Tag Archives: Coleoptera

Entomological classics – the sweep net

I am certain that everyone who has studied biology at university and/or been on a field course, will have used a sweep net and heard the phrase “It’s all in the wrist”.  Along with the pitfall trap it is the most commonly used entomological sampling technique used today.  Although the premise is simple enough, a sturdy net, attached to a handle that is swept along, through or above low-lying vegetation, when used as a scientific tool and not just as a collecting device, things become somewhat more complex.  The sweep net, as an insect collecting device, has been around for at least 180 years, the earliest reference that I have been able to find being Newman* (1835).  There are a number of slightly later references in both general entomology texts and group specific books (e.g. Newman, 1844; Clark, 1860; Douglas, 1860; Douglas & Scott, 1865). Instructions for their use at this time are minimal, as this extract from Newman (1841) illustrates.

Newman (1841) a very brief description indeed.

This slightly later description of how to make a sweep net is, however, much more detailed, albeit somewhat sexist.

From Stainton (1852), although he seems to be quoting Newman.  Apparently Victorian men were unable to sew.

More detailed, albeit fairly basic instructions on how to use a sweep net can be found in those two invaluable sources, Ecological Methods (Southwood & Henderson 2004) (two pages) and Practical Field Ecology (Wheatear et al., 2011) (one page).  I was amused to see that the text in Southwood & Henderson was identical to that of the first edition (Southwood, 1966).

Now we come to the wrist action. There are a surprising number of ways in which you can swing a sweep net, but they all depend on the wrist moving your hand, and hence the net, in a figure of eight. The two most commonly used are what I think of as the one row side step, and the double front step.  In the former you walk in a straight line swinging the net backwards and forwards at your side, ideal for sampling a row crop. The latter, the double front step, is similar, but instead of swinging the net at your side, you swing it side to side in front of you as you walk along.  In a crop, this is great for sampling multiple rows, in a non-crop a good way of covering a nice wide area of vegetation. There are a further two techniques specifically designed for sweeping the upper part of vegetation, both originally devised for sampling soybean insects, the lazy-8 and the pendulum (Kogan & Pitre, 1980).  Both these involve having the net raised, the lazy-8 with the net raised above the crop at the back and front swings, whereas in the pendulum, the net is kept within the crop on the fore and reverse swings.  The final bit of wrist action, and arguably the most important and difficult to learn, is the flick-lock, which neatly seals the net and stops your catch escaping.

Having completed your sample of however many sweeps (remember a complete sweep is the figure of eight), and sealed your net, the next step is to transfer your catch to your collecting tubes, bags or jars.  A good sweep net, as well as being made from tough material, should be a bit sock shaped.  By this I mean that there is a ‘tail’ at the base of the net which helps make your catch more manageable if you are transferring directly to a plastic bag, as you are able to grab the net above the ‘tail’ end and push it into the collecting bag, before everting the net.

Two examples of sweep nets, a large and a small one.  You can also get a medium one in this series supplied by the NHBS web site for about £34. http://www.nhbs.com/professional-sweep-net

When I was a student, the sweep nets we were supplied with, were large enough to stick not just your head inside, but also to get your arms in, so that you could Poot up anything interesting, your shoulders forming the seal to the net.  Admittedly you did sometimes have an angry bee or wasp to contend with, but that was a rare event 🙂  Nowadays, sweep nets seem to be constructed on a much more modest scale, which makes sticking your head, let alone your shoulders into one, somewhat difficult.

Even the biggest modern one is too small for me to get my arms in to do some Pooting.

I was pleasantly surprised on an ERASMUS exchange visit to the University of Angers a few years ago, to find that the French, or at least those in Angers, were using sweep nets that were big enough for me to actually delve inside just as I did when I was a student 🙂

The joys of a sweep net with a view 🙂

Despite their undoubted popularity, value for money and relative ease of operation, there are a number of problems associated with sweep netting as a sampling technique.  Although these problems are summarised elsewhere (Southwood & Henderson 2004; Wheater et al., 2011) I can’t resist putting my own personal slant on the subject.

  • The type of habitat can have a marked effect on what you catch. Not all habitats are equally amenable to sweeping; spiny and woody vegetation poses more problems than a nice meadow and you need a really tough net for moorlands 🙂
  • A sweep net doesn’t necessarily give you an accurate picture of the species composition of the habitat. Not all insects are equally catchable, you are for example, much more likely to catch Hemipterans than you are Coleopterans (e.g. Standen, 2000)
  • The vertical distribution of the insects also affects what you catch. Many insects have favourite positions on plants e.g. the cereal aphid, Sitobion avenae prefers the ears and leaves, whereas the bird cherry-oat aphid, Rhopalosiphum padi is usually found at the bottom of the plant (Dean, 1974).
  • The weather; anyone who has tried sweep netting during, or after, a rain storm knows that this is the ultimate act of folly 🙂 Wet nets and wet samples are not a marriage made in heaven.
  • Time of day can also affect what you are likely to catch, pea aphids for example, are found at different heights on their host plants at different times of day (Schotzko & O’Keeffe, 1989). To be fair, this is of course not just a problem confined to sweep net sampling.
  • Sweep nets have a fairly well-defined height range at which they work best, they are not good at sampling very short grass and once the vegetation gets over 30 cm you start to miss a lot of the insects associated with it as the net doesn’t reach that far down. Also the efficiency of the sweep netter is reduced.
  • Finally, how the hell do you standardise your sweeps, not only between sweepers, but as an individual? Additionally, can you reliably use them quantitatively? This has been recognised as a problem for a long time (DeLong, 1932).  No one disagrees that sweep netting, provided all the caveats listed above are taken into account, gives a very good qualitative and comparative idea of the arthropod community of the area you are sweeping and they have been so used in many important ecological studies (e.g. Menhinick, 1964; Elton, 1975; Janzen & Pond, 1975) and extensively in agricultural systems (e.g. Free & Williams, 1979; Kogan & Pitre, 1980).  Comparing any sampling technique with another is difficult, and any attempt to quantify a catch so that specific units can be assigned to the area or volume sampled is welcome.  This has been attempted for the sweep net (Tonkyn, 1980), although I confess that I have never seen anyone use the formula developed by him.  In fact, although, according to Google Scholar his paper has been cited thirteen times, only one of the citing authors actually uses the formula, the rest just use him to cite sweep netting as a sampling method. Poor practice indeed.

An illustration of how the various components of the sweep net volume formula is derived (from Tonkyn, 1980).

Sweep nets are, despite the inability to get inside them anymore, great fun to use, extremely good at collecting material for ecology and entomology practicals and of course, a great ecological survey tool when used properly.  Google Scholar tells me that there are over 38 000 papers that mention them.  That many people can’t possibly be wrong 🙂

References

Clark, H. (1860) Catalogue of the Collection of Halticidae in the British Museum. Physapodes and Oedipodes Part 1. Published by the Trustees, London.

Dean, G.J. (1974) The four dimensions of cereal aphids. Annals of Applied Biology, 77, 74-78.

DeLong, D.M. (1932) Some problems encountered in the estimation of insect populations by the sweeping method.  Annals of the Entomological Society of America, 25, 13–17.

Douglas, J.W.  (1856) The World of Insects: A Guide to its Wonders. John van Voorst, London.

Douglas, J.W. & Scott, J. (1865) The British Hemiptera Volume I Hemiptera – Heteroptera. Ray Society, Robert Hardwicke, London.

Elton, C.S. (1975) Conservation and the low population density of invertebrates inside neotropical rain forest.  Biological Conservation, 7, 3-15.

Free, J.B. & Williams, I.H. (1979) The distribution of insect pests on crops of oil-seed rape (Brassica napus L.) and the damage they cause. Journal of Agricultural Science, 92, 139-149.

Janzen, D.H. & Pond, C.M. (1975) A comparison, by sweep sampling, of the arthropod fauna of secondary vegetation in Michigan, England and Costa Rica. Transactions of the Royal Entomological Society of London, 127, 33-50.

Kogan, M. & Pitre, H.N. (1980) General sampling methods for above-ground populations of soybean arthropods. Pp 30-60 [In] Sampling Methods in Soybean Entomology. (Eds.) M. Kogan & D.C. Herzog, Springer, New York.

Menhinick, E.F. (1964) A comparison of some species-individuals diversity indices applied to samples of field insects. Ecology 45, 859-861.

Newman, E. (1844) The Zoologist. A Popular Miscellany of Natural History, Volume 2. John van Voorst, London.

Newman, E. (1841) A Familiar Introduction to the History of Insects. John van Voorst, London.

Newman, E. (1835) The Grammar of Entomology. Frederick Westley & A.H. Davis, London.

Schotzko, D.J. & O’Keeffe, L.E. (1989) Comparison of sweep net., D-Vac., and absolute aampling., and diel variation of sweep net sampling estimates in lentils for pea aphid (Homoptera: Aphididae)., Nabids (Hemiptera: Nabidae)., lady beetles (Coleoptera: Coccinellidae)., and lacewings (Neuroptera: Chrysopidae). Journal of Economic Entomology, 82, 491-506.

Southwood, T.R.E. (1966) Ecological Methods, Methuen & Co., London.

Stainton, H.T. (1852) The Entomologist’s Companion; Being a Guide to the Collection of Microlepidoptera and Comprising a Calendar of the British Tineidae. John van Voorst, London.

Standen, V. (2000) The adequacy of collecting techniques for estimating species richness of grassland invertebrates.  Journal of Applied Ecology, 37, 884-893.

Tonkyn, D.W. (1980) The formula for the volume sampled by a sweep net.  Annals of the Entomological Society of America, 73,452-454.

Wheater, P.C., Bell, J.R. & Cook, P.A. (2011) Practical Field Ecology: A Project Guide, Wiley-Blackwell, Oxford.

 

*Of interest to me, but perhaps not to my readers, Edward Newman was one of the founder members of the oldest and most exclusive, yet low-key, entomological society in the world, The Entomological Club, of which I have the honour of being a member 😊 https://en.wikipedia.org/wiki/Edward_Newman_(entomologist)  founder member of the Entomological Club

 

 

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An inordinate fondness for biodiversity – a visit behind the scenes at the Natural History Museum

Last week  (13th February) I traveled with the MSc Entomology students to the Natural History Museum, London.  As part of their course they are taken behind the scenes and meet some of the curators and their favourite beasts.  This one of my favourite course trips and although I have made the pilgrimage for many years I always find something new to marvel at as well as reacquainting myself with some of my old favourites.  After an early start (0645) we arrived exactly on time (for a change), 10.30, at the Museum site in South Kensington.  I always have mixed feelings about South Kensington, having spent twenty years of my life commuting to Imperial College, just up the road from the museum.  I loved teaching on the Applied Ecology course I ran, but over the years the working atmosphere in the Department became really toxic* and I was extremely glad to move to my present location, Harper Adams University.  After signing in, which with twenty students took some time, Erica McAlister (@flygirl) led us through the thronged galleries (it was half term) to the staff

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Nostalgia time, my first biological memory, aged 3.

areas, where the research, identification and curating takes place.  Our first port of call was the Diptera where Erica regaled us with lurid tales of flies, big and small, beneficial and pestiferous.

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Erica McAlister extolling the virtues of bot flies

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Any one fancy cake for tea?  Kungu cake, made from African gnats

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Early advisory poster

As we left to move on to the Hymenopteran, hosted by David Notton, I noticed this classic poster warning against mosquitoes.  David chose bees as the main focus of his part of the tour, which as four of the students will be doing bee-based research projects was very apt.

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Admiring the bees

Whilst the students were engrossed with the bees I did a bit of fossicking and was amused to find that tobacco boxes were obviously a preferred choice by Scandinavian Hymenopterists in which to send their specimens to the museum.

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Finnish and Swedish tobacco boxes being put to good use

Next was that most eminent of Coleopterists, Max @Coleopterist Barclay who as usual enthralled the students and me, with stories of

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Max Barclay demonstrating a Lindgren funnel and talking about ‘fossilised’ dung balls

beetles large and small, anecdotes of Darwin and Wallace and the amusing story of how ancient clay-encased dung balls were for many years thought by anthropologists and archaeologists to be remnants of early humankind’s bolas hunting equipment.  It was only when someone accidentally broke one and found a long-dead dung beetle inside that the truth was revealed 🙂

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Often overlooked, the Natural History Museum is an exhibit in itself

 As we were leaving to move on to the Lepidoptera section, I felt obliged to point out to the students that not only is the outside of the museum stunningly beautiful but that the interior is also a work of art in itself, something that a lot of visitors tend to overlook. Once in the Lepidoptera section  Geoff Martin proudly displayed his magnificent collection of Lepidoptera, gaudy and otherwise, including the type specimen of the Queen Alexandra’s Birdwing which was captured with the aid of a shotgun!

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Lepidopterist, Geoff Martin, vying with his subjects in colourful appearance 🙂

Lunch and a chance to enjoy the galleries was next on the agenda.  Unfortunately, as it was half term this was easier said than done, although I did find a sunny spot to eat my packed lunch, as a Yorkshireman I always find the prices charged for refreshments by museums somewhat a painful.  In an almost deserted gallery I came across this rather nice picture.

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A lovely piece of historical entomological art.

Then it was on to the Spirit Collection.  Erica had laid on a special treat, Oliver Crimmen, fish man extraordinaire.  I may be an entomologist but I can sympathise with this branch of vertebrate zoology.  Fish, like insects are undeservedly ranked below the furries, despite being the most speciose vertebrate group.  I have been in the Spirit Room many times but have never seen inside the giant metal tanks.  Some of these, as Ollie demonstrated with a refreshing disregard for health and safety, are filled with giant fish floating in 70% alcohol.

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Fish man, Oliver Crimmen, literally getting to grips with his subjects.

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A fantastic end to the day culminated with a group photo with a spectacular set of choppers 🙂

Many thanks to Erica McAlister for hosting and organising our visit and to the NHM staff who passionately attempted to convert the students to their respective ‘pets’.

*one day I will write about it.

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Baxter Saves the Day – Beetle Boy – a tour de force by M G Leonard

Beetle Boy front

Beetle Boy, Chicken House Books, Paperback  ISBN: 9781910002704  £6.99

 “The sad fact is, that the number of insect is in decline. As we destroy their habitats, so we destroy their species, but we desperately need them. If all the mammals on the planet were to die out, the planet would flourish – but if all the insects disappeared, everything would very soon be dead.”

Not that I am biased, but any book that has the above in it gets my vote. Joking aside, this is a real gem of a book.  Although aimed at a younger audience than me, I found this a fascinating book.  I read it in one sitting, on the coach returning from a visit to the entomologists at the Natural History Museum, in company with the MSc Entomology students from Harper Adams University; a very appropriate setting.

Darkus, whose father, Dr Bartholomew Cuttle, a closet entomologist and the Director of Science at the Natural History Museum in London, has disappeared in mysterious circumstances, is one of a pair of unlikely heroes who help make this story the tour de force it is. The authorities believe that Dr Cuttle suffered some sort of breakdown and has walked away from his responsibilities.  Newspaper headlines ensue and the distraught Darkus, who remains convinced that his father has been spirited away or worse, now regarded as an orphan by social services, as his mother died four years earlier, is sent to an orphanage where he receives an unfortunate hair-cut.  Fortuitously, three weeks later, his eccentric Uncle Max, a somewhat unconventional archaeologist, returns from Egypt and Darkus is allowed to move in with his Uncle, who houses him in his attic, where he unknowingly meets his best friend to be, Baxter, and the adventure begins.  You will have to excuse this breathless introduction, but all this happens in the first sixteen pages!  What a roller-coaster of a read.

Next he is sent to a new school, (the worst nightmare for those of us of a nerdish persuasion) where he is befriended by two odd-balls, the lanky Virginia and the small, pale, bespectacled Bertholt.  We have school bullies, beetles with more than a dash of humanity mixed in, an evil businesswoman with a dark past and even darker secrets, a beautiful heiress thrown in for good measure, very odd neighbours, a secret den, evil henchmen, poison gas, death, destruction, entomology, successes, setbacks, laughter and sadness but a happy ending.  This is a story with something for everyone.  This is what my father, if he were still alive, would have called a rattling good yarn and I would agree with him wholeheartedly.

This is a hard book to describe without introducing spoilers so I am not going to give away any more of the plot than I already have. Imagine a mix of Swallows & Amazons, Stalky & Co*, the Famous Five, Five Find-Outers and Dog**, Artemis Fowl and any other of your favourite young detectives/adventurers that you can think of, and you will get somewhere close to imagining what a gripping read Maya Leonard has produced.   Beetle Boy owes nothing to any of these books, I only use them to illustrate, that in my opinion, this book is destined to join the classics.

It is of course the beetles that really make this book stand out from the crowd, and in more than one way, the fore edge of the book is decorated with beetles; beetles inside and out, what more can an entomologist ask for?

Beetle boy fore edge

Maya Leonard is a superb ambassador for beetles; they form an integral part of the story working in partnership with the human protagonists. She also subtly introduces the wonderful diversity of the beetle world to the non-initiated.  How many books can mention tiger beetles, powder post beetles, blister beetles, bombardier beetles, rhinoceros beetles, titans, stags, harlequins,  Goliath beetles and dung beetles and keep the plot moving along at a breath-taking pace.  Outside an entomology text book I don’t think I have ever come across so many beetle references.   Not only has Maya Leonard mentioned the beetles by name, she has managed to endow them with believable personalities but in a very unsentimental way, although that said, there is a very tragic scene near the end of the book.   I have been a professional entomologist for almost forty years and, yes some of what happens in this book might not be entomologically feasible, but the story carried me along on waves of excitement and totally enthralled and enchanted me and that is what matters.  I liked this book very much.  In fact, I was so excited about this book that I couldn’t wait for an appropriate grandson’s birthday so sent it to their mother, my daughter in Australia, for her birthday, and suggested that she could make it a family readathon 🙂

Maya Leonard, on the behalf of entomologists everywhere, I salute you. Roll on the sequel.

Dung beetles ZSL

The wonderful dung beetle sculpture at London Zoo.

Postscript and notes

Did I say that I really liked this book 🙂

*Rudyard Kipling’s fictionalised account of his school days at the United Services College – coincidentally, the character based on Kipling, is nicknamed Beetle! Well worth a read and in my opinion, possibly the inspiration for Frank Richard’s Billy Bunter books.

**Less well-known than the Famous Five, but I actually liked them better 🙂 http://www.enidblytonsociety.co.uk/five-find-outers.php

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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.

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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.

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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.

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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?

 

References

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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Entomological classics – the Window (pane) Flight Intercept Trap

A couple of years ago I received a paper to review in which the authors detailed how they had invented a new trap for sampling and collecting beetles in tropical forests. I was astounded to see that they were describing a window pane trap, something that I had known about since I was a student and which has been used by entomologists worldwide for many years.  I quite politely pointed this out in my review and directed the authors to Southwood ‘s Ecological Methods (1966).  The other referee was less tolerant, her/his report simply read “see Southwood page 193”.  At the time I wrote the review it was firmly stuck in my mind that the technique was as old as the hills, or at least as old the invention of cucumber frames 🙂  I certainly thought of it as a Victorian or Edwardian invention.  To my surprise when I started delving into the literature all the Victorian references to window traps turned out to be ways to protect households from invasion from houseflies and other unwanted flying insects; nothing to do with entomological sampling or collecting. E.g. this patent from 1856 where the inventor describes its operation as follows “The flies enter the trap through the passage B, as illustrated, and after satisfying their wants from the baitboard seek to escape, and being attracted by strong light from the glass back they fly in that direction and being headed out crawl up the glass back until they nearly reach the upper edge of the same, when, being still attracted and deluded by light from the glass top, they attempt to fly upward or through the same and in doing so instead of rising, are, owing to the inclination of the glass top, precipitated into the trough of soap suds and drowned, as illustrated in the drawing.

This fly trap is exceedingly simple, quite cheap, and only costs about twenty-five cents, and has been tried and found to answer well the purpose intended.”

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Unfortunately not what I was looking for 🙂

Despite scouring Google and Google Scholar, to the lengths of even getting to page 30, which apparently no-one does, it seems that the earliest reference to what we think of as a Window (pane) trap was not invented until 1954 (Chapman & Kinghorn, 1955)  to sample Ambrosia beetles (Trypodendron spp.) and other scolytids in Canadian forests.  There is unfortunately no picture to illustrate the trap, but the written description is fairly clear “ a piece of window glass (2 X 2 ft) set in a three-sided wooden frame from which a sheet metal trough is hung. The trough is filled with fuel oil or water….Traps are hung from various types of pole framework  depending on their location, and guy wires are used to keep them from swinging.”  I am pretty certain that this 1954 date is the earliest record as even that vade mecum of the entomologist, Instructions for Collectors No. 4a (Smart, 1949) has no mention of it.

The theory behind the window (pane) trap is that flying insects are unable to see the clear glass (or Perspex), bang into it, and stunned, fall into the collecting trough where they drown to be collected and identified later. A fantastically simple idea, which is why I was surprised that it took entomologists so long to invent it. As far as I can tell from the written description given by Chapman & Kinghorn (1955), the trap was suspended from a ground based framework.  I think that this version I found in Chapman (1962) is probably the original design or at least very close to it.

2

Chapman & Kinghorn’s original window flight trap? Chapman (1962).

They also used this is a much more ambitious way as shown below.

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Multiple Chapman & Kinghorn Window traps in operation (Chapman & Kinghorn, 1958).

This design in a slightly modified version  is shown in Lundberg (1979) and designs very

4

Ground based window trap in use in a Swedish forest (Lundberg, 1979).

similar to these are still in use.

5

A modern ground-based window(pane) flight intercept trap. http://www.qm.qld.gov.au/Find+out+about/Animals+of+Queensland/Insects/Collecting+insects/~/media/51C96B0159AF463C9E11CC1B100244DE.jpg?w=400&h=260&as=1

 

Despite its efficiency the ‘classic’ windowpane trap has perhaps not been used as much as it deserves, instead, a plethora of alternative designs have been described since the mid-1970s. So for example we have a small-scale tree hanging version, with a four-way window being used to catch forest coleoptera (Hines & Heikkenen, 1977).  Although the small area flight intercept traps were

6 6a

The Hines & Heikkenen (1977) small area window flight intercept trap.

relatively easy to deploy, they obviously just weren’t big enough for some people. In 1980, Peck & Davies, described a large-area window trap used to catch small beetles. This used the central panel of a Malaise trap as the window under which they placed a large metal collecting trough.  Unlike the Hines & Heikkenen trap, this like the original Chapman & Kinghorn trap, was ground-based.  The

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The Peck & Davies(1980) large-area “window” trap.

authors, in an attempt to impose order on to the entomological collecting world, urge other coleopterists to adopt a similar trap design.  In 1981 we see a modification to the Hines & Heikkenen

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The Omnidirectional flight trap (Wilkening et al., 1981).

trap to improve its efficiency (Wilkening et al., 1981).  Despite the name omnidirectional, implying that it catches insects from all directions,  this trap catches large fast-flying insects in the lower chamber, into which they fall stunned on bumping into the window pane and slow upwards flying insects in the upper chamber.  The authors argue that the original version of the trap did not catch slow-flying insects as they were able to detect the pane early enough to avoid being stunned and then took evasive action by flying up and away from the collecting bottle.  The new improved version takes advantage of this behaviour and traps them in the upper bottle into which they inadvertently fly.

In 1988, my fellow editor, Yves Basset, then at Griffiths University in Australia, now at the Smithsonian Tropical Research Institute in Panama, decided to combine a Malaise trap with a Hines & Heikkenen trap to produce what he called a composite interception trap (Basset, 1988),

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The Basset composite interception trap (Basset, 1988).

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The Basset composite trap in action. http://web.uvic.ca/~canopy/sampling.html

 

Despite this ingenious trap, trapping forest canopy insects obviously continued to occupy the minds of forest entomologists and in 1997 another pair of entomologists working in Australia came up with yet another design for a flight intercept trap, this time one that could be suspended at different heights in the canopy and left for long periods of time (Hill & Cermak, 1997). The novelty of this trap

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The Hill & Cermak modified Window trap

 

as far as I can make out is the use of multiple collecting chambers (ice cream tubs) and a plastic instead of a Perspex, ‘window’.

Entomologists are forever tinkering and ‘improving’ with sampling methods, so it should not be a surprise to find a group of entomologsist from the USA describing the ultimate in a composite trap,  this time a combination of four different traps, the cone, the Malaise, the yellow pan trap and the flight intercept trap (Russo et al., 2011). Interestingly, the authors describe this as a passive trap,

x

The ultimate composite insect trap (Russo et al., 2011).

but as it incorporates a yellow pan trap, which actively attracts insects, this is not strictly true.

Returning to the more conventional flight intercept trap design, Lamarre et al (2012) compared their very slightly modified window pane trap with Malaise traps in tropical forests in French Guiana and

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According to the paper, the first attempt to develop a standardised Window pane trap. https://commons.wikimedia.org/wiki/File%3AA_modified_windowpane_trap.jpeg

concluded that their model was more efficient and “should be used as an alternative and standardised method for future empirical studies”  a bold statement indeed, as they did not compare their trap with any of the other traditionally used window pane traps described above.

And finally and right up to date, and in the best entomological tradition of using cheap easily obtainable materials, yet another variant on the flight intercept trap; this time using plastic bottles – pop, soda, water, cider, beer, take your pick J (Steininger et al., 2015).

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The simple, effective and accessible bottle window intercept trap. http://jee.oxfordjournals.org/content/108/3/1115

I am sure, however, that as I write, some ingenious entomologist out in the field somewhere, is thinking of yet another modification to the window (pane) flight intercept trap to make my post out of date!

 

References

Basset, Y. (1988) A composite interception trap for sampling arthropods in tree canopies.  Journal of the Australian Entomological Society, 27, 213-219

Chapman, J.A. (1962) Field studies on attack flight and log selection by the ambrosia beetle Trypodendron lineatum (Oliv.) (Coleoptera: Scolytidae). Canadian Entomologist, 94, 74-92

Chapman, J.A. & Kinghorn, J.M. (1955) Window flight traps for insects.  Canadian Entomologist, 87, 46-47.

Chapman, J.A. & Kinghorn, J.M. (1958) Studies of flight and attack activity of the ambrosia beetle, Trypodendron lineatum (Oliv.) and other Scolytids. Canadian Entomologist, 90, 362-372

Hill, C.J. & Cermak, M. (1997) A new design and some preliminary results for a flight intercept trap to sample forest canopy arthropods.  Australian Journal of Entomology, 36, 51-55

Hines, J.W. & Heikkenen, H.J. (1977) Beetles attracted to severed Virgina pine (Pinus virginiana Mill.). Environmental Entomology, 6, 123-127

Lamarre, G.P.A., Molto, Q., Fine, P.V.A. & Baraloto, C. (2012) A comparison of two common flight interception traps to survey tropical arthropods.  ZooKeys, 216, 43-55

Lundberg, S. (1979) Fångst av skallbaggar med hjälp av fönsterfällor. Entomologisk Tidskrift (Stockolm), 100, 29-32

Peck, S.B. & Davies, A.E. (1980) Collecting small beetles with large-area “window” traps.  Coleopterists Bulletin, 34, 237-239

Russo, L., Stehouwer, R., Heberling, J.M. & Shea, K. (2011) The composite insectrrap: an innovative combination trap for biologically diverse sampling.  PLoS ONE, 6, e21079.doi:10.1371/journal.pone.0021079

Wilkening, A.J., Foltz, J.L., Atkinson, T.H. & Connor, M.D. (1981) An omnidirectional flight trap for ascending and descending insects.  Canadian Entomologist, 113, 453-455

 

Postscript

Apropos of the ultimate composite trap, I came across this combination four-way window-yellow pan trap combination some years ago, but have not been able to find a published inventor of it.  I should also add that flight intercept traps are also sometimes known as impact traps.

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*Vade mecum, a handbook or guide that is kept constantly at hand for consultation.

 

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Being inspired by the BES

This week (20th July) I have had the privilege of being able to interact with 50 undergraduates (mainly just finished their first year) under the auspices of the British Ecological Society’s new undergraduate summer school held at the Field Studies Council’s Malham Tarn Centre. The scheme enables aspiring ecologists to have “an opportunity to enhance their existing knowledge with plenary lectures from senior ecologists, fieldwork, workshops, careers mentoring and more at a week-long residential course” This was especially pleasurable for me because as a school boy and student I spent several enjoyable camping holidays at Malham and it gave me an opportunity to take part in a field course again, something I have missed since leaving Silwood Park where I ran the now defunct annual two-week long Biodiversity & Conservation field course. The programme included two ecological luminaries and old friends of mine, Sue Hartley from the University of York and plant scientist and author, Ken Thompson formerly of Sheffield University and also Clare Trinder from the University of Aberdeen.  Also in the programme was conservation biologist, Stephanie Januchowski-Hartley,  and additional input from the Chartered Institute of Ecology & Environmental Management (CIEEM), microbial ecologist, Dr Rob Griffiths from CEH and ecologist Dr Peter Welsh of the National Trust.

I arrived mid-morning of the Tuesday, having driven up from Shropshire to Yorkshire the night before, having taken the opportunity to stay in the old family home in Kirk Hammerton before it is put up for sale. Whilst there I also set a few pitfall traps to collect some insects that we might not catch otherwise. As it happened they were a dismal failure, returning mainly spiders, harvestmen and woodlice, plus one nice carabid beetle, more of which later. The weather didn’t look all that promising for an insect sampling session but I kept my fingers crossed and hoped that it wouldn’t rain as much as it did almost 40 years ago when my best friend from school and I aborted our camping holiday at nearby Malham Cove after three days of solid rain 😉

Malham Tarn

Malham Tarn – not quite raining

  I was greatly amused on arriving to be greeted by a very large arachnid lurking on an outhouse.

Malham spider

We breed them big in Yorkshire!

Malham Tarn FSC

Malham Tarn Field Studies Centre

After checking my equipment and locating suitable sampling sites I joined the students, Karen Devine, the BES External Affairs manager and some of the PhD mentors for lunch. After lunch it was my slot, a chance to infect (sorry, inspire), fifty ecologically included undergraduates with a love of insects. After being introduced by Karen I launched into my talk to a very full room of students.

Karen Devine

Karen instilling order and attention 😉

Ready to be inspired

Ready and waiting to be inspired

The undergraduates came from thirty different UK universities with a strong female bias, 34:16. Exeter University had four representatives, with Reading, Liverpool John Moores, UCL and Bristol with three each. I was sorry to see that there were no students from my Alma mater Leeds, or from my former institution, Imperial College, once regarded as the Ecological Centre of the UK, although UEA where I did my PhD, had two representatives.  There was also one representative from my current place of work, Harper Adams University. Incidentally one of the students turned out to have gone to the same school that I did in Hong Kong, King George V School, albeit almost fifty years apart; a small world indeed.

I set the scene by highlighting how many insect species there are, especially when compared with vertebrates.

The importance of insects

The importance of insects and plants

Number of animal species

Or to put it another way

After a quick dash through the characteristics of insects and the problems with identifying them, exacerbated by the shortage of entomologists compared with the number of people working on charismatic mega-fauna and primates, I posed the question whether it is a sound policy to base conservation decisions on information gained from such a small proportion of the world’s macro-biota.

Then we were of into the field, although not sunny, at least it was not raining so I was able to demonstrate a variety of sampling techniques; sweep netting with the obligatory head in the bag plus Pooter technique, butterfly netting, tree beating and, as a special treat, motorized suction sampling, in this instance a Vortis.

Sampling

With aid of the PhD mentors and Hazel Leeper from the Linnaen Society, the students were soon cacthing interesting things (not all insects) and using the Pooters like experts.

Students sampling

Getting close up with the insects

I also let some of the students experience the joy of the Vortis, suitably ear-protected of course. All good things come to an end and it was then time to hit the microscopes, wash bottles, mounted pins and insect keys.

In teh lab

Getting stuck in – picture courtesy Amy Leedale

Down the microscope

What’s this?

I was very impressed with how well the students did at getting specimens down to orders and families and have every confidence that there are a number of future entomologists among them. After the evening meal, Kate Harrison and Simon Hoggart from the BES Publications Team introduced the students to the tactics of paper writing and publishing which I think they found something of an eye-opener. The students, after a rapid descent on the bar, enjoyed a Pub Quiz whilst I relaxed with a glass of wine until it was dark enough for me to demonstrate the wonders of using fluorescent dust to track our solitary carabid beetle using my UV torch before heading off to bed.

Fluorescent carabid Eloise Wells

Glow in the dark carabid beetle – the bright lights of Malham Tarn – photo courtesy of Eloise Wells

I was sorry to have to leave the next morning, it would have been great fun to have stayed the full week, but next year I do hope to be able to be there for at least two days and nights so that we can do pitfall trapping and light trapping and of course, have more fun with fluorescent insects.

I hope the students found the whole week inspirational and useful, I was certainly inspired by their obvious enjoyment and interest and will be surprised I if do not come across some of them professionally in the future.

Well done BES and congratulations to Karen and her team for providing such a great opportunity for the students. I am really looking forward to next year and being able to see great Yorkshire features like this in the sunshine 😉

Yorkshire grit

 

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Entomological classics – The Malaise Trap

More years ago than I care to remember, my friends and I were playing the now, very non-PC game of Cowboys and Indians, when we saw through the trees, what we thought was a tent. On sneaking up to it we found that, if it was a tent, it wasn’t very watertight!  There were no sides, instead there was a central panel and the whole thing was made of netting.  What we had actually found, was of course a Malaise trap, although of course we did not know this at the time.  It was only later as an undergraduate that I realised what we had found all those years before.

So exactly what is a Malaise trap and how did it come into being? The Malaise Trap is a relatively new invention.  It was invented by the Swedish entomologist, Dr René Malaise in the 1930s (hence the name) and revealed to a more general entomological audience in 1937 (Malaise, 1937).  It was actually designed as a replacement for the traditional hand-held collecting net, which as Malaise states in the introduction to his paper ‘”Since the time of Linneaus, the technique of catching insects has not improved very much, and we are to-day using the same kind of net as then for our main instrument”.

I was amused, when reading on further, to find that my childhood gaffe of confusing a Malaise Trap with a net was fully justified. Malaise, later in the same paper writes, ”During my extensive travels I have repeatedly found that insects happened to enter my tent, and that they always accumulated at the ceiling-corners in vain efforts to escape at that place without paying any attention to the open tent door”. He then goes on to describe how he conjectured that “a trap made as invisible as possible and put up at a place where insect are wont to patrol back and forth, might catch them much better than any tent, and perhaps better than a man with a net, as a trap could catch them all the time, by night as by day, and never be forced to quit catching when it was best because dinner-time was at hand”.

He thus set about constructing a trap based on the idea of an open tent with a collecting device attached to the central end pole to take advantage of the fact that most insects when encountering an obstacle tend to fly upwards. On reaching the apex of the tent, the only way out is into the collecting device which is filled with a killing agent.  It is in effect, a flight intercept trap, but unlike window traps (subject of a later post), the insects instead of falling into a collecting device, head upwards and collect themselves. Malaise tested his first version of the trap on an expedition to Burma and found them to be a great success “every day’s catch from the traps grew larger and larger, and sorting it required more and more time”. He found the traps particularly good for Diptera and Hymenoptera but also very good for Coleoptera and Noctuid and Sphingid moths.  He also mentions catching Hemiptera.

In outward form, the Malaise Trap has remained fairly unchanged since its invention. The first versions were apparently fairly heavy, having a brass insect collecting cylinder and also only had one opening.  Malaise recognised the disadvantages of the single entrance version and suggested in the 1937 paper that a bilateral model would be more effective.  These followed in due course. Modified versions using plastic cylinders and different netting material were  invented in the 1960s (Gressit & Gressit, 1962; Townes, 1962; Butler, 1965).  Townes’s paper gives a very detailed description of the construction and use of modified Malaise traps (90 pages) in contrast to Butler’s three page description of a cheap and cheerful version made from a modified bed-net.

Nowadays, entomologists world-wide, particularly Dipterists and Hymenopterists, use Malaise traps of various designs and colours, and cost.  In the UK they are available from commercial outlets at prices ranging from £60 to £165. They are extremely effective and we use them to collect insects for our practical classes in the Entomology MSc based at Harper Adams University.

    Malaise traps

Malaise trap in operation, Harper Adams University, Shropshire, UK.

 

References

Butler, G.D. 91965) A modified Malaise insect trap. The Pan-Pacific Entomologist, 41, 51-53

Gressitt, J.L. & Gressitt, M.K. (1962) An improved Malaise Trap. Pacific Insects, 4, 87-90

Malaise, R. (1937) A new insect-trap.  Entomologisk Tidskrift, Stockholm, 58, 148-160

Townes, H. (1962) Design for a Malaise trap. Proceedings of the Entomological Society of  Washington, 64, 162-253

 

Post script

Malaise was not just an entomologist; he was an explorer and a passionate believer in the existence of Atlantis. A detailed biography of this extraordinary character can be found here, including a photograph of the original Malaise trap.

 

Post post script

I was amused to find in the 1949 edition of Instructions for Collectors No. 4a, Insects (Smart, 1949), this somewhat dismissive comment about the Malaise Trap “It is a very novel idea and captures large numbers of insects, but as at present designed is rather cumbersome, and since its design will probably be modified with experience it is not described here

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Entomological classics – The insect olfactometer

In 1924, Norman McIndoo (1881-1956) an entomologist at the Fruit Insect Investigation Department in the USDA Bureau of Entomology based in Washington DC was instructed by his boss Dr. A.L. Quaintance, to make a study of insect repellents and attractants.   After two years of frustrated experimentation McIndoo invented a piece of apparatus that would revolutionise the study of insect behaviour, the Y-tube olfactometer (McIndoo, 1926) . He freely admitted in his paper that he had borrowed the name from the Zwaademaker olfactometer (Zwaademaker, 1889) a device used to test the sense of smell in humans.  As you can see however, his apparatus bore no resemblance to that of Zwaademaker.

Zwaardemaker olfactometer    McIndoo olfactometer

McIndoo ‘s apparatus was first used to find out whether Colorado potato beetles (Leptinotarsa decemlineata) responded to the odour of the potato plants. The beetles were placed in a dark bottle in a light-tight box, the bottle being attached to the stem of the Y-tube by a tube through which the beetles were able to move, at first being attracted to the light. Once they reached the junction of the Y they then had to make a choice between the two forks this time using their sense of smell. A pump was used to draw air from the two forks, one of which was connected to a jar containing a potato plant, the other which held the control substance. In theory, once at the fork the beetles were confronted with two streams of air, one smelling of potato, the other being odourless. McIndoo was indeed able to show that about 70% of the beetles responded positively to the odour produced by the potatoes. He also showed that the beetles responded to extracts made from the foliage of a number of different host plants.  He briefly mentions in the paper that the beetles were able to tell the opposite sex by smell and that the males would follow sexually mature females. He had accidentally discovered insect sex pheromones but did not realise it at the time. In the last part of his paper he provides data showing that other insect species, including Lepidoptera, were also able to respond to host plant odours.  The Y-tube olfactometer and the closely related T-tube olfactometers soon became the accepted way to test insect response to odours and are widely used in laboratories around the world to this day, for example http://weslaco.tamu.edu/research-programs/entomology/subtropical/behavior/ and http://sciencebykathy.wordpress.com/

Two way olfactometer

http://openi.nlm.nih.gov/detailedresult.php?img=3422343_pone.0043607.g005&req=4

They do however have some limitations; there is a tendency for turbulence to occur at the junction of the Y- and T-tubes which means that there is some mixing of the test odours and this means that there is not a clearly delineated odour field into which the insects can enter, leave and re-enter if they so wish. In 1970, Jan Pettersson from the Swedish University of Agricultural Sciences at Uppsala, invented the four-way olfactometer with which to test the existence of a sex pheromone in the aphid Schizaphis borealis (Pettersson, 1970).

Pettersson 4 way   Pettersson 4 way 1

The four-way olfactometer provides a neutral central zone which is surrounded by four very distinct odour boundaries which the test insects can enter, sample the odour and then either stay or leave and move into another area of the apparatus. Louise Vet and colleagues (Vet et al., 1983) from the University of Leiden added some modifications to the original Pettersson version, with which to study the behaviour of aphids and their parasitoids.

Vet 4 way

 The four-way olfactometer, whether a Pettersson or Vet version, or a modification of the two, is now regarded as the ‘gold’ standard and is used very widely around the world.

Four way - Indian

http://www.nrcb.res.in/gallery8.html

It is certainly our research group’s favoured version and we use it for testing the responses of aphids, hymenopteran parasitoids, lepidoptera and beetles to a range of odours (Trewhella et al., 1997; Leahy et al., 2007; Pope et al., 2012). We are currently using mini-versions to test the olfactory responses of predatory mites. Watch this space.

References

Leahy, M.J.A., Oliver, T.H., & Leather, S.R. (2007) Feeding behaviour of the black pine beetle, Hylastes ater (Coleoptera: Scolytidae). Agricultural and Forest Entomology, 9, 115-124. http://onlinelibrary.wiley.com/doi/10.1111/j.1461-9563.2007.00328.x/full

McIndoo, N.E. (1926) An insect olfactometer. Journal of Economic Entomology, 19, 545-571

Pope, T.W., Girling, R.D., Staley, J.T., Trigodet, B., Wright, D.J., Leather, S.R., Van Emden, H.F., & Poppy, G.M. (2012) Effects of organic and conventional fertilizer treatments on host selection by the aphid parasitoid Diaeretiella rapae. Journal of Applied Entomology, 136, 445-455. http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0418.2011.01667.x/full

Pettersson, J. (1970). An aphid sex attractant I Biological studies. Entomologia Scandinavica 1: 63-73.

Sanford, E.C. (1891) Laboratory course in physiological psychology. American Journal of Psychology, 4, 141-155, http://psychclassics.yorku.ca/Sanford/course2.htm

Trewhella, K.E., Leather, S.R., & Day, K.R. (1997) The effect of constitutive resistance in lodgepole pine (Pinus contorta) and Scots pine (P. sylvestris) on oviposition by three pine feeding herbivores. Bulletin of Entomological Research, 87, 81-88. http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=2497592

Vet, L.E.M., Van Lenteren, J.C., Heymans, M., & Meelis, E. (1983) An airflow olfactometer for measuring olfactory responses of hymenopterous parasitoids and other small insects. Physiological Entomology, 8, 97-106. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3032.1983.tb00338.x/abstract

Zwaademaker, H. (1889) On measurement of the sense of smell in clinical examination. The Lancet, 133, 1300-1302

 

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It’s a Wonderful Life – an Inordinate Fondness for Insects

On Tuesday (4th February) I had the very pleasant task of escorting the MSc Entomology and Integrated Pest management Students from Harper Adams University on a trip to visit the Entomology Department at the Natural History Museum, London.  Despite having to leave at six in the morning all the students were on time (I hesitate to add bright-eyed and bushy-tailed as that would be a patent untruth), but they were there on time.  I almost didn’t make it on time, as being a Yorkshire man, I decided that rather than leave my outside light on all day, I would try to make it to my garden gate in the dark.  Consequently, I had a very close encounter with my garden pond and turned up at the coach with a wet sleeve, a bruised knee, skinned knuckles and one leg of my jeans tastefully decorated with pond-weed.  Still the four-hour journey from Edgmond to London gave me plenty of time to dry out 😉

We arrived as planned at 10 am and were met by Max Barclay , the Collections Manager of Coleoptera  and Hymenoptera, otherwise known as @Coleopterist who first told us that there were 22 000 drawers of beetles surrounding us, much more than either the Dipterists or Hymenopterists would be able to show us!

Beetle Collection

He did confess however, that he was no longer able to claim that beetles were the most speciose group in the world and that the famous quotation might now have to be “ an inordinate fondness for wasps (or possibly flies)”.  Nothing daunted he wowed us with the largest beetles in the world, the aptly named Titans, quickly followed by a few of Charles Darwin’s collection from his famous HMS Beagle trip.

Max Titans   Darwin's

Next came some glorious metallic coloured specimens which looked as if they had been painted; interestingly if they had been painted, they would actually be too heavy to fly.

Gold beetles

Max kept the students, and me, enthralled for some time and then led us upstairs to the Coleopterist’s Offices.  These were fantastic; thanks to an added mezzanine floor, they get to work surrounded by carvings and magnificent windows.  What a fantastic place to work.

Beetle offices  Max talking in offices Office space  Owl

Some of the researchers such as my friend Chris Lyal @Chrislyal are so dedicated that they rarely leave their chairs resulting in dramatic wear patterns 😉

Chris' chair

Next on the agenda was the Hymenopteran collection where we were greeted by Gavin Broad also known as @BroadGavin, the Senior Curator of Hymenoptera.  I don’t want you to think that entomologists are competitive and try to out-do each other, but

Gavin Broad

 we were shown the longest wasp in the world; quite impressive, but not a patch on the Titans 😉

Longest wasp

This was followed by a fantastic selection of wasp nests (of which I only show a few),

Wasp nest 1   Wasp nest 2

including one wearing a tweed jacket and woolly jumper!

Wasp nest jumper

We left the Hymenopteran collection with a reminder of how few taxonomists there are and how much material needs to be sorted and identified; the picture shows just a tiny fraction of the material that comes in each day.

to be sorted

After lunch we joined Erica McAlister @FlygirlNHM, the Collection Manager for Diptera, Fleas and Spiders.  She regaled us with stories

Erica

of bot flies, maggot-ridden corpses, showed us the maggots from the Ruxton murders (a forensic entomology first)

Ruxton maggots

and demonstrated how some flies twerk!  I really should have had a video camera.  I must also not forget to mention how many boxes of Dipteran specimens there are still left to identify and catalogue.  Again this is only a small selection.

Flies to sort

Erica then led us into the bowels of the museum to see some of the largest invertebrates on the planet, giant squids,

Squid

albeit not insects but quite impressive.  These are not on display to the public because they are preserved in formaldehyde, now deemed to be too dangerous to expose to all and sundry, despite the fact that as a school boy and undergraduate I spent a lot of time dissecting specimens preserved in the stuff, and as I recollect, not wearing gloves or face masks!  If you do want to see it, it is possible to take a free tour of the Spirit Collection http://t.co/U49HRoFbhV.  It was then time to get back on the coach and head back to Shropshire and Harper Adams University.   Here I am, captured on film by one of the students @Ceri_Watkins  as I try to make sure that everyone gets back on to the coach!

Loading the bus

All in all, a most enjoyable day and many thanks to our hosts for making it so memorable.

Post Script

I think that the thing that impressed us most was the enthusiasm everyone we met had for their particular group.  Even we general entomologists tend to have a favourite group of insects, in my case aphids, but the passion that Max, Gavin and Erica have and displayed for their specialities, is something very special indeed.  People tend to think of insect taxonomists as weird, introverted, bearded old gentleman.  Anyone who has the privilege to meet any of our three hosts will realise how wrong this stereotype is and will wonder why the Government and Research Councils are so reluctant to adequately fund proper taxonomy.

Without a thorough knowledge of the taxonomy and diversity of insects and allied organisms we will continue to be at risk from invasive pests and diseases.  If we don’t know what is out there, then how can we be ready to protect our crops and environment from outbreaks, or indeed, know how and what to protect to preserve the wonderful biodiversity which our planet supports.  It is time to admit that the funding for the study of vertebrates needs to be scaled back by at least 90% and those resources diverted to the identification and study of the biology and ecology of the dominant animal species of the world, the invertebrates.  In case anyone thinks that I am total partisan, I would also call for 20% of the funding devoted to vertebrate research should be dedicated to training plant scientist and funding whole organism botanical research.  Please spread the message.

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Saproxylicphilia – dead wood alive and well

As some of my followers on Twitter will know, I have the habit of when certain so-called general ecology and conservation journals issue their new contents list, of highlighting how few invertebrate papers have been published in that particular issue.  The journal Animal Conservation, has often been the recipient of my Tweets in that they, despite their name, pretty much ignore most of the animal world, concentrating instead on those minority organisms, the vertebrates and then, mainly mammals.

Animal Conservation tweets

I was thus a little surprised when at the beginning of June I received an email from the Editorial Office of Animal Conservation asking me if I would be willing to provide a commentary piece on a paper that would be coming out shortly

From: Elina Rantanen

Sent: 05 June 2013 14:11

To: Simon Leather

Subject: Animal Conservation – Invitation to write a commentary for Feature Paper

 Dear Prof. Leather,

 I am writing on behalf of the Editors of Animal Conservation to enquire whether you would be interested in writing a short commentary on a paper which will be published in our August issue.  The paper (attached) is entitled: ‘Protected areas and insect conservation: questioning the effectiveness of Natura 2000 network for saproxylic beetles in Italy’ by Manuela D’Amen et al. We would be delighted if you would be willing to contribute.

 By way of background, the editors of Animal Conservation select a topical article in each issue, and invite experts in the field to provide short commentaries on the study.  These commentaries are then published alongside the original paper, together with a concluding piece by the original authors.  The intention of the commentaries is to discuss the findings of the study and to draw out some of their wider implications.

 Commentaries can also be used to critique a study and can generate debate although this is not the primary intention.  We normally aim to publish about three commentaries with every highlighted article.  The commentaries are usually about 1,000 words in length, and do not require an abstract.  If you agree, I would need to receive your commentary by 19th June. The commentary will be checked by the Editor of the Feature paper before it is accepted.

 If you would like to see examples of previous commentaries, please visit the Animal Conservation homepage: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-1795 where previous featured articles and commentaries are available with free access.

 Please let me know as soon as possible whether or not you will be able to accept this invitation.

 I look forward to hearing from you – it would be great to have you involved.

 Kind regards,

 Elina

 Dr. Elina Rantanen

Editorial Office, Animal Conservation

I was of course hoist with my own petard and had no other choice but to agree.  Actually, I was delighted and grateful to have the opportunity.

Petard cartoon

The paper, by D’Amen and colleagues dealt with the mismatch between the Natura 2000 network and the conservation of saproxylic beetles in Italy.  The authors pointed out that basically saproxylic beetles were badly served by the network in Italy which had been designed with the large charismatic mega-fauna in mind, and not the small things that run the World.  This of course allowed me a platform from which to further highlight yet another example of institutional vertebratism and reiterate my call for a less biased approach to conservation and ecology in general, which I was very happy to do indeed.

It was while I was writing this that I came across a blog post by Jeff Ollerton of Northampton University in which whilst discussing the huge amount of pollination literature that today’s PhD students are faced with, he described a phenomena that he aptly called The Cliff

Now it just so happens that I have recently had a PhD student successfully defend her thesis on saproxylic beetles and their natural enemies.  Her PhD was a follow-up to another one of my former students who investigated the volatiles given off by those fungi that cause the decay in dead and dying trees.  In addition, in my role of Editor-in-Chief of Insect Conservation & Diversity, I have noticed an increasing number of papers on saproxylic insects being submitted to the journal.  Jeff’s article thus stimulated me to see if there was also a cliff effect in the saproxylic literature.  I thus turned to that invaluable source of data, the Web of Knowledge and using the terms saproxylic , and saproxylic  beetles set the search going.   I did indeed find a Cliff effect, albeit slightly later than the pollination one.  The first published item appeared to be in 1976 which is surprising as according to Grove (2002), the term was first coined by Dajoz in France in 1966.  I have, however, so far been unable to find this paper to confirm this assertion.  Apparently, prior to Dajoz, anything that fed on wood, dead or alive, was termed xylophagous or as a xylobiont.  It was perhaps Martin Speight’s ground breaking report of 1989 extolling the importance of the dead wood habitat that caused the first cliff in about 1991.  This was followed by another ten years later or so, and since then there has been a huge increase in interest in the subject.  The incomplete data for 2013 indicate that the trend is still upwards.  Most work appears to be on beetles which given their relative abundance, makes sense.

Saproxylic published   Saproxylic citations

So, yes here we have another example of a step change in a research area.  I wonder how many more examples there are out there and if it is possible to tie them in to a particular government policy or influential publication.

References

Dajoz R. (1966) Ecologie et biologie des coléoptères xylophages de la hêetraie. Vie Milieu 17:525–636

Grove,  S. J. (2002). Saproxylic insect ecology and the sustainable management of forests. Annual Review of Ecology and Systematics 33: 1-23.  http://www.annualreviews.org/doi/abs/10.1146/annurev.ecolsys.33.010802.150507?journalCode=ecolsys.1

Speight MCD. 1989. Saproxylic Invertebrates and their Conservation. Strasbourg, Fr: Counc. Eur. 79 pp.

In case you wondered

What is Natura 2000 ?

Natura 2000 is the centrepiece of EU nature & biodiversity policy. It is an EUwide network of nature protection areas established under the 1992 Habitats Directive. The aim of the network is to assure the long-term survival of Europe’s most valuable and threatened species and habitats. It is comprised of Special Areas of Conservation (SAC) designated by Member States under the Habitats Directive, and also incorporates Special Protection Areas (SPAs) which they designate under the 1979 Birds Directive. Natura 2000 is not a system of strict nature reserves where all human activities are excluded. Whereas the network will certainly include nature reserves most of the land is likely to continue to be privately owned and the emphasis will be on ensuring that future management is sustainable, both ecologically and economically.  The establishment of this network of protected areas also fulfills a Community obligation under the UN Convention on Biological Diversity.

http://ec.europa.eu/environment/nature/natura2000/

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