Category: Interview

Entomologist Erica McAlister is the senior curator for Diptera at the Natural History Museum, London. In 2017, she authored the very successful book The Secret Life of Flies which looked at their diverse lifestyles. Now she returns with The Inside out of Flies, which is a great popular science book marvelling at their anatomy.

We took the opportunity to ask her some questions about why flies matter to us all.

First off, tell us a little bit about how you got started. Why study flies? Having read your book now, I agree that they are fascinating and beautiful, but presumably, you did not know this when you started?

I have always been interested in nature, but I was more fascinated by the smaller creatures – the ones everyone else seemed to ignore. Insects were an obvious choice and I combined my love for them with my love of ecology from the beginning. Although I had worked with ants and beetles, it was the flies that properly tickled my fancy as they were the most diverse in life cycles and ecological function, and so the most interesting. They got everywhere, they did everything and they were wonderful to observe. I have a liking for all things natural – from decomposing dung heaps to parasitic lifestyles – both of which involve the fabulous flies.

You are quite involved in public outreach, speaking on radio programmes and giving public talks. Most people regard flies with a certain amount of disgust. Do you find it is easy to change people’s perceptions? 

Generally, yes. Most people just think about one or two examples of the thousands of species of flies such as the nuisance fliers or the transmitters of disease. So when I  tell them about the hoverflies, the bee flies, the chocolate pollinators, the forensic detectives, the scuba divers and so on, that opens up a whole new world to most people, and when I go on to talk about their gardens being alive with these beneficial creatures, you can see a change in many folks. Flies are animals and are essential for many ecosystems – it is odd that many naturalists seem to want to forget this!

After two decades of researching them, has your own attitude towards them changed?

Nope. In fact, I feel that I have got worse in my obsession with them as I realise that I have so much to learn and not enough time. Initially I was fascinated by their ecology, then their looks, then their behaviour, but there is also their genetics, their mechanics and many more other areas that we need to explore and understand. The more I have read and studied the more I realise that we have still so much to learn.

Your 2017 book The Secret Life of Flies was very well received. The design of your new book The Inside Out of Flies suggests it is a companion to the first book. Why write a second book?

Because there is so much more to write about them. We have thousands of books about mammals and there are just over 6100 of them. There are more flies in the UK than that and living in more extreme environments – the flies have adapted to all sorts of weird and wonderful habitats with a whole range of morphological changes to help them not just cope but thrive. The first book focused on their feeding ecology, this one is about their morphology, but there is still much, much more that I have left out from both of these subjects (I get emails all the time telling me so!)

You mention many people seem to think adult flies lack brains, this misconception being fuelled by watching them fly into windows again and again. This may seem like a very mundane question but why, indeed, do they do this?

This is a common question – but the answer is not really known. Firstly, the glass could be disorientating the flies as it blocks out UV-B which are used by the flies to help them navigate. The actual glass may be perceived as something different to them – they would realise that it was some form of wall due to the change in air currents, but we don’t know as yet what and presumably it could be multiple factors. There are many footprints of previous insects that have crawled across that pane and maybe there are hints about food sources (flies taste with their feet) that further distracts them. There is still so much about these creatures that we don’t know.

As you go through each body segment of a fly’s body in this book, you show that there is astounding variation in traits, and you back this up with some fantastic photography. One striking example was of a soldier fly species, Platyna hastata, whose abdomen is almost as wide as it is long, you affectionately call them fat-bottomed flies. Is this another example of sexual selection run rampant?

In flies – there are so many examples of extreme sexual selection and I discuss this throughout the book – from eyestalks to flags on their abdomen to hidden internal modifications. One of my favourites is the fly Drosophila bifurcata that has sperm that is 5.8 cm long and the actual adult male is but a few millimetres!

You explain how insect taxonomists use morphological details such as the position and numbers of hairs on their body to define species. I have not been involved in this sort of work myself, but I have always wondered, how stable are such characters? And on how many samples do you base your decisions before you decide they are robust and useful traits? Is there a risk of over-inflating species count because of variation in traits?

Ahhh there is the dilemma that many a taxonomist has faced – is it a true species??? The NHM collection has many thousands of species but often the specimen that the species was described from is the only specimen that anyone has of that species! Only time will tell if it is a true species. However, many of these characters are very stable with many of the bristle arrangements having been around for thousands of years. There is a risk of over-inflating species but then again there is a risk of under-inflating – and taxonomists fall into two groups – the splitters or the lumpers depending upon what they feel are important characters. What we do know for certain is that the sexually derived characters – the genital structures change at a faster rate and so this is why we appear to be obsessed with such things!

There are some fantastic examples in this book of the applied aspects coming out of dipterology as a field of study, with forensic entomology and miniature robotics being good examples. What are some of the most exciting applied developments that you think will make a splash in the near future?

Oh, what a question! I feel that we are on the cusp of many exciting developments – especially in aeronautics and medicine. Personally, I am loving the development of smart needles – the idea of bending these around sensitive structures is incredible and so very useful. But as technology develops so does our ability to look at these creatures and try to mimic their millennia-old adaptations.

I imagine some aspects of entomology rely on decades- and centuries-old methods from when the field got started. Simultaneously, like most academic disciplines, the field has benefited from technological advances. How have new technologies changed how you work and the sorts of questions you ask? 

Yes, absolutely. I can ask so much more from the specimens in the collection at the Natural History Museum now, even though the flies may have been dead for hundreds of years. I can image them inside and out and in doing so I can see what pollen is in their guts or around their mouthparts; I can analyse their DNA and see how the populations developed or when insecticide resistance developed; and I can transfer all of this information around the world in seconds – no longer is research hindered by physical distance or financial constraints as much as it once was. And on a general level, I and many others have the resources of millions of people making observations and taking photos which massively adds to our knowledge. New technologies have made scientists out of all of us.

One of the more remarkable and little-appreciated things you draw attention to is that flies are an important group of pollinators worldwide. There has been much public concern regarding bees, pollination, and the future of our crops. Do we have reason to be concerned about the ecological function provided by pollinating flies?

We need to care about flies as much as all of the other insects that are more commonly talked about. Not only are the adults amazing pollinators but the larvae of many of these species are also carrying out key ecological roles such as predation or decomposition. And often it is only the flies that are the pollinators, especially in the more extreme habitats or crops. If you don’t look after the flies, you will find the world bereft of many food products that everyone loves such as chocolate.

Lastly, has the pandemic influenced your work and that of those around you? 

I would say yes. Hopefully, more people have realised how important the natural world is. I have spent the last couple of moths answering questions and identifying flies that folks would not have spent time observing before, and I have seen appreciation grow in all things fly. I think we have realised that we need to work more in balance with our environment and so the work that I, and millions of other entomologists undertake, is now seen with a new appreciation – we are not just going around looking at pretty flies, but are trying to help understand our climate and the impact the changes are having on it, our food security, and the impact of disease and vectors to name but a few examples.

The Inside Out of Flies
By: Erica McAlister
Hardback | September 2020| £12.99 £14.99

All prices correct at the time of this article’s publication.

In our latest Q&A we talk to Andrew Duff, keen naturalist and author of the new book Beetles of Britain and Ireland Volume 3, which joins a monumental 4-volume identification guide to to the adult Coleoptera of the Republic of Ireland, the United Kingdom of Great Britain & Northern Ireland, and the British Crown Dependency of the Isle of Man. By bringing together reliable modern keys and using the latest taxonomic arrangement and nomenclature, it is hoped that budding coleopterists will more quickly learn how to identify beetles and gain added confidence in their identifications.

Andrew has taken his time to answer our questions about his book and about the fascinating world of beetles.

 Aside from the most conspicuous species, beetles seldom seem to attract as much attention as some other insect orders. What is it that has drawn you to study this group? 

My initial attraction to beetles was by coming across some of the larger and more colourful species, as you might expect. The first occasion was in about the late 1970s. I was out birdwatching with my oldest and best friend, the Ruislip naturalist Mike Grigson, when he found a species of dor beetle. These are large black beetles, often found wandering in the open on heaths and moors. They have the most striking metallic blue undersides. Picking one up, Mike said to me: “beetles are really beautiful ”, and I can still picture him saying it. The next occasion was when I was assistant warden at the Asham Wood reserve on the Mendip Hills in Somerset, in the summer of 1982. The warden, Jim Kemp, was an expert mycologist with a side interest in beetles. One day we were on the reserve and he pointed out a black-and-yellow longhorn beetle sat on an umbel. I thought it was very exotic-looking, every bit as worthy of a naturalist’s attention as butterflies and orchids! So I resolved to find out more about the beetles found in Asham Wood. Bristol Reference Library had a copy of Norman Joy’s Practical Handbook of British Beetles and it was obvious that I needed to buy it. Once I had my own copy of ‘Joy’, there was no stopping me. I started finding beetles and was able to identify most of them. The more you study beetles, the more you realise that all of them have their own special kind of beauty, and this is what ultimately led me to become a coleopterist. That, and the intellectual challenge of identifying small brown beetles, are what continue to inspire me. 

 What motivated you to write and publish Beetles of Britain and Ireland?

Joy’s Practical Handbook of British Beetles was the standard beetle identification guide for at least two generations of British coleopterists, ever since its publication in 1932. Joy’s book provided concise keys to every British beetle in a handy two-volume set, one volume of text and one of line drawings. The trouble with this idea is that the keys were oversimplified and misleading because of all the detail that wasn’t included. By the 1980s ‘Joy’ was already long past its ‘best before date’. Talk started about somebody producing a successor set of volumes and the late Peter Skidmore made a start—after his death I was fortunate to obtain his draft keys and drawings, and in particular have made much use of his drawings in my book. Peter Hodge and Richard Jones then published New British Beetles: species not in Joy’s practical handbook (BENHS, 1995). This was a fantastic achievement because it brought together in one place a list of the species not included in ‘Joy’, as well as notice of recent changes in nomenclature and of some errors in his keys. But it was still only a stop-gap measure.

By around 2008 still nothing had been produced by anyone else. I reckoned it might be achievable and began to discuss with other coleopterists the idea of writing a new series of volumes. The turning point was a discussion with Mark Telfer at a BENHS Annual Exhibition in London. My main concern was over the use of previously published drawings in scientific papers, but Mark reassured me that provided the drawings were properly credited and that the book was clearly an original work in its text and design then it should not fall foul of any copyright issues. By 2010 I’d already made a start on Beetles of Britain and Ireland and in the summer of that year took early retirement so that I could work on it more or less full time. My own professional background is as a technical author in the world of IT and from the 1980s onwards I’d had extensive experience of what used to be grandly called desktop publishing, what we would now call simply word processing! I’d decided to go down the self-publishing route so that I could ensure the production values matched what I thought coleopterists would want: a book which was laid out clearly and would stand up to a lot of wear. It’s really for others to judge whether my volumes meet the needs and expectations of most coleopterists, but so far I’ve been pleasantly surprised at how well they’ve been received.

 How did production of this book compare to the previous volumes in the series? Was it difficult to bring together information on so many families exhibiting such a diversity of life histories?

As this is the third volume to have been completed I’d already learnt a lot about the best way to collate all of the material and summarise it, while trying to make as few mistakes as possible. The previous two volumes (vols. 1 and 4) were written in a rather erratic fashion, so that at any one time some sections would be more or less complete while others would not even have been started. This time I was determined to be more disciplined by starting with the first family, completing a draft which included the family introduction, keys to genera and species, and all of the line art illustrations, before going on the next family and doing the same again. In a way, having many families was an advantage because it meant I could use a ‘divide-and-rule’ strategy by breaking down a fauna of 1088 species into 69 smaller chunks. The fact that there are so many families in this volume didn’t generate any special problems, indeed families with only a few species like the stag beetles, glow-worms and net-winged beetles are relatively straightforward to document. But some of the family introductions were a challenge, insofar as some families are poorly defined taxonomically and hard to characterise in a way which would be accessible to amateur coleopterists. For example the darkling beetles (Tenebrionidae) exhibit a bewildering diversity which makes it well nigh impossible to say why a particular species is or is not assigned to this family. I made extensive use of the two-volume American Beetles (Arnett et al., 2002), which contains succinct summaries of nearly all of our beetle families, and this made my job a lot easier. But at the end of the day, the family diagnoses are not as important as the keys to genera and species. Most coleopterists won’t be coming to a particular family chapter as a result of methodically working through the key to families in volume 1. I imagine that in most cases people start by comparing their beetle with the colour plates, getting a shrewd idea as to what family it belongs to, and then going straight to the keys to genera and species. Picture-matching will always have its place in natural history, and I hope that Udo Schmidt’s 473 colour photos in this volume will be put to good use.

 This volume covers some of our most familiar beetles – the ladybirds and chafers, for example. What advice would you give to anyone seeking to extend their interest beyond these well-known families to the more ‘obscure’ groups? 

I would say that it largely depends on what kind of naturalist you are. What I mean by this is that there are two main ways of studying beetles, and you have to decide which path is right for you. On the one hand, many naturalists take photographs of beetles and by using the Internet or an expert validation service such as iRecord (www.brc.ac.uk/irecord/) they can usually achieve reliable identifications, at least to genus level, for medium-sized and large beetles. Some spectacular finds of beetles new to Britain have been found by general naturalists posting their images on the Internet, a very recent example being the flower-visiting chafer Valgus hemipterus, first posted to iRecord in April 2019 and already given the full works treatment in my volume 3. The problems start as soon as you try to identify smaller and more obscure beetles, because most of them are simply not identifiable from photographs. It’s not their small size and lack of bright colour patterns as such, so much as the need to view the underside, or the fore legs from a particular angle, or the head from the front, or the body orthogonally from directly above to ascertain the precise shape, which makes field photography impractical as a way to identify small beetles. So what you need to do is to go down the second path and start a beetle collection. This enables you to examine your specimen with a bright light source under a good stereomicroscope, turn it over to examine the underside, stretch out its legs to look for the pattern of teeth and spines, straighten it to measure its length and width, and if you’re feeling brave dissect out the genitalia which often provide the only definitive way to arrive at a species identification. Many naturalists balk at the thought of collecting beetles, but I would argue that the scientific value of having a comprehensive species list for a site outweighs any squeamishness I might feel about taking an insect’s life. In any case, my guilt is assuaged by the fact that insects are being eaten in their trillions every day, everywhere, by all manner of insectivorous animals and plants, so that the additional negative effect of my collection on beetle populations is vanishingly small.

Could you tell us a little about the process of compiling keys for the identification of the more challenging species? Were you able to draw upon the existing literature, or did you have to create them from scratch?

Some of the genera treated in this volume have been giving problems for coleopterists ever since the scientific study of beetles began. These are genera with a number of very similar, small and plain species that appear to have few distinguishing features. Nine genera in particular stand out for me as being conventionally ‘difficult’: Contacyphon, Dryops, Cryptophagus, Atomaria, Epuraea, Carpophilus, Meligethes, Corticaria and Mordellistena. It was always going to be a challenge for me to provide workable keys to these ‘nightmare nine’ genera, but I was keen to give it a go. It helps that I take a perverse interest in very difficult identification challenges, so I was motivated to come up with keys which would work. Fortunately I was able to pull together information from a variety of different sources until I had draft keys which could be put out for testing. The testing went through a number of iterations and by reworking the keys—for example adding my own illustrations, simplfying or reorganising couplets, or adding new couplets to account for ambiguous characters—they were gradually improved until I was happy with them. A second source of difficulty concerned the aphodiine group of dung beetles. The formerly very specious genus Aphodius was recently broken up into 27 smaller genera, and our leading dung beetle expert, Darren Mann, recommended to me that we should adopt the new taxonomy. This meant that I needed to construct a completely new key to genera, and that took a great deal of time and effort searching for characters. Incidentally I’d like to pay special thanks to Steve Lane and Mark Telfer for their advice and help with these difficult genera; I owe them both a great deal for their encouragement and support. The keys to challenging genera in this volume will certainly not be the last word on the subject, but I believe they are an improvement on previous keys.

 When gathering information on habitat and biology of the various families, did you notice any glaring omissions? Are there any families that could particularly benefit from further study?

Some of the families treated in this volume are well understood, in terms of their identification, ecology and distribution in Britain and Ireland. The scarab beetle family-group, jewel beetles, click beetle family-group, glow-worms, soldier beetles, ladybirds, oil beetles and cardinal beetles are all popular groups and have been reasonably well studied, while the ladybirds have received a huge amount of attention! But that accounts for just 13 of the 69 families treated in volume 3, and the remaining 56 families are in general much less well known. Modern identification keys in English already existed for some of the other families but for most the information is very basic. I would say that the biggest gap in our understanding concerns the synanthropic and stored-product beetles. Not only do amateur coleopterists rarely come across these species, but the information that has been gathered (mostly by food hygiene inspectors) has not been made publicly available. In a few cases it’s not even clear which country a species has been found in, and all we know is that it has been found at some time, somewhere in Britain. I would like to think that this group will one day be much better documented.

A particular favourite of mine are the silken fungus beetles (Cryptophagidae). This family contains two of the ‘nightmare nine’ genera: Cryptophagus with 35 species and Atomaria with 44 species. I’ve tried hard to produce workable new keys for these two genera, but their identification is never going to be easy and it will be necessary to validate records for a long time to come. But I hope that at least this family will begin to benefit from a greater level of interest, on the back of my new keys.

 There will be one more volume to come before this monumental series is complete – are you able to provide an estimation as to when that will come to fruition?

Volume 2 covers just one huge family: the rove beetles (Staphylinidae). This has been left until last for two good reasons. Firstly, the subfamily Aleocharinae, and in particular the hundreds of species in the tribe Athetini, are so poorly understood that it’s just not clear where the generic limits are drawn. This means I will have my work cut out trying to construct a new key to Aleocharinae genera. Preferably the key won’t involve dissecting out the mouthparts and examining them under a compound microscope, as we are expected to do now! Secondly, it has to be admitted that rove beetles are not the most exciting to look at. As publisher as well as lead author of my series of volumes it was always going to be difficult to sell a book which didn’t contain a lot of colourful plates. My plan all along, then, was to leave the rove beetles until last, in the hope that people would buy the book in order to complete their set! Volume 2 has already been started, and Udo has been working hard on the colour plates, but there is still a mountain to climb to complete the Athetini keys and illustrations to my satisfaction. My best estimate currently is that it will be published no later than 2024. Once that is done, and if I still have my wits about me, I suppose I’ll have to think about revised editions of the earlier volumes!

Beetles of Britain and Ireland: Volume 3 Geotrupidae to Scraptiidae

By: Andrew G.Duff
Hardback | Due July 2020| £109.00

Browse the rest of the Beetles of Britain and Ireland series on the NHBS website

All prices correct at the time of this article’s publication.