Monthly Archives: December 2015

Merry Christmas

Merry Christmas to all my readers and many thanks for your comments and likes over the past year.

Christmas cake 2015aChristmas cake 2015

Traditionally all the family get together to decorate our cake in the most ‘tasteful’ way possible – this year Santa in the downhill slalom at the Winter Santalympics, held at the South Pole 🙂



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Mee(a)ting Issues with the British Ecological Society – Why I boycotted the 2015 Annual Meeting

Normally at this time of year I would be recovering from the enjoyable after-effects of the British Ecological Society (BES) annual meeting, too much talking, too much eating, too much coffee, too much beer and wine and not enough sleep.

This year however, I denied myself the traditional end to the academic year as I decided to boycott the meeting. As someone who has, since 1977, missed only a handful of meetings, this was a big personal sacrifice, but I felt very strongly that I needed to make a protest , hence the one person boycott! So what prompted this action?

I was fully intending on attending the meeting in Edinburgh, having spent ten years living in Peebles and working at the Forest Research Station at Roslin, Edinburgh is full of pleasant memories for me. I logged on to the site to register for the meeting and was stunned and annoyed to come across this statement:

Food Policy In an effort to help reduce greenhouse gas emissions, the BES has decided to remove all farmed ruminant meat from its catering. Ruminants and their farming are key producers of methane. We run several large events a year, serving thousands of meals to participants and are keenly aware of the impact of human activity on natural systems. We will continue to cater for non-vegetarians, but will remove farmed ruminant meat from menus and will also only serve MSC certified fish. We take seriously our commitment to greening our events and hope you understand and support our decision. For more information on the background to this decision, read the paper by Ripple, W.J. et al: Ruminants, climate change and climate policy. – See more at:

Two things about this statement really got my goat (ruminant pun intended) – first, the non-democratic nature of this decision, the membership were never polled about this and second, the patronising and insulting statement, “We will continue to cater for non-vegetarians” This is tantamount to the comments by the vegan Shadow Minister for Agriculture, Kerry McArthy who suggested that meat eaters should be treated like smokers. As ecologists, and presumably all scientists with some biological background, the people running the BES know that we are omnivores by nature, look at our dentition and gut structure folks!

Meat Fig 1


I would also point out that the UK dairy herd is bigger (1.9 million) than the beef herd (1.5 million) and that you can’t have one without the other. The UK is the world’s tenth largest producer of milk (2.2%). So why not ban all dairy products and make delegates drink their tea and coffee black or with a vegetable based milk substitute? What about ruminant derived products? Whilst we are about it, how about penalizing delegates wearing wooly jumpers, leather shoes, leather belts and carrying their cash in leather wallets, purses and handbags?

I raised my concerns via Twitter and Facebook and did have a minor discussion with Andrew Beckerman, the chair of the Meetings Committee, but to no real satisfaction. I pointed out that why should people who enjoy beef and lamb be singled out, when those BES members who fly and drive everywhere were not targeted? I made the decision many years ago that I would not fly if at all possible, basically unless work dictated it, and as a result have flown (including return flights) only six times in the last twenty years. I recycle obsessively and my foreign travel is by train, ferry or Skype! So yes, tropical field work and international conferences on the other side of the world are a thing of the past, but I see no need for flying visits by western ecologists to indulge in brief exotic field work. Either go for the duration of the study or stay at home and discover the wonders of your own back yard, or rather than be an ecological imperialist, trust the local scientists to collect the data for you to number crunch. Or if you feel that your presence is indispensable, then go by ship and take the opportunity to write and read papers on the way 🙂

Although Ripple et al (2014) make a convincing case for slowing down greenhouse gas emissions by reducing ruminant production they do so from the highly biased minority viewpoint of those with “ecological privilege” (Nevins, 2014). They thus singularly fail to address the equally effective and more attainable actions that can be made by targeting travel, especially by air and private motoring Girod et al., 2012). There are over 100,000 flights a day and air travel is set to double by the year 2050 despite the fact that fossil fuels (oil at any rate) will run out in about 40-50 years (the former estimate according to the Institute of Mechanical Engineers, the latter by BP). One might ask then why do we have politicians wanting to build more airports and runways? As an ecologist this does not compute, but then looking at how many of my colleagues boast about their cheap flights compared with my more expensive rail trips, perhaps it does. As Nevins (2014) points out, a privileged few enjoy the ability to travel quickly and comfortably (although I would dispute the comfortably) around the world to conferences and field sites and this has a very significant effect on carbon emissions. Nevins calculated the carbon emissions generated by the Association of American Geographers to attend their 2011 meeting in Seattle as 5,352 metric tons, pointing out that the annual total per capita carbon emissions from energy consumption in Haiti is 210 kg and for Bangladesh 290 Kg, i.e. the air travel alone to and from the Seattle conference per delegate was more about three times the total annual emissions of an average Haitian or Bangladeshi which by any standard is unbalanced and profligate. Whilst other travel forms are amenable to very large future reductions in carbon emissions by improvements in technology, the evidence is that air travel will prove intractable and that the only feasible way forward is to drastically reduce flights made (Girod et al., 2012, 2013). Given that only 2-3% of the world’s population flies internationally (Peeters et al., 2006), this would seem a realistic aim and cause less harm to livelihoods and ways of life of people in less developed nations (note that 31 % of the global cattle herd are found in India, compared with 0.35% in the UK – Table 1). Unfortunately, although many of this wealthy airborne 2-3% are keen to embrace ‘light green habits’ such as home recycling and composting, they are the most likely to indulge in long distance flights and not want to be denied the ‘privilege’ of flying (Barr et al., 2010).

I don’t think that it is in the BES’s remit to impose life style choices on its membership by banning particular food groups. If the BES directorate want to make an environmental point using food as an example, then perhaps they should concentrate on food miles instead and serve locally sourced meat and seasonal vegetables. Delegates at the Edinburgh meeting could then have enjoyed the excellent Scottish beef that is available served with ‘tatties and neeps’ and perhaps also have experienced that particularly Scottish delicacy, the Scotch pie 🙂

Meat Fig 2

I do hope that the BES will reconsider their food policy as I would hate to have to miss any of the many excellent meetings scheduled for 2016.


Barr, S., Shaw, G., Coles, T. & Prillwitz, J. (2010) “A holiday is a holiday”: Practicing sustainability, home and away. Journal of Transport Geography, 18, 474-481.

Girod, B., van Vuuren, D.P. & Detman, S. (2012) Global travel within the 2oC climate target. Energy Policy, 45, 152-166.

Girod, B., van Vuuren, D.P. & Hertwich, E.G. (2013) Global climate targets and future consumption level: an evaluation of the required GHG intensity. Environmental Research Letters, 8, 014016.

Nevins, J. (2014) Academic jet-setting in a time of climate destabilization: ecological privilege and professional geographic travel.   The Professional Geographer, 66, 298-310.

Peeters, P., Gössling, S. & Becken, S. (2006) Innovation towards tourism sustainability: Climate change and aviation. International Journal of Innovation and Sustainable Development, 1, 184-200

Ripple, W.J., Smith, P., Haberl, H., Montzka, S.A., McAlpine, C. & Boucher, D.H. (2014) Ruminants, climate change and climate policy. Nature Climate Change, 4, 2-5.


Post script

Some meaty facts for the British Ecological Society to ruminate upon.

Meat Fig 3

The global cattle herd peaked in 1990 and has been declining, albeit gradually, ever since.

Meat Fig 4

There are approximately 1 billion sheep in the world, of which 187,000,000 (18%) are in China; in the UK there are 22,900,000. There are 674,000,000 goats in the world, most of which are in the tropics.

Post post script

Annual UK total GHG  emissions from meat eating are 17,052,000 metric tonnes per year, CO2 emissions alone from cars is 164,500,000, almost ten times more and aviation not far behind agriculture.

UK emissions

Post post post script

Here is a link to a paper that suggests increasing beef production could lower greenhouse gas emissions, at least in Brazil –


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Ten Papers that shook my World – Root (1973) – When more means less – crop diversity reduces pest incidence

I can’t remember when I first read this paper but judging by the record card and the state of the actual hard copy of the paper, it was probably when I was doing my PhD in the late 1970s. This paper and its companion, which was published a year earlier* (Tahvanainen & Root, 1972), have had a significant effect on the scientific understanding and development of inter-cropping as a method of crop protection worldwide. Although inter-cropping in some form or another has been around a long time, the idea that it could be used as part of an integrated pest management programme was not proven.  In this landmark study, Root compared pure stands (plots) of collards (spring greens in the UK) (Brassica olercaea) with adjacent rows of collards grown intermingled with other herbaceous plants.  His premise being that it was well documented that pest outbreaks tend to be associated with pure monocultures of crops (Pimentel, 1961; Janzen, 1970) and he wished to test the hypothesis that natural enemies were more abundant and effective in vegetationally diverse areas  than in pure monocultures, the so-called ‘enemies hypothesis’.  This idea had been around a surprisingly long time e.g. Ullyett (1947) who remarked  “where weeds occur around headlands and in hedges, they should be left for the purpose of supporting parasites and predators important in the natural control of the diamond-back moth (Plutclla maculipennis Curt)”.  A decade later, Elton (1958,) refers to this statement, explaining that “these hedge rows form a reservoir for enemies and parasites of insects and mite pests of crops”.  I am not sure what it indicates but note that many groups around the world, including mine, are still working on this both at the local (field-scale) level (e.g. Ramsden et al., 2014) and landscape level (e.g. Rusch et al., 2013; Raymond et al., 2015).

Root explained the premise of the ‘enemies hypothesis’ as follows.  Predators and parasites are more effective at controlling herbivore populations in diverse habitats or plant communities because, diverse plant communities support a diversity of herbivores with a variety of phenologies, providing a steady supply of prey for the predators.  In addition, complex environments provide prey refugia, thus allowing the prey not to be completely eradicated.  Diverse plant communities also provide a broad range of additional resources for adult natural enemies e.g. pollen and nectar.

Root ran his experiment for three years and did indeed find a significant difference in herbivore load between the pure plots and the weedy rows, the former having a greater abundance of pests (mainly aphids and flea beetles) than the latter.

Fig 1

From Root (1973)

To his disappointment (I assume), he did not find any difference in the numbers of natural enemies between the two treatments. He thus had to come up with another idea to explain his results. His ingenious explanation is encapsulated in what he termed the Resource concentration hypothesis which states that herbivores are more likely to find and stay on hosts growing in dense or nearly pure stands and that the most specialised species often reach higher relative densities in simple environments.

Fig 2

Typical modern monocultures, beans, cabbages and wheat

He hypothesised that specialist herbivores were ‘trapped’ on the crop and accumulated whilst more generalist herbivores were able to and likely to move away from the crops to other host plants.  Root added that the ‘trapping effect’ of host patches depends on several factors such as stand size and purity.

In 1968, presumably as a result of what Root was discovering, Jorma Tahvanainen (one of the many great Finnish entomologists who appeared on the scene in the 1970s -, he retired in 2004) came to Cornell to do his PhD with Richard Root. Working on the same system and in the same meadow, Tahbanainen developed two new hypotheses to explain why more diverse cropping systems have fewer pest problems than monocultures. His experiments as he too found little evidence of natural enemies having an effect. He developed two new hypotheses, one he termed Associational resistance which I reproduce below exactly as published:

A natural community, such as a meadow, can be treated as a compound system composed of smaller, component communities (Root, 1973). The arthropods associated with different plant species represent important components in terrestrial systems. The available information indicates that the biotic, structural and microclimatic complexity of natural vegetation greatly ameliorates the herbivore pressure on these individual components, and consequently, on the system as a whole. Thus, it can be said that in a compound community there exists an “associational resistance” to herbivores in addition to the resistance of individual plant species. If the complex pattern of natural vegetation is broken down by growing plants in monocultures, most of this associational resistance is lost. As a result, specialized herbivores which are adapted to overcome the resistance of a particular plant species, and against which the associational resistance is most effective, can easily exploit the simplified system. Population outbreaks of such herbivores are thus more likely to occur in monocultures where their essential resources are highly concentrated

The other, is the Chemical Interference Hypothesis, in which he postulated that reduced herbivory in diverse communities due to chemical stimuli produced by non-host plants interfering with host finding or feeding behaviour of specialist herbivores.  His experimental set-up was very simple, but very effective.

Fig 3

How to send mixed signals to specialist herbivores – reproduced from Tahvanainen & Root (1972)

In simple terms, a monoculture sends out a very strong signal, it could be olfactory, e.g. a strong bouquet of crucifer volatiles, or for other herbivores it could be visual, or a combination of the two.

Fig 4

Conventional intensive agricultural landscape sending out strong ‘signals’ to specialist herbivores

Inter-cropping increases crop diversity and changes the crop ‘signal’ to one that now ‘confuses’ specialists. Note that I am not necessarily advocating a combined crop of wheat, beans and cabbages, as harvesting would be a nightmare 😉

Fig 5


The intercrop melange effect

These two papers have had a huge influence on the theory and practice of inter-cropping and agricultural diversification, although Root (1973) has had many more citations (1393 according to Web of Science on 11th December 2015) than Tahvanainen & Root (1972) which has only had a meagre 429 citation to date.  The message coming out from the many studies that have now investigated the effect of intercropping crop diversification on pest abundance, is, that in general, polyculture is beneficial in terms of promoting biological control and that incorporating legumes into the system gives the best yield outcomes (Iverson et al,  2014).

Another take on intercropping that overcomes the potential problems of harvesting different crops from the same field, is the concept of planting different genotypes of the same species. Resistant plants tend to have fewer generalists present, although their individual yield may be reduced.  By planting a mixture of susceptible and resistant genotypes it is however, possible to have your cake and eat it, especially if it is not essential to have a single genotype crop.  This approach has been used to good effect in the production of short rotation willow coppice, where planting diverse genotypes of the same species reduces both pest and disease levels (Peacock et al., 2000, 2001).

Who would have that two simple field experiments conducted in an abandoned hay meadow outside Ithaca, New York almost fifty years ago would have such a far-reaching influence?



Elton, C. S. (1958) The Ecology of Invasions by Animals and Plants. London: Methuen & Co., Ltd. 159 pp.

Iverson, A. L., Makin, L. E., Ennis, K. K., Gonthier, D. J., Connor-Barrie, B. T., Remfret, J. L., Cardinale, B. J. &Perfecto, I. (2014). Do polycultures promote win-win or trade-offs in agricultural ecosystem services? A meta-analysis. Journal of Applied Ecology. 51, 1593-1602.

Peacock, L. & Herrick, S. (2000) Responses of the willow beetle Phratora vulgatissima to genetically and spatially diverse Salix spp. plantations. Journal of Applied Ecology, 37, 821-831.

Peacock, L., Hunter, T., Turner, H., & Brain, P. (2001) Does host genotype diversity affect the distribution of insect and disease in willow cropping systems? Journal of Applied Ecology, 38, 1070-1081

Janzen, D.H. (1970) The unexploited tropics.  Bulletin of the Ecological Society of America, 51, 4-7

Pimentel, D. (1961). Species diversity and insect population outbreaks. Annals of the Entomological Society of America, 54, 76-86.

Ramsden, M. W., Menéndez, R., Leather, S. R. & Wackers, F. (2014). Optimizing field margins for biocontrol services: the relative roles of aphid abundance, annual floral resource, and overwinter habitat in enhancing aphid natural enemies. Agriculture Ecosystems and Environment, 199, 94-104.

Raymond, L., Ortiz-Martinez, S. A. &Lavandero, B. (2015). Temporal variability of aphid biological control in contrasting landscape contexts. Biological Control , 90, 148-156.

Root, R. B. (1973). Organization of a plant-arthropod association in simple and diverse habitats: the fauna of collards. Ecological Monographs, 43, 95-124.  1393 citations

Rusch, A., Bommarco, R., Jonsson, M., Smith, H. G. &Ekbom, B. (2013). Flow and stability of natural pest control services depend on complexity and crop rotation at the landscape scale. Journal of Applied Ecology, 50, 345-354.

Tahvanainen, J. & Root, R. B. (1972). The influence of vegetational diversity on the population ecology of a specialized herbivore Phyllotreta cruciferae (Coleoptera: Chrysomelidae). Oecologia, 10, 321-346. 429 citations

Ullyett, G. C. (1947) Mortality factors in populations of Plutella maculipennis Curtis (Tineidae: Lep.) and their relation to the problem of control. Union of South Africa, Department of Agriculture and Forestry, Entomology Memoirs, 2, 77-202.

Post script

*I suspect, judging by how the two papers cite each other, that the Root (1973) paper was actually submitted first but that the vagaries of the publication system ,  meant that follow-up paper, Tahvanainen & Root (1972) appeared first.

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Not all books about aphids are for grown-ups!

A couple of weeks ago I was preparing a new lecture on the endocrine control of alary polymorphism in aphids. As is my wont when I want to get myself in the right frame of mind for aphid lecture writing, I went across to my book shelf to get down my copy of Tony Dixon’s excellent little book The Biology of Aphids (it might be old but it has some of the simplest and clearest explanations of complex aphid biology that I know of).

Anna aphid1

To my horror (and shock) it wasn’t here.  I had obviously lent it to a student and not instilled the fear of death into them 🙂  Once I got over my shock I turned to the internet (Amazon to be exact), and searched for an acceptable copy, which I successfully found*.  Whilst browsing the virtual shelves however, my eye was caught by a book with the intriguing title Anna Aphid.    I was stunned and amused, and as it cost less than a fiver including postage, I added it to my virtual basket.

A few days later it arrive and I was the proud owner of Anna Aphid  by Christine Goppel.

Anna aphid2

Anna Aphid

I instantly sat down and read it cover to cover (it isn’t very long). I don’t usually post book reviews, but having read it and pedantically groaned at the aphidological errors, I thought I might as well as share my thoughts with you all.  Anna Aphid was published by North-South Books in September  2005, and if they had any in stock you could buy it new for £9.99, (or $8.45 in the USA); don’t worry, there are plenty of used copies available, and mine was in very good condition.

The blurb for states “A tiny aphid named Anna lives on a big green leaf with her family. But Anna is different from the other aphids. She is curious to discover what lies beyond their green world. So Anna sets off to explore. In an entertaining visual guessing game, we see things from Anna’s point of view”

This is a fairly accurate statement of the content, although it gives things away a bit by saying that she lives on a leaf, as in the book Anna thinks she is living on a planet (remove the letter e and you get the pun).  The book which is very well-written, details the adventures of Anna from her beginnings as an apterous (non-winged) aphid, living with her family, including her father, (yes, a big aphidological blooper).  She expresses a wish to see the rest of the universe, and despite everything I had just read about endocrine control of alary polymorphism 🙂 suddenly sprouts wings, although given that her living conditions as shown in the illustrations seem quite crowded, this would be acceptable if she had just moulted to adulthood.  As an aphid pedant, I couldn’t help noticing that she only had one pair of wings instead of the normal two that I would expect.  The cephalo-thorax-abdomen body structure was also hard to ignore, as was the fact that poor Anna seemed to have mislaid a pair of legs somewhere.

Anna aphid3

Anna takes flight (she looks more like a frog with wings than an aphid)

Having taken flight and set off into the unknown vastness of space (from an aphid’s point of view), Anna has a series of adventures and near escapes from death.  She flies too near to the sun, narrowly escaping being burnt to a cinder, then lands on the moon where she attempts

Anna aphid4

Anna landing on the moon and giving us an interesting view of aphid feet!

to eat the strange vegetation she finds there , in the course of which she reveals that instead of having piercing and sucking mouthparts, she appears to be equipped with chewing ones.

Anna aphid5

Anna exhibiting non-standard mouth parts as she eats moon fodder.

Anna then hitches a lift on a comet, and lands on a shaggy red planet, which turns out to be yet another dangerous place as she is almost sucked into a black hole. Luckily, an exploding planet hurls Anna into a bubbling sea where she only just escapes drowning by climbing onto a small island.

Anna aphid6

The bubbling sea

 Safe from drowning, a gentle warm breeze helps her recover her strength enabling her to fly back to her home planet, and an excited

Anna aphid7

A warm breeze sending Anna safely on her way home

welcome from her whole family. She reports back to her father “I didn’t meet any other forms of intelligent life, but the universe is so big! Who knows what is out there”  Taken as an analogy for the huge number of insects that remain to be discovered, classified and researched, I can only agree with her sentiments.

Anna aphid8

The universe revealed! Can you guess which objects were which planetary features?

Actually, pedantic aphidological quibbles aside, I quite enjoyed the book.  It was a very pleasant surprise to find aphids featuring in such a positive and amusing way in fiction.  It would have been nice if the biology, especially the mouth parts, eyes, and other anatomical features were a bit more true to life, but it is just possible that I am slightly jealous that it had never occurred to me to write a story about an aphid 🙂  If you have children, grand-children, nieces or nephews of a suitable age I would certainly recommend it as a very suitable present and hopefully having read it, or had it read to them, they will learn to love aphids as much as I do.



Dixon, A.F.G. (1973) The Biology of Aphids, Edward Arnold, London


Post script

*I actually bought two copies of The Biology of Aphids, one which was in less good condition.  The sale details included the phrase “having owner’s name on inside front cover”, so I had to buy it just to check that it wasn’t my original copy that had been sold on by whichever student had ‘borrowed’ it.  As I should have expected it wasn’t mine 🙂 but still, it is always handy to have a spare copy in case one goes walkabout like my original did.


Post post script

In one of my emails to my daughter who lives in Australia, I mentioned that I had bought Anna Aphid and to my surprise received the following reply “I bought that book! The boys know about aphids, especially Toby; “ladybugs eat them” “so I was behind the curve yet again!




Filed under Aphidology, Aphids, Book Reviews