The scientific name for the house mouse is Mus domesticus taken from the Roman mus minimus (small mouse).  A Roman rat was mus maximus (big mouse).  The Welsh for mouse is llygod.  The Welsh for rat is llygod fawr (big mouse).

It’s thought that all mammals evolved from a rodent-like common ancestor many millions of years ago.

There are 5 species of mouse in the UK:  The wood or field mouse, the yellow-necked mouse, the common dormouse, the harvest mouse and the one most likely to be found in your house, the house mouse.

Occasionally, especially in winter you might get wood mice moving in with you.  If you can trap one and keep it reasonably still it’s quite easy to tell the difference between house and wood mice.  Wood mice look more appealing to most people, having very large eyes and a tail as long their head and body.  House mice have small eyes and a shorter, scaly tail

The dead giveaway is their problem with personal odour.  In short, house mice are smelly.  This is probably mainly because they have virtually no means of storing urine and so rather than releasing a bladderful of the stuff in one place they leave a continuous trail of it wherever they go.  This, together with their tendency to leave faeces everywhere means you probably don’t want them in your kitchen.  Some people believe that the domestication of cats began because ancient humans, plagued by mice and other rodents realised that carnivorous cats would provide a means of biological control.

Mice like to be near humans because we provide them with somewhere warm and dry to build a nest and with food. Most commonly they are vegetarian, eating nuts and grains and fruits.  One of the keys to their success though is that they can eat almost anything including the dead bodies of other mice and their own tails.  From personal experience I believe mouse nirvana is reached when they are offered a supply of chocolate.  When I lived at Dale Fort (among the silverfish) I was given a large Easter-egg by a group of students.  I put it on a shelf waiting for Easter.  I opened the box on Easter Sunday to find a hollow silver-paper structure entirely devoid of Easter-egg and some mouse droppings.  They had nibbled their way in through the back of the box, through the foil and eaten the lot from the inside of the wrapper.  There were a few red Smarties left inside but I felt they were best thrown away.  I have occasionally speculated as to whether they missed the red ones because they have no red-detecting eye pigments and they just didn’t see them.

Less well known is the fact that in Zambia and Malawi mice are eaten by humans to this day.  The Romans also kept dormice for food.  They were fattened up and when they went into hibernation were stored in a barrel for consumption over the winter.

Mice are not simply a nuisance.  They are the most commonly used mammal in laboratory experiments.  Their genome has been sequenced and there are many homologues for human genes.  (Bits of mouse DNA that resemble closely bits of human DNA).  This means they can be used as mammalian models for the study of human diseases.  They reproduce very quickly and are easy to look after.  This means you can follow several generations in rapid time.

Coming soon:  Nunzilla’s guide to common seaweeds.  Don’t miss it.

The History of Dale Fort Part 6

This blog continues the long (some might say interminable; but not me) history of Dale Fort.  Readers of previous articles may remember our hagiographic diversions as we entered and passed beyond the Roman period.   We looked at the legends of the saints local to Dale Fort (see blogs 12 and 13) and took our story up to the 8th and 9th Centuries.   We begin again from The Norman Period:

The Normans

The Domesday Book suggests that Rhys ap Tewdor, the ruler of South Wales had an arrangement with William the Conqueror

William  had visited St David’s in 1081  and allowed Rhys to continue in power.  Rhys died in 1093 and things began to change.  In 1115 Wilfred the last of a long line of Welsh bishops died and the  Normans made their move.  The monks of St Davids were summoned to London and the king ordered them to elect his man (Bernard) as their leader.  Bernard reorganized St David’s along Norman/English lines.  There were now fixed territorial boundaries, canons supported by cathedral properties and a system of clerical courts.  In 1123 Pope Calixtus II recognized the new arrangements formally and recognized David as a saint.  Bernard began rebuilding the cathedral and the new building was consecrated in 1131.  In 1171 King Henry II visited and conferred expensive gifts.  (To help make up for the murder of Thomas a Becket).

The Normans rapidly took over South Wales.  Visitors to Dale Fort will notice the castellated building west of Dale Village near to the church.  This is Dale Castle; it has mediaeval origins but little from that time remains.

In 1993, excavations 500m to the west at Great Castle Head revealed evidence of much later occupation of that site than had been thought.  High status goods were found, in particular a lump of orpiment.  This was an arsenic sulphide compound imported from either present day Italy or Kurdistan.  It was the only means of producing a clear yellow colour in expensive manuscripts.  If people were making manuscripts there, it’s possible that the Great Castle Head site was occupied right through the early mediaeval period up until the Norman invasion.  There is a major land-slip at the site, the occurrence of which might have precipitated a move to the current site of Dale Castle nearer to the village.   The De Vales occupied it from the 12th Century (Robert de Vale was granted market rights in 1293).  The current building is mostly early 18th Century, heavily restored and decorated in the early 20th Century.

The church, despite severe restoration in recent times is of the Norman style with a square castellated tower.  Nearby St. Ishmaels has a Norman motte and bailey castle on high ground above the present settlement.  That this structure was not reinforced and rebuilt in stone (as for example at Pembroke) indicates this was probably not a rebellious neighbourhood.

Henry Tudor

He was born at Pembroke Castle and had a tenuous claim to the English throne.  As a result, there was serious concern for his safety and he spent most of his early life in France.  On the 1st of August 1485 he sailed from Harfleur with 2000 French mercenaries and a few English exiles.  He had decided to stake his claim to the throne of England.

Some of Henry’s men knew the Pembrokeshire coast and Mill Bay, less than two miles from Dale Point was chosen as a landing site.  It is probably not too fanciful to suppose that the only Welsh king of England rode within spitting distance of where Dale Fort is now on his way to Bosworth Field.  Legend has it that he stopped for a drink at St. Ishmaels (from what was subsequently called “The King’s Well”).

Having landed on the evening of August 7th he and his men had reached Bosworth Field in Leicestershire and defeated Richard III by August 22nd.  A story survives concerning local landowner Rhys ap Thomas of Carew Castle.  Rhys had sworn allegiance to Richard III promising the king that only over my bellie would Henry Tudor get beyond his bit of Pembrokeshire.  Rhys did not want to be thought of as the sort of chap who would break his word to the king but as a Welshman he also supported Henry Tudor.  As a compromise measure, he waited for Henry and his men at Mullock Bridge on the road out of Dale.  As Henry reached the bridge Rhys lay down, bellie up, in the mud underneath the bridge, so Henry in crossing literally passed over his bellie.  Rhys then changed allegiance and joined Henry on the march to Bosworth.  He is one of several claimants to the ‘honour’ of having struck the final blow to Richard III.  Richard was the last English King to die in battle.

Henry Tudor and his men cross the mighty River Gann.  Eagle-eyed readers may just be able to spot Rhys ap Thomas lying under the bridge

  An account of the Battle of Bosworth Field states that the body of Richard was subjected to many indignities.  If Rhys was happy to both bludgeon the life out of the old king and have a ripping time desecrating his corpse, why did he bother slithering about in the slime beneath Mullock Bridge?  A similar story exists concerning the Shrewsbury Bailiff, Thomas Milton.  Henry crossed the River Severn at Shrewsbury where Milton had vowed that Henry would enter the town only over his dead body.  As Henry entered the town Milton feigned death and allowed the King’s horse to step over him.  These symbolic gestures indicate that there was a fair body of opinion that Henry was going to win

Rhys was well rewarded for his efforts.  He spent vast sums on home improvements at Carew Castle and in 1507 organized a Royal Tournament.  This remains the biggest party that Wales has ever seen.  Henry and the court turned up and lots of people ended up with immense hangovers.

There are no records of Henry VII doing anything about the defences of Milford Haven.  This is not surprising in that most of Henry VII’s troubles came from within his kingdom, there was little threat of invasion from without.  Having dealt with the remaining Yorkists, Henry died in 1509.  On the whole Britain was a richer, more peaceful place than it had been before.  All the action happened at the beginning of his reign.  In his irreverent history John O-Farrell sub-titles the section on Henry VII thus:

Cry havoc and let loose the dogs of accountancy!

Henry VIII

Henry VIII became involved in wars against the French and the Scots.  Wars are expensive and by 1535 Henry was bankrupt.  The dissolution of the monasteries solved that problem.

Henry was now estranged from Rome and eventually excommunicated.  His aggressive intentions in France had led to the signing of a peace treaty between France and another old enemy, Spain.  The result was that there was a real danger of invasion for the first time in many years.

Henry had used the cash generated from the dissolution of the monasteries to create a large aristocracy and landed gentry.  Thus there was now a new class of influential people who had a lot to lose.  Hence, Henry had to develop a policy for the defence of the nation.  He ordered a survey of all the coasts with a view to determining where invading forces might conveniently make their landings.  The report was completed by February 1539 and resulted in the building of new fortifications around many parts of the coast of Britain.  These strongholds included the first historically documented defensive structures around the coasts of Milford Haven.  They are known as Device Forts from the original document The Device by the King.  Two blockhouses were built on opposite sides of the entrance to Milford Haven.  The ruins of East Blockhouse can be seen to this day.

Don’t miss Blog Number 17……….Nunzilla approaches, breathing sparks

This Blog looks at what could well be the most dangerous animal in the world:

The Mosquito

Mosca is the 16^th Century Spanish for a fly (from the Latin Musca).  Mosquito is Spanish for little fly.

The problem with sharing our accommodation with these animals is that since the beginning of humanity they have been responsible for the deaths of millions and millions of us.  They continue to facilitate the deaths of millions of people every year.

Flies can only consume liquid food and both male and female mosquitoes feed on nectar.  Difficulties  arise when the female has to produce eggs.  She needs extra protein for this and it must be in liquid-form.  Her mouth-parts are designed for such occasions and can penetrate the skin of a nearby mammal and suck up high-protein blood from the vessels beneath.

The mammal being pierced tends not to notice because the fly injects a mild anaesthetic and an anti-coagulant prior to penetrating deeper.  You only notice you’ve donated some blood by the immune reaction which develops some time afterwards (itching and swelling).  This blood-sucking habit (haemophagy) causes the transmission and spread of many hideous diseases.

It is estimated that 70 million people become infected with something as a result of mosquito “bites” (actually “sucks”) every year.  One of the worst examples (for humans) is afforded by the Anopheles mosquito.  This carries the single celled parasite Plasmodium  which is responsible for malaria.  The parasite infests the liver and red blood cells and results at best in multiple bouts of debilitating fever and at worst death.  As with all diseases the old and weak are affected most and in 2007 more than 5 million children were estimated to have been killed by malaria.

Yellow fever is also transmitted by mosquitoes as is dengue fever and many other viral diseases.  All in all, it’s a good idea to avoid being pierced.  Having said that, in a temperate climate you are unlikely to get malaria.  Malaria was rife in the Netherlands and around boggy low-lying parts of the UK up until the 19^th Century.  The reasons for its decline are not entirely clear but vastly improved sanitation, drainage, sewage treatment and land reclamation are almost certainly important.

The larvae are water creatures and develop rapidly in still water (I found huge numbers in a bucket of rainwater earlier this year).  You can keep them away from you by using a suitable net to sleep under and/or  repellents.  Since they are not strong flyers, a punkawallah or electric fan can be enough to deter them.  The more violently inclined may employ a rolled up newspaper or similar weapon.  This approach is undoubtedly effective but you might have to stay up all night despatching them.

They definitely attack some people more than others,  seeking out their prey by detecting carbon dioxide in exhaled breath.  I am especially attractive to female mosquitoes and have on occasion been left drained, a mere husk of a man by their attentions.  My wife recumbent beside me is left alone with no bites and all her blood.

Look out for the next blog which will denounce the theory of chromatic adaptation (you wouldn’t want to miss that would you?).

Number 1

All about nematodes

http://dalefort.wordpress.com/2012/03/

Number 2

3 You Tube clips:

Starlings at Mabesgate

 Error Bars in Excel 2007

 Measuring Heights on Seashores

http://dalefort.wordpress.com/2012/04/02/dale-fort-blog-number-2/

Number 3

The History of Dale Fort part 1 (all about the rocks)

http://dalefort.wordpress.com/2012/04/03/dale-fort-blog-number-3/

Number 4

The History of Dale Fort part 2  (the construction  materials of Dale Fort).  Far more exciting than it sounds, you won’t want to miss it, go there NOW

http://dalefort.wordpress.com/2012/04/18/dale-fort-blog-number-4/

Number 5

Sargassum muticum in Britain (with a video on how it makes babies)

http://dalefort.wordpress.com/2012/04/25/dale-fort-blog-number-5/

Number 6

The History of Dale Fort part 3, The First Humans

http://dalefort.wordpress.com/2012/04/

Number 7

Silverfish and their ways

http://dalefort.wordpress.com/2012/05/10/dale-fort-blog-number-7/

Number 8

The fat-bellied book chewer

http://dalefort.wordpress.com/2012/05/

Number 9

Seaweed research at Dale Fort

http://dalefort.wordpress.com/2012/07/

Number 10

Wormhole research at Dale Fort

http://dalefort.wordpress.com/2012/08/07/dale-fort-blog-number-10/

Number 11

Limpets and their mysterious ways

http://dalefort.wordpress.com/2012/08/27/dale-fort-blog-number-11/

Number 12

Anne, Bridget, Cadoc and David

http://dalefort.wordpress.com/2012/12/07/dale-fort-blog-number-12/

Number 13

St David and his friend Elvis

http://dalefort.wordpress.com/2012/12/10/dale-fort-blog-number-13/

Number 14

Dancing bananas:  Just how many are there?

http://dalefort.wordpress.com/2013/01/16/dale-fort-blog-number-14/

Number 15

Six-legged female vampires

http://dalefort.wordpress.com/2013/01/23/dale-fort-blog-number-15/

Number 16

Cry Havoc!  And let loose the dogs of accountancy………The History of Dale Fort part 6

http://dalefort.wordpress.com/2013/04/22/dale-fort-blog-number-16/

Number 17

Wee timorous beasties

http://dalefort.wordpress.com/2013/04/30/dale-fort-blog-number-17/

The Lincoln Index

P = AN/r

P = Population    A = Total in the first sample (i.e. marked)  

N = Total in the second sample      r = Number recaptured

As I mentioned in the video, there are several assumptions that the Lincoln Index makes about the population and what you do to it.  Here they are:

1) The size of the population doesn’t change during the experiment. 

What might happen if it did?  If there were a lot of births (or immigration which is much the same in terms of population numbers) what would that do to the estimate?

Answer: You’ll be diluting the marked animals among more unmarked individuals so the estimate will go up

If there were a lot of deaths (or emigration which is much the same in terms of population numbers) what would that do to the estimate?

Answer: Assuming the marked animals die or emigrate at the same rate as the unmarked, the ratio of marked to unmarked will stay the same.  So your estimate will remain unchanged even though the population has actually gone down (an over-estimate).

The key is to work out what the assumptions are likely to do to the number of recaptures and hence the population estimate.

2) The mark should last for the duration of the experiment

If it doesn’t, what does that do to the number of recaptures?

Answer:  It reduces it leading to an over-estimate

What if wet paint or dye rubbed off on to unmarked animals?

3) The marking procedure should not harm the animals

If the animals were impeded by the procedure are they going to mix up OK?  If the marking material was toxic are they going to feel like socialising with their chums?  What about predators?  Will a predator find the marked animals more easily, or might the mark put a predator off?

4) The population has to have boundaries and inhabit an area which you can define

This might be OK if you’ve got a small pond with some goldfish but it’s likely to be problematical in lots of situations.  How could you define the boundaries of a woodlouse population for example?

5) The individuals in the population (including the marked ones) should mix at random

Apart from drunken people staggering out the pub what population mixes at random?  Motile creatures are going to move in response to stimulation e.g. towards food or shade or moisture.

I think this is one of the biggest problems with mark/recapture.

6) There should be no trap-happy or trap-shy individuals in the population

Often this technique is used in small mammal surveys.  To catch and mark a small mammal you use a baited trap with nesting material in it (a Longworth trap, look it up).  Mammals are good at learning and some quickly realise that getting trapped means free bed and breakfast, no predators and the enticing prospect of escaping into the huge beard of the bloke who opens the trap and there building a cosy nest.  Such individuals are called trap-happy because they actively seek out traps.  The opposite extreme is where individuals find the prospect of being trapped and meeting the ecologist with his vile smelly beard appalling.  These individuals actively avoid the traps and are known as trap-shy animals.  If you have individuals of either persuasion (or both) in the population then your estimate is unlikely to be correct.

Other Points

Sample size

It’s reckoned that you should sample until you get 10% of the marked animals back in the second sample.  So, if you marked 50 in the first sample you should keep sampling in the second sample until you get at least 5 recaptures.

Why do this if it’s got so many problems?

The Lincoln Index is loved by A-Level Exam setters because it allows them to give you a simple calculation to do and then ask you what might have gone wrong.  It’s worth knowing about because the basic idea is easy and it can score you marks.

The Blog will return when I get time to write another one.

Happy Christmas Blog Readers

As promised in Blog 12, here is the story of St David.

St David (Dewi Sant)

Born 495, died 589

He was known as “The Waterman” because he only drank water, his followers were sometimes called the Watermen.  Merlin (from Carmarthen (Caerfryddyn)) is supposed to have prophesised his birth.

David’s mum was St Non, a pagan princess who had been raped by Prince Sant.  She was disowned by her family and her father was going to kill the baby.  However as Non’s contractions began a great storm blew up and this prevented him from finding her.  The spot is on the cliffs and a healing spring spouted up.  There is a shrine to the Blessed Virgin and a nunnery and chapel there now.  The water is supposed to be good for eye problems, try it at your own risk.

David was baptised at Porth Clais by St Elvis  who had arrived opportunely from Ireland. Non and David left Wales for Brittany, she died there, he returned.  David was trained for the priesthood at various Christian Colleges.  He became a Bishop but maintained a simple lifestyle.  He dressed in animal skins (like Elvis) and carried a branch with a magical bell hanging from it.  He also owned a magic horse which was ridden across the Irish Sea.  David travelled all over Britain and to Brittany and the Holy Land.  Between 530 and 540 he and his mates St Ishmael, St Teilo and St Aiden established his monastic settlement at present day St Davids.  As soon as he arrived he lit a fire.  This meant he was declaring ownership of the site and was most annoying to the local pagan chief Boia.  His wife was even more annoyed and made him send a bunch of thugs to duff up David and his chums.  Before they got to the settlement they all became ill and couldn’t go on.  They returned home and found all their cows had died.  Boia decided that negotiations were in order, so he came to an arrangement with David and the cows were miraculously restored.  Boia’s wife was not happy so she decided that she would get rid of the Christians if her husband was too weak to do it.  David’s men were celibate and went down to the river everyday for water.  Mrs. Boia assembled all the attractive girls in the tribe and told them to go down to the river, remove their clothes and frolic about in a suggestive manner.  The aim was to excite the Christians to such a degree that they would break their vows and run away in shame.  It failed because David fasted against them and they all went mad. (A response echoed 14 centuries later by IRA hunger strikers).

She then tried a stronger method.  Taking her step-daughter down to the river she offered to do her hair.  When the girl’s head was in her lap she cut it off and threw it into the river as a sacrifice.  This didn’t work either so Boia’s wife went madder and ran away screaming foul curses.  Boia was now extremely miffed and set about destroying the settlement.  Sadly for him he was murdered by the Irish pirate Lysgi before he could begin.

An important event in David’s life was The Synod of Brefi in 545.  On his way to the meeting David restored to life an apparently dead boy.  The boy converted to Christianity and joined David on his journey.  The purpose of the synod was to put down the Pelagian Heresy (a doctrine which rejected original sin).  David began to speak but could not be heard by the large crowd.  The boy put his shroud down at the feet of David whereupon a huge mound grew up out of the ground under the saint.  He could now be seen and heard by all and with a white dove on his shoulder (representing the Holy Spirit) he spoke against the heresy and convinced them all.  This was when the distinctive Celtic version of Christianity began to tow the line and follow more conventional Roman lines.

David died aged 94 having survived an assassination attempt.  3 monks gave him some poisoned bread.  David broke it into 3 pieces and fed one to his dog which died, one to a raven, which died and then (possibly unwisely) ate the last one, he was unharmed.

One day the monks heard voices and David informed them that an angel had appeared and told him he would die on March 1st.  That morning the monastery was permeated by a sweet smell and the sounds of angelic singing.  Jesus appeared to David and escorted him up to heaven.

Look out for the next blog on a topic yet to be decided….

Until quite recently it was believed that the Roman Invasion left no visible remains in Pembrokeshire.  The ancient Roman walls at Carmarthen were thought to be the maximum westward extent of Roman construction.  That was before 1992 when the Royal Commission on the Ancient and Historic Monuments of Wales took some aerial photographs that revealed a possible Roman Road running east of Carmarthen towards Wiston and Haverfordwest. Near a quarry at Wiston were some marks in the ground that further Lidar analysis (Light Detection and Ranging) suggested might be a Roman Fort.  It has long been thought that the disappearance of the Roman Fleet from the Irish Sea when Britain was abandoned in 383 AD precipitated the invasion of West Wales by Irish tribes.  There are many early stone crosses and some stones inscribed with Ogham script that support this hypothesis.

The Post-Roman early mediaeval period is sometimes called  The Age of Saints.  It was a time when a distinctive form of Christianity developed in the west.  Sometimes known as Celtic Christianity it developed along more traditional Middle Eastern lines than the unified Roman form developed by St Paul.  The remains comprise inscribed stones, place-names, traditions and beliefs.  Dale Fort’s buildings are named after 4 local saints from this period (with the possible exception of St David (see below)).

Saint Ann

Saint Bride

Saint Cadoc

Saint David

Astute readers will have noticed that these names begin with A, B, C and D.  This is because the buildings used to be named A-Block, B-Block, C-Block and D-Block.  It became evident that this nomenclature gave a prison like impression to potential visitors.  This was something we did not wish to encourage, hence the renaming.  Using local saints with the same starting letter as the old names allowed ancient staff members (such as myself) to remember which one was which.

Here’s some interesting stuff about them:

Saint Ann

    Saint Ann (or Hannah in Hebrew) is known as the mother of Mary the mother of Jesus Christ.  The story of St. Ann comes from the apocryphal gospel of St. James (also called The Protoevangelium).

Joachim and Hannah lived in Nazareth.  They were wealthy and respectable but childless.  One feast-day Joachim grabbed a goat and made his way to the temple to make the expected sacrifice.  Upon arrival he found his entrance barred by Big Reubin the Bushily Bearded Bouncer.  Reubin was a keen proponent of manly virtues and began hurling abuse at Joachim.  The gist of this was that since Joachim was firing blanks, he wasn’t rugged enough to call himself a man and thus should not be allowed to sully the testosterone rich interior of the temple.

Joachim found all this most upsetting and in his shame decided to go for a long walk in the mountains.  While he was there he asked God to intervene on his behalf and supply him with some live ammunition.

Meanwhile Hannah noticed the absence of her husband and gossip being what it is, soon discovered the reason why.  Hannah was filled with grief and between wailing and gnashing her teeth asked God to make her fertile so she and Joachim could have a child.

God heard their prayers and sent an angel to speak to Hannah thus:

“Hannah, the Lord has looked upon thy tears; thou shalt conceive and give birth and the fruit of thy womb shall be blessed by all the world”.

The angel next visited Joachim and said:

“Get thee out of the desert lad, thou’s had some lead put in thy pencil”

Joachim returned home and did the business.  Hannah became pregnant and gave birth to a girl they called Miriam (westernized to Mary).  The child was presented in the temple and Reuben felt foolish.  Joachim died soon after, as happy as a man who is dying can be.

Ann then married a chap called Cleophas.  She had another child who she also called Mary.  This Mary became the mother of three apostles: James the Lesser, Simon, Judas and Joseph the Just.

The first Mary married a carpenter called Joseph, met the Angel Gabriel and you probably know the rest.

St. Ann was not a very popular saint in the Roman church but did attain cult status in France.  An interesting local link is provided by Magnus Maximus (Big Max) who invaded Roman Gaul (France) from South Wales (Pays de Gaul in French) in 383 AD.  The similarities of the Breton and Welsh languages hint at early links between Brittany and Wales as does the Northern side of the entrance to Milford Haven which is known of course as St Ann’s Head.  A chapel dedicated to Ann existed there up until the 19^th Century

Saint Bride

Saint Bride (or Saint Brigit, or San Ffred or San Ffraid and probably others) is a Christian saint whose predecessor was a Celtic Goddess called Brigantia (or Brighid and probably other names).

The early Christian church appropriated existing gods as their saints and took on traditional ceremonies, modified for their own purposes.  Modification of existing traditions is easier than wholesale abandonment and it’s no coincidence that the major Christian festivals coincide with the major festivals of the pre-Christian era.  These early saints often had powers attributed to them that were very similar to those of the gods and goddesses they replaced.  It is thus sometimes difficult to separate the earlier figures from the later.  This is especially so for Saint Bride.

Before the Christian period Bride was the tutelary (protector) goddess of the Brigantes, a large tribe that dominated Northern Britain.  She was a triple goddess, representative of the three aspects of femininity: Young girl (virgin), Mother (not virgin anymore), and Hag (wise old bag).  She was one of three sisters all named Bride (or Brigit) each of whom had a power.  One had healing powers, one had smith-craft and one had craft-ship.  The three became one and we are left with our triple goddess.

There are many, many references to Bride in British place names: St. Bride (Pembrokeshire), Brentford (Middlesex), Brechin (Scotland).  There are also many churches named for Bride; Saint Brides in London is known to have been built on the site of a pre-Christian temple to Brigantia.

When she was a girl she was out tending sheep in the rain when a message arrived that St. Brennain had come to see her.  She hurried back and hung her wet cloak on a sunbeam to dry.  St. Brennain was unable to repeat this feat and was miffed but he realised that there was something special about the girl.

In later life ride founded a nunnery at Kildare (Eire) and there a perpetual flame was kept in her honour.  It was said to burn without producing ash and (with a brief period of extinction in the 13^th Century) burned for getting on for a thousand years.  Henry VIII’s reformation put a stop to it since it was considered pagan, which indeed it was.  The flame was tended by 19 women, a different one for each day.  This is significant because the moon’s cycle is slightly less than 19 years (the Metonic cycle = the time taken for the moon’s phases to fall on the same days of the week).  The monthly menstrual cycle is also linked to the moon and the feminine principal that Bride represents.  She had the amazing ability to turn her bathwater into beer for the consumption of visitors.  (I bet they didn’t get hangover either).

In some miraculous way Bride is sometimes referred to as the mid-wife for Mary the mother of Jesus.  Given that she was also a contemporary of St. Patrick (who died in about 493 AD) she must have been very young at the time.  Like other female saints she is said to have plucked out her own eyes to make herself unattractive to men.  Placing such a high value on chastity is likely to be a Christian tradition.

Unlike other female saints, Bride put them back again, possibly an allusion to her pre-Christian origins.

Saint Cadoc

A major advantage of using scientific names for plants and animals is that there is only one name for each species.  Common names are not like this, there can be many, sometimes dozens.  This means using the latter can be confusing.  The old Celtic saints are a bit like this in that their names may have many variations.  As well as Cadoc this saint is also known as: Cadog, Caradoc, Carodog, Cadfael, Cadvael, Cathmael, Cattwg, Catwig, Docus.

He was born in 498 AD in South Wales, the son of a local chieften called Gwynllyw y Barf (Gwyn the beard) (“Gwynllyw” means “white leader”).  Gwnllyw was not known for his subtle approach to life.  When Cadoc was born he went on a maniacal drunken rampage with several of his chums.  In those days there were no traffic cones and road signs for wild drunken rampagers to purloin, so they stole a cow from Tathyw the monk.  Tathyw however was a monk of some spunk and confronted the hungover Gwynllyw next morning.  Gwynllyw was so impressed by his pluck that he had Tathyw baptise the baby into the Christian faith.  When he was 7 Cadoc was sent to Tathyw to be educated.  This was how Cadoc began his transition from potential hooligan to becoming one of the greatest of the Welsh saints.

Cadoc as a man founded the abbey at Llancarfan and traveled far and wide teaching and church founding.  There are church and place names that allude to him all over Dyfed, Cornwall and Brittany.  He also traveled to Jerusalem and Rome.

After a large bout of travelling Cadoc settled for a while at Llanspyddid, where he founded another abbey.  One year, the crops failed and everyone was on the brink of starvation.  While Cadoc was praying for divine intervention, he looked up and saw a suspiciously rotund mouse.  He captured the animal, tied a thin thread its leg and released it.  He then followed the thread which led to a forgotten underground grain store, packed with wheat and barley (and probably lot more mice).

Cadoc was distressed by his dad’s dissolute lifestyle and prayed for his conversion.  God sent a dream to Gwyllyw where he informed him he would find a valuable white ox on Stow hill.  He went there next day, found the ox, was very impressed and converted immediately.  He founded the church of St. Mary on the spot and became a saint himself (St. Gwnllyw’s is in Newport S. Wales).

St. Cadoc has a local connection in that he is said to have spent his retirement at St. Ishmaels.  He is also one of the three knights whose mission is to guard the holy grail.

The story of Saint David will appear in the next blog.  Learn why he was different to the earlier saints.  Just what was The Pelagian Heresy?  What actually transpired at Llandewi Brefi?  Was Matt Lucus involved? (No).

Come back to this blog and be the first on your block to read it.

This blog contains some interesting stuff about limpets.

It’s concerned mainly with the common limpet Patella vulgata. 

Classification:

PHYLUM: Mollusca     CLASS: Gastropoda   Subclass: Prosobranchia

Family: Patellidae    Genus: Patella  Species: vulgata

Limpets are among the commonest and well known of intertidal creatures. They are found all over Europe from The Mediterranean to Western Norway.

Feeding:

They are grazing animals, feeding on a variety of organisms like red green and brown algae (though they exhibit a preference for green) and lichens.   They scrape these up from the rocks using a rasp-like tongue called a radula.

The Radula is made of chitin and is impregnated with iron oxides to make it harder.  It wears as it scrapes and a new bit is pushed out.  The Radula can be 11 times longer than the body of the limpet (it coils up inside).  Limpets graze when the tide is in or at night or when it’s damp and cool or when it’s raining.   They have to walk over the top of their food to eat it so they only feed on seaweeds when the weeds are very small (usually not noticeable to us humans).  You can often see zig-zag scrape marks on the rocks where they have been feeding, if you have good hearing you can actually hear them scratching.

 The mature large seaweeds we see on rocky shores are therefore the ones that were lucky enough to escape being grazed by limpets.  An oil spill or similar thing that results in the death of lots of limpets can have a profound effect on the shore.  Usually you would see a “green flush” of green algae, doing very well without the attentions of limpet grazers.  Limpets have a big effect on what the shore looks like.

Predators:

As members of the plankton they presumably get eaten by other plankton and filter feeders.  They are not in the plankton for very long (see Reproduction and Dispersal) and once they settle are available to both seashore predators when the tide is high and terrestrial predators when the tide is low.  I suspect they are easy prey for things like shore crabs when very small and there are records of dogwhelks attacking them too.  Settled baby limpets are probably eaten by fish like the common blenny as well.  Once they get bigger with a thicker shell, they are less vulnerable to the creatures just mentioned.  They are however eaten by gulls and oyster catchers.  When I had the privilege of living in a small room overlooking the shore at Dale Fort I observed oyster catchers sliding their bill under the edge of the victim’s shell, turning their head and flipping the limpet over.  They would then slide their bill under the soft parts inside, detach them from the shell and swallow.  Herring gulls had a less subtle approach.  They would club the shell with their bill until it broke and then eat the contents.  Some birds carry the limpet to solid ground before eating, I found limpet remains on the parapet at Dale Fort only yesterday, left there (presumably) by a bird.

Behaviour:

Limpets can move considerable distances on their grazing missions 1 to 2 metres in a few hours is not uncommon.  Many limpets walk off grazing and then return home to the spot on the rock they started from.  This behaviour is called homing.  It is not known how they do this.  Some say they leave a slime trail which they follow back (how does it persist under water?) Some say they have a knowledge of the micro-topography of their bit of rock stored somehow in their simple molluscy brains (more neural swellings really), some say they use satellite navigation.  Whatever it is, a lot of them do it.  Some do not, nobody knows why; but you can say that if it homes it can be pretty sure of finding an unoccupied space when it has finished grazing.  Animals also scrape their own bit and grow to fit it exactly and the bare bit of rock is known as their “home scar”.  If you fit your bit of rock exactly you can probably hold on tighter and lose water less readily when the tide is out.  You can tell which way around the animal is without pulling it off the rock (you’ll probably kill it if you do this) because the head is directly underneath the apex (pointy top) of the shell.  Interesting investigations can be done on the orientation of limpets on seashores.  For instance, do they all face the same way?  Do they face into or away from the waves?  Is there a difference in orientation between shores of different exposure?  Is there a difference in orientation between different shore heights?  And so on and so on.

Limpets live from the upper part of the sub-littoral zone up to the upper shore.  They are well protected against wave action possessing a thick conical shell and they can hold on as tightly as limpet.  They adhere more tightly than they would by air pressure alone.  There is a chemical bonding effect as well, produced by a

reversible reaction that converts the mucous on their foot from a lubricant into a sort of natural super-glue.  This is achieved very rapidly by enzymes that join chains of muco-polysaccharides together.

Respiration:

They also have a cunning ruse that allows them to respire on the upper parts of shores when the tide is low.  The mantle cavity (between the body and the shell) houses the gills (ctenidia).   When the animal is emersed the gills do not collapse but remain supported by water trapped in the mantle cavity, thereby providing a large surface area for gas exchange.  The animal can loosen off its grip on the rock and raise its shell just enough to allow gases to diffuse in and out but not so much as to let the water escape.

Shell shape:

Limpet’s shells vary in shape from shore to shore and from part of shore to different part of shore.  A common observation (at least in text books) is that limpets of exposed shores are pointier than limpets of sheltered shores.  The explanation given for this (by J.H. Orton in the Journal of the Marine Biological Association of the UK in 1929) is that in exposed conditions the limpets spend more of their time with their foot muscle contracted.  The mantle (which secretes the shell) surrounds the foot and is  therefore pulled downwards and inwards a lot.  The animal therefore grows up tall and thin instead of short and squat.

Some biologists scoff at this and one of the most knowledgeable limpet-men of all (Bill Ballantine) reckons limpets are simply fatter and grow faster on sheltered shores because they have more food available and longer feeding time because of the generally more favourable abiotic environment.  Limpets do very well on exposed shores and usually there are more of them per unit area than on sheltered shores, so maybe intraspecific competition could play a part here as well?  Also there are more barnacles on exposed shores, so maybe there is less room to grow outwards (interspecific competition).

Reproduction and dispersal:

Limpets reproduce in autumn (in West Wales).  Like humans, bouncing up and down gets them sexually excited.  (In limpets it’s the stormy Autumnal waves that do it not other limpets).  Unlike many humans, lower temperatures also jazz them up.  The males eject cream coloured sperm and the females eject green eggs into the water.  Fertilization is external.  Fertilized eggs turn into trocophore larvae which live in the plankton for a few days.  When the larvae are about 0.2mm long they settle out on the shore and grow into limpets.  When they settle they have no sex (neuter), after a while they all turn into chaps and then after about two years about 40% turn into girls.  A typical population would be about 60% males, 20% females and 20% either immature or spent (knackered).  This is called protandric hermaphrodity and is quite common in the zany, crazy world of the invertebrates.  P. vulgata can live for a long time, older individuals might 15 to 20 years of age.

There are 3 species in UK waters: Patella vulgata  the common limpet (which has a greyish coloured foot)(see above), Patella  ulyssiponensis (formally P. aspera) (which has a yellowish coloured foot) and Patella depressa  (which has a black foot).  If you look on the middle shore and avoid rockpools they’ll mostly be P. vulgata
 

Watch out for the next blog where we may return to historical matters

Imagine a lump of matter with a mass so huge that its gravitational pull distorts the very fabric of space-time.  If you could find this warp in space (or wormhole), you might use it to defy relativity and visit unfeasibly  distant parts of the cosmos

   Adventurous readers may be disappointed to find The Dale Fort Wormhole Project slightly more prosaic.  The wormholes we investigated were not massive warps in space, nor were they the burrows excavated by worms themselves.  We were interested in the holes dug in muddy shores by people seeking bait for fishing.

People have been concerned about the impact of bait-digging on the soft-sediment shores of Milford Haven for at least 40 years.  The Countryside Council for Wales decided that an investigation might be appropriate and they employed Dale Fort Field Centre to carry it out.

  The aims of the study were to find out:

Which species were being collected ?

Where they were being collected from ?

What was the intensity of collection?

Did collecting vary seasonally?

Who was doing the collecting ?

How they were doing it ?

How abundant were the bait species ?

Where did the local bait shops obtain their stocks ?

What Species are Collected and from Where?

   Ragworms and lugworms are the two main species dug for in Milford Haven.  Ragworms are by far the most popular.

Easily the most important site for ragworms is The Gann followed in a distant second place by Angle Bay.  There is evidence of small scale digging at Sandy Haven, Gelliswick, Pembroke Dock and Pennar and a miniscule amount at Lawrenny and Llangwm.

Lugworms are harvested on a much smaller scale than ragworms and at fewer sites.  The main lugworm digging site was at Angle Bay, followed by Sandy Haven.  A few holes were found at The Gann, Gelliswick and Pennar.  Anecdotal information from bait-diggers suggested that sites like Saundersfoot and Pembrey were better for lugworms and more frequently dug for this species.  The only site where there was evidence of collection of razor clams was on the Dale village side of The Gann Flats.  Crabs were collected only from Sandy Haven and Dale.

How Intense is the Collecting and is it Seasonal?

We used a Garmin GPS (Global Positioning System) to map precisely the locations of bait-holes.  At the same time, holes were aged on a scale of 1 to 4, based on the nature of the sediment and the structure of the hole.  This work concentrated on the main sites: The Gann and Angle Bay.  We mapped and aged a total of 35,536 holes.  26,615 of these holes were in The Gann.

There were so many holes in The Gann that we divided the area into 50x50m grid squares and mapped the density of holes (as in the diagram above).  A typical grid square towards the central, most intensively dug area might easily contain over 500 holes.

We used the hole-age data to determine the proportion of holes of different ages to shed some light on the seasonal intensity of digging.  This data seemed to indicate intensive digging towards the end of the winter period, followed by a reduction in digging intensity until autumn.

Who is Doing the Collecting and How do They Do It?

Dale and beaches on the north side of the Haven are mainly visited by diggers from Milford.  We know of only one fulltime professional digger and he says he digs up to 2000 worms a day from The Gann.  Angle is visited by people from the Pembroke/Tenby area.  The less productive sites such as Gelliswick and Pembroke dock/ Pennar are only visited by people who live locally.  The summer period finds occasional holidaying anglers digging on the flats.  For the most part holiday makers probably purchase bait from shops rather than dig it for themselves.  The survey team met only two holidaying anglers over the whole period of field work.

Ragworms and lugworms are usually dug with a fork.  Peeler crabs are collected by turning over stones and boulders.  Razor clams are collected by skilled and fast use of a fork which may be helped by encouraging the animals to the surface by sprinkling salt onto the burrow holes.

How Abundant are the Bait Species?

   The highest density of ragworms was found at Sandy Haven Pill. This site also possessed the worms of lowest average weight of all 9 sites investigated.  The second highest ragworm densities were found at The Gann.  The mean weight of ragworms at The Gann was much higher than at Sandy Haven.  The animals sold by bait farmers seem to weigh 5-6g each. This is similar to the mean weight at The Gann.  It would therefore seem reasonable to suggest that this is the size anglers most desire.  The high density and high mean weights of ragworms found at The Gann, together with ease of access account for its huge popularity among worm digging enthusiasts.

Where Do the Local Bait Shops Obtain Their Stocks?

   We surveyed all the bait shops in West Wales and discovered:

Each shop sells an estimated average of 1265 worms per week

50% of shops sell ½ farmed and ½ locally dug worms

The number of locally dug worms sold per week is 7274 or 48.5 Kg

(= 378248 per year or 2522Kg per year)

Conclusions

If The Gann was populated by fluffy pink seaweed-bunnies that bait collectors impaled on hooks to lure bunny-guzzling dolphins to their doom, there would be much public concern for both the bunnies and the dolphins.  It’s hard to elicit a similar degree of sympathy for worms.  But The Gann is a Site of Special Scientific Interest (SSSI).  It’s (still) an extremely diverse sediment shore.  This diversity depends hugely upon its variety of sediments, some fine, some coarse and some in between.  As well as worms, it’s of vital importance for wading and other birds; it’s home to many interesting seaweeds and molluscs; and it’s got over 26,000 large holes in it.  The effect of all this digging is to mix and homogenise the sediments.  This is bad news for species that need specific conditions (E.g. Coarse sediment).

Species that can cope with these changes can do really well.  One such adaptable species is the ragworm.  It can feed on almost anything in a number of different ways.  It can actively prey on other creatures, it can feed directly on the sediment, it can spin a mucous net and filter food from the water and it can tolerate a variety of physical conditions.  Studies carried out at The Gann in 1960 and 1992 indicate a decline in species richness, coupled with a massive increase in the abundance of ragworms.  You might say that the area has been transformed inadvertently into a giant ragworm farm.

Return here for Blog Number 11 which will probably be another episode in the history of Dale Fort

Ascophyllum nodosum (egg wrack) and to a lesser extent, Laminaria digitata (oarweed), L. hyperborea  (tangle) and Fucus serratus (serrated wrack) are marine algal species used in the commercial production of seaweed extracts used in agriculture.

These extracts are known to protect crops species against drought, viral infections and attack by  nematodes (see Blog Number 1).  Their use could have profound consequences for humans.  Imagine manipulating food crops so that they could withstand dry conditions. The drier parts of the world currently of no use for agriculture might become fertile farmland.

Betaines are proteins that have been shown to be important constituents of these extracts.  The precise mechanisms of how they work in drought protection are not known but it might be like this:

When plants are water stressed one of the problems is that their enzymes change shape.  Enzymes are very large protein molecules and for them to function it’s vital that they retain the correct shape.  They have to be capable of fitting into the corresponding shape of the molecule they are to help modify; rather like a key fitting into a lock.

Large protein molecules are so big that the retention of their gross structure requires them to be supported and this is where water is so useful.

Water molecules have a small negative charge at the oxygen end and a small positive charge at the hydrogen ends.

The oppositely charged ends of the molecules have a tendency to stick together. The process is known as hydrogen bonding and it is the reason why water is the only liquid which expands when it freezes.  As it cools the molecules slow down and the electrical attractions cause them to line up and  form the more open crystalline structure of ice.

In a cell they form a similar sort of matrix which is able to surround big protein molecules and support them.

One of the problems of desiccation is that these watery support structures are lost.  The enzymes change shape and do not recognise their substrates.  This is not great for the plant and ultimately leads to death.

Betaines are also proteins and it is believed that in times of drought stress they are able to wrap themselves around other proteins (like enzymes) and help preserve the correct shape.

There had been no study made on whether there are variations in the betaine contents of seaweeds based on either the place or date of collection.  So we did one.

  Samples of each of the four species were collected from widely separated areas at different times of the year.

In the case of A. nodosum, Steve also made monthly collections over 18 months from Cliff Cottages Beach near Dale.

The betaines detected in the various collections of the same species showed little variation, although in the case of A. nodosum, glycinebetaine was found as a minor constituent in some samples, but was not detected in others. Trigonelline was found in all the tested samples of the two Laminaria species; this is, to our knowledge, the first record of this betaine in marine algae. With the exception of trigonelline in the Laminaria species, the betaine yields from the various samples of L. digitata, L. hyperborea and F. serratus showed little variation, regardless of either the place or date of collection. The trigonelline contents of the Laminaria species collected at one location (Finavarra, Ireland), in particular of L. hyperborea, appear to be substantially greater than those from the other places of collection.

In the case of A. nodosum, the betaine yields from samples collected at Dale were much higher than those from the other places of collection, which were very similar to each other.  We don’t know why Dale had higher yields.   There was no clear indication of seasonal variation in betaine yields from A. nodosum.

So, some obscure substances from some common seaweeds might have huge implications for food production.  It’s very difficult to tell where a piece of basic research might lead but there are enough examples of serendipitous discoveries^* to remind us that the pursuit of knowledge and understanding is never wasted effort.  It’s what makes our species  worthwhile.

^*Penicillin, microwaves ovens, Viagra, The Dead Sea Scrolls, LSD, America; you may not agree that all of these are  serendipitous but it’s mainly a matter of opinion anyway.

Anyone who wants to read the original paper can find it here:

Betaine Yields from Marine Algal Species Utilized in the Preparation of Seaweed Extracts Used in Agriculture

Gerald Blunden, Peter F. Morse, Imre Mathe, Judit Hohmann, Alan T. Critchley and

Stephen Morrell

Natural Product Communications

2010 Vol 5 No. 4  581  -  585

Look out for the next exciting blog.  Even I don’t know what it will be about because we live life close to the edge at Dale Fort.