and in the land of conspicuous moths, one that's a bit 'sticky' is also king.

You might start off by fooling predators only in poor light or a long way off. But, by small steps, you'd graduate from this to full blown, accurate mimicry.

The illustrations in my moth book are so lifelike they almost seem to jump off the page!
The Blood Vein, another camouflage solution that natural selection has come up with

Peppered moth
I'm very lucky to regularly catch Peppered moths in the trap, it's almost a 'poster child' (or should that be 'poster moth') for evolution.

It is the first recorded and experimented case of  natural selection and remains "one of the clearest and most easily understood examples of Darwinian evolution in action".

Moths often to show considerable variation within the same species, this variation means that natural selection has 'something to work with' Small pheonix
During the Victorian era trees were blackened due to pollution. The light coloured form of the moth became conspicuous, while the dark form became better camouflaged and so the dark form came to predominate in industrial areas.

The light form didn't turn into the dark form - the dark form, which was there already - gained a selective advantage and so produced more offspring.

Yet another camouflage solution to the predator avoiding problem - the Scorched wing - a moth I'd only seen in photographs and illustrations. In my job as a web designer I use graphics programmes a lot and the pattern on the wings immediately suggested a photoshop-style 'radial blur'. Well I saw my first Sorched wing last month and it didn't disappoint - a fabulous looking moth.

Other strategies -  the Poplar hawk moth looks a lot like a dead leaf when resting. If it fails to escape detection it has a fall back strategy - it attempts to startle a predator, giving an opportunity to escape. The moth in the short clip below certainly startled me! The red under wing markings (probably) serve no camouflaging purpose - they are a kind of 'break glass in case of emergency'.

Other moths make no attempt at camouflage, especially day flying ones, instead they adopt warning colours - advertising their distastefulness or imitating other dangerous insects.

The function of these markings is presumably to immitate eyes and startle a would-be predator. The Spectacle.
Not all moth markings serve a predator avoiding function. Some moths are sexually dimorphic so sexual selection may play a role Bee moth.

So is it possible to ascribe a function for every minute feature of a moth's wing? Probably not, that's certainly not to say that no such reason exists - it possibly does. However the web of factors, influences, effects, is probably much too complicated to be unravelled.

Still, I'm looking at moths with fresh eyes now. Things of great beauty - certainly - but also trying to get just a glimpse of a glimpse of the reason that things are the way they are.

Recent Patch Sightings 
St Georges Mushroom
Birds - Grey wagtails successfully bred, family party. Willow tits bred.
23/6 - 2 Juvenile Siskins on the feeders (I suspected them of breeding on the patch). Tree sparrow on the garden feeder.
Fallow deer - first for the patch, Hedgehog
Dragonflies - Emperor Dragonfly & Several Black tailed skimmers
Moths - new for the garden species include White spotted pug, Small Yellow wave, Anania perculidalis, Green arches
Plants - Bee Orchids in flower, Golden melilot in profusion
Fungi - a flush of summer fungi after the wet second half of June, including St Georges Mushroom - new for the patch

1 H. Martin Schaefer, Nina Stobbe  2006, Disruptive coloration provides camouflage independent of background matching

NB I've only discussed adult moths in this post, most of this applies to all stages of a moth's life cycle.

Thanks to Andrew Caddy for this thoughts on the Burnished Brass

Thursday, 9 June 2016

The Symmetrical Patch

For the past couple of weeks, on my patch walks, I’ve been symmetry spotting.

To see if something is symmetrical:
  1. Pick it up
  2. Transform it (rotate, scale, reflect, flip etc)
  3. Put it down again
  4. If it looks the same as before the transformation it’s symmetrical
Popular items for this kind of transformation are spoons, static caravans and grandparents.

The most obvious kind of symmetry is reflectional (or bilateral).  An object has reflectional symmetry if there is a line going through it which divides it into two pieces which are mirror images of each other. There are several other kinds, however, and it's flippin' well everywhere.

Symmetry in the Physical world

Bubbles have rotational symmetry as do a the sun, moon, earth and the Death Star. 

In a bubble, surface tension pulls molecules of water into the tightest possible groupings.  sphere is the tightest possible grouping that any collection of particles can achieve.

Symmetry Animals
99% of members of the animal kingdom have two identical halves - they are bilaterally symmetrical. This is a consequence of two things - locomotion and gravity.  Animals mostly move around in their environment, one end inevitably encounters stimuli before the other end. It makes sense, therefore, to have a head  - with all the sense organs. This head will also encounter food first, so it makes sense to put the mouth there.

Elephant hawk moth
locomotion so front / back; gravity so top / bottom; identical environment on either side so reflectional symmetry

Much about the way a body is organized - with a nervous and digestive system - follows on from this. Internal organs, on the other hand, are often  laid out asymmetrically - the space inside the body is best utilised, by packing them to one side or the other.

The environment will tend to be the same on both left and right so sense organs can be the same on either side.

Having two identical halves is genetically economical - you only need DNA that codes for one half, then 'flip this stuff'. Furthermore you'll be more streamlined and it's easier for the brain to propriocept  - to know where the body is in space.

When considering your next body plan - this is the one I heartily recommend to clients.

Living on a planet where gravity is constantly pulling you downwards, you are probably going to want some legs to hold you up (if on land). If fact, the whole top / bottom carry-on is a result of gravity.

To see how the left / right symmetry differs from the top / bottom asymmetry you just have think about easy it would be for a mirror image of yourself to function. Now compare that to an upside down copy of yourself.  Furthermore, an upside down copy of yourself would look quite ridiculous.
Sense organs placed symmetrically
on this jumping spider - Salticus scencius

White legged snake millipede
segmented animals display 
strip pattern symmetry
repetitions of a pattern in one direction

Symmetry in plants

Symmetries in an Oak Tree - Oaks don't locomote so there is no underlying head / tail, bilateral symmetry at play.  They do exhibit symmetry though - sometimes it's less obvious. 
  • Leaf - approximate reflectional symmetry
  • Truck / whole tree / catkins - rotational symmetry about a vertical axis 
  • Branches - a branch is approximately a copy of the whole tree - Oaks are 'self similar' therefore they display fractal symmetry. (my blog post on fractals)
  • The crown / root system is (very approximately) reflectionally symmetrical
Plant growth is very modular in nature - it is governed by simple rules. The genes often code for perfectly symmetrical structures, however very little in nature is perfectly symmetrical - to paraphrase John Lennon 'life gets in the way'. There are always asymmetries - environmental factors such as weather, light & wind direction, disease, a squirrel building a drey, come into play.

Although most trees don't locomote the exception are The Ents of Lord of the Rings fame...they can walk...obviously. Who can forget that line of Frodo Baggins's - "cor blimey Charlie! look at that walking tree exhibiting reflectional symmetry!!"

Symmetries in flowers on the patch - flowers demonstrate that there can be degrees of symmetry - the number of ways you can transform them symmetrically. There are an infinite number of ways a circle can be rotated, about its center, for it to look the same. A Bee Orchid flower has just one line of reflectional symmetry. A Yellow Flag iris has 3 lines of reflectional symmetry and three of rotational symmetry.

Flowers often act as targets for insects - the petals radiate from a central points. They are like arrows pointing  to the 'goodies' - the nectar at the centre. Experiments have shown that bees prefer flowers which are symmetrical.

Orchids, Peas, Himalayan Balsam etc, have pollination strategies which result in the bilateral symmetry of insect bodies being passed on to the flower design.

Seeing Symmetry

Humans are naturally attracted to symmetry. A symmetrical face is often considered beautiful. We are drawn to even proportions, as are many of our fellow creatures. Animals often choose mates, partly, on the basis of symmetry. Female Swallows prefer males with tail streamers of equal length.

It is believed that the absence of asymmetry is an indicator of genetic fitness. Only a healthy organism can resist environmental stresses throughout its development to maintain a symmetrical plan. Healthy animals make the best mates, with the best chance of producing offspring.

Our brains are constantly on the look out for symmetry. If we are in a jungle, and we see something symmetrical, we know it is likely to represent an island of order in the sea of chaos. This, in turn, probably represents something we can eat, or is going to eat us. Symmetry is important, therefore, in that it carries a message. Symmetry has been described as nature's language - a language our brains are adapted to understand.

It's been speculated that the whole realm of aesthetics, art, beauty, and even truth, follows on from the way our brains perceive our environment. Symmetry makes visual processing easier for our brains. - so we respond with a sensation of pleasure.

Recent Patch Sightings
Diamondback moth - massive numbers have migrated to the uk over the last few weeks, I've been getting 20 to 30 a night in the moth trap
2/6 - Raven - 2 south
3/6 - Tawny owlets
4/6 - Northern Marsh Orchid in flower
Last week - good mothing in the warmer weather - Poplar & Elephant hawk, Ruby tiger, Pale tussock, White-spotted pug, Grey pine carpet, Gold Spot, Beautiful Golden Y etc
6/6 - Ruby-tailed wasp

Beautiful Golden Y
Tawny owlet
Ruby-tailed wasp

1 There other kinds of symmetry which I haven't touched on - language, music, time, physical laws