Tag Archives: insects

The most difficult thing I have ever had to write – Insects – A Very Short Introduction

The book!

I have written a lot of papers (more than 220 according to Web of Science) and quite a few books, two real ones (Leather et al., 1993; Leather & Bland, 1996) and eight edited volumes, over the last forty odd years. Up until now I thought the most exacting piece of writing I had ever done was my entry for the Biological Flora (Leather, 1996).  I mention this because it has a very similar feel to my most recent, most difficult piece of writing, Insects, A Very Short Introduction.

I did my PhD on the bird cherry aphid, Rhopalosiphum padi (Leather, 1980) during which I developed a real love for the bird cherry tree, Prunus padus. Just to illustrate this, my second son’s middle name is Tuomi – Finnish for bird cherry. Over the next decade or so I expanded my studies on to the different insects associated with it and also became quite adept at striking scions, grafting it and manipulating its phenology. I could (and still can), thanks to sampling bird cherry trees in Finland in the depths of winter, identify it in the dark by the smell of the bark 😊 In the mid-1980s, I jumped on to the species-area relationship bandwagon (Leather, 1985, 1986) and discovered the wonderful Biological Flora of the British Isles, hosted by the British Ecological Society. Armed with the arrogance of youth, and obviously at the time, not suffering from ‘imposter syndrome’, I contacted Arthur Willis (the then Editor of the series) and volunteered to write the entry for bird cherry. Pretty cheeky for an entomologist, but hey, both my parents were botanists and me and bird cherry were old pals! Arthur said yes and sent me the instructions for contributors which included all the headings and sub-sections required. It looked pretty straightforward to me; go down the headings, insert the information and write the narrative. Easy peasy lemon squeezy.  Or so I very naively thought ☹ I whipped through the headings, filled in the data that I had, wrote the accompanying narrative and posted it off to Arthur.  Job done! A few weeks later he returned my manuscript telling me that I was also expected to fill in the missing data gaps with data collected by me, not just leave them blank! 

Reality strikes!

So, over the next two years that is exactly what I did.  I checked out which mycorrhizae were associated with bird cherry, collected seed and calculated germination rates, sketched the different seedling stages, did NVC surveys at six different sites, characterised the growth structure of the tree and shrub forms and looked at responses to defoliation. I learnt a lot of botany! Arthur was an incredibly helpful editor and without his encouragement I would never have completed the entry.  I did, however, turn down Arthur’s suggestion that I do the entry for Prunus avium 😊

In 2018 I was contacted by Latha Menon, a Senior Commissioning Editor for OUP, who wanted to know if I would be interested in writing a book for their Very Short Introduction series, in this case, insects.  Having since 1990 grown older and picked up imposter syndrome on the way, I was initially a bit hesitant and asked if it would be possible to have a co-author.  Latha was somewhat lukewarm about this, saying that what the series was about was producing an extended essay (35 000 words) for a general audience reflecting the expertise and enthusiasm of the author.  I pondered about it and thought, well I’ve been a professional entomologist for more than forty years, and an amateur for my whole life, and taught entomology for more than thirty years, so how hard could it be to write 35 000 words about insects? I have also been blogging for what I have envisaged as a mixed audience since 2012, so surely within my capabilities?

I should have known better

It turns out that you can know too much about insects at the same time as you don’t know enough about them! First, I had to decide on a structure for the essay and also what particular aspects of entomology would leap off the page and grab my readers.  Much as I love aphids, other insects would have to feature.  The obvious place to start, I thought, would be to look at how our entomology course introduced the subject to new students, so Chapter 1, In the beginning was born. This was actually not that simple as I had to deal with the evolution of insects, their classification, their anatomy, a lot of their physiology, and also why they were and are so successful. Trying to make that not like a series of Wikipedia sections was not easy.

Now to me, one of the things that make insects so spectacular and evinces amazement in non-entomologists, is how good they are at reproducing themselves, hey presto, Chapter 2, Prolific procreators and the need to discuss sexual selection, mating behaviour, courtship, lekking and much more. I had originally planned to cover host selection and life history strategies in this chapter, but found that it didn’t sit very well in that context.

Instead, I moved on to Chapter 3, On the move, which began with the evolution of flight, much, of which, despite my decades of experience, was quite a revelation to me. From flight I moved onto host selection, and the physiology and ecology of specialist and generalist feeding. These first three chapters were the most difficult to write, bearing in mind that my readers need to understand the basics of how insects work to fully grasp the wonder of what insects are actually achieving. I had to rewrite these first chapters three times before my Commissioning Editor, my non-entomologist lay-reader (my wife, a humanities graduate), a botanist colleague and an entomological colleague, were happy with them.

Those chapters behind me, I now felt it was time to move on to those aspects of entomology that had super wow factor, those facts that would make my readers exclaim things like “I didn’t know that” and encourage them to pass them on to their friends and relatives. Heavily influenced by my childhood love of social insects, Chapter 4, Living together, appeared on the scene. As well as talking about the well-known bees, ants and termites, it also gave me the chance to discuss lesser known examples such as dung beetles, social bugs, insect symbionts, insect-plant interactions, and yes, of course, aphids get more than a passing mention😊

The next three chapters are a bit niche, but gave me the chance to launch Chapter 5, Aquatic Insects, into the mix and talk about the importance of freshwater insects and even more excitingly, wax lyrical about the little known truly marine Ocean Skaters, which I first came across on a work trip to Mauritius in the mid-1990s. Judging by what I see on social media platforms, non-entomologists are, in the English vernacular, totally gob-smacked by how insects can pretend to be something else, so this made Chapter 6, Crypsis, mimicry and blatant advertising, an obvious heading.  I had a lot of fun with this, but was slightly hampered by the restriction placed by OUP on how many illustrations I was allowed to include, and also sadly not being allowed colour.

To me, the ability of insects to live in very inhospitable conditions, from deserts, to ice caves, to mountain tops and to survive arctic winters and other extreme weather conditions without the benefit of fur coats and cold baths, made Chapter 7, Against the odds, a natural.

I have, over the years, been amazed by how limited many people’s appreciation of the positive economic, social, artistic and health benefits of insects to the human world are (Leather, 2015), hence Chapter 8, The good, the bad and the ugly.  Here I dealt with pests, disease vectors, biological control, maggot therapy, pollinators, the role of insects as ecosystem engineers, as waste-disposal specialists and as recyclers.

I began my book by describing the diversity and ubiquity of insects. I discussed their origins and marveled at the ways in which insects have adapted to a wide range of environments and the roles that they play in maintaining ecosystem health. Given that for at least the last twenty years or so, entomologists and ecologists have been warning about the dangers of losing species I felt it fitting to end it by discussing the harm that we are doing to insects and the planet that we, and they, inhabit, and ways in which we might act to halt or reverse our course, if it is not already too late.  I finished with a warning, and the hope that we are not too late to stem disaster, Chapter 9, Ecological Armageddon—insects in decline?

It was, primarily due to the fact that at times, for every word I took out, I seemed to add another ten, both one of the most frustrating but also satisfying pieces of writing that I have ever done. I just hope that when it hits the shops, my readers will find as much to enjoy as I have since I first came across insects just over sixty years ago.

References

Leather, S.R. (1980) Aspects of the Ecology of the Bird Cherry-Oat Aphid, Rhopalosiphum padi L., PhD Thesis University of East Anglia, Norwich.

Leather, S.R. (1985) Does the bird cherry have its ‘fair share’ of insect pests? An appraisal of the species-area relationships of the phytophagous insects associated with British Prunus species. Ecological Entomology, 10, 43-56.

Leather, S.R. (1986) Insect species richness of the British Rosaceae: the importance of hostrange, plant architecture, age of establishment, taxonomic isolation and species-area relationships. Journal of Animal Ecology, 55, 841-860.

Leather, S.R. (1996) Biological flora of the British Isles Prunus padus L. Journal of Ecology, 84, 125-132.

Leather, S.R. (2015) Influential entomology: a short review of the scientific, societal, economic and educational services provided by entomology. Ecological Entomology, 40 (Suppl. 1), 36-44.

Leather, S.R. & Bland, K.P. (1999) Insects on Cherry Trees, Richmond Publishing Co, Ltd, Slough.

Leather, S.R., Walters, K.F.A. & Bale, J.S. (1993) The Ecology of Insect Overwintering, Cambridge University Press, Cambridge.

8 Comments

Filed under Science writing

Pick & Mix 62 – bees, orchards, bugs, pollinators, blowflies, birds, beetles and spuds

Another great piece of natural history writing from Philip Strange – Sunday in the orchard with butterflies

Carrion flowers and their pollinators – Don’t stop and smell the flowers

One of the biggest challenges facing emerging pollinators each spring is finding food. What we plant in our gardens, parks and around our workplaces can be a huge help for foraging insects. So take a bow Dance Connect in Kinross who have skilfully transformed the area around their dance and fitness studio into a pollinator-friendly hot spot.

Great review of bee emojis – very amusing

Is your local council verge friendly?  Very interesting and useful article revealing which councils are taking biodiversity issues seriously 

Nice article from one of my former MSc students about the usefulness of blowflies and also has a nice graphic showing the pollinator league of fame

Six reasons why potatoes are good for you – I have always been a great fan of the not so humble spud as my carbohydrate source – so much more tasty and versatile than rice

Is our kindness to garden birds harming other bird species?  Garden bird feeders are boosting blue tit numbers – but leaving other species hungry

Bug splatter – please take part

What’s that beetle? Ask the algorithm.  Machine learning and beetle identification 

3 Comments

Filed under Pick and mix

Let your dandelions and other flowering ‘weeds’ be

This last couple of weeks parts of my daily walks have been accompanied by, the to me, unwelcome din of motor lawnmowers as lots of my fellow villagers strive to turn their lawns into ecological deserts. One of my neighbours has, to my knowledge, cut his lawn five times since the beginning of March, me I’ve done my spring cut and that’s it until autumn.

An ecological desert 😦

This mania for close-cropped lawns, sometimes ‘artistically’ striped, is, I think, the fault of my grandparent’s generation, which took a municipal park attitude to gardens, especially the bit that the neighbours could see; close-cropped, weed-free grass with regimented flower beds, also equally weed-frees. Out of sight, back gardens could be less manicured, and depending on the space available, might include a vegetable garden (also scrupulously weed-free), and a patch of lawn to be used by children for ball games and other activities. Unfortunately they drummed this philosophy into their children, who in their turn, with only a few exceptions (me for one), passed this fetish on to my generation. Sadly, my father, a keen gardener, also espoused this view as did the parents of all my friends. I spent many a grumpy hour removing dandelions and thistles from our front lawn and flower beds at my father’s behest!

So what are these weeds that so many people seem to hate? To those growing crops of economic value, be they agricultural, horticultural or silvicultural, then I guess the following definitions are very reasonable and relatable.

Plants that threaten human welfare either by competing with other plants that have food, timber of amenity value, or by spoiling and thus diminishing the value of a product

Weeds arise out of the mismatch between the habitats we create and the plants we choose to grow in them

Begon, Harper & Townsend (1996)

A plant that originated under a natural environment and, in response to imposed and natural environments, evolved and continues to do so as an interfering associate with our desired plants and activities” Aldrich & Kremer (1997)

There are more tolerant descriptions of weeds available, which are much more in accord with my views:

What is a weed? A plant whose virtues have not yet been discovered” (Emerson, 1878)

, “A weed is but an unloved flower!” (Wilcox, 1911)

A plant condemned without a fair trial” (de Wet & Harlan, 1975)

I have, as I have mentioned several times already, been doing a lot of walking during the covid pandemic, or should it now be referred to as the Covid Pandemic? At this time of year, Spring, the early flowers of the hedgerows and roadside verges are alreday out; cherry plum (Prunus cerasifera), blackthorn or sloe (Prunus spimosa) and closer to the ground, but as equally pretty, daisies (Bellis perennis), dandelions (Taraxacum officinale), Lesser Celandines ( Ficaria verna (although some of you may know it as Ranunculus ficaria), and Wood Anemones (Anemonoides nemorosa). The latter two species, although relatively common, are unlikely to be found in the average garden, as they have fairly specific habitat requirements.  Daisies and dandelions on the other hand, are pretty much ubiquitous, although the former do not attract as much opprobrium from the traditional gardener as dandelions do. This is a great shame, as ecologically speaking dandelions are an extremely important resource for pollen and nectar feeding insects.

Given the concerns about the decline of insects in general over the last forty years, we should be celebrating the dandelion, not trying to eradicate it from our lawns. Just feast your eyes on some of the beauties that I have seen over the last few days.

Pollen beetles March 20th 2021

Male tawny mining bee Andrena fulva – Sutton March 25th 2021

Bumble bee, Sutton March 30th 2021

Seven spot lady bird, too early for aphids, Oulton Road March 30th 2021


Peacock butterfly in a very striking pose, Guild Lane, Sutton, April 3rd 2021.

I’m not alone in my love of dandelions 🙂

We shouldn’t forget the humble daisy either. It provides nectar to many butterfly species, including among others, the Green Hairstreak, the Grizzled Skipper, the Small Copper and the Small White. They are also important resources for honey bees (Raquier et al., 2015), bumblebees and hoverflies (Blackmore & Goulson, 2014).

A nice patch of daisies.

Domestic gardens, if managed correctly, have tremendous potential as reservoirs of insects and other invertebrates of ecological importance (Davies et al, 2009). The easiest thing that you can do to help the insects is to reduce the frequency at which you mow your lawn and grass verges. To sum it up in a nutshell, the less you move, the more flowers you get and the more flowers you get the more nectar and pollen feeding insects you make happy, some of which can be rare and endangered (Wastian et al., 2016).  

The less frequently you mow, the more flowers you get. The more flowers you get, the more bumblebees you get (George, 2008).

It is not just flower feeding insects that benefit from reducing your lawn mowing activities; grass feeding insects also benefit from longer grass ( Helden & Leather, 2005) and if, for some strange reason, you are not a great fan of bugs, just remember that the more bugs you have the more birds you will attract (Heden et al.,  2012). So do your bit to save the planet, be like me, only mow your lawn twice a year.

References

Aldrich, R.J. & Kremer, R.J. (1997) Principles in Weed Management. Panima Publishing Corporation.

Begon, M., Harper, J,L. & Townsend, C.R. ( 1996) Ecology, 3rd Edition, Blackwell Science, oxford.

Blackmore, L.M. & Goulson, D. (2014) Evaluating the effectiveness of wildflower seed mixes for boosting floral diversity and bumblebee and hoverfly abundance in urban areas. Insect Conservation & Diversity, 7, 480-484.

Davies, Z.G., Fuller, R.A., Loram, A., Irvine, K.N., Sims, V. & Gaston, K.J. (2009) A national scale inventory of resource provision for biodiversity within domestic gardens. Biological Conservation, 142, 761-771.

De Wet, J.M.J., Harlan, J.R.  (1975) Weeds and domesticates: Evolution in the man-made habitat. Economic Botany, 29, 99–108.

Emerson, R.W.(1878) The Fortunes of the Republic. The Riverside Press, Boston, USA.

Garbuzov, M., Fensome, K.A. & Ratnieks, F.L.W.  (2015)   Public approval plus more wildlife: twin benefits of reduced mowing of amenity grass in a suburban public park in Saltdean, UK. Insect Conservation & Diversity, 8, 107-119.

George, W. (2008) The Birds and the Bees: Factors Affecting Birds, Bumblebees and Butterflies in Urban Green Spaces, MSc Thesis, Imperial College, London.

Helden, A.J. & Leather, S.R. (2005) The Hemiptera of Bracknell as an example of biodiversity within an urban environment. British Journal of Entomology & Natural History, 18, 233-252.

Helden, A.J., Stamp, G.C. & Leather, S.R. (2012) Urban biodiversity: comparison of insect assemblages on native and non-native trees. Urban Ecosystems, 15, 611-624.

Lerman, S.B., Contostac, A.R., Milamb, J. & Bang, C. (2018) To mow or to mow less: Lawn mowing frequency affects bee abundance and diversity in suburban yards. Biological Conservation, 221, 160-174.

Requier, F., Odoux, J., Tamic, T.,Moreau, N., Henry, M., Decourtye, A. & Bretagnolle, V. (2015)  Honey bee diet in intensive farmland habitats reveals an unexpectedly high flower richness and a major role of weedsEcological Applications, 25, 881–890.  

Wastian, L., Unterweger, P.A.& Betz, O. (2016) Influence of the reduction of urban lawn mowing on wild bee diversity (Hymenoptera, Apoidea). Journal of Hymenoptera Research, 49, 51–63.

Wilcox, E.W. (1911) Poems of Progress and New Thought Pastels. London: Gay & Hancock, 1911.

3 Comments

Filed under EntoNotes

Pick & Mix 59 – countryside and colonialism, climate change, urban greening, native trees, natural history and public rights of way

Corinne Fowler on colonialism’s imprint on the British countryside.

I’m a climate scientist – here’s three key things I have learned over a year of COVID

Ancient leaves preserved under a mile of Greenland’s ice – and lost in a freezer for years – hold lessons about climate change

Why entomologists kill – understanding the need for collections

In case of emergency — break glass – Richard Jones on the trials and tribulations of trying to copy a bank note 🙂

Torino – showing the world how to make a green city

Perfectly explains why I prefer real books to e-books – The Multisensory Experience of Handling and Reading Books

Plant native, save insects – also in the UK it will benefit birds as well (if you want a copy email me)

Time to make nature studies a compulsory school subject – before it’s too late – and here is a blog post by me about the same subject from last year

Britain’s ancient footpaths could soon be lost forever, and here is a blog post by me about the same subject written a few weeks earlier – ahead of the curve that’s me 🙂

2 Comments

Filed under Pick and mix

The Natural World in Haiku Form – volume 4

Thanks to covid and cancer, I spent most of last year (2020) away from the campus.  Luckily, I live in a very rural area so I was able to do a lot of walking and interacting with Nature.  This year’s collection of haikus are thus geographically constrained.  I hope that some of them will strike a chord with some of you.

Memories

Oak, standing alone

Hoarding Nature’s memories,

Safe, beneath her bark.

February 6th 2020 Sutton

Nature prevails

Stalwart oak still stands.

Despite lightning’s flashing bolt

Nature will prevail

15 April 2020 Forton

Sentry duty

Oaken sentinels;

marking the perimeter

of the farmer’s field

Sutton 18th May 2020

Inner strength

Pointing at the sky

Twin stags, hoarding resources

Not ready to die

1st June 2020 Sutton

Fresh air

Busy buzzing bees
Old hedgerow oaks in a row
Loud Lapwings mewing

25th March 2020 Sutton

Covid-19

Together apart,

Socially distancing pines,

A sign of our times

24th March 2020 Sutton

Insect Heaven

Yellow furze crowned slope

basking in April’s warm sun.

Heaven for insects

22nd April 2020 Oulton by Sutton

Dandelions

Spherical fluffy

timely seed distributing,

dandelion clocks

4th May 2020 Sutton

Welcome trespassers

A part but apart,

encroaching the wheat desert;

delightful colour

16th August 2020 Sutton

Spring flush

Spring, pinkly blushing,

but soon to be clipped and hacked

By the groundsman’s shears.

Harper Adams 16th March 2020

Farmscape

Green ivy, brown thorn
frame the farmer’s verdant fields;
awaiting spring’s warmth

Sutton 28th March 2020

Sloe gin beckons

Blackthorn, lustrous white

brightening up our spring hedges;

later on, sloe gin

Sutton 10th April 2020

Wrekin view

Bird, high in the sky

Soars above the farmer’s fields;

Views Hazy Wrekin

Sutton April 3rd 2020

Grey

Sultry leaden sky.

Oh for a clap of thunder

To bring the rain down

May 26th 2020 Sutton

Wonder

Blue, glimpsed behind

the cloud rippled firmament.

A wondrous beauty

March 31st 2020 Sutton

Leave a comment

Filed under Uncategorized

Pick & Mix 54 – lots do with food, invasive species, horror films, urban biodiversity, museum collections, corona virus spread and much more

The last post – been fun but nothing lasts forever

Why eating an invasive species won’t solve the problem

Freshwater horror films, but where are the ecosystems? 🙂

The state of Nature in the UK is not as good as it should be

Museum collections are really useful research tools

Encouraging urban insect life – great article by a former student

A soundscape of what Somerset might have sounded like 2000 years ago

What does organic food really mean?

Is liquorice safe for all of us? This sweet treat could kill some of us

The witches’ brew of frogs, snails and newts – perhaps not quite as advertised?

A really effective explanation of how corona virus is spread and the importance of masks and ventilation

3 Comments

Filed under Pick and mix

Pick & Mix 50 – conservation, misogyny, media misinformation, citizen science, healthy gardens and insect-inspired eye make-up

“Conservation should indeed be a global priority. But understanding of the complexity and colonial roots of this problem and the shocking double standards that exist, is vital” Very important article by conservation scientist Tarsh Thakaekara

Adam Hart and colleagues on the harm that celebrities and media misinformation are doing to conservation

Misogyny alive and well in the world of shark conservation – time for a change of attitude

Top tips on keeping your plants and gardens healthy

Interesting Open Access article on urban conservation

Fantastic essay about Rosalind Franklin by Matthew Cobb (author of The Brain and Very Short Introduction to Smell)

Sophie Yeo asks ‘Does citizen science make you happier?”

Insect inspired eye make-up

The benefit of an insect collection, said Floyd Shockley, the insect collection manager at the Smithsonian Natural History Museum, is that “a dead specimen, if properly preserved, can be there forever.” A 153-year-old insect collection is being used to solve modern problems.

Another insightful blog post from Manu Saunders about the insect apocalypse stories and the data  behind them

 

6 Comments

Filed under Pick and mix

Should entomologists change their name to insectologists?

In case you are wondering, this is not a totally tongue in cheek post. Over the years it has become very clear to me, that many people, even those with degrees, have no idea what an entomologist is. On being told that I am an entomologist, most people look blankly at me, and pass on rapidly to another topic. Despite the importance of the subject, the term entomology is not very widely known.  Sadly, to those of us who study insects, this is no longer hugely surprising.  More surprising though, is how few of those people then ask me what an entomologist is. I haven’t asked any ornithologists, botanists, zoologists, my paediatrics daughter, or my consultant gynaecologist brother if they suffer similar responses on being asked their occupations, but I suspect that they suffer from far fewer blank looks than I do.

So, what can we do about this lamentable state of affairs?  I, and other entomologists have long lamented the lack of knowledge and interest in these, the most important, and to me, most fascinating members of the animal world, shown by the majority of humans. What is it about entomology that makes it such a niche subject?

All is not lost. When I do get the chance to enlighten those that ask, and tell them that entomologists study insects, I am relieved to find that they do know what they (insects) are, even if they do respond, with “oh bugs, that’s what I thought”, which is at least preferable to “creepy crawlies” which is another common response. So are we too elitist, too proud of our discipline to give it a more accessible name? Ornithologists don’t, as far as I know, call themselves birdologists, and herpetologists don’t need to go around describing themselves as frogologists, snakeologists or whateverologists?  They don’t have to, they live in a world surrounded by the constant stream of vertebrate propaganda coming from the biased charismatic mega-fauna, backbone dominated world we live in. (I’m not bitter, honest).

Going back to my question about elitism in our discipline.  Our societies worldwide are known as entomological societies, some such as the one I have been a proud Fellow since 1977, are even preceded by the word Royal, and the Royal Entomological Society of London is not alone, there is also the Royal Belgian Entomological Society :-). What about the journals that entomological societies produce and those in which entomologists publish?  As you might expect the majority of the titles contain the word entomology but not exclusively.  The two biggest entomological societies, The Royal Entomological Society (RES) and the Entomological Society of America (ESA), produce six and eight journals respectively in addition to their newsletters and handbooks.  Of the six RES journals, two use insect instead of entomology, Insect Conservation & Diversity and Insect Molecular Biology. Similarly the ESA have two insect named journals, Journal of Insect Science, Insect Systematics and Diversity, and also two that eschew mention of both entomology and insects, Journal of Integrated Pest Management, and Arthropod Management Tests. The International Union for the Study of Social Insects, not technically a society, produces the well-known and highly respected journal, Insectes Sociaux.

Outside the world of learned entomological societies there are a handful of entomological journals that use insect instead of entomology, namely, Journal of Insect Conservation, Journal of Insect Physiology, Insects and Insect Science, three of which I have published in (Cameron & Leather, 2012; Oliver et al., 2012, Cooper et al., 2014). There is also of course, The Bulletin of Insectology, in which I have also published (Benelli et al, 2015).

Entomology is obviously not a sacred term, and in the interests of getting more people interested in the wonderful world of insects and letting them know what it is we do, we should perhaps, be less precious about being entomologists, and become insectologists when appropriate.  That said, I don’t think I will ever be able to bring myself to say that I am a bugologist or creepycrawlyologist, but I I could certainly live with being an insectologist now and then.

 

References

Benelli, M., Leather, S.R., Francati, S., Marchetti, E. & Dindo, M.L. (2015) Effect of two temperatures on biological traits and susceptibility to a pyrethroid insecticide in an exotic and native coccinellid species. Bulletin of Insectology, 69, 23-29.

Cameron, K.H. & Leather, S.R. (2012) Heathland management effects on carabid beetle communities: the relationship between bare ground patch size and carabid  biodiversity. Journal of Insect Conservation, 16, 523-535.

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

Oliver, T.H., Leather, S.R. & Cook, J.M. (2012) Ant larval demand reduces aphid colony growth rates in an ant-aphid interaction. Insects, 3, 120-130.

18 Comments

Filed under Bugbears

Ten more papers that shook my world – complex plant architecture provides more niches for insects – Lawton & Schroeder (1977)

Some years ago I wrote about how one of my ecological heroes, Sir Richard Southwood (later Lord Southwood), influenced my research and stimulated what has become a lifelong interest of mine, island biogeography, in particular the iconic species-area relationship. Apropos of this it seems apposite to write about another huge influence on my research, Sir John Lawton.  I first encountered John*, as he was then, at the tender age of 17, when our Sixth Form Science class were bussed from Ripon Grammar School to York University to hear a very enthusiastic arm-waving young ecologist, yes John Lawton, talking about food webs. Excellent as it was, it wasn’t, however, this talk that inspired me :-), but a paper that he and Dieter Schroeder wrote a few years later (Lawton & Schroeder, 1977), in which they showed that structurally more diverse plants potentially hosted more insect species per unit range than those plants with less complex architecture.  A couple of years later Strong & Levin (1979) showed that this also applied to fungal parasites in the USA.  The mechanism behind the finding was hypothesised to be based on apparency – the bigger you are the easier you are to find, the bigger you are, the more niches you can provide to be colonised, pretty much the same reasoning used to explain geographic island biogeography and species-area accumulation curves (Simberloff & Wilson, 1969). John Lawton, Don Strong and Sir Richard Southwood also highlighted this in their wonderful little book (Strong et al, 1984) which has provided excellent material for my lectures over the years.

As someone who is writing a book, theirs is an excellent example of how you can improve on other people’s offerings.  Staying with the theme of plant architectural complexity, Strong et al (1984) brilliantly reported on Vic Moran’s masterly study on the relationship between Opuntia growth forms and the number of insects associated with them (Moran, 1980).  Vic’s study was an advance on the previous studies because he examined one family of plants, rather than across families, so reducing the variance seen in other studies caused by phylogenetic effects. I should also point out that this paper was also an inspiration to me.

The figure as shown in Victor Moran’s paper.

The revamped Moran as shown in Strong & Lawton (1984).

Okay, so how did this shake my world? As I have mentioned before, my PhD and first two post-docs were on the bird cherry-oat aphid, Rhopalosiphum padi, a host-alternating aphid that uses bird cherry, Prunus padus, as its primary host.  Never being one to stick to one thing, I inevitably got interested in bird cherry in general and as well as eventually writing a paper about it (Leather, 1996) (my only publication in Journal of Ecology), I also, in due course, set up a long term experiment on it, the outcome of which I have written about previously. But, I digress, the first world shaking outcome of reading Lawton & Schroeder, was published in Ecological Entomology (incidentally edited by John Lawton at the time), in which I analysed the relationships between the insects associated with UK Prunus species and their distribution and evolutionary history, and showed that bird cherry had a depauperate insect fauna compared with other Prunus species (Leather, 1985).

I’m not working with very many points, but you get the picture (from Leather, 1985). Bird cherry (and also Gean, the common wild cherry. Prunus avium) hosts fewer insect species than would be expected from its range and history.

This in turn led me on to an even more ambitious project.  Inspired by a comment in Kennedy & Southwood (1984) that a better resolution of the species-plant range relationship would result if the analysis was done on a taxonomically restricted group of plants and by the comment in Southwood (1961) that the Rosaceae were a very special plant family, I spent several months wading through insect host lists to compile a data set of the insects associated with all the British Rosaceae.  Once analysed I submitted the results as two linked papers to the Journal of Animal Ecology.  Having responded to Southwood’s demand that “this manuscript be flensed of its too corpulent flesh” it was eventually published (Leather, 1996).  My somewhat pompous introduction to the paper is shown below.

“This relationship is modified by the structure or complexity of the plant, i.e. trees support more insect species than shrubs, which in turn support more species than herbs (Lawton & Schroder 1977; Strong & Levin 1979; Lawton 1983).”

“Kennedy & Southwood (1984) postulated that if taxonomically restricted groups of insects and/or plants were considered, the importance of many of these variables would increase. Few families of plants cover a sufficiently wide range of different growth forms ranging from small herbs to trees in large enough numbers to give statistically meaningful results. The Rosaceae are a notable exception and Southwood (1961) commented on the extraordinary number of insects associated with Rosaceous trees. It would thus appear that the Rosaceae and their associated insect fauna provide an unparalleled opportunity to test many of the current hypotheses put forward in recent years concerning insect host-plant relationships.”

Cutting the long story short (I am much better at flensing nowadays), I found  that Rosaceous trees had longer species lists than Rosaceous shrubs, which in turn had longer lists than herbaceous Rosaceae.

Rather messy, but does show that the more architecturally complex the plant, the more insect species it can potentially host (from Leather, 1986).

Flushed by the success of my Prunus based paper, I started to collect data on Finnish Macrolepidoptera feeding on Prunus to compare and contrast with my UK data (I can’t actually remember why this seemed a good idea).  Even if I say so myself, the results were intriguing (to me at any rate, the fact that only 19 people have cited it, would seem to suggest that others found it less so), in that host plant utilisation by the same species of Macrolepidoptera was different between island Britain and continental Finland (Leather, 1991).

 

 

From Leather (1991) Classic species-area graph from both countries but some intriguing differences in feeding specialisation.

Despite the less than impressive citation index for the UK-Finland comparison paper (Leather, 1991), I would like to extend the analysis to the whole of Europe, or at least to those countries that have comprehensive published distributions of their Flora.  I offer this as a project to our Entomology MSc students, every year, but so far, no luck ☹

Although only four of my papers can be directly attributed to the Lawton & Schroeder paper, and taking into account that the insect species richness of Rosacea paper, is number 13 in my all-time citation list, I feel justified in counting it as one of the papers that shook my World.

References

Kennedy, C.E.J. & Southwood, T.R.E. (1984) The number of species of insects associated with British trees: a re-analysis. Journal of Animal Ecology, 53, 455-478.

Lawton, J.H. & Schroder, D. (1977) Effects of plant type, size of geographical range and taxonomic isolation on numbers of insect species associated with British plants. Nature, 265, 137-140.

Leather, S.R. (1985) Does the bird cherry have its ‘fair share’ of insect pests ? An appraisal of the species-area relationships of the phytophagous insects associated with British Prunus species. Ecological Entomology, 10, 43-56.

Leather, S.R. (1986) Insect species richness of the British Rosaceae: the importance of host range, plant architecture, age of establishment, taxonomic isolation and species-area relationships. Journal of Animal Ecology, 55, 841-860.

Leather, S.R. (1991) Feeding specialisation and host distribution of British and Finnish Prunus feeding macrolepidoptera. Oikos, 60, 40-48.

Leather, S.R. (1996) Biological flora of the British Isles Prunus padus L. Journal of Ecology, 84, 125-132.

Moran, V.C. (1980) Interactions between phytophagous insects and their Opuntia hosts. Ecological Entomology, 5, 153-164.

Simberloff, D. & Wilson, E.O. (1969) Experimental zoogeography of islands: the colonization of empty islands. Ecology50, 278-296.

Southwood, T.R.E. (1961) The number of species of insect associated with various trees. Journal of Animal Ecology, 30, 1-8.

Strong, D.R. & Levin, D.A. (1979) Species richness of plant parasites and growth form of their hosts. American Naturalist, 114, 1-22.

Strong, D.R., Lawton, J.H. & Southwood, T.R.E. (1984) Insects on Plants – Community Patterns and Mechanisms. Blackwell Scientific Publication, Oxford.

 

 

Leave a comment

Filed under Ten Papers That Shook My World

Ten more papers that shook my world – When it comes to plant-insect interactions its growth stage, not age that counts Watt (1979)

This is not just about a paper, but also about mentoring!  At the beginning of October 1977, I hesitantly knocked on the door of Professor Tony Dixon’s outer office in the School of Biological Sciences at the University of East Anglia, Norwich.  Tony was to become my PhD supervisor for the next three years and my friend and colleague for the next forty plus years, but until that day I had never met him, as my interview had been conducted entirely by telephone and in those pre-internet days, unless you had met someone at a conference you really only knew them by their papers and reputation.  I knew Tony because of his great little book, The Biology of Aphids which I had bought as an undergraduate in 1975, when I realised that aphids were really cool 😊 I told his secretary who I was and she directed me through to his office.  Tony looked up, said hello and asking me to follow him, took me down to the lab where I was to spend the next three years and introduced me to a tall, moustachioed Scotsman, Allan Watt, whom I was later to discover had a wicked sense of humour, and was to become not just a colleague and collaborator, but also a great friend, a friendship that continues to this day.  Tony’s introduction was roughly along the lines of “This is Allan, he’ll tell you what to do” and he did. Allan was just starting the final year of his PhD which was, like a number of us in Tony’s lab, on cereal aphids, in Allan’s case Sitobion avenae and Metopolphium dirhodum, the two major pests of cereals in the UK at the time.  My PhD was on a less abundant (in cereal crops), but equally problematic aphid, due to its ability to transmit Barley Yellow Dwarf Virus, the bird cherry-oat aphid Rhopalosiphum padi.  Having got my aphid cultures set up and done a couple of practice mini-experiments, I asked Allan what he was doing with his aphids.  He told me that he was looking at the effect of cereal growth stage on the survival and reproduction of his two aphid species and that the age of the plant had a significant effect on the aphids and that this varied between the two species, which he published a couple of years later (Watt, 1979).  Having been immersed in the cereal aphid literature for a couple of months, I knew that no one had done this for my aphid, and even then, being a great believer in “standing on the shoulders of giants” I figured that I could do the same for my aphid, but, in that never ending treadmill of adding novelty, also look at the effect of feeding position*. Allan’s advice and help stood me in good stead, and in due course I successfully published the results of my experiment (Leather & Dixon, 1981).

So, leaving aside me getting a publication as a result of Allan’s paper, how did this shake my World?  Well, first of all, it really drove home to me that plant phenological stage was incredibly important for insect-plant interactions and that unless you know the precise growth stage at which an interaction is happening it is difficult to compare other peoples’ results to yours and each other’s. As a result, it has led me as a reviewer and reader of papers, to be very scathing of phrases such as “ten-day old wheat plant”, “week old cabbage seedlings”, “young pea plant” (Leather, 2010).  It is deeply unhelpful for anyone wanting to repeat or compare similar work.  Just a few degrees difference in temperature over a week can move a plant from one phenological stage to another. There is no excuse for this type of sloppiness.

Two seven-day old wheat plants, same cultivar, same germination date, one reared at 20⁰C the other at 10⁰C. Growth stage 12 versus Growth stage 10 (Growth stages as described by Tottman & Makepeace, 1979).

The same two plants now fourteen day sold, GS 13 versus GS 12

It is not hard to find a solution.  The World has been blessed by the invention of the BBCH** system for coding plant phenological stages (Meier et al., 2009).  This system, which now exists for most major crop plants, including trees, means that there is no excuse for anyone to ever use the phrase “ten-day old plant” or similar wording. If by some chance, your plant does not yet have a BBCH description, either describe the growth stage that your plants are at in very precise terms or take the time to codify it yourself and submit it to a journal such as Annals of Applied Biology which has a long history of publishing such articles.

To be fair, before the BBCH system came into being, people had published descriptions of plant growth stages for some of the major crops, e.g. cereals (Feekes, 1941; Large, 1954), but they were not standardised, and in some cases, too broad-brush.  The stimulus for a standardised, decimal system of coding plant phenological stages was the publication of the Zadoks scale for cereals (Zadoks et al., 1974) and the illustrated follow-up a few years later (Tottman & Makepeace, 1979), the latter being the blueprint on which phenological growth stage papers are now based.

I look forward to the day when authors understand that a precise knowledge of plant growth stage is essential to understanding insect-plant interactions and I do NOT have to chide authors for not using the BBCH codification when I review their papers.

 

References

Feekes, W. (1941) De Tarwe en haar milieu. Vers. XVII Tech. Tarwe Comm. Groningen, 560-561.

Large, E.C. (1954) Growth stages in cereals. Plant Pathology, 3, 128-129.

Leather, S.R. (2010) Precise knowledge of plant growth stages enhances applied and pure research. Annals of Applied Biology, 157, 159-161.

Leather, S.R. & Dixon, A.F.G. (1981) The effect of cereal growth stage and feeding site on the reproductive activity of the bird cherry aphid Rhopalosiphum padi. Annals of Applied  Biology, 97, 135-141.

Meier, U., Bleiholder, H., Buhr, L., Feller, C., Hack, H., Hess, M., Lancashire, P.D., Schnock, U., Strauss, R., Vanden Boom, T., Weber, E. & Zwerger, P. (2009) The BBCH system to coding the phenological growth stages of plants – history and publications. Journal fur Kulturpflanzen, 61, S.41-52.

Tottman, D.R. & Makepeace, R.J. (1979) An explanation of the decimal code for the growth stage of cereals, with illustrations. Annals of Applied Biology, 93, 221-234.

Watt, A.D. (1979) The effect of cereal growth stages on the reproductive activity of Sitobion avenae and Metopolphium dirhodum. Annals of Applied Biology, 91, 147-157.

Watt, A.D. & Dixon, A.F.G. (1981) The effect of cereal growth stages and crowding of aphids on the induction of alatae in Sitobion avenae. Ecological Entomology, 6, 441-447.

Watt, A.D. & Wratten, S.D. (1984) The effects of growth stage in wheat on yield reductions caused by the rose grain aphid, Metopolophium dirhodum. Annals of Applied Biology, 104, 393-397.

Zadoks, J.C., Chang, T.T. & Konzak, C.F. (1974) A decimal code for the growth stages of cereals. Weed Research, 14, 415-421.

 

 

 

*

*Rhopaloisphum padi, in contrast to Sitobion avenae, is usually found on the lower stem and leaves of cereals.

**

The abbreviation BBCH derives from the names of the originally participating stakeholders: “Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie”. Allegedly, the abbreviation is said to unofficially represent the four companies that initially sponsored its development; Bayer, BASF, Ciba-Geigy, and Hoechst.

 

 

Leave a comment

Filed under Ten Papers That Shook My World