Monthly Archives: May 2018

Working from home in France

My wife and I are lucky enough to own a second home in France, in the Pays D’Oc. Hopefully, when we fully retire, it will be our main, if not only home.  At the moment, I get to spend much less time there than I would like, but since I semi-retired this academic year, the frequency of my visits has increased.

I have just finished a two-week spell there, not on holiday, but working from home, five days of which were spent working on a field skills handbook with two former colleagues of mine from Imperial College who used to help me run our two-week long final year Biodiversity & Conservation Field Course.  We have been working on this book for more than six years but to say that progress had been snail-like would be an exaggeration, glacial would be a better description.

Being away from our respective campuses, and the day-to-day academic trivia, meant that we were able to concentrate fully on the task at hand. We made incredible progress, and that was despite being connected to the internet and having access to Skype and email.  We now, in just five days and with very relaxed lunch-times, have a pretty good skeleton to show our prospective publisher.   A proper retreat works wonders; I can thoroughly recommend it.  It would be great if I could persuade my Head of Department to fund an official retreat for me and some of my colleagues to get together to write papers and grant proposals. It would definitely repay itself in increased grant income 🙂

The authors, looking relaxed but thinking hard.

The location certainly helps, with an office window view like this, who can help but be inspired 😊

The view from my office


In fact, I was so inspired I turned to verse.


Mountainous thunder

Sends ants scuttling to their nest.

Seeds await the wind



Ants, sensing distant thunder,

Scuttle to their nest,

While seeds pods wait for the wind




Filed under The Bloggy Blog

Waifs and strays – those papers nobody cites (or reads?)

I guess, like most, if not all of us, who publish papers, we hope that not only will our papers be read, but that they will be cited by others, not just ourselves.  From a purely practical point, it is after all, how academics impress promotion boards or prospective employers. From a more personal point of view, the papers we publish represent a lot of effort, not just in gathering the data or having the idea, but also the nightmare of turning it into deathless prose and then the battle with editors and reviewers.  We all have a few papers that we hope will make our name and perhaps become a citation classic, although as Stephen Heard has pointed out not just once, but twice, our favourites are not always everyone else’s, with some papers significantly failing to meet expectations.  A recent article in Times Higher Education, showed that in some disciplines, notably in the arts, 77% of papers were still uncited five years after publication and even in the sciences, about 40% of papers suffered a similar fate.  For ecologists, the hot area is ecological modelling, with only 6% of papers remaining uncited after five years. As someone with an advanced case of imposter syndrome, this is really quite reassuring; although I have twelve papers that are uncited (according to Web of Science), they only represent 6% of my output (and I am not a modeller 😊), of which only one dates back to 2012 (0.5%).  I do, however, have another 34 papers, that although they have been cited, have been cited fewer than five times, 17% of my output, or, if I add in my never been cited papers, 23% of my work has had relatively little impact on the ecological and entomological world.

Despite this, I was curious about what, if anything, these unwanted (=uncited) waifs and strays had in common, and how they differed from my most cited papers; absolutely nothing to with the fact that Stephen Heard only had four zero papers, all of which were recent papers 😊 In Steve’s analysis he looked at time since publication and found a positive correlation, his oldest papers had accrued the most citations.  I have a somewhat larger corpus of work than Steve, so concentrated my analysis on my top twenty papers.  There was absolutely no relationship (Figure 1), all pretty much of a muchness apart from the massive outlier, but even with that removed, still nada.

Figure 1. My top twenty papers.  The massive outlier is my single Annual Review of Entomology paper.

My least cited papers, do however, show a relationship between years since publication and the paltry number of citations that they have received (Figure 2).

Figure 2. The foot of the table papers.

If I combine the two data sets and leave out my star paper, there is a relationship between time since publication and the number of citations gained (Figure 3), so I expect, but I could be wrong, and I am not going to invest the time in finding out, that if I analysed all my papers that there would be a similar relationship as that shown by Steve’s analysis.

Figure 3. Relationship between time since publication and number of citations accrued for my most and least cited papers (excluding the massive outlier).

So, what makes a paper a waif, or reversing the question, a star?  Editors, of which I am one, are great fans of Reviews, believing, usually correctly, that they garner a lot of Impact Factor points, authors perhaps less so, as they tend to take away citations from your other papers. After all, who writes a review without citing themselves? 😊 The other thing that helps a paper get cited is their title, Andrew Hendry over on Eco-Evo Evo-Eco suggests that two main factors come into play. The first is that those papers that have a very good “fill in the box” titles are much more likely to be cited than those with more specific titles. He points out that a paper he and colleagues published in Philosophical Transactions of the Royal Society of Biology paper is the only one in the literature with Eco-Evolutionary Dynamics being the sole words in the title so, any paper writing about eco-evolutionary dynamics can use that citation to “fill in the citation box” after their first sentence on the topic.  The second inflation factor he cites, is that citations beget citations. When “filling in the box”, authors tend to cite papers that other authors used to fill in the same box.  In other words, authors tend to be lazy and use what other people have cited in their introductions.  This is not something to be encouraged, as it can lead to people being wrongly attributed; I have raged against this practice in the past.  Stephen Heard over at Scientist See Squirrel reckons that his most original papers are cited less because they report research from “outside the box” and most people are working “inside the box”.  Dorothy Bishop over at Bishopblog suggests that the best way to bury your work is to put it in a book chapter in an edited book.

So, what about my stars and strays?  My most cited paper is indeed a review, and for an entomologist, being in that most prestigious of review journals, the Annual Review of Entomology, it is no surprise to me that it tops my top ten chart, with just over 1000 cites.  Incidentally, number 4 (Leather et al., 1999) and number 7 (Leather et al., 1989) in my top 10, are also reviews.  My second most cited paper (Leather, 1988), is also, I guess, a review of sorts, albeit very short, although I prefer to think of it as more of a synthesis cum speculation paper.

What about the duds, those that no-one cites, not even me.  If I ignore the most recent papers, those published this year (2018) and last 2017), as being unlikely to have had time to be read, let alone cited, then all my zero papers are either editorials or commentary papers (e.g. Leather, 2014).  Don’t let yourself be fooled by the hope that a commentary paper, even with a sexy title and published in a top-notch journal will get cited.  My effort in Journal of Animal Ecology in early 2015 being a prime example, even the magic words, “climate change” failing to elicit a single citation to date (Leather (2015).

It is hard to see a pattern in my other lesser cited papers, they don’t seem to be markedly different from my more frequently cited papers, being published in my usual journals and covering the same subject matter, aphids, agricultural and forest pests and biological control in the main.  I confess to being very disappointed in the low number of citations to my aphid cannibalism paper (Cooper et al., 2014) especially as it got a lot of media attention, but I guess it falls into the too original box, not many people work on aphid cannibalism 😊

Sadly, it seems that Steve Heard is right, despite the journal blurbs, we don’t value originality, and the message for both journal editors and authors, is clear, if you want citations, publishing reviews and sticking to well ploughed fields is the safest bet.


Cooper, L.C., Desjonqueres, C. & Leather, S.R. (2014) Cannibalism in the pea aphid, Acyrthosiphon pisum. Insect Science, 21, 750-758.

Leather, S.R. (1988) Size, reproductive potential and fecundity in insects – things aren’t as simple as they seem. Oikos, 51, 386-389.

Leather, S.R. (2014: Modifying glucosinolates in oilseed rape – Giamoustaris & Mithen (1995): a top-twenty paper in the Annals of Applied Biology. Annals of Applied Biology, 164, 318-319.

Leather, S.R. (2015) Title: Onwards and upwards – aphid flight trends follow climate change. Journal of Animal Ecology, 84, 1-3.

Leather, S.R., Walters, K.F.A. & Dixon, A, F.G. (1989) Factors determining the pest status of the bird cherry-oat aphid, Rhopalosiphum-padi (L) (Hemiptera, Aphididae), in Europe – a study and review.  Bulletin of Entomological Research, 79, 345-360.

Leather, S.R., Day, K.R. & Salisbury, A.N. (1999) The biology and ecology of the large pine weevil, Hylobius abietis (Coleoptera: Curculionidae): a problem of dispersal? Bulletin of Entomological Research, 89, 3-16.



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Entomological classics – Aphids spit: visualising aphids feeding, the electrical penetration graph

Aphids as a taxonomic group, have been recognised since at least 1758 when Linnaeus coined the genus Aphis and have been cited as important pests for more than 200 years “The Aphis or Blighter, as we now for the first time venture to call it, from its being the most general cause of what are termed blights in plants..” (Curtis, 1802).  A detailed understanding of how they fed, was however, longer in being reached, but by 1914 the anatomy of the aphid mouthparts and the process of stylet insertion was fully described (Davidson, 1914).  Davidson (1923) also described the role that aphid saliva plays in helping the aphid feed by making it easier for the stylet to move between cells on its convoluted journey to the phloem, made visible as the so-called stylet tracks.

Drawings showing the effects produced by the passage of aphid stylets of three different aphid species through leaf tissue (Davidson, 1923).

Fast forward a couple of years and we have intrepid entomologists producing photographic evidence of aphid stylets in action (Smith, 1926).

Photomicrographs of the stylet of Myzus persicae in situ and the resultant stylet track (Smith, 1926).

One of the reasons that applied entomologists were so interested in aphid feeding was the role that aphids, and other insects, played as vectors of plant viruses, which until the 1920s, was not formally proven (e.g. Kunkel, 1926, Smith, 1926, 1929). You would be forgiven for thinking that once the connection between aphid feeding and plant virus transmission had been demonstrated then that would be it.  But no, much wants more, and aphidologists became intrigued about the link between aphid feeding and salivation, in particular when and exactly where these activities occurred in the plant.  Those entomologists working on plant viruses wanted to know which part of the feeding process was linked to the acquisition and inoculation of the viruses from and to the aphid host plant.  A possible solution to these conundrums, was, however, on the horizon.

In the early 1960s, two entomologists from the Department of Entomology, at the University of California, Davis, Donald McLean and Marvin Kinsey,  came up with a system that was to revolutionise the study of the feeding behaviour of aphids and other insects that feed internally on plant using piercing mouthparts (McLean & Kinsey, 1964). In essence, what they did was to make an aphid part of an electrical circuit by attaching a thin copper wire to its back using a quick-drying silver paint.  The feeding substrate, a leaf, had a 2.0 Volt, 60-cycle alternating current introduced to it and this was placed on an insulated grid connected to an amplifier connected in parallel with an oscilloscope, a chart-recorder and a speaker. The wire attached to the aphid, was joined to the grid and when the aphid began to feed this completed the circuit, and changes in voltage were able to be observed and recorded.  The next step was to identify which chart recordings were associated with sap ingestion and salivation by the aphid.  Using an artificial leaf, Parafilm stretched over a well containing a sucrose solution, and watching the aphids under a high power microscope, these innovative entomologists were able to identify four different stages involved in aphid feeding (Mclean & Kinsey, 1965).

The ground-breaking chart recording (Mclean & Kinsey, 1965) and as you might expect it was a pea aphid 🙂


A visual summary of what McLean and Kinsey were watching and recording (from Dixon (1973).

Not satisfied with these findings McLean and Kinsey modified their equipment and intensified their observations, sacrificing a number of aphids in the process.  When different waveforms were seen the poor aphids had their stylets amputated and the plant material with the stylet still in place was then examined under a high power microscope.  This meant that they were able to definitively correlate their recordings with the position of the stylet in different leaf tissues and during different behaviours (McLean & Kinsey, 1967).  As well as trying to understand how, when and where plant viruses were acquired or transmitted, it turns out that using the waveforms generated by the aphid mouthparts as they weave their way through the leaf tissues, is not only a useful way of assessing the resistance mechanism of a plant (e.g. Nielson & Don, 1974; Paul et al., 1996; ten Broeke et al., 2016) but also for detecting resistance to insecticides (e.g. Garzo et al., 2016).

Modifications to the original equipment happened very quickly; by 1966, a more compact and easier to use version using Direct Current had been developed (Schaefers, 1966). That said, the first correlation of a specific waveform and virus acquisition by the pea aphid, was shown using the original AC equipment (Hodges & Mclean, 1969).  A further modification of the Schaefers DC equipment was developed during the 1970s, such that test aphids were able to live and reproduce for up to ten days whilst attached to the set-up, thus allowing very detailed investigation of the correlations between the electrical signal patterns produced and the feeding behaviours of the aphids (Tjallingii, 1978).

Those of you who take note of such things, will have noticed, that so far, some 14-years after its invention, the term electrical penetration graph has not yet appeared, either here or in the scientific literature.   Earlier references to recordings using the technique use the term actograph which was somewhat non-specific, as it refers to any graphical representation of behavioural activity.  So when did the term Electrical Penetration Graph (EPG) first appear in the literature.  Google Scholar gave me a date of 1984 from a paper looking at the resistance of lettuce to the cabbage aphid Brevicoryne brassicae, a paper that includes Freddy Tjallingii in the authorship list (Mentink et al., 1984).  In this paper the authors refer to a conference proceedings paper (Tjallingii, 1982) as being the source of the name.  On tracking down that paper I found that it doesn’t actually mention the term EPG.  The first paper that specifically mentions and defines the term as “the recorded graph as a result of an overall electrical signal caused by stylet penetration activities” is Tjallingii (1985).  Strangely the author introduces the term thus “Here we introduce the term ‘electrical penetration graph (EPG)”, which I found slightly odd as it is a single author paper 😊  Inputting EPG or electrical penetration graph into Web of Science shows an increasing number of papers using and mentioning the technique, but surprisingly the first paper recorded is from 1999.

NGram finds the first mention slightly earlier, 1981.  A puzzle waiting to be solved for anyone with the time or inlcination.

The frequency of the occurrence of the phrase “Electrical penetration graph” according to Ngram Viewer (accessed and downloaded May 1st 2018).

The technique is now very well established and used around the world.  The equipment is commercially available through EPG Systems, which is where we got ours from and just in case you were wondering, this is what it looks like.

Faraday Cage (an earthed metal screen) surrounding the equipment to exclude electrostatic and electromagnetic influences

Our test plants in situ connected up to the electrical supply, recording equipment and amplifier.

Close up of the plants and EPG electrodes

Aphids connected up to the EPG. Photo courtesy of

A simple guide to interpreting the waveforms

For Open Days and public displays it is not unknown for mischievous entomologists to link particular waveforms to recordings of sucking and spitting sounds and to play these back when the equipment is being demonstrated 🙂



Curtis, W.L. (1802) IV. Observations on aphides, chiefly intended to show that they are the principal cause of blights in plants, and the sole cause of the honeydewTransactions of the Linnaean Society of London, 6, 75-94.

Davidson, J. (1914) On the mouth-parts and mechanism of suction in Schizoneura lanigera, Hausmann. Zoological Journal of the Linnaean Society, 32, 307-330.

Davidson, J. (1923) Biological studies of Aphis rumicis Linn. The penetration of plant tissues and the source of the food supply of aphids.  Annals of Applied Biology, 15, 35-54.

Gabrys, B., Tjallingii, W.F. & van Beek, T.A. (1997) Analysis of EPG recorded probing by cabbage aphid on host plant parts with different glucosinolate contents. Journal of Chemical Ecology, 23, 1661-1673.

Garzo, E., Moreno, A., Hernando, S., Marino, V., Torne, M., Santamaria, E., Diaz, I. & Fereres, A. (2016) Electrical penetration graph technique as a tool to monitor the early stages of aphid resistance to insecticides. Pest Management Science, 72, 707-718.

Hodges, L.R. & McLean, D.L. (1969) Correlation of transmission of Bean Yellow Mosaic Virus with salivation activity of Acyrthosiphon pisum (Homoptera: Aphididae). Annals of the Entomological Society of America, 62, 1398-1401.

Kunkel, L.O. (1926) Studies on Aster Yellows. American Journal of Botany, 13, 646-705.

McLean, D.L. & Kinsey, M.G. (1964) A technique for electronically recording aphid feeding and salivation. Nature, 202, 1358-1359.

McLean, D.L. & Kinsey, M.G. (1965) Identification of electrically recorded curve patterns associated with aphid salivation and ingestion. Nature, 205, 1130-1131.

McLean, D.L. & Kinsey, M.G. (1967) Probing behavior of the pea aphid, Acyrthosiphon pisum. I. Definitive correlation of electronically recorded waveforms with aphid probing activitiesAnnals of the Entomological Society of America, 60, 400-405.

Mentink, P.J.M., Kimmins, F.M., Harrewijn , P., Dieleman, F.L., Tjallingii, W.F.,  van Rheenen, B. &  Eenink, A.H. (1984)  Electrical penetration graphs combined with stylet cutting in the study of host plant resistance to aphids. Entomologia experimentalis et applicata, 35, 210-213.

Nielson, M.W. & Don, H. (1974) Probing behaviour of biotypes of the spotted alfalfa aphid on resistant and susceptible and alfalfa clones.  Entomologia experimentalis et applicata, 17, 477-486.

Paul, T.A., Darby, P., Green, C.P., Hodgson, C.J. & Rossiter, J.T. (1996) Electrical penetration graphs of the damson-hop aphid, Phorodon humuli on resistant and susceptible hops (Humulus lupulus).  Entomologia expeimentalis et applicata, 80, 335-342.

Powell, G. (1991) Cell membrane punctures during epidermal penetrations by aphids: consequences for the transmission of two potyviruses. Annals of applied Biology, 119, 313-321.

Schaefers, G.A. (1966) The use of direct current for electronically recording aphid feeding and salivation. Annals of the Entomological Society of America, 59, 1022-1024.

ten Broeke, C.J.M., Dicke, M. & van Loon, J.J.A. (2016) Feeding behaviour and performance of Nasonovia ribisnigri on grafts, detached leaves, and leaf disks of resistant and susceptible lettuce.  Entomologia experimentalis et applicata, 159, 102-111.

Tjallingii, W.F. (1978) Electronic recording of penetration behaviour by aphids. Entomologia experimentalis et applicata, 24, 521-530.

Tjallingii, W.F. (1982) Electrical recording of aphid penetration. [In] J.H. Visser & A.K. Minks (eds.) Proceedings of the 5th Symposium on Insect Plant-Relationships, 1-4 March, 1982, Wageningen, Pudoc, pp 409-410.

Tjallingii, W.F. (1985) Electrical nature of recorded signals during stylet penetration by aphids. Entomologia experimentalis et applicata, 38, 177-185.

Smith, K.M. (1926) A comparative study of the feeding methods of certain Hemiptera and of the resulting effects upon the plant tissue, with special reference to the potato plant. Annals of Applied Biology, 13, 109-139.

Smith, K.M. (1929) Studies on potato virus diseases, V. Insect transmission of potato leaf roll.  Annals of Applied Biology, 16, 209-229


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Pick and mix 18 – odds and ends from the web

The illegal orchid trade and its implications for conservation

On choosing titles for papers that actually tell you what they are about

When museums get it wrong, holiday booze or exhibit?

How earwing wings inspired a robotic gripper

What spiders can teach us about ecology

More bad news on the huge decline in numbers of insects and birds, this time in France

Manu Saunders is convinced that robotic bees will not be a success – what do you think?

An important report about the pollinator deficit from the Cambrigde Institute for Sustaianability Leadership

Great advice from Steve Heard on to rewrite your often-used methods and materials to avoid charges of plagiarism and copyright infringement

Are universities in loco parentis?


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