Hugh Loxdale

Hugh Loxdale
Hugh Loxdale at Utting, Bavaria in September 2016

Hugh David Loxdale D.Phil, FLS, Hon. FRES, FRSB, MBE is an entomologist, professor of ecology at the Institute of Ecology, University of Jena from 2008 to 2010, president of the Royal Entomological Society from 2004 to 2006, and the society's honorary treasurer from 2011 to 2016. Loxdale works on the population biology, ecology, and genetics of insects. Currently he is an honorary visiting professor at the School of Biosciences, Cardiff University. Besides his scientific studies, he is also a poet, having written many volumes of poetry since 1988, as well as a genealogist. He is also keen on classical music, especially 20th-century, and has written (with Adalbert Balog) an article concerning the entomological interests and endeavours of the great Hungarian musician, musicologist and composer Béla Bartók (1881–1945).[1]

In entomology, Loxdale has worked principally on the population genetics of small insects, especially aphids and their parasitic wasps (parasitoids) using molecular markers, initially protein markers (allozymes), more recently DNA markers such as microsatellites. To date, he has written over 130 papers published in a range of international scientific journals, including 33 overviews on a range of topics, notably on molecular markers, aphid migration, clonality, rapid genetic evolution in insects, and specialism versus generalism, with special reference to insects.[2] He has co-organized four international conferences under the aegis of several learned societies ─ electrophoretic studies on agricultural pests (1988; Systematics Association); intraclonal genetic variation (2002; RES-LS, the Royal Entomological Society and Linnean Society of London); lost sex in parthenogenetic organisms (2005; LS); and evolution in insects below the species level (2009; RES-LS). For the last conference, which celebrated the 150th anniversary of the publication of Darwin's Origin of Species in 1859, he wrote an introductory review about the enormous contributions of both Charles Robert Darwin (1809–1882) and Alfred Russel Wallace (1823–1913) to our understanding of evolution and zoogeography.[3] Besides his association with the RES over many years (1985 to present), Loxdale has served on the Council of the Systematics Association (1986–1989) and was secretary (1999–2002) and later chairman (2003–2006) of the Beds, Essex and Herts Branch of the Institute of Biology (now the Royal Society of Biology), of which he is a fellow.

Early life

Loxdale was born in Horley, Surrey, England, on 9 September 1950, the second eldest child of three sons and two daughters born to Phyllis Marjorie Loxdale, née Duke (1921–1970) and John David (‘Jack’) Loxdale (1916–1993). He was named Hugh by his mother in honour of her late brother, Major Hugh Victor Duke (1918–1944), MC & Bar of the Devonshire Regiment, killed on D-Day, 6 June 1944.[4] In the early 1950s, his parents moved to Hemel Hempstead in Hertfordshire where he grew up. Outside school, he spent much time roaming the local countryside observing and studying insects. As he remarked “I was a poor student at school, certainly initially and was told off for looking out of the window observing the clouds instead of looking at the blackboard and paying attention to what the teacher had to say!”

Jack Loxdale in 1940
Phyllis M. Duke in WAAF uniform, c. 1944

His mother was born at Lezayre on the Isle of Man and later served from 1941 to 1946 in the Women’s Auxiliary Air Force (WAAFs) as a Morse operator in a Royal Australian Air Force Sunderland Squadron stationed at Mount Batten Base, Plymouth.[5] His father, a manufacturing optician born in Hampstead, London, joined the Royal Naval Volunteer Reserve (RNVR) at the outbreak of the Second World War in 1939, later serving in the Merchant Service and finally in Royal Navy motor torpedo boats (MTBs) patrolling the Channel at the end of the war. He was sunk twice in the Battle of the Atlantic, once off the Azores by an Italian submarine in 1940 whilst serving on the British Fame, an oil tanker[6], later off St. Anne’s Head in Pembrokeshire in March 1941 by a lone Heinkel He 111 bomber whist serving on the cable ship, CS Faraday [7], and was also attacked by two Focke-Wulf Fw 190 fighters whilst his ship was loading ammunition at Dartmouth for the D-Day landings.[8] He was awarded the Atlantic Star for his services during the Battle of the Atlantic. Loxdale’s parents met at a dance in Plymouth at the end of the war and were married on 3 September 1946 in St. Andrew’s Parish Church in the city, which, as his father told him, still had a large section of the roof missing following the Blitz of March 1941.

Ancestry

Loxdale’s paternal grandfather, Matthew Henry Loxdale (1882–1918), an electrical engineer working for the London tramways system, and who married Ruth Adelaide Brambleby (1886–1973) in 1908, died age 36 in the great Spanish flu epidemic of 1918, leaving a wife and four young children, three boys and one girl, Jack being the youngest. The Loxdales had latterly come from London, although Loxdale’s great great grandfather, Henry Loxdale (1803–1883) of Chelsea, who made his fortune as an Admiralty chart printer and was editor of a local newspaper, was born in Shrewsbury and married Eliza Hough (1816–1851) in London in 1838.[9] He was the third of four sons born to Richard Loxdale (1769–1848), a solicitor of Whitchurch, Shropshire and later Maughold in the Isle of Man, and his first wife, Jane Jeffreys (1774–1823). Richard was the youngest son of three sons and four daughters born to Thomas Loxdale (1720–1793), Mayor of Shrewsbury in 1774, and his wife Hanna Skitt (1728/29-1805).[10][11] By a very strange coincidence, Loxdale’s mother Phyllis Duke, who became a Loxdale on marriage to Jack Loxdale in 1946, was born in the same village (Lezayre) on the Isle of Man that Richard Loxdale had once lived in during his sojourn on the island between the years c.1817 to his death in 1848.[12]

The Loxdales, who originated from Forton in Staffordshire, were twice Mayors of Stafford in the mid-18th century before moving to Shrewsbury where they held the mayoralty six times during the late 18th and 19th centuries.[13][14][15][16][17] John Loxdale (1799–1885) was Mayor on three occasions as well as Clerk of the Peace for Shropshire from 1833 to 1872.[18] Due to their long service to the local government of the town of Shrewsbury, the Loxdales were granted the Hereditary Freedom of Shrewsbury in perpetuity, Hugh and his younger brother Peter Anthony in 1993.

The genetically related Loxdales have passed through two severe genetic bottlenecks during their 500-year traceable history. Thus all the present day genetically related Loxdales descend from the founding couple in the late 15th-early 16th century, Robert Loxdale and his wife Joan Undyrwood of Mere Town, parish of Forton in Staffordshire, who married in 1513, and later, Thomas Loxdale and Hannah Skitt of Shrewsbury, as aforementioned, who married in 1749.[19] Loxdale also claims possible Viking ancestry via his red-headed Brambleby ancestors and French Huguenot ancestry via Ruth Brambleby’s mother, Emma Pettit, born in Soho in 1854 (died in West Hampstead in 1938), whose father, Thomas Napoleon Pettit (1820–1882), also born in London, was seemingly named by his parents after Emperor Napoleon I of France.

On his mother’s side, Loxdale’s maternal grandmother Mildred Jessie Duke, née Pemberton (1889–1971) was born in Nainital, Uttar Pradesh, India, and married William Victor Duke, MA (later the Reverend Duke; 1886–1954), a graduate in history and economics and first class senior moderator and gold medalist in 1909 at Trinity College Dublin.[20][21][22] They had five children, two sons and three daughters, of whom Hugh Victor was the 4th child, Phyllis the youngest. All except Phyllis were born in India. W.V. Duke had a strange and somewhat remarkable career. It seems he was training to become an Anglican priest just prior to the First World War, although during the war, he was actually an active soldier (Lieutenant) in the 88th Carnatic Infantry of the British Indian Army,[23] fighting in the Balkans and later Mesopotamia (modern day Iraq) against the Turks, including at the Siege of Kut in 1916. After the war, he spent many years as an Indian School Inspector based at Cuttack in Bihar & Orissa Province and ultimately became Principal of Ravenshaw College, Cuttack, before returning with his wife to England in the mid-1930s. Thereafter, he took Holy Orders and was ordained as a C. of E. priest at Holne Village in 1937 (later becoming Rural Dean of Totnes in south Devon), where his daughter Phyllis grew up prior to joining the WAAFs, and where he is buried.[24][25] According to family legend, Mildred Jessie was nearly eaten by a tiger at around sunset on her trip with native bearers through the forest to meet up with her fiancé just prior to their marriage in Hazaribagh in 1912. Mildred’s parents were Jessie Potter (1861–1936), born in Roorkee, Uttar Pradesh, daughter of Henry Edwardes (‘Harry’) Potter (1825–1887), a soldier in the Bengal Army and later civil engineer, and his wife Jane Smith (1829–1903), both parents originating from Haverfordwest in Pembrokeshire, Wales, and Walter Aubrey Herbert Pemberton (1858–1908), a teacher and ultimately Principal of Sherwood College (then the Diocesan Boys’ School), Nainital in the early years of the 20th century.[26]

Walter A.H. Pemberton, who died of cholera age 50 at Hazaribagh, had been born on the island of Nevis in the Caribbean, where his family had lived since the late 17th century, mainly as sugar planters or priests. Prior to that, this particular line of the Pembertons came from Peterborough and before that St. Albans in Hertfordshire,[27] where Roger Pemberton (1556–1627) was High Sheriff of the County in 1618.[28] Sometime before his death, Roger was out hunting in the local forest and accidentally killed an old woman collecting firewood with an arrow. As an act of atonement, he left land and money for the building of Almshouses to house six poor widows, the buildings still standing on St. Peter’s Street opposite St. Peter’s Church, where many of the St. Albans’ members of the Pemberton family where baptized, married and are buried. A bronze arrow has been placed skywards on the top of the brick arch leading to these houses as a permanent reminder of Roger’s folly and his subsequent benevolence. The Nevis branch of the Pembertons possibly descend from Philip Herbert, IV Earl of Pembroke (1584–1650),[29] and further back, via Roger Pemberton of St. Albans' (1556–1627) mother Catherine Stokes (c.1531 – 1628), and her ancestors, the Arnold, de Gamage, de Turberville and Talbot families, to William de Beauchamp, 9th Earl of Warwick (1237–1298).

Of the Potter family, Jessie’s grandfather was Joseph Potter (1783–1846), Mayor of Haverfordwest in 1843 and Sheriff four times.[30] His claim to fame was to found the Pembrokeshire Herald in 1844, whilst he was also, when Mayor, "instrumental in quelling the Rebecca riots, after having read the Riot Act from the drawing room window over the shop and library. On that occasion, the military had to be turned out, and the rioters ‘were put to flight after a sharp tussle at Prendergast Turnpike Gate.’ "[31] Joseph was a son of John Theophilus Potter (1752–1839), an actor from Ireland who also later became Sheriff of Haverfordwest in 1790.[32] John Theophilus Potter was “one of the inhabitants who took up arms when the French invaded Pembrokeshire in February, 1797, and was present at their surrender on Goodwick Sands, near Fishguard.”[33] The Potters were a very literary family who, as well as founding a successful printing and publishing house in Haverfordwest, also started a very successful literary and scientific society in the town.

Education and career

Hugh Loxdale was educated at Corner Hall Secondary Modern Boys’ School, Hemel Hempstead, Hertfordshire, England from 1962 to 1967, and Apsley Grammar School, Hemel Hempstead (now Longdean School) from 1967 to 1969. On leaving school, he joined the Entomology Department at Rothamsted Experimental Station (now Rothamsted Research), in Harpenden, Hertfordshire, working in the Insect Survey, then run by L.R. (Roy) Taylor (1924–2007),[34] studying the demography of moths and aphids as part of the national light trap and 12.2 metre high suction trap surveys, respectively.[35] Meanwhile, he studied mathematics and chemistry at night school and during day-release from Rothamsted at the Dacorum College of Further Education, Hemel Hempstead, allowing him to thereafter win an Agricultural Research Council (ARC) Bursary to study for a bachelor's degree at university (apparently the first such grant to be awarded at Rothamsted). On gaining his Honours degree in zoology with biochemistry and physiology at Reading University in 1974, he then pursued comparative studies for a DPhil in the ARC Unit of Insect Physiology & Muscle Mechanisms, Zoology Department, Oxford (Linacre College, awarded 1980) on the mechanics and biochemistry of asynchronous (fibrillar) insect flight muscle (from the giant water bug, Lethocerus spp; Hemiptera: Belostomatidae) and vertebrate skeletal muscle (rabbit and tortoise especially). On completing his doctoral studies, he returned to Rothamsted in October 1977 and the following year became Head of the newly established Aphid Genetics Group, a post he held until his retirement there after 36 years in June 2005.

In 2006, he travelled with his wife Nicola Loxdale, PhD (née von Mende, a molecular nematologist) to Jena, Germany to take up a two-year post as an EU Marie Curie Senior Research Fellow to work on the population genetics of tansy-feeding aphids and their wasp parasitoids at the Institute of Ecology (IoE), Friedrich-Schiller University and Max Planck Institute for Chemical Ecology. Later, his contract was extended and he briefly became professor of ecology at the IoE from 2008 to 2010. He officially retired in 2011, spending two years in the city of Augsburg, Bavaria, before returning to the UK with his wife in 2013. They now live in Taunton, Somerset, where she runs a natural history publishing business, whilst he acts as an entomological consultant, and helps in the editing of manuscripts, both scientific and for the book publishing company. He also continues to write some scientific papers, both research papers and overviews.

Besides his conference organizing, he served for two years as Editor of the RES journal The Entomologist (which he helped re-launch in 1987) and on the editorial boards of various scientific journals, including Molecular Ecology, the Bulletin of Entomological Research and the European Journal of Entomology (for which he was also English language editor), whilst he is currently an Assistant Editor of the RES’s house journal Antenna. He has also refereed scientific papers for a plethora of scientific journals for over 30 years and has to date successfully supervised 12 PhD students.

In 2007, Loxdale was awarded an MBE for Services to Entomology in the Queen’s Birthday Honours List, whilst in 2016, he was elected an Honorary Fellow of the RES in recognition of his entomological achievements as well as his various services to the Society over many years.

Scientific contribution

During his time at Oxford, Loxdale designed and development a continuous, circulatory NADH+-coupled enzyme ADP assay system which allowed for the first time accurate measurement of pico-mole quantities of ADP released from small bundles of glycerol-extracted fibres (c. 60μm diam.; c. 1.2 cm. long) during activation by threshold calcium ion concentration [Ca2+] and stretch activation of fibrillar insect flight muscle (IFM), or [Ca2+] activation of vertebrate skeletal muscle; meanwhile the mechanical performance of the fibres could be simultaneously measured by oscillating them at a range of frequencies and amplitudes[36][37]. From this, he was able to demonstrate that, contrary to theory, the tension cost (ratio of ATPase activity over tension) did not change markedly as a function of the level of activation, i.e. the ATPase versus tension relationships remained essentially constant.[38] It was thus concluded that the rate constant of detachment of myosin from actin during the acto-myosin cross bridge cycle was not, as hitherto assumed, more especially for fibrillar IFM, the rate-limiting step in determining contraction speed of the muscle. Indeed, he was able to demonstrate using ATP solutions buffered with phosphate ions, that the tension cost and mechanical performance could even be dissociated from one another. In light of these findings, Roger H. Abbott formulated a four-state cross bridge cycle as most adequately accounting for the phenomena observed.[39] In addition, using glycerol extracted rabbit psoas muscle fibres activated in the absence of threshold concentrations of calcium ions using reduced ionic strength, Loxdale was also able to demonstrate that magnesium ions are necessary to stabilize the troponin-tropomyosin regulatory system, i.e. maintain this in the non-activated condition.[40]

Apparatus for simultaneously monitoring the ATPase activity and mechanical properties of small bundles of insect flight muscle fibres
Close-up of same showing series of water cooled muscle fibre immersion baths and specially designed circular UV cuvette
Original recording of simultaneous monitoring of ATPase activity, tension and oscillatory properties of small bundles of Lethocerus flight muscle fibres upon dual calcium ion and stretch activation, c. 1977

In terms of his insect population genetics studies, Loxdale in collaboration with Cliff Brookes, was the first to demonstrate at Rothamsted, using single locus polymorphic allozyme markers, that as with birds, different aphid species had different migratory urges and abilities as a consequence of their innate migratory behaviours (a notion supported by wind tunnel experiments performed at the Imperial College Field Station at Silwood Park, Ascot, by Professor Jim Hardie and colleagues).[41][42] In comparative studies performed over many years, later involving polymorphic microsatellite markers and a range of aphid species (Hemiptera: Aphididae), both pest and non-pest, it was revealed that some species such as the grain aphid, Sitobion avenae (F.), a predominantly asexual pest of cereals in Europe and elsewhere, did indeed appear capable of travelling long distances[43][44] In contrast, other species like the closely related blackberry-grain aphid, S. fragariae (Walker), a host alternating species with an autumn-winter sexual life cycle phase (i.e. the sexual females, on mating, laying cold hardy eggs), only travelled mainly short distances, perhaps less than 30 km.[45] Other species still, including the host alternating damson-hop aphid Phorodon humuli (Schrank)[46] and two species of non-host alternating tansy-feeding aphid − Macrosiphoniella tanacetaria (Kaltenbach) and Metopeurum fuscoviride Stroyan − also showed local dispersal behaviours.[47] Such data has considerable relevance to efforts to control aphid pests, globally amongst the most serious insect pests of many cash crops, more especially due to their ability to transmit pathogenic plant viruses of various kinds.[48] This work has been extensively reviewed in various publications, e.g.[49][50]

Macrosiphoniella tanacetaria, a non ant associated tansy aphid. Note mixed colony with two colour polymorphic forms, brown and green
Metopeurum fuscoviride, an ant attended tansy aphid species, also here showing two colour forms, brown and green

Loxdale and colleagues were also the first to demonstrate from their studies conducted in Jena that in the tansy aphid M. fuscoviride parasitized by its specialist wasp parasitoid Lysiphlebus hirticornis Mackauer (Hymenoptera: Braconidae), as the local genetic variation of the aphid increased, so did that of its parasitoid. This suggested a fine-grained co-evolutionary tracking to be in operation.[51] Such a scenario is supportive of the Red Queen hypothesis,[52] whereby a host organism (here an aphid) is attempting to evolve away from its antagonist (here a parasitoid), which is meanwhile co-evolving in order to retain the ability to attack it, i.e. keep pace with it in an ecological-evolutionary sense. Loxdale, in collaboration with G.M. Tatchell at Rothamsted, were also the first to determine the insecticide resistance status (here conferred by carboxylesterases, i.e. R1, R2 and R3 genotypes) of the serious agricultural pest the peach-potato aphid, Myzus persicae (Sulzer) captured in the UK network of 12.2. m high suction traps.[53] This involved using pH-buffered glycerol solutions containing antibiotic and gel electrophoresis to identify the level of carboxylesterase gene expression of the individual genotypes (the result of amplification of the E4 and FE4 resistance genes involved)[54][55] From this work, the spatial and temporal dynamics of this important (and now highly cross-resistant) pest aphid could be followed, thereby leading to more rational and effective control measures in the field.

With moths, Loxdale and his then PhD student Ian R. Wynne, were able to show using polymorphic allozyme markers, that in local populations of the November moth Epirrita dilutata (Denis & Schiffermüller) (Lepidoptera: Geometridae) inhabiting fragmented woodlands within the agro-ecosystem of the Rothamsted estate (330 ha), little inter-population gene flow was found to occur, even at distances of only a few kilometres. From these findings, it was concluded that the moths, which seemingly displayed high levels of habitat fidelity, possessed an innate reluctance to fly over flat, cultivated farmland. This study, here on a model Lepidopteran species, emphasizes the importance and utility of such genetic markers, even at a very local geographic scale, in studies of natural insect populations, both for purpose of conservation or control.[56]

Loxdale has written a series of overviews, many with colleagues, especially Dr. G. Lushai, highlighting the improbability of strict genetic uniformity in populations of clonal organisms such as aphids. This lack of uniformity is due to the rapid rate of mutation resulting from various mechanisms (e.g. point mutations due to errors of replication, inversion polymorphisms related to transposon effects, etc.) amplified by the huge reproductive potential of the animals concerned, e.g., not only do aphids show ‘telescoping of generations’ such that an adult asexual female has her children and grandchildren within her, but also display so-called ‘genetic inflation’, i.e. the production of a large number of asexual copies produced by a single female (10-100 offspring) in a short time (~ 10-14 days). Hence, a single aphid can, in theory (i.e. without mortality factors such as climate, predators, parasitoids and pathogens) produce enough offspring to cover the entire planet to a depth of many kilometres in a single growing season![57] This of course has serious potential consequences for the agricultural, horticultural and forestry industries worldwide.[58]

Aphids are known to show much variation − morphological, genetic, behavioural, etc. − which emphasizes the fact that they need to evolve quickly in the face of continuously developing ecological-evolutionary pressures and selective regimes (like the use of new kinds of insecticides), and hence need to be highly adaptive, rather than ecologically stagnant, i.e. living as large-scale clonal copies spread over wide geographic areas and persisting for long periods of time. Although some aphids such as M. persicae do show some insecticide resistant genotypes of this type,[59] these are maintained within the cultivated and manicured agro-ecosystem, hardly the real world in a long-term ecological sense.

In relation to theory, Loxdale & Lushai proposed in 2007 that the sexual cycle of aphids, rather than obligate asexuality, might be due to the necessity of telomere re-setting of the end of the chromosomes.[60][61] [“A telomere is a region of repetitive nucleotide sequences at each end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes.”; see Wikipedia for further details]. If such telomere re-setting does not occur, then, as the authors posit, the asexual lineages will become non-adaptive and die out as a function of transgenerational telomere shortening, a so-called aphid clone being, in effect, some kind of transgenerational entity, persisting (or so it was earlier believed) genetically unchanged over many generations

Critics of this theory[62][63] point out that telomere length in aphids is not highly regulated as it is in vertebrates (especially mammals), may occur even in the parthenogenetic phase of reproduction, and apparently aphid species colonies kept in culture over very many asexual generations (accepting something like 20 asexual generations per annum) have long telomere lengths. However, as is known, aphids can produce sexual forms (males and sexual females = oviparae) from time to time, even on secondary herbaceous hosts, when environmental stimuli are favourable, i.e. reduced light and temperature. Thus, it is possible that unless culture conditions are strictly maintained, some cryptic sexual reproduction may continue and hence some telomere re-setting occasionally occur.

In empirical studies of aphid chromosomes Loxdale, Lushai and colleagues were also able to demonstrate using RAPD (random amplified polymorphic DNA) markers that in asexual lineages (= 'clones' sensu lato) of cereal aphids (S. avenae and the bird cherry-oat aphid, Rhopalosiphum padi (L.)) maintained under strict conditions of rearing hygiene (i.e. each lineage was founded from a single parthenogenetic adult female reared on individual barley leaves in separate net-covered glass tubes standing in water), intra-clonal, trans-morph (sexual vs. asexual, winged vs. wingless) genetic changes were seen to occur. These may relate to changes in the RAPD primer binding sites in turn due perhaps to transposon effects.[64][65] At the chromosome level, recent studies by Loxdale in collaboration with Professor G. Manicardi, Dr. V. Monti and colleagues have demonstrated the existence of intra-clonal, inter-embryo genetic variation in terms of chromosome karyotype within individuals, and within and between clones of M. persicae.[66] Studies with both RAPDs and AFLPs (amplified fragment length polymorphic DNA) have also shown that aphid clones display both somatic and germline mutational changes within a few generations.[67] Hence the aphid clone is a very dynamic entity[68], not an invariant one as hitherto believed.

Loxdale has also written overviews on several key areas of biological thought and research. These include the migration and dispersal of insects in relation to their genotype and habitat[69]; intra-clonal genetic variation[70]; rapid evolution in insect populations due to various genetic-ecological mechanisms[71]; population proteomics (with Dr David Biron, Prof. Frédéric Thomas and colleagues)[72]; and most recently, on the improbability of generalism in nature, with special reference to insects, work in collaboration with G. Lushai and Professor Jeffrey Harvey.[73][74] The consensus of these articles is that the act of filling a new ecological niche is of course the fundamental act of specialization for any new species or sub-specific population. Whilst some species may be polyphagous to varying degrees, which the authors define, nevertheless diet breadth tends to involve preference for certain prey items in predatory as well as herbaceous species. Generalism, if it exists, is highly dependent upon an animal’s morphology-anatomy, genetics, physiology-biochemistry, and chemistry, especially chemical ecology. This in turn governs the behaviour of the animal concerned and restrains it in terms of its habitat choice and what it can eat. In this light, the age old ‘arms race’ of insect herbivores with plants has led to the plants evolving an armoury of secondary chemical defenses which cause, more often than not, specialisms in terms of host and indeed habitat on the part of the herbivore/s involved. Ultimately, even apparently highly polyphagous species such as the aphid M. persicae, said to attack plants in 40 families,[75] may be because of its highly specialised biochemistry-enzymology. Most aphids are highly specialised on one host or closely related hosts (often in the same genus/family)[76], probably due to biochemical constraints, and if so, perhaps what one is seeing in M. persicae is a unique specialization rather than generalization.[77]

The picture is also complicated by the recent discovery in many species, including M. persicae and other aphids, following the application of high-resolution molecular markers, of morphologically similar/identical cryptic species. The discovery and realization of such cryptic entities is essential for successful pest control, especially including use of natural control agents such as hymenopterous wasp parasitoids and predators, as well as for the conservation of rare and endangered species.[78]

In terms of Loxdale’s proteomics studies with Biron and colleagues in France, these have shown that nematomorph worms parasitizing crickets and grasshoppers (Orthoptera) cause fundamental neurological changes in the brain of their hosts. This induces the host to seek water and effectively commit suicide by jumping into it, whereupon the adult worm exits the host and seeks a mate and the females so mated then lay eggs to complete the life cycle.[79]

Recently, Loxdale has published an overview on the decline of entomological studies, especially in the UK, as a result of cutbacks in government and other funding sources. This problem not only seriously impacts directly on the importance of such studies in the fields of agriculture, horticulture, forestry, medicinal, veterinary and conservation studies, but also on the membership of the learned societies supporting entomology and the careers of those seeking long-term employment in this vital discipline.[80]

Poetry

Loxdale has written over 500 poems in a variety of styles over the last 50 years or so, mainly on natural history themes, often with a philosophical slant. His first poem, Dragonfly, was published whilst he was still at Apsley Grammar School (now Longdean) in the late 1960s. To date he has published ten volumes of his poetry, including one for children, Zoooo[81], whilst many poems have been published in books and magazines, on the www and the BBC website (e.g. his poem Across this Land, an epic poem on the destruction of the English countryside as a result of overzealous road construction). Because the author is a scientist, he tends to embrace realism in his poetic endeavours, having a duty, as he feels, to tell ‘it as it is’, even about such beloved and iconic animals as cats and dogs. Thus he does not shirk from providing thought-provoking and possibly often controversial ‘takes’ on a plethora of subjects, everything in fact from viruses and bacteria, animals, including pets, and plants, the sea, the cosmos, human love, life and death, including the tragic slaughter on the Western Front in the First World War. Loxdale argues that there may be a poetry ‘gene’ in his family, or at least a disposition to write poetry: his father Jack and Jack’s brother Hubert John Loxdale RN (1913–1970) both wrote poetry as have some more distant relatives, including the soldier-poet Pt. Edward Loxdale (1887–1916), London Bn. Prince of Wales's Own Civil Service Rifles, killed at Vermelles, France on 1 January 1916.[82]

Personal life

Loxdale has been married to Nicola von Mende, scientist and now publisher of natural history books, since 1993. Alone or together with his wife, he has travelled extensively, including Britain and mainland Europe, North and South America, the Middle East, Asia, Australasia and the Pacific region, more especially to observe and study the wildlife of these regions and/or to attend scientific meetings. In 1990, with his younger brother David Ian Loxdale (born 1959), he travelled for over a month around the world by commercial airline, stopping en route in Denver, Colorado and Los Angeles, USA, the Hawaiian Islands, Fiji, New Zealand, Australia, including Sydney, Alice Springs and Perth, Thailand and Singapore before returning home to the UK.

Entomology Department at Rothamsted, May 1971. Dr. C.G. Johnson, Head of Department, is 6th from left in the first row; L.R. (Roy) Taylor 7th from left in the second row, whilst Loxdale, then age 20, is on the far left in the back row
Loxdale, then age 18, with his home made Williams-design moth trap, Hemel Hempstead, 1968

References

  1. ↑ Loxdale, H.D. & Balog, A. (2009) Béla Bartók – musician, musicologist, composer…and entomologist! Antenna 33(4), 175–182.
  2. ↑ Research Gate
  3. ↑ Loxdale, H.D. (2010). Setting the scene...meeting up with Darwin and Wallace. Ecological Entomology (special issue) 35, 1-9.
  4. ↑ https://www.cwgc.org/find-war-dead/casualty/2956161/duke,-hugh-victor/
  5. ↑ http://www.griffon.clara.net/ccmaa/ccmaa_contribution1.htm
  6. ↑ http://www.tynebuiltships.co.uk/B-Ships/britishfame1936.html
  7. ↑ http://atlantic-cable.com/Cableships/Faraday(2)/index.htm
  8. ↑ http://www.bbc.co.uk/history/ww2peopleswar/stories/29/a2082629.shtml
  9. ↑ Henry Loxdale: Obituary in The West Middlesex Advertiser and Chelsea and Pimlico Chronicle for Saturday, January 27th, 1883, p. 5.
  10. ↑ http://www.shrewsburytowncouncil.gov.uk/mayoral-information/former-mayors
  11. ↑ Blue Pedigree of the Loxdale family dated 1863. Possibly compiled by Joseph Loxdale (1798–1890), High Sheriff of Cardiganshire, 1867. Unpublished MS. https://www.shropshirearchives.org.uk/
  12. ↑ Richard Loxdale, 1841 Census, Lezayre, Isle of Man, HO 107/1464/1, pages 20-21.
  13. ↑ Blue Pedigree of the Loxdale family dated 1863, possibly compiled by Joseph Loxdale (1798–1890), High Sheriff of Cardiganshire, 1867. Unpublished MS. https://www.shropshirearchives.org.uk/
  14. ↑ Morris, G. (MS) Pedigree of the Loxdale Family, pp. 8-11. https://www.shropshirearchives.org.uk/
  15. ↑ White Pedigree of the Loxdale family dated c. 1805, possibly compiled by Joseph Loxdale (1759–1846), Mayor of Shrewsbury, 1797. Unpublished MS. https://www.shropshirearchives.org.uk/
  16. ↑ Loxdale, H. A. R. & Loxdale, H.D. (1996) Revised Pedigree of the Loxdale Family, 1513–1996. Unpublished MS.
  17. ↑ Phillips, W. (MS) Shropshire Men, Vol. 5, The Jeffreys Family Pedigree, pp. 260-263. https://www.shropshirearchives.org.uk/
  18. ↑ http://shrewsburylocalhistory.org.uk/loxdale.htm
  19. ↑ Blue Pedigree of the Loxdale family dated 1863, possibly compiled by Joseph Loxdale (1798–1890), High Sheriff of Cardiganshire, 1867. Unpublished MS. https://www.shropshirearchives.org.uk/
  20. ↑ A Catalogue of Graduates of the University of Dublin. Volume IV (First Edition). containing the names of those who proceeded to degrees from the year 1906 to the summer commencements of the year 1917. Hodges, Figgis & Co, Ltd, Grafton Street, Dublin, Ireland. Page 29.
  21. ↑ India List, 1937.
  22. ↑ Totnes Deanery Magazine, June 1954, Vol. 20(6).
  23. ↑ British Army WWI Medal Rolls Index Cards 1914–1920. William Victor Duke. Lieut. Carnatic Infantry. W5/5/3510 and NW/5/14217. Theatre of war first served in: Balkans. E7.9. returned 26.9.21. Address: Patna, Bihar, India.
  24. ↑ India List, 1937.
  25. ↑ Totnes Deanery Magazine, June 1954, Vol. 20(6).
  26. ↑ The Sherwoodian Times, December 1997, pp. 18-19 (Magazine of Sherwood College, Nainital, Uttarakhand 263002, India)
  27. ↑ Pemberton, R. (1923) (ed.) Pemberton Pedigree, compiled by the late Major General R.C.B. Pemberton, CB, CSI, RE, edited by his son The Rev. R. Pemberton, Rector of Ingatestone, Essex. The Sidney Press, Bedford, U.K. Chart 10. St. Albans Family. The Founders. Chart 13. St. Albans Family. West Indian Branch. (Reference copy held by the Shropshire Archive, Shrewsbury).
  28. ↑ http://www.stalbanshistory.org/page_id__297.aspx
  29. ↑ Loxdale, H.D. & N. (2000) Evidence that the Hebert Family of Nevis, West Indies descended from Philip, IV Earl of Pembroke and 1st Earl of Montgomery (1584–1650); 30 April, 2000, unpublished MS. Pp. 4.
  30. ↑ James, D. G. (1950) Historical Notes of Haverfordwest with a List of Mayors and Sheriffs. J. W Hammond & Co. Ltd.
  31. ↑ Unpublished letter by J.C. Bucher of the Hackney Gazette & North London Advertiser, 250-256, Kingsland Road, London E8 4DJ, proprietors of Potters Press Ltd., about the Potter Family, as sent to Miss M. Patch, The County Archivist, Pembrokeshire Records Office, Haverfordwest, dated 10th May 1973. Q12/96.
  32. ↑ James, D. G. (1950) Historical Notes of Haverfordwest with a List of Mayors and Sheriffs. J. W Hammond & Co. Ltd.
  33. ↑ Watkins, P. (2012) The life and times of John Theophilus Potter, 1752–1839, Pembrokeshire Life, January, 2012, pp. 14-16.
  34. ↑ http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2656.2007.01243.x/pdf
  35. ↑ Harrington, R. (2014) The Rothamsted Insect Survey strikes gold. Antenna 38, 159–166.
  36. ↑ Loxdale, H.D. (1980) Molecular parameters of diverse muscle systems. DPhil thesis, University of Oxford.
  37. ↑ Loxdale, H.D. (1976) A method for the continuous assay of picomole quantities of ADP released from glycerol-extracted skeletal muscle fibres on MgATP activation. Journal of Physiology 260, 4-5.
  38. ↑ Loxdale, H.D. & Tregear, R.T. (1985) Dissociation between mechanical performance and the cost of isometric tension maintenance in Lethocerus flight muscle. Journal of Muscle Research & Cell Motility 6, 163-175.
  39. ↑ Abbott, R.H. (1977) The relationship between biochemical kinetics and mechanical properties. 269-273. In: Insect Flight Muscle (ed. by R.H. Tregear), Proceedings of the Oxford Symposium, 3rd-5th April, 1977. North-Holland Publishing Company, The Netherlands. Pp. 367.
  40. ↑ Loxdale, H.D. & Tregear, R.T. (1983) Generation of tension by glycerol-extracted vertebrate skeletal muscle fibres in the absence of calcium. Journal of Muscle Research & Cell Motility 6, 543-556.
  41. ↑ Loxdale, H.D., Hardie, J. Halbert, Susan, Foottit, R., Kidd, N.A.C. & Carter, C.I. (1993) The relative importance of short- and long-range movement of flying aphids. Biological Reviews 68, 291-311.
  42. ↑ Hardie, J. (1993) Flight behaviour in migrating insects. Journal of Agricultural Entomology 10, 239–245.
  43. ↑ Loxdale, H.D., Tarr, I.J., Weber, C.P., Brookes, C.P., Digby, P.G.N. & Castañera, P. (1985) Electrophoretic study of enzymes from cereal aphid populations. III. Spatial and temporal genetic variation of populations of Sitobion avenae (F.) (Hemiptera: Aphididae). Bulletin of Entomological Research 75, 121-141.
  44. ↑ Llewellyn, K. S., Loxdale, H.D., Harrington, R., Brookes, C.P., Clark, S.J. & Sunnucks, P. (2003). Migration and genetic structure of the grain aphid (Sitobion avenae) in Britain related to climatic adaptation and clonal fluctuation revealed using microsatellites. Molecular Ecology 12, 21-34.
  45. ↑ Loxdale, H.D. & Brookes, C.P. (1990) Genetic stability within and restricted migration (gene flow) between local populations of the blackberry-grain aphid Sitobion fragariae in south-east England. Journal of Animal Ecology 59, 495-512.
  46. ↑ Loxdale, H.D., Brookes, C.P., Wynne, I.R. & Clark, S.J. (1998) Genetic variability within and between English populations of the damson-hop aphid, Phorodon humuli (Hemiptera: Aphididae), with special reference to esterases associated with insecticide resistance. Bulletin of Entomological Research 88, 513-526.
  47. ↑ Loxdale, H. D., Schöfl, G., Wiesner, K.R., Nyabuga, N.N., Heckel, D.G. & Weisser, W.W. (2011) Stay at home aphids: comparative spatial and seasonal metapopulation structure and dynamics of two specialist tansy aphid species studied using microsatellite markers. Biological Journal of the Linnean Society 104, 838–865.
  48. ↑ Katis, N.I., Tsitsipis, J.A., Stevens, M. & Powell, G. (2007) Transmission of plant viruses. In: Aphids as Crop Pests (ed. by H.F. van Emden & R. Harrington), pp. 353–390. CABI, Wallingford, Oxford, UK.
  49. ↑ Loxdale, H.D. & Lushai, G. (2007) Population genetic issues: the unfolding story revealed using molecular markers. In: Aphids as Crop Pests (ed. by H.F. van Emden & R. Harrington), pp. 31-67. CABI, Wallingford, Oxford, UK.
  50. ↑ Loxdale H. D., Edwards, O., Tagu, D. & Vorburger C. (2017) Population genetic issues: new insights using conventional molecular markers and genomics tools. In: Aphids as Crop Pests, 2nd edn. (eds. H.F. van Emden & R. Harrington). pp 50-80, CABI, Wallingford, Oxford, U.K.
  51. ↑ Nyabuga, F.N., Loxdale, H.D., Heckel, D.G. & Weisser, W. W. (2012) Coevolutionary fine-tuning: evidence for genetic tracking between a specialist wasp parasitoid and its aphid host in a dual metapopulation interaction. Bulletin of Entomological Research 102, 149 – 155.
  52. ↑ van Valen, L. (1973) A new evolutionary law. Evolutionary Theory 1, 1–30.
  53. ↑ Tatchell, G.M., Thorn, M., Loxdale, H.D. & Devonshire, A.L. (1988) Monitoring for insecticide resistance in migrant populations of Myzus persicae. In: Proceedings of Brighton Crop Protection Conference - Pests & Diseases - 1988. 439-444.
  54. ↑ Foster S.P., Harrington, R., Dewar, A.M., Denholm, I. & Devonshire, A.L. (2002) Temporal and spatial dynamics of insecticide resistance in Myzus persicae (Sulzer). Pest Management Science 58, 895–907.
  55. ↑ Loxdale, H.D. (2009) What’s in a clone: the rapid evolution of aphid asexual lineages in relation to geography, host plant adaptation and resistance to pesticides. Pp. 535-557 in: Lost Sex: The Evolutionary Biology of Parthenogenesis, (ed. by Isa Schön, Koen Martens & P.J. van Dijk), Springer-Verlag, Berlin.
  56. ↑ Wynne, I.R., Loxdale, H.D., Brookes, C.P. & Woiwod, I.P. (2003) Genetic structure of fragmented November moth (Lepidoptera: Geometridae) populations in farmland. Biological Journal of the Linnean Society 78, 467-477.
  57. ↑ Harrington, R. (1994) Aphid layer (letter). Antenna 18, 50.
  58. ↑ Loxdale, H.D. (2016) Insect biology - a vulnerable discipline? Entomologia Experimentalis et Applicata 159, 121–134.
  59. ↑ Fenton, B., Margaritopoulos, J.T., Malloch, G.L. & Foster, S.P. (2010) Micro-evolutionary change in relation to insecticide resistance in the peach–potato aphid, Myzus persicae. Ecological Entomology 35, 131–146.
  60. ↑ Loxdale, H.D. & Lushai, G. (2003) Maintenance of aphid clonal lineages: images of immortality. Infection, Genetics & Evolution 3, 259-269.
  61. ↑ Lushai, G. & Loxdale, H.D. (2007) The potential role of chromosome telomere resetting consequent upon sex in the population dynamics of aphids: an hypothesis. Biological Journal of the Linnean Society 90, 719-728.
  62. ↑ Monti V., Giusti, M., Bizzaro, D., Manicardi, G. C. & Mandrioli M. (2011) Presence of a functional (TTAGG)n telomere-telomerase system in aphids. Chromosome Research 19, 625–633.
  63. ↑ Monti, V., Mandrioli, M., Rivi, M. & Manicardi, G. C. (2012) The vanishing clone: karyotypic evidence for extensive intraclonal genetic variation in the peach-potato aphid, Myzus persicae (Hemiptera: Aphididae). Biological Journal of the Linnean Society 105, 350–358.
  64. ↑ Lushai, G., Loxdale, H.D., C.P. Brookes, von Mende, Nicola, Harrington, R. & Hardie, J. (1997) Genotypic variation among different phenotypes within aphid clones. Proceedings of the Royal Society, Series B 264, 725-730.
  65. ↑ Loxdale, H.D. & Balog, A. (2018) Aphid specialism as an example of ecological-evolutionary divergence. Biological Reviews 93, 642-657. doi: 10.1111/brv.12361
  66. ↑ Monti, V., Lombardo, G., Loxdale, H.D., Manicardi, G.C. & Mandrioli, M. (2012) Continuous occurrence of intra-individual chromosome rearrangements in the peach potato aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). Genetica 140, 90-103.
  67. ↑ Loxdale, H.D., Vorwerk, S. & Forneck, A. (2013) The unstable 'clone': evidence from monitoring AFLP-based mutations for short-term clonal genetic variation in two asexual lineages of the grain aphid, Sitobion avenae (F.). Bulletin of Entomological Research 103, 111-118.
  68. ↑ Lushai, G., Loxdale, H.D. & Allen, J. A. (2003) The dynamic clonal genome and its adaptive potential. Biological Journal of the Linnean Society 79, 193-208.
  69. ↑ Loxdale, H.D. & Lushai, G. (1999) Slaves of the environment: the movement of insects in relation to their ecology and genotype. Philosophical Transactions of the Royal Society, Series B, Biological Sciences 354, 1479–1495.
  70. ↑ Loxdale, H.D. & Lushai, G. (2003) Rapid changes in clonal lines: the death of a ‘sacred cow’. Biological Journal of the Linnean Society 79, 3-16.
  71. ↑ Loxdale, H.D. (2010) Rapid genetic changes in natural insect populations. Ecological Entomology (special issue) 35, 155-164.
  72. ↑ Biron, D.G., Loxdale, H.D., Ponton, F., Moura, H., Marché, L., Brugidou, C. & Thomas, F. (2006) Population proteomics: an emerging discipline to study metapopulation ecology. Viewpoint article. Proteomics 6, 1712–1715.
  73. ↑ Loxdale, H.D., Lushai, G. & Harvey, J.A. (2011) The evolutionary improbability of ‘generalism’ in nature, with special reference to insects. Biological Journal of the Linnean Society 103, 1-18.
  74. ↑ Loxdale, H.D. & Harvey, J.A. (2016) The ‘generalism’ debate: misinterpreting the term in the empirical literature focusing on dietary breadth in insects. Biological Journal of the Linnean Society 119, 265–282.
  75. ↑ Blackman, R. L. & Eastop, V. F. (2000) Aphids on the World’s Crops: An Identification and Information Guide, Second Edition, John Wiley & Sons Ltd., Chichester.
  76. ↑ Loxdale, H.D. & Balog, A. (2018) Aphid specialism as an example of ecological-evolutionary divergence. Biological Reviews 93, 642-657. doi: 10.1111/brv.12361
  77. ↑ Mathers, T. C., Chen, Y., Kaithakottil, G., Legeai, F., Mugford, S. T., Baa-Puyoulet, P., Bretaudeau, A., Clavijo, B., Colella, S., Collin, O., Dalmay, T., Derrien, T., Feng, H., Gabald´on, T., Jordan, A., et al.(2017) Rapid transcriptional plasticity of duplicated gene clusters enables a clonally reproducing aphid to colonise diverse plant species. Genome Biology 18, 27. https://doi.org/10.1186/s13059-016-1145-3.
  78. ↑ Loxdale, H.D., Davis, B.J. & Davis, R.A. (2016). Known knowns and unknowns in biology. Biological Journal of the Linnean Society 117, 386–398. doi: 10.1111/bij.12646
  79. ↑ Biron, D.G., Marché, L., Ponton, F., Loxdale, H.D., Galéotti, N., Renault, L., Joly, C. & Thomas, F. (2005) Behavioural manipulation in a grasshopper harbouring hairworm: a proteomics approach. Proceedings of the Royal Society, Biological Sciences 272, 2117–2126.
  80. ↑ Loxdale, H.D. (2016) Insect biology - a vulnerable discipline? Entomologia Experimentalis et Applicata 159, 121–134.
  81. ↑ https://hughloxdalepoetry.co.uk/home
  82. ↑ http://aur.home.xs4all.nl/layout/frames.htm?Individuals/loxdale.htm

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