Tag Archives: Leeds

A Winter’s Tale – aphid overwintering

Aphids that live in temperate or boreal regions have to be able to survive overwinter. Aphids, depending on species, are able to pass winter in two ways. If they are holocyclic i.e. possess an egg-laying stage, they usually overwinter as eggs. Aphid eggs are extremely cold-hardy; they have been reported to have super-cooling points of about -42oC (Somme ). If laid on a woody host, eggs are usually laid in the bud axils as in the case of the apple aphid, Aphis pomi, the black bean aphid Aphis fabae and the bird cherry aphid, Rhopaloishum padi.

aphid eggs

In some instances, such as the sycamore aphid, Drepanosiphum platanoidis, eggs are laid directly on the tree bark or in crevices in the bark or even in lichen growing on the bark.  See if you can spot the eggs in the picture below.


If however, the aphid in question lives on an herbaceous host, the eggs may be laid directly on the ground, on or amongst fallen leaves or at the base of grass tussock.

The other strategy adopted by those aphids that are anholocyclic, such as the green spruce aphid, Elatobium abietinum, is to pass the winter as an active stage, either as an adult or immature nymph. Those holocyclic aphids that have anholcyclic strains are also able to adopt this strategy. Despite their soft bodies and fragile appearance, aphids have quite low super-cooling points values such as -26oC having been reported (Griffiths & Wratten, 1979).

A potential advantage of using an active overwintering stage and not an egg, is that if they survive the winter, they are able to start reproducing sooner, particularly if they are a host –alternating aphid, where the aphids hatching from eggs, have to spend time developing and reproducing on the primary woody host before being able to migrate to the secondary hosts. This also applies, to a lesser extent, to those holoyclic aphids living on herbaceous plants, although the temporal advantage is not as great. One would assume that given the relative cold-hardiness attributes of aphid eggs and adults that in a country such as the UK where winter temperatures below -10oC are both infrequent and short lasting, winter survival of aphids would be extremely high if not guaranteed. This is not the case. For example, eggs mortality of the bird cherry aphids is typically around 70-80% as shown in my first ever publication (no fancy graphics packages in those days, just Letraset , Indian ink, stencils and tracing paper). Actually people had measured aphid egg mortality much earlier than this (Gillette, 1908) but I was the first person to monitor mortality throughout the winter and show that it occurred at a steady rate irrespective of the severity of the winter.

 Egg survival

It is actually a function of the length of the winter that determines how many eggs survive, the longer the winter the greater the mortality.

Egg mortality

This level of mortality is typical for all aphid species for which I have data (Leather, 1993). Some of this mortality can be attributed to predation, but most of it is intrinsic (Leather, 1981), possibly due to cryo-injury.

Similarly, those aphids that overwinter as adults or nymphs, despite their ability to super-cool to temperatures below -20oC, experience even greater levels of mortality as shown elegantly by Jon Knight and Jeff Bale in 1986 studying overwinter survival of the grain aphid Sitobion avenae near Leeds.

Knight & Bale

In fact one wonders how any aphids at all survive winter this way, but they certainly do if the winters are mild enough, as in the case of Myzus persicae and Sitobion avenae in southern England and E. abietinum throughout most of its range (Day et al., 2010). An interesting anomaly is Iceland where hot springs abound and the bird cherry aphid is able to survive anholocyclically on grasses growing around the springs whereas in other countries with similar winter temperatures it would only be able to survive as the egg stage.

Despite the importance of winter to aphid population dynamics we still know very little about their winter ecology, our knowledge being confined to a handful of economically important species. Despite the discomfort of field work in the winter this is an area which would be very rewarding to anyone in need of an interesting and good research project.  Finger-less mittens are, however, definitely recommended 😉

Useful references

Bale, J. S. (1996). Insect cold hardiness: a matter of life and death. European Journal of Entomology 93, 369-382. http://www.eje.cz/pdfs/eje/1996/03/09.pdf

Day, K. R., Ayres, M. P., Harrington, R. & Kidd, N. A. C. (2010). Interannual dynamics of aerial and arboreal spruce aphid populations. Population Ecology 52, 317-327. http://link.springer.com/article/10.1007/s10144-009-0190-0#page-1

Gillette, C. P. & Taylor, E. P. (1908). A few orchard plant lice. Colorado Agricultural Experimental Station Bulletin, 113, 1-47.

Griffths, E. &Wratten, S. D. (1979). Intra-and inter-specific differences in cereal aphid low temperature tolerance. Entomologia experimentalis et applicata 26, 161-167. http://onlinelibrary.wiley.com/doi/10.1111/j.1570-7458.1979.tb02912.x/abstract

Knight, J. D. & Bale, J. S. (1986). Cold hardiness and overwintering of the grain aphid Sitobion avenae. Ecological Entomology 11, 189-197.

Leather, S. R. (1980). Egg survival in the bird cherry-oat aphid, Rhopalosiphum padi. Entomologia experimentalis et applicata 27, 96-97. http://onlinelibrary.wiley.com/doi/10.1111/j.1570-7458.1980.tb02951.x/abstract

Leather, S. R. (1981). Factors affecting egg survival in the bird cherry-oat aphid, Rhopalosiphum padi. Ent omologia experimentalis et applicata 30, 197-199. http://onlinelibrary.wiley.com/doi/10.1111/j.1570-7458.1981.tb03097.x/abstract

Leather, S. R. (1993). Overwintering in six arable aphid pests: a review with particular relevance to pest management. Journal of Applied Entomology 116, 217-233. http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0418.1993.tb01192.x/abstract;jsessionid=9FC2ED8174E96317F192CF42A19092FE.f03t03?deniedAccessCustomisedMessage=&userIsAuthenticated=false

Strathdee, A. T., Howling, G. G. & Bale, J. S. (1995). Cold hardiness of overwintering aphid eggs. Journal of Insect Physiology 41, 653-657. http://www.sciencedirect.com/science/article/pii/002219109500029T


Filed under Aphidology, Aphids

Letters from School – Two school boys write home in the time of William IV

This week is a family history week (entomology next week I promise).  I am privileged to own copies of  a number of old letters from my great-great grandfather John Wignall Leather and other relatives.  This joint letter was written by George Henry Leather (1815-1897)  (my great-great-great Uncle, aged 13, and his 18-year-old brother, John Wignall Leather (1810-1887) to their parents George and Sarah (Wignall) Leather.  It was posted on 25 May 1828 in Durham where George and his older brother John were at school.  [Comments in square brackets are mine.]

Letter from home1

Letter from home2

[This is not that easy to read in the original so I have transcribed it below.]

Durham, May 24th 1828

 My dear Parents

At your desire, I now sit down to write a few lines to you, and am happy to say, John and myself are both well.  Our journey to Sunderland was not so pleasant as I expected; the pleasantest day I spent was when John and I went about 4 miles along the sands and returned on the tops of the cliffs; that was the only time I was out of the town except once we went on the ocean, one of Mrs Hustler’s ships, about half a mile from the Pier; it was going to Miramichi in America [there is a Miramichi River in Canada], and the  wind  being  very favourable we did not go so far out as we otherwise should have done.  I liked the motion of the ship when she rose upon the waves, but when she went down again, it felt rather queer: we came back in a small boat, with oars.  One night from the pier, we could see not less than 63 ships.  I have got as far as simple Interest, [I remember doing simple and compound interest at school – how many of you do?] and am reading Ovid and Cornelius Nepos, all of which I like very well.  I am 4th in my class this week, I have got my Register [I guess that this was a school report] for last half-term, which (with the one for this) I will bring with me next Midsummer.

I am very much obliged to you for the 5s which you sent me before Easter.  I look forward with very great pleasure to the prospect of seeing you all so soon: Midsummer is now fast approaching: I expect to leave Durham in about 6 weeks or thereabouts, and I hope we shall find you all well.

Give my best love to Billy and Sam [his two younger brothers: Canadian readers may be interested to know that Billy, William Beaumont Leather (1820-1907) later emigrated to Canada and was the great-grandfather of that famous Canadian, Sir Edwin Hartley Cameron Leather (1919-2005) former Governor of Bermuda] and also to my Sisters Sarah Anna and little Bell; and accept the same yourselves from,

My dear Parents,

Your dutiful and affectionate Son,

 G H Leather

Certainly a better effort than the letters I used to have to write on a Sunday afternoon when at boarding school.  I have no picture of George as a schoolboy only the one below of him as a well-established factory owner in Bradford.

George Henry Leather

The letter below from John Wignall Leather, was written on and across the same letter form written by George Henry Leather above.  John Wignall Leather was 18 and in his last term at school.  The letter is addressed to Geo. Leather Esq, Park Terrace, Leeds and is endorsed by John Wignall Leather at a later date as being “from GH and self to our parents”.

Letter from home3 Letter from home4

My Dear Parents,

I think I cannot do better than attempt to fill up the space which George Henry has left blank – this from the slackness of news: tis very much to be doubted how far I may succeed.  We had a whole holiday on Thursday last, the 15th inst. it being Ascension day; and I, accompanied with William from Gateshead the boy with whom we both stayed at Easter, set off on Wednesday evening after school, and spent the night and next day at his house in Gateshead.  On the Thursday we visited everything which he thought worth shewing to me in Newcastle.  There are very few public buildings but the library is really grand; the roof and cornice of this and the adjoining room (the Museum, which we visited) are in a style far surpassing anything of the kind I ever saw – and near the top of the former is constructed a kind of terrace, or gallery (with bookcases as below) which has also a very splendid appearance – it is a fancy cast iron railing with a three brick top or bar; the museum is not as good (in my opinion) as that of Leeds [being from Yorkshire nothing can be as good of course], and the birds or most of them seem to be very badly presented.  They are decaying away.  Oh! Mother you did not say whether you had got the owl back or not from curing and how it looked did you return my moth book [I was very pleased to see that despite becoming a very eminent civil engineer in later life, that he had not only zoological interests, but entomological ones.  I would dearly love to know exactly what moth book he had].

The Mayor and Corporation go on procession (on Ascension Day every year) down to Preston, and up the river again past Newcastle as far as Lemmington in barges, with a band of music; and are accompanied by numbers of small boats in this day’s excursion.  I had the pleasure of watching their departure from the mansion house and a very enlivening sight it was, tho I understand it much fallen off from what it was; but my time even if my paper would, does not allow me to enter into detail at present.

Friday the 19th was our bespeak, and as I had the whole management and conduct of the affair to myself this time I was kept very closely employed – but was very much gratified to find the pains taken was not in vain for I fetched them the best houses they have had for many years, the whole of the regular boxes were taken long before hand, and part of the pit, which was railed off for that purpose.  The receipts amounted to 42£ 16s – and it would have been fifty, but for the system they have of admitting schools at ½ prices.

I return many thanks to my Dear Mother for her short, but very kind letter – and hope to hear from her again very soon, when she is more at leisure to write longer.  Pray what do they call the six young ladies; how long are they going to stay; you say Maria wants to know whether I shall be at home as soon as she; without mentioning the time her vacation commences: I expect to be with you in six weeks, from yesterday, or so – but cannot say for certain yet.  I should have written to London last week but I was so very busy that I had not time; have looked daily for a letter from my Dear Father and cousin John [both also eminent civil engineers; his cousin John Towlerton Leather was the contractor for many ambitious projects including the Spithead sea-forts and was High Sheriff of Northumberland and had a house in Carlton House Terrace close by the Royal Society], I hope they will both write me ere long.  I learnt from the Newspaper that you would be at home in a day or two, and was happy to hear of your success – there will be no want of practice in the office for some time to come – which I will trust be of advantage to me – I have spoken my sentiments on this head to my Mother, and now repeat that I hope these will not be too much like warmness (if I may call it such) which it so unhappily represented in an elder branch of our family, but that arrangements may be made for me to be considered (in the office) in the same light as any other clerk, if any difference is made, may it only be an extra earnestness in seeing me do my duty, in instructing me – and directing my studies.  I think I can promise most firmly that no exertion shall be wanting on my part – as my ambition shall be not only to become an engineer, but (if possible) an eminent one [which indeed he did become].   I anticipate very great pleasure from the prospect of seeing my dear friends so soon – and of spending my future time in their society; under the guidance (and I trust) the approbation of those Dear Parents, whom it shall be my constant care to cherish and obey; In the hope of hearing from you both very soon – and with kindest love and every endearing remembrance of affection to all of you, I remain

My Dearest Parents

Your dutiful and affectionate son

J W Leather

P.S. Tell John to write.  Pray what business is it that calls you back to London.

(in haste).  JWL

Note that to save postage, as letters at the time were charged by the number of pages, John has written both ways across the page; quite hard to read but apparently common practice. Again I do not have a picture of John Wignall Leather as a school boy but do possess a picture of him with the plans of one of his engineering achievements (the Crown Point Bridge Leeds) on the desk, plus a photograph of him in distinguished middle-age.

 John Wignall Leather portrait  John Wignall Leatherr

Crown Point Bridge

The Crown Point Bridge, Leeds

I realise that I am incredibly lucky to actually have something as personal as a letter from my great-great grandfather.  So many people don’t even have photographs of  their more distant ancestors.  Personal letters like these are almost as good as a time machine; you can almost hear them speaking and almost certainly with a Yorkshire accent!


Filed under Roots

From Company Solicitor to Victorian Lunatic Asylum




One of the things that sticks in my mind from my youth is how relatives of my grandmother’s generation (those born in the 1870s and 1880s) who spoke of my great-great Uncle Alexander William Dow Leather, always in the following breath sighed and uttered the phrase “poor Pritchard”.  This of course made the subject of my great- great Uncle Alec (as he was apparently known) one of great interest to the budding family historian that I then was.

There was not a great deal known about my great-great uncle, at least in our branch of the family.  In fact I was to find out that there was surprisingly little known about him at all.  All we really knew was that he was the eldest son of my great-great grandfather John Wignall Leather (1810-1887).  My great-grandfather John Henry Leather was born in 1842 and was the youngest child of the family, preceded by Walter (1840-1869) and Florence Mary (1838-1886), so we knew that Alec must have been born in about 1836.

Some years later my first cousin once removed, Michael Leather of Knaresborough, supplied me with some additional information.  It transpired that Alec had been a solicitor and had led a somewhat riotous youth, drinking and womanising.  Once, whilst under the influence, he had fallen off his horse into a pond in Askham Richard.  Michael supplied the further information that he had been married twice, first to “poor Pritchard” whom he had deserted, leaving her and their two children in Herfeford where she had relatives.  These two children were Francis Holdsworth and Isabella Gertrude Leather.  Francis Holdsworth Leather became in time Michael’s godfather.  According to Michael, Alec had a second family – Percy, Mabel and Alan.   He also knew that Francis Holdsworth Leather had three children, one of them John Francis, died of influenza shortly after Michael was born in 1918.

The Yorkshire IGI informed me that Alexander William Dow Leather was christened in St Peter’s, Leeds on 24 May 1837.  His names puzzled me for some time, because they were so unfamilial; George, William, John and James were the normal first names at that time for our branch of the family.  I later found out that the family doctor was named Dow.  The 1860 Post Office Directory of the West Riding informed me that Alexander William Dow Leather was a solicitor at 4 Finsbury Park, Leeds.  The 1864 Woollen Districts Directory listed him at 1 Bond Street, Leeds, which was also the business address of his father John Wignall Leather.

I searched the St Catherine’s House Indexes assiduously and found that Alexander William Dow Leather had married Ellen Elizabeth Pritchard at Great Barfield Parish Church, Middlesex on 12 June 1860.  His wife was born in Hereford in 1839 and was described as the daughter of Thomas Pritchard, Gentleman of Park Gate, Essex.  At last I had found “poor Pritchard”, but where Alec had met her I still do not know.  Ellen died in Hereford in 1872, by which time Alec had disappeared from the Leeds Directories.  I continued searching through the indexes and found that his eldest son Francis Holdsworth was born in 1864 in Kensington, and his daughter Isabella in 1862 in Leeds.  She subsequnetly maried the Revd John Swire at Tupsley Parish Church, Hereford in 1882 and died in Wantage in 1891. The youngest child, Alexander Ernest, was born in 1866 and died the following year as a result of a scald, a surprisingly common form of death, even in middle-class families.

Some time later I obtained a copy of John Wignall Leather’s will (made in 1886) and this fuelled my interest in Alec to an even greater extent.  It told me that Alec’s second wife was called Jenny and that she and her children were living in Leeds.  Kelly’s Directory of Leeds 1888 confirmed this, indicating that she lived at 52 Samuel Street.  The Leeds Grammar School records show that her son Percy Alexander Leather attended Leeds Grammar School’s commercial division in the 1880s and that his tuition was paid for by his grandfather John Wignall Leather.  The two codicils to the will excited my interest greatly.  Here was John Wignall in his final illness (the last codicil is witnessed by his surgeon) and yet he took the time to alter his will to make sure that his eldest son Alec would not in any circumstances be allowed any of his money, particularly that left to his daughter-in-law Jenny.  What could Alexander have done or be doing, to have caused this much anxiety to his father?  I was hooked.  I had to find out more about Alec.

What about his second family?  I found his second marriage to Jane (Jenny) Potter, daughter of Edward Potter, Farmer, at the Parish Church of St Margaret West, Essex on 5 April 1873.  This confirmed that Alec was a bit of a gad-about and certainly not a full-time resident of Yorkshire.  At about this stage in my research, the Yorkshire Family Historian published an article I had written about my search for Yorkshire Leathers.  In this article I mentioned the infamous Alec and named his children as given to me by my cousin Michael.  I was pleasantly surprised to receive a letter from David Burnet of Guiseley who had had, my article drawn to his attention by an Australian cousin.  His great-grandfather had been the solicitor for my great great-great uncle George Henry Leather (1815-1897), and had been responsible for drawing up and administering the terms of his will.  As well as being George Henry’s solicitor he was also his brother-in-law.  David had in his possession a notebook that detailed all the beneficiaries of the will including their addresses up until 1907: a real treasure trove.  I found out that Alec’s youngest son was not called Alan but was in fact Cyril John Cadman Leather.  Armed with this fact I soon found his birth certificate.  He too was born in London, in Greenwich in 1879.  I also located the birth of certificates of more children of the marriage, Percy Alexander born in Camberwell in 1875, Mabel Caroline born in Peckham in 1877 and Violet Bertha born in Lewisham in 1888. Interestingly enough, Alex’s profession moves from being Company Solicitor of the family firm, George Leather & Sons Navigation, to solicitor’s clerk as his family grew and his dwellings moved down-market.   Then I came across Alec’s photograph in an old family album and was stunned to see that his nose was almost identical to mine – I had always thought that my nose was unique!  I was also struck by his resemblance to Del Boy (played by David Jason) in the BBC TV series Only Fools and Horses!

Alexander Wm Dow Leather

I scoured the St Catherine’s House Indexes of deaths and eventually located an entry for an Alexander William Leather in Barnet in 1890.  This seemed promising so I wrote to Somerset House to see if they had a copy of his will.  Wills are a great source of family history, if you are lucky enough to have a family who believed in writing them.  They give much more information about the individual and his family than the death certificate, and are only half the price.  As a solicitor I felt sure that Alec would have made a will, but to my surprise none was registered.  I sent off for the death certificate and found that Alec had died in Friern Barnet Lunatic Asylum, the causes of death being cystitis and disease of the kidneys.  This suggested that he had been an alcoholic and that the riotous living of his youth had caught up with him at last.  It also solved the problem of why his father had been so anxious to ensure that no money came his way.  Interestingly enough the death certificate, although listing him as a solicitor, had no known address for him.  His family had obviously cut all links with him or vice versa.  I wrote to the Greater London Record Office who hold the records for Colney Hatch (as Friern Barnet Lunatic Asylum is more popularly known), but unfortunately the casebooks for the period 1885-1890 are not yet available for public perusal.

Since that appeared to be as far as I could go with Alec I decided to search for his descendants.  I found that his eldest son Francis Holdsworth had married Ella Mary Smith of Weobley in Herefordshire in 1893.  They had three sons, John Francis (1894-1918), Geoffrey Clifford (1897-1901) and Godfrey Clifford (1902-1943).  Francis lived his whole life in Weobley apart from his service in the First World War.  He was a Lieutenant-Colonel in the RASC and was awarded the DSO.  Like his father he was a solicitor.  He died a year after his wife, in 1929.  His wife Ella is famous as the author of Folklore of Herefordshire http://en.wikipedia.org/wiki/Ella_Mary_Leather .  Their youngest son Geoffrey was also a solicitor and, although married, left no direct issue.  That line is thus extinct.  Isabella, the eldest daughter, married the Reverend John Swire in 1882.  They had three children, John (1884-1905), Mercy born 1886 and Nona born 1888.  Isabella died in 1891 and her husband in 1902.  I do not know what became of the daughters.

The second family has proved equally elusive.  I have found the marriages of Percy Alexander, Mabel Caroline, Cyril John Cadman and Violet Bertha.  Percy Alexander, at the time of his marriage to Emma Wilson in Leeds in 1896, is described as a salesman.  I know that in 1907 he was living in Red Deer, Alberta, Canada and later found that he died in Leslieville, Alberta in 1921.  I have also managed to contact his descendants who are now natives of Calgary.  Mabel Caroline married a widower, George Hampton in Knaresborough in 1898 and subsequently moved to Bath and married secondly, Augustus Davies, with whom she had four children.  She died in 1951.  Cyril John Cadman married in Rotherham in 1906 and died in 1931 in Rochford, with no offspring that I have been able to discover.  Violet Bertha married Herbert Colville in 1912 and died in 1957 leaving behind four children.  I know nothing further.  It is interesting to note that – of their marriages, neither Percy nor Mabel listed their father as deceased; presumably they were unaware of his death.

I am always hopeful that one day I will hear something more about this branch of the family and look forward to meeting any long-lost cousins who may turn up.

The great thing about family history is that you are never sure what you are going to find out or whereabouts in the world you have relatives.  This story is also an illustration of how the computerisation of paper records, which is all I had available when I began my research into Alex, has enabled me to add more detail to a story that was rather sparse almost twenty years ago when I first wrote about him in the Yorkshire Family Historian.

Leather, E.M.  (1912)  The Folklore of Herefordshire. http://www.amazon.co.uk/Folk-lore-Herefordshire-Collected-Printed-Sources/dp/0951858904/ref=la_B001KIXX3C_1_1?ie=UTF8&qid=1362929648&sr=1-1

Leather, S.R. (1990)  The Leathers in Yorkshire.  Yorkshire Family Historian 16 (3), 69-72

Leather, S.R. (1994)  Alexander William Dow Leather – black sheep of the family?  Yorkshire Family Historian  20 (4), 99-101


Filed under Roots