Insectageddon, Ecological Armageddon, Global insect Apocalypse – why we need sustained long-term funding

“To him that countryside, largely unspoiled in his early days, was an inexhaustible source of delight and a subject of endless study and mediation…And as the years passed and the countryside faded away under the withering touch of mechanical transport, that knowledge grew more and more precious. Now, the dwindling remnants had to be sought and found with considered judgement and their scanty material eked out with detail from the stores of the remembered past”  R Austin Freeman The Jacob Street Mystery (1942)

The recent release of the IPBES report highlighting the significant global declines in biodiversity has prompted me to revisit the “Insectageddon” debate, some of the ramifications of which I wrote about earlier this year.

 

Summary from the IPBES report – note that even a well-known group like dragonflies is quite data deficient*.

Insects may be in decline, but papers about their decline have been around for almost twenty years and even more are appearing as we entomologists begin to hope that people may at last be beginning to listen to us.

A selection of some of the many papers that have documented insect declines over the last several years.

Using the now infamous search term “insect decline” in the Google Trends function I was not surprised to see the steep increase since 2016, as 2017 was the year in which the paper reporting  the 75% decline in flying insect biomass appeared (Hallmann et al., 2017), but I was intrigued by what appeared to have been a peak in mentions since 2004.

Google Trends using the phrase insect decline – last data point is 2019 at the time of writing

I wondered what caused the peak in 2004, so using the same key words as Sánchez-Bayo & Wyckhuys (2019), checked Google Scholar and Web of Science to see if I could track down a paper that might have caused a media splash at the time.  I also checked 2003, in case there was a delay in reporting. To my surprise I couldn’t find anything relevant in 2004, but 2003 threw up three papers (Hopkins & Freckleton, 2002; Kotze & O’Hara, 2003; Dennis & Shreeve, 2003).  The first was about the decline of taxonomists, which although a serious problem is unlikely to have generated that much attention, the other two were about long-term declines in Carabid beetles (Kotze & O’Hara, 2003) and the third about the decline of French butterflies (Dennis & Shreeve, 2003) which again, I suspect were probably not high enough profile to generate a big splash.  I was puzzled but then I thought, why not just put it into Google with the date 2004, and sure enough it directed me to a Nature News item with the headline Insect deaths add to extinction fears, which in turn led me to Thomas et al., (2004) which I am pretty certain generated the peak in interest and also highlights the fact that ecologists and entomologists have been worrying about this problem for some time.

Since the appearance of the, now, infamous paper, that sparked the most recent round of Armageddon stories (Sánchez-Bayo & Wyckhuys, 2019), a lot has been, quite justifiably, written about the short-comings of the study both in scientific journals (e.g. Komonen et al., 2019, Simmons et al., 2019; Thomas et al, 2019, Wagner, 2019) and in blog posts, such as this thoughtful piece from Manu Saunders.

What does need to be stressed, is that although these commentators recognise the shortcomings of the paper, none of them, including the most scathing of commentators (Mupepele et al., 2019) dispute the fact, that insects, in general, are in decline. Unfortunately, the climate change deniers and their ilk, have, of course, used the criticisms to try and spread a message of “nothing to fear folks”.

Hopefully a failed attempt at downplaying the insect decline stories, but a great example of how climate change deniers are keen to muddy the waters

For humans with our relatively short lifespans, shifting baselines can be a problem (Leather & Quicke, 2010; Tree, 2018), in that people accept what they have known in their childhoods as the natural state of nature.  It can of course work the other way. I can remember the late great Miriam Rothschild telling me in the early 1990s, how as a “gel” in the 1920s a particular butterfly species that was currently at very low numbers compared with the 1970s which was what I and similar aged colleagues were remarking upon, was 50 years before that, also very low, her message being “populations cycle”.  It is because of this propensity, which is nicely illustrated by some of my 20-year data sets, all from the same 52 trees, that we need access to long-term funding to monitor insect populations.  Chop my data sets into three-year concurrent periods, the time-span of a typical PhD study or research grant, and you end up with some very different pictures of the populations of three common insect species.

The Silwood Park Winter moth, Operophtera brumata – dramatic shifts in population levels

Twenty years of the Sycamore aphid, Drepanosiphum platanoidis, at Silwood Park.  First five years versus last five years – what happened? Does this fit with the recent paper by Stephen Heard and colleagues that species chosen for study because they are common or easy to find, are almost certainly to show declines over the long-term?

 

The Maple aphid, Periphyllus testudinaceus – twenty-year data run from Silwood Park

Given the above, and the fact that most of the evidence for insect declines is largely based on studies from Europe, the UK heading the list (Wagner, 2019) and on top of that, the evidence from tropical locations is open to different interpretations (e.g.  Willig et al, 2019), there is an urgent need for something to be done.  So, what do we need to do?  I think there are three things that need addressing, sooner, rather than later.

Monitoring

First, we need to build on the work that has been done in Germany (Hallmann et al., 2017) and the UK via the Rothamsted Insect Survey (Bell et al., 2015) and establish active insect monitoring networks using repeatable sampling methods, but on a global scale. New monitoring programs will not help establish past baselines, but they can help us determine trends from this point forward. We can make this truly global by engaging the public through community science. These programs will need to use standardized methods, such as Malaise traps, pitfall traps, light traps, and effort-based counts, with species diversity, abundance and biomass being primary measures. Although biomass is an imperfect estimator because it can be sensitive to changes in abundances of large species, it is still a valuable metric from the ecosystem perspective. Determining biomass trends also does not require fine-scale taxonomic knowledge, which is often lacking in citizen science initiatives. It would, even if it were possible, be incredibly expensive, to try to monitor all insect species from any community with appreciable diversity.  A much better option, and one that will certainly appeal to a wide range of citizen scientists would be to monitor taxa like butterflies, macro-moths, dragonflies, bees, and some beetle groups.  All these can serve as indicator species for other insect groups and, tongue in cheek, many can be observed using binoculars, thus encouraging ornithologists and mammalologists to join in 😊

Innovative use of past data

At national levels, a few long-term monitoring schemes already exist, for example, the UK Environmental Change Network (http://www.ecn.ac.uk/ ) collects biotic and abiotic data, including many insect groups, from 57 different sites across the UK using identical protocols (Rennie, 2016).   Multiple Long-Term Ecological Research projects track different facets of ecosystems in different ways (Magurran et al., 2010). In fact, the LTER network, if expanded to a global scale, could be the natural framework to make a global network proposal feasible, possibly through a targeted step change in funding (Thomas et al., 2019).  This is great for the future, but unfortunately, all the active long-term monitoring schemes are younger than modern agricultural intensification.  A way forward would be to use museum collections and to construct data sets by going through back numbers of those entomological journals that pre-date the 1940s.  There are some long-term historical long-term data that are already accessible, for example the 150 year record pine beauty moth infestations in Germany dating from 1810 (Klimetzek, 1972) and I am sure that others must exist.

Funding

Whatever we do, it will need long-term funding. There needs to be a recognition by state research funding agencies that entomological survey and monitoring work, although appearing mundane, should receive a step-change in funding, even if it is at the expense of other taxa  Funding should reflect the diversity and abundance of taxa, not their perceived charisma (Clark & May, 2002; Leather, 2013).  Crowd-funding may draw in some funding, but what is required is stable, substantial and sustained funding that will allow existing and future international collaborations to flourish.  For this to happen and failing sustained state funding, we need to convince philanthropic donors such as the Gates Foundation to turn their attention from insect eradication to insect conservation.

We do, however, need to act quickly, stop talking to just our peers, meet the public, and, if needs be, personally, or via our learned societies, lobby governments; there is no Planet B.

 

References

Bell, J.R., Alderson, L., Izera, D., Kruger, T., Parker, S., Pickup, J., Shortal, C.R., Taylor, M.S., Verier, P., & Harrington, R. (2015) Long-term phenological trends, species accumulation rates, aphid traits and climate: five decades of change in migrating aphids. Journal of Animal Ecology, 84, 21-34.

Cordoso, P. & Leather, S.R. (2019) Predicting a global insect apocalypse.  Insect Conservation & Diversity, 12, 263-267.

Dennis, R.H.L. & Shreeve, T.G. (2003) Gains and losses of French butterflies: tests of predictions, under-recording and regional extinction from data in a new atlas. Biological Conservation, 110, 131-139.

Hallmann, C.A., Sorg, M., Jongejans, E., Siepel, H., Hoflan, N., Schwan, H., Stenmans, W., Muller, A., Sumser, H., Horren, T., Goulson, D., & De Kroon, H. (2017) More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLoSONE, 12(10), :e0185809.

Hopkins, G.W. & Freckleton, R.P. (2002) Declines in the numbers of amateur and professional taxonomists: implications for conservation. Animal Conservation, 5, 245-249.

Klimetzek, D. (1972) Die Zeitfolge von Ubervermehrungen nadelfressender kiefernraupen in derPfalz seit 1810 und die Ursachen ihres Ruckanges in neuerer Zeit. Zeitschrift fur Angewandte Entomologie, 71, 414-428.

Kotze, D.J. & O’Hara, R.B. (2003) Species decline – but why?  Explanations of Carabid beetle (Coleoptera, Carabidae) declines in Europe. Oecologia, 135, 138-148.

Leather, S.R. & Quicke, D.J.L. (2010) Do shifting baselines in natural history knowledge threaten the environment?  Environmentalist, 30, 1-2

Magurran, A.E., Baillie, S.R., Buckland, S.T., Dick, J.M., Elston, D.A., Scott, M., Smith, R.I., Somerfiled, P.J. & Watt, A.D. (2010) Long-term datasets in biodiversity research and monitoring: assessing change in ecological communities through time. Trends in Ecology and Evolution, 25, 574-582.

Møller, A.P. (2019) Parallel declines in abundance of insects and insectivorous birds in Denmark over 22 years. Ecology & Evolution, 9, 6581-6587.

Mupepele, A.C., Bruelheide, H., Dauber, J., Krüß, A., Potthast, T., Wägele, W. & Klein, A.M. (2019). Insect decline and its drivers: Unsupported conclusions in a poorly performed meta-analysis on trends—A critique of Sánchez-Bayo and Wyckhuys (2019).  Basic & Applied Ecology, 37, 20-23.

Rennie, S.C. (2016) Providing information on environmental change: Data management, discovery and access in the UK Environmental Change Network data.  Ecological Indicators, 68, 13-20.

Sánchez-Bayo, F. & Wyckhuys, K.A.G. (2019) Worldwide decline of the entomofauna: A review of its drivers. Biological Conservation, 232, 8-27.

Thomas, C.D., Jones, T.H. & Hartley, S.E. (2019) “Insectageddon”: a call for more robust data and rigorous analyses. Global Change Biology, 6, 1891-1892.

Thomas, J.A., Telfer, M.G., Roy, D.B., Preston, C.D., Greenwood, J.J.D., Asher, J., Fox, R., Clarke, R.T. & Lawton, J.H. (2004) Comparative losses of British butterflies, birds, and plants and the global extinction crisis. Science, 303, 1879-1881.

Tree, I. (2018) Wilding, Picador, Pan Macmillan.

Wagner, D.L. (2019) Global insect decline: comments on Sánchez-Bayo and Wyckhuys (2019). Biological Conservation, 233, 332-333.

Willig, M.R., Woolbright, L., Presley, S.J., Schowalter, T.D., Waide, R.B., Heartsill Scalley, T., Zimmerman, J.K.,  González, G. & Lugo, A.E. (2019) Populations are not declining and food webs are not collapsing at the Luquillo Experimental Forest. Proceedings of the National Academy of Sciences, 116, 12143-12144.

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A recent paper has shown that European dragonflies are doing quite well; yet another example of how different groups respond in different ways.

Pick and Mix 32 – something for everyone?

Can writing poetry make you a better scientist?

A great story about the history of a butterfly’s name from Steve Heard and it has a poetical connection

Here Judy Fort Brenneman writes about keeping your writing short and sweet

Is it just me or do conservation biologists need to learn to write without jargon?

Some species of wasps are capable of logical reasoning

An interesting Open Access paper about how being on social media and taking selfies helps make scientists appear more human to the general public

With the population of the distinctive species in decline, cities around the U.S. are trying to add monarch-friendly spaces.

Novel approaches to crop protection – replacements for conventional insecticides?

Terry McGlynn on the joys of not having to worry about publishing or chasing grants

Jeremy Fox over on Dynamic Ecology discusses the results of his poll on the biggest problems facing ecological research

 

Entomological Classics – The Beating Tray or Japanese Umbrella

Southwood writing in 1966 in Ecological Methods, somewhat disparagingly refers to the beating of insects as “This is a collector’s method and originally the tree was hit sharply with a stick and the insects collected in an umbrella held upside down under the stick.” Unfortunately, he committed the cardinal sin of not supplying a supporting reference for his statement – tut, tut!  This of course set me off on one of my procrastinatory quests 🙂 Despite the fact that a certain type of beating tray is sold commercially as a Japanese umbrella I was unable to find any mention to the term in the older entomological literature.

Japanese Umbrella available from Insecta.Pro http://store.insecta.pro/catalog/2041 Also described as Clap Net (Japanese Umbrella) by a Czech company EntoSphinx http://www.entosphinx.cz/en/47-sklepavadla

Mentions to umbrellas being used to collect insects, yes, and this rather nice colour image with an umbrella shown as an essential part of an entomologist’s equipment (Schaeffer, 1766), also yes; Japanese umbrella, no.

Entomological equipment in the 18^th Century from Elementa Entomologia (1766) by Jacob Christian Schaeffer (1718-1790).

It seems that the modern beating tray is descended from two ancestors, the entomological umbrella, which judging by the earliest illustrations must have arisen sometime prior to 1766, and the clap net or clap-net, which was in use by

The entomological umbrella in use (Howard, 1910).  Note that the illustration is taken from a work by Ernest August Hellmuth von Kiesenwetter (1820-1880) which I have been unable to track down ☹

British entomologists from at least the same time (Wilkinson, 1978) and which fits in with the usage data from Collins English Dictionary.

Record of usage of the term clap-net (From Collins English Dictionary) Clap nets are used nowadays by ornithologists and bear very little resemblance to the entomological clap net but may explain the couple of more recent peaks in the usage data.

It is likely that the clap net was invented by Benjamin Wilkes possibly in the 1740s (Wilkinson, 1966) as he described how to make one.  It is interesting to see that although the clap net was used in a similar way in which we use butterfly nets today, Wilkes points out the need to have a stick with which to beat shrubs and trees to, as he puts it “wherewith to put the flies and moths on the wing”

The clap net in butterfly net mode (Wilkinson, 1966)

Here Newman (1835) highlights the use of the clap net as a beating tray

The clap net (circled) and other entomological equipment, from Ingpen (1849). Note the resemblance to a beating tray.

Ingpen (1849) in his description of the use of the clap net specifically mentions its use as a beating tray “When beating into the net, it will be necessary to keep both sticks in the left hand*, at the same time keeping the head of the net as wide open as possible”.  This pretty much how I use my rathe superior(and expensive) beating tray 😊 We then get a mention of the entomological umbrella “In the absence of a clap-net, an open umbrella, will in general be found convenient for beating into; particularly if the inside be lined with white cotton and made to cover the whalebone”. It seems that the umbrella as a beating tray was in common use by the middle of the nineteenth century, for example, “these may be captured by beating the branches over a large net or umbrella” (Douglas & Scott, 1865).  This is not to be confused with the beating-net which was an early name for the sweep net (Packard, 1873), the history and use of which I have written about earlier.

So when do beating trays become recognised as beating trays? Banks (1909) refers to both the umbrella, incidentally also using the Keisenwetter illustration, but comments that “A substitute for the umbrella, and in many cases better than it, is the beating cloth. It consists of a piece of common unbleached cot- ton cloth, 1 yard square, to each corner of which a loop of stout twine is sewed, or a corner turned over. Upon reaching the woods, two straight sticks, each about 5 feet in length, and not too heavy, also not so small as to break or bend too easily, are cut from a convenient bush. The sticks are placed crosswise over the cloth and fastened to the loops at the four ends. This is easily and quickly done by making sliding loops of the simple loops. The cloth is thus kept spread out between the sticks. To the center of the sticks another stick may be fastened, so as to hold the cloth out under the branch.”  George Day in his 1916 Presidential address to the Entomological Society of British Columbia refers to umbrellas and beating trays in the same sentence “Another method is by beating the foliage of trees and shrubs over a beating tray or inverted umbrella” (Day, 1918). Given that the biologist and novelist, Elliot Grant Watson (1885-1970) refers, somewhat caustically, to beating trays in his essay published in The English Review  “Enthusiastic entomologists smashing the young buds from the bushes, holding out beating trays” (Watson, 1923), I am failry confident that the beating tray as we know it, had replaced umbrellas, entomologcial or otherwise, by about 1920. I have still to find out where the term “japanese umbrella” arose.  Let me know in the comments if you are able to help.

My modern beating tray – costs about twice as much as the Japanese Umbrella, modern clap net or collapsible beating tray.

Modern beating tray in use – more like the original entomological umbrella depicted by Howard (1910), albeit I am somewhat stouter than the entomologist in his illustration.

References

Banks, N. (1909) Directions for Collecting and Preserving Insects.  United States National Museum Bulletin 67, Smithsonian Institute, Washington.

Day, G.O. (1918) Larva rearing.  Journal of the Entomological Society of British Columbia, 8, 21-27.

Douglas, J.W. & Scott, J. (1865) The British Hemiptera, Volume 1, Hemiptera-Heteroptera. Ray Society, London.

Howard, L.O. (1910) The Insect Book. A popular account of the bees, wasps, ants, grasshoppers, flies and other North American insects exclusive of the butterflies, moths and beetles, with full life histories, tables and bibliographies. Doubleday, Page & Company, New York, xxvii + 429 pp.

Ingpen, A. (1849)  Manual for the Butterfly Collector or instructions for Collecting, Rearing and Preserving British and Foreign Insects. David Bogue, London.

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

Packard, A.S. (1873) Directions for Collecting and Preserving Insects. Smithsonian Miscellaneous Collections 261, Washington.

Watson, E.L.G. (1923) The New Forest, The English Review (September), 318-320

Wilkinson, R.S. (1966) English entomological methods in the seventeenth and eighteenth centuries II: Wilkes and Duffield. Entomologist’s Record and Journal of Variation, 78, 285-292.

Wilkinson, R.S. (1978) The history of the entomological clap-net in Great Britain. Entomologist’s Record and Journal of Variation, 90, 127-132.

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Were all Victorian entomologists right-handed?  I think not 😊. Though that said, even as recently as my mother’s and father’s generation (born in the 1920s) left-handed children were often forced to use their right hands.