Roger Blackman – An appreciation
The text of this appreciation is taken from Harrington R, Polaszek A, Watson GW, Kanturski M, Favret C, Ouvrard D. 2022. Roger Blackman 1941-2022—an appreciation. Zootaxa, 5183(1): 7-21 (DOI: 10.11646/zootaxa.5183.1.4) respecting the Creative Commons Attribution-N.C. 4.0 International license cited in the publication.
Introduction
Dr Roger Laurence Blackman passed away on 17 March 2022, after more than 50 years dedicated to advances in aphid science. There can be very few scientists studying any aspect of aphids whose papers have not cited the works of Roger Blackman. To his name, we add that of Victor Eastop (1924–2012), for the two of them formed an inspirational, complementary and indefatigable pair at London’s Natural History Museum. Together they were responsible for, amongst many other seminal works, the three testaments of the aphidologists’ bible: Aphids on the World’s Crops, Aphids on the World’s trees and Aphids on the World’s Herbaceous Plants and Shrubs, now brought together and regularly updated by Roger until very recently in the online version, Aphids on the World’s Plants (www.aphidsonworldsplants.info). Victor was an out-and-out taxonomist, absolutely amongst the best the world has known, whilst being very familiar with most aspects of aphidology. Roger’s contributions were broader, as we shall see.
Life and times
The back cover of Roger’s extraordinarily brilliant introductory book on aphids, just called Aphids (Blackman 1974), tells us a little about his early life; but first we want to tell you about the book (now out of print). Following a succinct introduction to aphid morphology, life-cycles, morph determination, genetics, development, behaviour, feeding and nutrition, natural enemies, ant mutualism and population dynamics, there is a host-plant list, notes on common British species and a key to common British genera. It finishes with techniques for studying aphids, including the world-renowned (amongst aphidologists!) “Blackman Box”. Roger arranged for one of us (RH) to visit the great Dick Hille Ris Lambers (DHRL) at his home in Ede-Wageningen. That’s another story, but DHRL told RH that he would never have been able to write that book himself as he wouldn’t have been able to generalise, and ignore the exceptions that would have detracted from the aims of the work. Dick described the book as a triumphant masterpiece. Roger was just 33 when it was published.
So, to the back cover. Roger was born in Heston, in the London borough of Hounslow, UK. He went to Isleworth Grammar School and then to Bristol University, where he graduated in Zoology in 1962. He studied for a Ph.D. at Imperial College’s field station at Silwood Park, working on the feeding habits of ladybirds. His supervisor was the aphidologist Michael Way, sometimes referred to as “the father of IPM”. Mike worked particularly on the ecology and control of Aphis fabae, so it is perhaps no surprise that Roger became as interested in the prey as the predator. His first job was as an entomologist with the Commonwealth Institute of Biological Control (now CABI) and he spent most of his three years in Patagonia (Argentina) funded by the New Zealand government, searching for parasitoids and predators of that country’s pasture insect pests. In 1968, he returned to Silwood to begin work on aphids, initially on their morphological variation, cytology and genetics. In 1973 he moved to the Natural History Museum, where in 1986 he gained Individual Merit Promotion to what used to be called “Senior Principal Scientific Officer”; he remained there for the whole of his working career and beyond. Officially, he retired in 2001 (in those days you had to leave at 60) but he continued to visit the Museum regularly as a Scientific Associate.
Research highlights
Overview
Roger was interested in the biology of aphids, particularly in their variability and its environmental and genetic control, the evolution of their relationships with their host plants and, of course, taxonomy. He made several notable discoveries which aphidologists now take for granted, the most important of which are outlined below.
Apomictic parthenogenesis
For aphidologists, it seems hard to imagine a time when it was not known that aphids reproduce by apomictic parthenogenesis. In other words, no meiosis is involved; mature egg cells are produced by mitotic divisions, and these cells develop directly into embryos. Offspring are thus clones of their mother, and genetically identical except for any mutations occurring during or after oogenesis. Roger showed this through both experimental and cytological techniques (Blackman 1978). He comprehensively rebutted a theory that, during development of a parthenogenetic egg, crossing over occurs between homologous chromosomes with consequent recombination of genetic material (“endomeiosis”; Cognetti, 1961). He also made big advances in the understanding of mechanisms of spermatogenesis in aphids, showing that it does not involve chiasmata during meiosis (Blackman 1976, 1985; Spence & Blackman 1998), also advancing understanding of oogenesis (Blackman 1976) and sex determination (Blackman & Hales 1986) in aphids; and he prepared the first comprehensive review of sex determination in insects (Blackman 1995).
A chromosome translocation linked to insecticide resistance
The aphid species with which Roger is most famously associated is Myzus persicae (the Peach–potato aphid or Green peach aphid). This aphid is a major agricultural pest, the more so because of its propensity for developing resistance to insecticides. The first insecticide group to fall victim was the organophosphates; Roger found this resistance to be associated with a chromosomal translocation in the gene otherwise conferring resistance (Blackman et al. 1978). Roger was the first person to apply in situ DNA hybridisation techniques to aphid chromosomes and, with the help of Jennifer Spence, he used these to study the location and inheritance of insecticide resistance genes in M. persicae (Blackman et al. 1996), the orientation of X chromosomes during spermatogenesis (Spence & Blackman 1998) and the inheritance of chromosome fusions and dissociations (Spence & Blackman 2000).
Androcycly
Another important phenomenon in aphids, discovered by Roger, is androcycly (Blackman 1972). In certain species, some lineages are parthenogenetic and never produce oviparae but can produce a few males. This is important because it means that the trait for overwintering in the mobile form as opposed to an egg (i.e., continuous parthenogenesis) can be passed through the sexual phase when males from lineages showing androcycly mate with oviparae from holocyclic genotypes. Myzus persicae is a prime example of this; thus, it can take advantage of warm winters by continuing parthenogenetic reproduction without host alternation, giving it a flying start in spring but, in cold winters which kill the mobile stages, it can survive as a cold-tolerant egg provided that the primary host (peach) is available. This adaptability contributes to the pest status of the species; the important cereal pest, Rhopalosiphum padi, is another example.
Taxonomy
Roger’s extensive taxonomic work has centred on the use of cytological, biochemical and morphometric data to analyse aphid species complexes (Blackman 1980, 1992; Blackman & De Boise 2002) and, in collaboration with Vic Eastop, providing identification and information manuals for the rest of the worldwide aphidological community (e.g., Blackman 2010; Blackman & Eastop 1994, 2000, 2006; Blackman et al. 1998, 2019). In no other economically important insect groups are researchers blessed with such resources.
In addition to his keys to aphids, at the first-ever International Symposium on Aphids (in Jablonna, Poland in 1981) Roger produced a marvellous key to the aphidologists there gathered. Here are some sample couplets:
| 4 | Colour of dorsal cephalic hairs mainly white or grey | 5 |
| – | Colour of dorsal cephalic hair not grey or white. Darker | 6 |
| 5 | Hairs on lower mandible forming a wedge-shaped mass, much longer than broad, and longer than rostrum | …..Hille Ris Lambers |
| – | Hairs on lower mandible forming a short, conical mass, shorter than broad, and shorter than rostrum | …..Eastop |
Another couplet uses “Opinions evident” vs “Opinions much less evident”. Some workers are described as “specimen only seen pickled in alcohol”!
Awards and honorary positions
Roger was presented with the Bicentenary Medal of the Linnaean Society of London in 1979. This is awarded to just one person each year in recognition of exceptional achievements of a biologist under the age of 40. He was President of the Royal Entomological Society for two years (1998 to 2000) and contributed much to the Society in numerous ways.
Conclusions
As well as accomplishing a phenomenal amount of pioneering research himself, Roger’s work has been invaluable to the achievements of almost all those studying aphids. He has never sought the limelight, his only ambitions being to do good science and make it easily accessible to others. Some aphids are pests, although many are completely benign. Most play an important part in ecosystem function and some are of conservation concern. They are good models for fundamental science. No matter what people’s motivations are for an interest in aphids, Roger will have made it easier for them to achieve their goals.
Acknowledgements
Much of the information given here was cribbed from Roger’s curriculum vitae. The authors thus thank him not only for his immense contribution to aphidology and to their careers, but also for unwitting help in preparing this account. We apologise for any errors, omissions, understatements and exaggerations. We are indebted to Mr Paul Brown (Natural History Museum, London) for his help in listing Roger Blackman’s publications.
References
Blackman, R.L. (1972) The inheritance of life-cycle differences in Myzus persicae (SuIz.) (Hem., Aphididae). Bulletin of Entomological Research, 62, 281–294. https://doi.org/10.1017/S0007485300047726
Blackman, R.L. (1974) Aphids. Ginn & Company Limited, London and Aylesbury (UK), 175 pp.
Blackman, R.L. (1976) Cytogenetics of two species of Euceraphis (Homoptera, Aphididae). Chromosoma (Berlin), 56, 393–408. https://doi.org/10.1007/BF00292958
Blackman, R.L. (1978) Early development of the parthenogentic egg in three species of aphids (Homoptera: Aphididae). International Journal of Insect Morphology & Embryology, 7, 33–44. https://doi.org/10.1016/S0020-7322(78)80013-0
Blackman, R.L. (1980) Chromosome numbers in the Aphididae and their taxonomic significance. Systematic Entomology, 5, 7–25. https://doi.org/10.1111/j.1365-3113.1980.tb00393.x
Blackman, R.L. (1985) Spermatogenesis in the aphid Amphorophora tuberculata (Homoptera, Aphididae). Chromosoma (Berlin), 92, 357–362. https://doi.org/10.1007/BF00327467
Blackman, R.L. (1992). The use of ordination techniques to discriminate within pest aphid species complexes. In: Sorensen, J.T. & Foottit, R. (Eds.), Ordination in the study of morphology, evolution and systematics of insects: applications and quantitative genetic rationals. Elsevier, Amsterdam, The Netherlands, pp. 261–275.
Blackman, R.L. (1995) Sex determination in insects. In: Leather, S.R. & Hardie, J. (Eds.), Insect reproduction. CRC Press, Boca Raton, Florida, USA, pp. 57–94. https://doi.org/10.1201/9781351073608-3
Blackman, R.L. (2010) Aphids – Aphidinae (Macrosiphini). Royal Entomological Society Handbooks for the Identification of British Insects, 2 (7), 413 pp + CD
Blackman, R.L. & De Boise, E. (2002). Morphometric correlates of karyotype and host plant in genus Euceraphis (Hemiptera: Aphididae). Systematic Entomology, 27 (3), 323–335. https://doi.org/10.1046/j.1365-3113.2002.00181.x
Blackman, R.L. & Eastop, V.F. (1994) Aphids on the World’s trees: An Identification and Information Guide. CAB International, Wallingford, UK, 1004 pp.
Blackman, R.L. & Eastop, V.F. (2000) Aphids on the World’s Crops: An Identification and Information Guide, 2nd Edition. John Wiley & Sons, Ltd, Chichester, UK, 466 pp.
Blackman, R.L. & Eastop, V.F. (2006) Aphids on the World’s Herbaceous Plants and Shrubs (Volumes 1 & 2). John Wiley & Sons, Chichester, UK, 1440 pp.
Blackman, R.L. & Hales, D.F. (1986) Behaviour of the X chromosomes during growth and maturation of parthenogenetic eggs of Amphorophora tuberculata (Homoptera, Aphididae), in relation to sex determination. Chromosoma (Berlin), 94, 59–64. https://doi.org/10.1007/BF00293530
Blackman, R.L.B., Brown, P.A., Furk, C., Seccombe, A.D. & Watson, G.W. (1989) Enzyme differences within species groups containing pest aphids. In: Loxdale, H.D. & den Hollander, J. (Eds.), “Electrophoretic studies on Agricultural Pests” Systematics Association Special Volume No. 39. Clarendon Press, Oxford, pp. 271‒295.
Blackman, R.L., Dransfield, R.D & Brightwell, R. (2019) Aphids – Anoeciinae, Lachninae, Eriosomatinae, Phloeomyzinae, Thelaxinae, Hormaphidinae, Mindarinae. Royal Entomological Society Handbooks for the Identification of British Insects, 2 (8), 215 pp.
Blackman, R.L., Eastop, V.F. & Kibby, G.G. (1998) Aphids on the World’s Crops. CD-ROM Edition (TAXAKEY). CAB International, Wallingford, UK, 476 pp.
Blackman, R.L., Spence, J.M., Field, L.M., Javed, N., Devine, G.J. & Devonshire, A.L. (1996) Inheritance of the amplified esterase genes responsible for insecticide resistance in Myzus persicae (Homoptera: Aphididae). Heredity, 77, 154–167. https://doi.org/10.1038/hdy.1996.120
Blackman, R., Takada, H. & Kawakami, K. (1978) Chromosomal rearrangement involved in insecticide resistance of Myzus persicae. Nature, 271, 450–452. https://doi.org/10.1038/271450a0
Blackman, R.L., Watson, G.W. & Ready, P.D. (1995) The identity of the pine woolly aphid: a multidisciplinary approach. EPPO Bulletin, 25, 337‒341. https://doi.org/10.1111/j.1365-2338.1995.tb01475.x
Cognetti, G. (1961) Endomeiosis in parthenogenetic lines of aphids. Experientia, 17, 168–169. https://doi.org/10.1007/BF02160362
Kati, A., Shufran, K.A., Taylor, M.S., Barjadze, S., Eastop, V.F., Blackman, R.L. & Harrington, R. (2013) Identity of Schizaphis species (Hemiptera: Aphididae) in the United Kingdom: are they a threat to crops? Bulletin of Entomological Research, 103, 425–440. https://doi.org/10.1017/S0007485312000909
Spence, J.M. & Blackman, R.L. (1998) Orientation of the ‘stretched’ univalent X chromosome during the unequal first meiotic division in male aphids. Chromosome Research, 6, 177–181. https://doi.org/10.1023/A:1009203500012
Spence, J.M. & Blackman, R.L. (2000) Inheritance and meiotic behaviour of a de novo chromosome fusion in the aphid Myzus persicae (Sulzer). Chromosoma (Berlin), 109, 490–497. https://doi.org/10.1007/s004120000100
APPENDIX
List of taxon names given in honour of Roger Blackman
Genus-group names
Blackmania Kanturski & Wieczorek, 2015
Species-group names
Acaudinum (Acaudinum) rogeri Kadyrbekov, 2022
Aphis blackmani Kadyrbekov, 2019
Aphis rogerblackmani Nieto Nafría, Ortego & Mier Durante, 2022
Aphis rogeri Qiao, 2022
Capraphis blackmani Mier Durante, Ortego & Nieto Nafría, 2009
Elatobium blackmani Binazzi & Barbagallo, 1996
Eulachnus blackmani Kanturski, Qiao & Favret, 2022
Eutrichosiphum blackmanum Agarwala & A.K. Ghosh in A.K. Ghosh & Agarwala, 1993
Geopemphigus blackmani Muñoz Viveros & Remaudière, 2000
Hamamelistes blackmani Dederich & von Dohlen, 2022
Maculolachnus blackmani Kanturski & Chakrabarti, 2022
Medocellodes blackmani Drohojowska & Szwedo, 2022
Metopolophium rogeri Mehrparvar, Rokni & Rakhshani, 2022
Neuquenaphis blackmani Nieto Nafría & Brown, 2019
Periphyllus blackmani Li & Huang, 2022
Pleotrichophorus blackmani Barjadze, Halbert & Kanturski, 2022
Sitobion blackmani Forbes & Chan, 1993
Stomaphis blackmani Lee, Kanturski & Lee, 2022
List of taxa established by Roger Blackman
Subgenus
Adelges (Annandina) Favret, Blackman & Stekolshchikov, 2015
Species
Amphorophora tuberculata Brown & Blackman, 1985
Aphidura corsicensis Nieto Nafría, Blackman & Martin, 2014
Aphidura libanensis Nieto Nafría, Blackman & Martin, 2014
Aphis bozhkoae Eastop & Blackman, 2005
Aphis cornuta Blackman & Brightwell, 2019
Aphis polii Barjadze, Blackman & Özdemir, 2015
Euceraphis borealis Blackman, 2002
Euceraphis papyrifericola Blackman, 2002
Euceraphis quednaui Blackman, 2002
Geoica harpazi Brown & Blackman, 1994
Geoica wertheimae Brown & Blackman, 1994
Glyphina pseudoschrankiana Blackman, 1989
Kaochiaoja sikkimensis Joshi & Blackman, 2017
Macrosiphum eastopi Barjadze & Blackman, 2017
Myzus icelandicus Blackman, 1986
Stomaphis knechteli Binazzi & Blackman, 2003
Stomaphis bratislavensis Czylok & Blackman, 2003
Subspecies
Myzus persicae nicotianae Blackman, 1987
List of publications by Roger Blackman
Articles published by Roger Blackman on Aphids on the World’s Plants
A year in the life of a birch aphid
Charles Bonnet and his “Danae” – the discovery of parthenogenesis
Eggs and embryos – how aphids develop without sex