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.

Not all aphids live on the underside of leaves

If I were to misquote Jane Austen and state “It is a truth universally acknowledged, that aphids are found on the underside of leaves” most people who know what aphids are would agree without quibbling. If natural enemies could speak, they would probably agree as this quote from an early paper by my former boss, Hugh Evans puts it  “since most aphids are found on the lower surfaces of leaves anthocorids must be wasting time in searching the upper leaf surface” (Evans, 1976). The only enemies that regularly search the upper surface of leaves are parasitoids, which use aphid honeydew as a host-findng cue (e.g. Volkl, 1994), which is where it falls if the leaves above them are infested with aphids.  We know that not all aphids feed on leaves, many using roots, flowers, stems and even tree trunks as their preferred feeding sites, but do all leaf-feeding aphids behave in the same way?

A few species of leaf-dwelling aphid buck the trend and live on the upper surface of leaves. Dogma has it that most leaf-feeding aphids prefer the underside because there are more stomata there and this makes access to the phloem easier.

Aphis grossulariae on the underside of a gooseberry leaf, – only revealed because I turned the leaf over.

Look, however, at a neat experiment that Graham Hopkins and Tony Dixon did (Hopkins & Dixon, 2000). They showed that the birch aphid Euceraphis betulae, which is normally found on the lower surface of leaves, will, if the leaves are held so that the upper surface faces the ground, move from the now facing upward lower surface to the now facing downward upper surface. The answer can’t all be to do with the stomata. That said, in grasses and other monocotyledonous plants, there are more stomata on the upper surface of the leaves andmMany grass-feeding aphids do seem to have a predilection for the upper surface. The green spruce aphid, Elatobium abietinum, another aphid that has a very strong preference for feeding through stomata, is found mainly on the upper surface of spruce needles which are where the stomata are more prevalent (Parry, 1971).

Utamophoraphora humboltdi feeding on the upper surface of Poa annua outside my office.

The Green Spruce Aphid, Elatobium abietinum feeding on the upper surface of spruce needles (Albrecht (2017)

It is possible, however, that the preference for the upper surface of grasses is not entirely due to the relative abundance of stomata there.  The grass aphid, Sipha kurdjumovi for example, although most commonly found feeding on the upper surface of grass and cereal leaves, prefers to settle on a concave ridged surface (Dixon & Shearer, 1974), a characteristic of the upper surface of many grasses  Lewton-Brain, 1904). Another advantage to living on the upper surface of grass leaves is that when grasses want to conserve water they roll inwards along the mid-vein, which has the added benefit of hiding the aphids and protecting them from their natural enemies.

Mainly, however, if you are an aphid, you feed where the stomata are plentiful, hence the tendency for aphids living on monocotyledonous plants to feed mainly on the upper surface of leaves, instead of the lower surface.  Conversely, a leaf-feeding aphid on a dicotyledonous host plant would be expected to feed on the lower surface of the leaves, where there are more stomata.  It also makes sense for those aphids to be underneath the leaf, as there is less chance of them being knocked off by the rain or being dislodged by leaves brushing against each other in the wind.

There are, however, two tree-dwelling aphids in the UK that live on the upper side of the leaves of their woody hosts, the very rare Monaphis antennata on birch (Hopkins & Dixon, 1997) and the less rare large walnut aphid, Panaphis juglandis on walnut (Heie, 1982). So what makes these aphids so contrary? According to Graham Hopkins and Tony Dixon (Hopkins & Dixon, 1997), M. antennata is taking advantage of enemy-free space and to compensate for living on top of the leaf is cryptic to avoid detection by enterprising predators, and has a flattened and contoured body shape to avoid accidental dislodgement.

When it comes to P. juglandis things are bit more conjectural.  Interestingly, despite being a pest in some parts of the world (e.g. Wani & Ahmad, 2014) we don’t know much about it. It is also hard to understand why it has adopted the upper side of the leaf as its habitat.  One very obvious downside

Panaphis juglandis – prominently lined up along the mid-vein of the upper surface of a walnut leaf and displaying their possible unpalatability by their conspicuous yellow and black colouration.  From Influential Points  https://influentialpoints.com/Images/Panaphis_juglandis_nymphs_on-vein_c2013-07-06_18-35-17ew.jpg

is that by so doing it has opened Itself up to competition from the other common walnut aphid, Chromaphis juglandicola, the honeydew of which falls from the leaves like acid rain on to P. juglandis and prevents them living on the same trees (Olson, 1974; Wani & Ahmad, 2014).  In the absence of C. juglandicola it is, however, very successful with a number of life history traits that presumably ensure its survival, although no one has quantified this. First, it is striped yellow and black, a clear warning sign.  Bob Dransfield and Bob Brightwell who run that fantastic site, Influential Points, suggest that perhaps P. juglandis sequesters juglone from its walnut host as a defence against predators. It therefore makes sense to advertise it by being conspicuously coloured.  Second, they also, point out that the way in which the nymphs line up along the mid-vein might act as a form of masquerade mimicry or disruptive camouflage, by looking from certain angles like a blemish caused  by a fungal disease or injury. Neither of these suggestions answer the question as to why it lives on the upper side of leaves. For M. antennata, escape from natural enemies and competition are cited as the reason why it lives where it does.  Neither seem to explain P. juglandis, as it is not, at least according to Olson (1974), safe from predation and parasitism, although there is some indication that it might be ant-attended (Fremlin, 2016), nor is it able to share its host plant with the other walnut specialist, Chromaphis juglandicola. On the other hand, unlike M. antennata, it is most definitely not a rarity.

As they used to say when I was young, “answers on a postcard please”. In the meantime, until someone has the time and inclination to delve into this intriguing conundrum, I guess we should add it to Ole Heie’s list of unsolved aphid mysteries 🙂

 

References

Albrecht, A. (2017) Illustrated identification guide to the Nordic aphids feeding on conifers (Pinophyta) (Insecta, Hemiptera, Sternorhyncha, Aphidomorpha). European Journal of Taxonomy, 338, 1-160.

Dixon, A.F.G. & Shearer, J.W. (1974) Factors determining the distribution of the aphid, Sipha kurdjumovi on grasses. Entomologia experimentalis et applicata, 17, 439-444.

Evans, H.F. (1976) The searching behaviour of Anthocoris confusus (Reuter) in relation to prey density and plant surface topography. Ecological Entomology, 1, 163-169.

Fremlin, M. (2016) The large walnut aphid (Panaphis juglandis Goeze) – A few observations. Nature in North-East Essex, 2016, 68-76.

Heie, O.E. (1982) Fauna Entomologia Scandinavia, Vol. 11. The Aphidoidea (Hemiptera) of Fennoscandia and Denmark. II. The family Drepanosiphidae. Scandinavian Science Press, Klampenbourg, Denmark.

Heie, O.E. (2009) Aphid mysteries not yet solved/Hemiptera:Aphidomorpha./. Monograph Aphids and Other Hemipterous Insects, 15, 31-48.

Hopkins, G.W. & Dixon, A.F.G. (1997) Enemy-free space and the feeding niche of an aphid. Ecological Entomology, 22, 271-274.

Hopkins, G.W. & Dixon, A.F.G. (2000) Feeding site location in birch aphids (Sternorrhyncha: Aphididae): the simplicity and reliability of cues. European Journal of Entomology, 97, 279-280.

Lewton-Brain, L. (1904). VII. On the anatomy of the leaves of British grasses. Transactions of the Linnaean Society of London, Botany, Series 2, 6, 312-359.

Olson, W.H. (1974) Dusky-veined walnut aphid studies. California Agriculture, 28, 18-19.

Parry, W.H. (1971) Differences in the probing behaviour of Elatobium abietinum feeding on Sitka and Norway spruces. Annals of Applied Biology, 69, 177-185.

Volkl, W. (1994) Searching at different spatial scales: the foraging behaviour of the aphid parasitoid Aphidius rosae in rose bushes. Oecologia, 100, 177-183.

Wani, S.A. & Ahmad, S.T. (2014). Competition and niche-partitioning in two species of walnut aphids. International Journal of Scientific Research and Reviews 3, 120 – 125.

Willmer, C. & Fricker W (1996)  Stomata, Springer, Berlin.

Arthropod orchids – who’s fooling who?

A few weeks ago I read the first volume of Jocelyn Brooke’s Orchid trilogy, The Military Orchid. I have never been a great fan of orchids, my main experience of them being as ornamental house plants in which context I have always found them ugly, ungainly and obtrusive.

My colleague Lucy’s orchid ‘brightening up’ our communal office kitchen area

‘Artistically displayed’ for sale by an on-line florist – still just as ugly

Jocelyn Brooke’s account of his search for the Military Orchid was however a bit of a revelation.  His obsession with the eponymous orchid reminded me of how I quite liked seeing the first emerging spikes of the common spotted orchid, Dactylorhiza fuchsii appearing in Heronsbrook Meadow at Silwood Park as I returned from my lunchtime run.  A little bit later Jeff Ollerton posted an interesting article about orchid pollination myths and this got me thinking about the common names of our native UK orchids, especially those named after arthropods.

It turns out that there are fewer than I thought; Bee, some varieties of which seem to be called the wasp orchid, the Fly, Lesser butterfly, Greater butterfly, Early spider and Late spider orchid being the lot.  My self-imposed mission was to first find a suitable photograph of each species to see if it did look like its namesake and secondly to identify the main pollinators.  Or to put it another way, exactly what are they mimicking and what or who are they really fooling?  Orchids generally speaking are honest brokers, providing nectar as a resource for pollination services (Nilsson, 1992).  About a quarter of orchid species are however frauds or cheats (Nilsson, 1992), either pretending to be a food source or a receptive female insect, nutritive deceptive or sexually (reproductive) deceptive as the jargon has it (Dafni, 1984).  Ophrys orchids are sexually deceptive (Nilsson 1992).

The Bee Orchid, Ophrys apifera, is pollinated by a solitary mining bee, Eucera longicornis  (Kullenberg, 1950) belonging to a group commonly known as long horned bees, which in the UK is rather uncommon meaning that the Bee Orchid is generally self-pollinated.

The Bee Orchid, Ophrys apifera.  https://thmcf.files.wordpress.com/2013/07/bee-orchid-imc-3702.jpg with pollinator Eucera longicornis http://www.bwars.com/bee/apidae/eucera-longicornis

If you look at the female bee, which is what we suppose the flower is mimicking, you can just about convince yourself that there is a slight resemblance between the two.  Insects of course do not see things the same way humans do (Döring et al., 2012) so what we think is almost certainly irrelevant.  That said, it doesn’t actually have to be a particularly good visual mimic for the insects either, as it is the smell that really matters and as long as the flower is the right shape to enable the deceived male to copulate in such a way that the flower is fertilized that is all that matters.   To quote Dafni (1984) “The olfactory specificity allows a high degree of morphological variability because the selective pressures leading to uniformity-as a means for better recognition-are relaxed. When odors become the main means of attraction, they efficiently serve as isolating agents among closely related species”

The fly orchid, Ophrys insectiflora, is also sexually deceptive, but despite its common name is pollinated by digger wasps and bees (Kullenberg, 1950; Wolff 1950).

Ophrys insectifera   Fly orchid  By Jörg Hempel, CC BY-SA 3.0 de, https://commons.wikimedia.org/w/index.php?curid=32968796  with pollinator Argogorytes mystaceus (formerly Gorytes) http://www.bwars.com/category/taxonomic-hierarchy/wasp/crabronidae/nyssoninae/gorytes

Oddly, despite being sexually deceptive it does, at least in my opinion, resemble its pollinators fairly well.

Next up (alphabetically), we have the Lesser Butterfly Orchid, Planthera bifolia, which despite its name is pollinated by night-flying hawk moths,

 

The Lesser Butterfly Orchid, Planthera bifolia.  By © Hans Hillewaert, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=4112191 and the two leading pollinators Hyloicus pinastri and Deilephila elpenor.

most commonly by the Pine Hawk Moth, Hyloicus pinastri and the Elephant Hawk Moth, Deilephila elpenor  (Nilsson (1983). These orchids provide a nectar reward, and attract their pollinators by producing a strong scent (Nilsson, 1978) easily detected by humans even at a distance (Tollsten & Bergström, 1989).  As an added extra, the flowers are very light-green and also highly light-reflecting, giving the moths a visual as well as an olfactory signal (Nilsson, 1978).  In terms of shape the flower more closely resembles H. pinastri.

The closely related Greater Butterfly Orchid, Planthera chlorantha is also pollinated by night-flying moths, the two Elephant hawk moths  Deiliphila porcellus and D.elpenor, 

Platanthera chlorantha,  The Greater Butterfly  Orchid https://c1.staticflickr.com/8/7795/17960863138_721033c527_b.jpg with hawk moth and Noctuid pollinators.

but mainly by Noctuid moths, most commonly, Apame furva (The Confused) and  A. monoglypha (the Dark Arches) Nilsson (1983).  Although recent video evidence has shown that the Pine Hawk moth also pollinates it (Steen, 2012).  Like the Lesser Butterfly Orchid, the flower only vaguely resembles its pollinators.  The chemicals responsible for the characteristic and intense fragrances of these two closely related orchids differ between the species and is probable that they are linked to the preferences of the different pollinator species (Nilsson, 1978).

Despite its name and suggested resemblance to its namesake, the Early Spider Orchid, Ophrys sphegodes is pollinated by a solitary bee,

Ophrys sphegodes, The Early Spider Orchid

https://species.wikimedia.org/wiki/Ophrys_sphegodes_subsp._sphegodes#/media/File:Ophrys_sphegodes_Taubergie%C3%9Fen_22.jpg

Andrena nigroaenea (Schiestl et al. 2000).  The scent of the nectarless flower, closely resembles the female sex pheromone of the bee and fools the male into ‘mating’ with it (Schiestl et al., 2000).  If you allow your imagination to run riot you could possibly just about see the flower as a giant female bee which might act as an extra stimulus for an excited male bee (Gaskett, 2011).

The final arthropod orchid is the Late Spider, Ophrys fuciflora; do be careful how you pronounce it, a soft c might be advisable 🙂

Ophrys fuciflora, the Late Spider orchid and two of its documented pollinators, Eucera longicornis (originally tuberculata) and Phyllopertha horticola.  Orchid Photo by © Pieter C. Brouwer and his Photo Website

As with all Ophrys orchids, they are sexually deceptive and attract male insects to their nectar-free, but highly scented flowers, with the promise of a good time Vereecken et al., 2011).  Most pollination is by solitary bees (Kullenberg, 1950) although the Garden Chafer, Phyllopertha horticola has been recorded as pollinating it in northern France (Tyteca et al., 2006).  Again both pollinators could be said to resemble the flowers to some extent

That concludes my tour of UK arthropod orchids.  Having learnt a lot about other orchids in the last couple of weeks while researching this article it seemed a shame to waste it.  So, as an added bonus, I’m going to finish with a few imaginatively named orchids, the names of which do not refer to their pollinators but rather to the imagination of their human namers.

Orchis anthropophora, The Man Orchid.  Photo by Erwin Meier

This not usually pollinated by sexually-deceived humans but by two beetles, Cantharis rustica (soldier beetle) and Cidnopus pilosus (click beetle) and also by two species of sawfly Tenthredopsis sp. and Arge thoracia (Schatz, 2006).

Orchis simia, The Monkey Orchid. Photo Dimìtar Nàydenov

Again, as with the Man Orchid, the Monkey Orchid, is not pollinated by cruelly deceived anthropoids.  There are, as far as I can discover, only a few confirmed pollinators of O. simia.  They include the beetle C. pillosus, the moth Hemaris fuciformis and some hymenopterans such as honeybees (Schatz, 2006).  According to PlantLife, hybrids of the Man Orchid and Monkey Orchid are called the Missing Link Orchid.

My fellow blogger Jeff Ollerton and his colleagues (Waser et al., 1996), point out that pollination systems are not as specialist as many might think, and even in sexually-deceptive orchids that use pheromone mimics, many of their pollinators can get ‘confused’ and pollinate closely related orchid species.  Hence the existence of what are termed ‘natural hybrids’ such as the Missing Link Orchid and the interesting hybrid between the Fly Orchid and the Woodcock Orchid pictured below.

The hybrid, Fly x Woodcock  Orchid.  Photo Karen Woolley‏ @Wildwingsand

It looks like a belligerent penguin to me, but is of course pollinated by insects.

Often regarded as one of the most bizarrely flowered orchids is the Flying Duck Orchid, Caleana major from Australia.

Flying duck orchid Caleana major (from Australia) sawfly pollinated (Adams & Lawson, 1993).

I was intrigued to notice what appears to be a Cantharid beetle, species of which are known to pollinate other orchids (Schatz, 2006), lurking in the background. There are a number of Cantharids noted as being pollinators in Australia, some of which have been recorded pollinating orchids, although not specifically on Calaena (Armstrong, 1979) so this may be an overlooked pollinator, just waiting to be confirmed by a dedicated pollinator biologist or orchidologist.  There is also, if you wondered, a Small Duck Orchid, Paracaleana minor.

Who would have thought that reading a biography would have started me off on such an interesting paper hunt?  Perhaps the most interesting new bit of information I discovered was that male orchid bees although they attract females with scents, do not produce their own pheromones but collect flower volatiles which they mix with volatiles from other sources like fungi, plant sap and resins (Arriaga-Osnaya et al., 2017).  They use these ‘perfumes’ as part of their competitive courtship behaviour to attract females; the best perfumier wins the lady J

And then you have Dracula vampira….

Dracula vampira (Vampire orchid) – only found in Ecuador (Photo: Eric Hunt, licensed under CC by 3.0).© Eric Hunt.  I hasten to add this is not pollinated by vampires, bats or otherwise.

 

But to finish, here is the one that started it all…

The one that started it all, The Military Orchid, Orchis militaris  https://upload.wikimedia.org/wikipedia/commons/d/d4/Orchis_militaris_110503a.jpg

 

Acknowledgements

Many thanks to Manu Saunders over at Ecology is Not a Dirty Word for sending me a key reference and also to her and Jeff Ollerton for casting critical ‘pre-publication’ eyes over this post.

References

Armstrong, J.A. (1979) Biotic pollination mechanisms in the Australian flora — a review.  New Zealand Journal of Botany, 17, 467-508.

Adams, P.B. & Lawson, S.D. (1993) Pollination in Australian orchids: A critical assessment of the literature 1882-1992.  Australian Journal of Botany, 41, 553-575.

Arriaga-Osnaya, B.J., Contreras-Garduño, J., Espinosa-García, F.J. García-Rodríguez, Y.M.,  Moreno-García, M., Lanz-Mendoza, H., Godínez-Álvarez, H., & Cueva del Castillo, R. (2016) Are body size and volatile blends honest signals in orchid bees? Ecology & Evolution, 7, 3037–3045.

Dafni, A. (1984) Mimicry and deception in pollination.  Annual Review of Ecology & Systematics, 15, 259-278.

Döring, T.F., Skellern, M., Watts, N., & Cook, S.M. (2012) Colour choice behaviour in the pollen beetle Meligethes aeneus (Coleoptera: Nitulidae). Physiological Entomology, 37, 360-368.

Gaskett, A.C. (2011) Orchid pollination by sexual deception: pollinator perspectives. Biological Reviews, 86, 33-75.

Kullenberg, B. (1950) Investigations on the pollination of Ophrys species. Oikos, 2, 1-19.

Nilsson, L.A. (1978) Pollination ecology and adaptation in Platanthera chlorantha (Orchidaceae).  Botaniska Notiser, 131, 35-51.

Nilsson, L.A. (1983) Processes of isolation and introgressive interplay between Platanthera bifolia (L.) Rich and P. chlorantha (Custer) Reichb. (Orchidaceae). Botanical Journal of the Linnean Society, 87, 325-350.

Schatz, B. (2006)  Fine scale distribution of pollinator explains the occurrence of the natural orchid hybrid xOrchis bergonii.  Ecoscience, 13, 111-118.

Schiestl, F.P., Ayasse, M., Pauklus, H.F., Löfstedt, C., Hansson, B.S., Ibarra, F. & Francke, W. (2000) Sex pheromone mimicry in the eraly spider orchid (Ophrys sphegodes): patterns of hydrocarbons as the key mechanism for pollination by sexual deception.  Journal of Comparative Physiology A, 186, 567-574.

Steen, R. (2012) Pollination of Platanthera chlorantha (Orchidaceae): new video registration of a hawkmoth (Sphingidae). Nordic Journal of Botany, 30, 623-626.

Tollsten, L. & Bergström, J. (1989) variation and post-pollination changes in floral odours released by Platanthera chlorantha (Orchidaceae). Nordic Journal of Botany, 9, 359-362.

Tyteca, D., Rois, A.S. & Vereecken, N.J. (2006) Observations on the pollination of Oprys fuciflora by pseudo-copulation males of Phyllopertha horticola in northern France. Journal Europäischer Orchideen, 38, 203-214.

Vereecken, N.J., Streinzer, M., Ayasse, M., Spaethe, J., Paulus, H.F., Stökl, J., Cortis, P. & Schiestl, F.P. (2011) Integrating past and present studies on Ophrys pollination – a comment on Bradshaw et al. Botanical Journal of the Linnean Society, 165, 329-335.

Waser , N.M., Chittka, L., Price, M.V., Williams, N.M. & Ollerton, J. (1996) Generalization in pollination systems, and why it matters. Ecology, 77, 1043-1060.

Wolf, T. (1950) Pollination and fertilization of the Fly Ophrys, Ophrys Insectifera L. in Allindelille Fredskov, Denmark. Oikos, 2, 20-59.

 

Butterflies Galore – visual treats from two very different books

I have written a lot of book reviews over the last thirty years or so; initially for mainstream scientific journals; those were the days when journal editors had never heard of impact factors and space was specifically set aside for such articles. And latterly, for the in-house member’s bulletins of learned societies such as Antenna; the excellent and very glossy publication of the Royal Entomological Society.  Book reviews are generally a bit of a chore, especially if the book in question is an edited volume, but busy academics can sometimes be persuaded to take a review on if they think that the book (the only payment you receive is a free copy) will justify the effort.  Occasionally one gets the chance, or feels the urge, to use a book review as a means of getting a particular message across to a wider audience.  I once managed to have one of my ‘on the importance of entomology’ rants published in Trends in Ecology & Evolution (Leather, 2008) using this route.  Up until now however, unless you count my somewhat tongue-in-cheek review of Anna Aphid, I have not used my blog in this way.   This is, however, about to change.

At the end of November last year (2015), I received an email from Caroline Young of Firefly Books who wondered if I would like to review a new entry to their catalogue, Butterflies, by Ronald Orenstein and Thomas Marent.   It was such a flattering email that I succumbed to her blandishments, hence this first official book review on my site.  To retain some scientific integrity however, I decided that I would do a comparative review.  Fortuitously, it just so happened, that I had to hand another book about butterflies; one that I had semi-promised to review for the Royal Entomological Society (Howse, 2014), but until now, had never got around to doing.  In one fell swoop I was thus able to salve my conscience and do two favours 🙂

When reviewing a book I have a little mental list of questions that I answer as I read it.

1. Would I buy it?
2. Would I recommend a colleague to buy it?
3. Would I recommend it to students as worth buying?
4. Would I ask the library to buy it?
5. Would I recommend it to anyone to buy it?

All these have the same subsidiary questions attached to them; If not why not, if yes, why?

First, Butterflies, billed by the publisher’s blurb as a “visual feast that showcases the beauty and mystery of butterfly and moth species from around the globe”.  A good place to start with a book review is with a summary of the contents and the aim(s) of the author(s).  There are eleven named chapters in total, with a thirty page introductory chapter, aptly titled Introducing butterflies.  This chapter, which like all the others, is beautifully illustrated with stunning photographs, briefly covers the main features of butterfly biology and ecology, from evolution, taxonomy, flight, mimicry, courtship, oviposition, development, feeding, predation, migration and concludes with climate change and conservation.  There is no overall ‘mission statement’ per se, but towards the end of the introduction the authors write “We need to know more and to do better. In many parts of the world, butterflies are disappearing at a rapid rate.  We need to understand what is happening to them, and why, if we are to stop or reverse their decline.  We need to create space for butterflies.”

From this I take it that the purpose of the book is to inspire adult non-entomologists to take an interest in butterflies in general and to create habitats for them in their gardens. I also think that there other aim is to inspire the younger generation to become involved with butterfly conservation either professionally or as an extra-mural interest.  The twelve chapters that follow the introductory piece are first, taxonomically based, e.g. Swallowtails, Skippers, Whites and then to do with their biology and ecology, covering topics such as wings, life history, diet, mimicry etc.  The last chapter is about those too-often overlooked Lepidoptera, the moths.  Each chapter is dominated by the beautiful photographs, each of which is accompanied by a succinct pen sketch giving a brief description of the species shown and some useful nuggets of information about the distribution, taxonomic position of the species and something about their biology.  Some of these nuggets were new to me, perhaps not surprisingly, as I am not primarily a lepidopterist 🙂

I was, for example, interested and intrigued by the suggestion that eggs of The Map, Araschnia levana are mimics of the flowers  of its larval host plant, nettle (Urtica spp.).

http://bioweb.uwlax.edu/bio203/2011/homolka_kail/reproduction.htm   ttps://commons.wikimedia.org/wiki/File:Urtica_dioica.JPG

In fact I was so intrigued that I felt the need to test it out by searching for photographs of nettle flowers. These shown are the closest I could find that come close to matching the eggs and so to a certain extent I remain unconvinced.  I will however, leave that up to you to decide for yourselves.

In summary, this book is as advertised, “a visual feast that showcases the beauty and mystery of butterfly and moth species from around the globe.”  It is not a text-book, nor is it an exhaustive pictorial catalogue, you could not use it as an identification guide. It does however, give a good and accessible overview of some basic butterfly biology and ecology and also great factoids to store away for use at an opportune moment.  So the bottom line:

1. Would I buy it?   – No, in my opinion, it does not contain enough entomological detail for me as a professional to justify the $45 price tag.
2. Would I recommend a colleague to buy it? Probably not for the same reason as above.
3. Would I recommend it to students as worth buying? Again, probably not, but I might suggest that they put it on their Christmas or birthday lists.
4. Would I ask the library to buy it? Yes, I think that it contains enough useful information to make it attractive to a non-specialist student reader interested in an easy to understand book with enough useful essay material in it.

and finally, would I recommend it to anyone else to buy it,? Yes it is a nice book, albeit of the coffee table variety, but in my opinion at the upper end of that market and anything that might spark an interest in entomology amongst the as yet unconverted, can only be a good thing.

And now, Philip Howse’s book, Seeing Butterflies, which is subtitled, New Perspectives on Colour, Patterns and Mimicry.  The publisher’s blurb in this instance states “See living butterflies and moths through new eyes through Philip Howse’s fascinating text and superb imagery….This new way of looking at these beautiful and iconic images will inform and inspire nature-lovers, photographers artists and scientists.”  Some major claims are being made here, implying that this is a serious book aimed at specialists, yet with the potential to appeal to a much wider readership.  Does it live up to these claims?

As with Butterflies, we are presented with twelve beautifully illustrated chapters.  Here though, with a chapter entitled, Seeing: Illusion, deceit and survival, we know from the start that this book is about vision, about visibility and invisibility and about optical illusions.  Chapter two continues this theme, being about defence and illusion while Chapter three examines the evolution of butterflies and mimicry.  The remaining chapters, as with Butterflies, are taxonomically based and examine the very varied visual defence mechanisms exhibited across the various butterfly families.  The photographs may not be as professional, as many or as stunning as those in Butterflies, but the science is much stronger, yet still very accessible to the lay reader.  There is also much more natural history, although again, this is not a book that would be useful for identification purposes.  On the other hand there are some marvellous nuggets and factoids, with which to regale friends, students and anyone else that you can catch.   One that sticks in my mind particularly, is that apparently the small tortoiseshell, Aglais urticae was once known as the ‘devil butterfly’ in Scotland. Philip speculates that this might be because it “comes out of the darkness of winter and hibernation, marked in red and black”.  As with Butterflies there were numerous factoids that intrigued and interested me.  In particular Philip’s claims for the eyed hawkmoth, Smerinthus ocellata, that he feels can impersonate a bracket fungus, a pile of dead leaves and a fox-like animal!

The first two I am quite happy about, but the third suggestion seems to need quite a stretch of the imagination 🙂

There is more of the author apparent in Seeing Butterflies than in Butterflies; Philip recalls childhood memories, and other personal experiences to illustrate the points that he makes and this gives the book a very user-friendly feel that is, to a certain extent, lacking in Butterflies. I also think that on the whole, the book manages to live up the somewhat over-hyped blurb.

And so the bottom line:

1. Would I buy it? – Yes I would, very nicely priced, well-written and enough science to keep me happy and interested.
2. Would I recommend a colleague to buy it? Yes, even a non-entomological colleague would be likely to find it worth the money.
3. Would I recommend it to students as worth buying? Yes, I would certainly suggest it to my PhD students and MSc Entomology students, but probably not to undergraduates although I would definitely suggest that they put it on their Christmas and/or birthday lists.
4. Would I ask the library to buy it? Yes, both as a recommended book for the entomologists and it contains enough useful information to make it attractive to a non-specialist student reader interested in an easy to understand book with useful essay material in it.

 and finally, would I recommend it to anyone else to buy it,? Yes it is a nice book and should appeal to anyone who has a genuine interest in the natural world.

 So there you have it, my first official ‘blog’ book review. There may be more to come, not necessarily commissioned ones, but just books that take my fancy, but if there are any publishers, or authors out there who think that I might like to review one of their books, feel free to contact me to discuss it.

 

References

Howse, P. (2014) Seeing Butterflies, Papdakis Publisher, Winterbourne, UK.  Paperback, 176 pp, £16.99 ISBN-13: 978-1-906506-46-9

Leather, S.R. (2008). Conservation entomology in crisis. Trends in Ecology & Evolution, 123, 184-185

Orenstein, R. & Marent, T. (2015) Butterflies, Firefly Books, Buffalo, USA. Hardback, 288 pp, $45 ISBN-13: 978-1-77085-580-0; ISBN-10: 1-77085-580-7

 

Postscript

For anyone seriously interested in writing academic book reviews I can recommend this site by Dr Perpetua Turner https://peptalkecology.wordpress.com/2016/01/13/writing-an-academic-book-review/

Insect egg mimics – plant parts that pretend to be insect eggs

Back in the 1980s I was a forest entomologist working for the UK Forestry Commission at their Northern Research Station based just outside Edinburgh.  I was working on two important pests of Lodgepole pine (Pinus contorta), the pine beauty moth, Panolis flammea and the European pine sawfly, Neodiprion sertifer.  The pine beauty moth lays its eggs in short rows on the upper surface of pine needles in late spring/early summer.

Eggs of the pine beauty moth, Panolis flammea  (Image courtesy of Stanislaw Kinelski, Bugwood.org http://www.invasive.org/browse/detail.cfm?imgnum=1258002).

They are pale yellow when first laid and gradually darken as they mature becoming a deep violet colour just before they hatch.  The eggs of Neodiprion sertifer are also laid on the upper part of the pine needles, but are ‘injected’ just under the cuticle of the needle.  After a few days a small necrotic patch develops at the oviposition site.

Eggs of the European pine sawfly, Neodiprion sertifer (image courtesy of A. Steven Munson, USDA Forest Service, Bugwood.org http://www.forestryimages.org/browse/detail.cfm?imgnum=1470178)

Spring field work for me was several days of rather tedious egg counting and as I scrutinised hundreds of pine needles, I noticed that some of the needles had little flecks or balls of resin on them,

Resin flecks on bristlecone pine, Pinus arsitata – often confused with scale insect infestations (Photo by Hans G. Oberlack via Wikipedia).

which were, especially on gloomy days in the depths of the forest, quite easy to confuse with pine beauty moth eggs.  Other needles had discoloured areas that looked like pine sawfly eggs or also a bit like pine beauty moth eggs, depending on how they were arranged.

Possible insect egg mimics on pine needles

Long days working alone in a forest allow one the time to think and it occurred to me one day that if I was being fooled by these ‘pseudo eggs’ then perhaps egg-laying pine beauty moths and pine sawflies might also be getting confused and avoiding laying eggs on these apparently already infested needles.   I wondered if there was any evidence to support my far-fetched hypothesis and to my delight found a paper by (Williams & Gilbert, 1981) that demonstrated quite convincingly that passion-fruit vines, produce structures resembling eggs of Heliconius butterflies and that these deter them from laying eggs on them.

Egg mimics on passion flower leaf – Photo by Lawrence Gilbert http://plantmimicrybz2820.blogspot.co.uk/2015/04/the-passiflora-genus.html

I also found papers that showed that other Lepidoptera (Rothschild & Schoonhoven, 1977; Nomakuchi et al., 2001) and beetles (Mappes & Mäkelä, 1993), are able to discriminate between leaves that already have eggs laid on them and avoid laying more eggs on those leaves, thus reducing larval completion.

Although I never formally checked it, I got the impression that needles bearing ‘egg mimics’ had fewer pine beauty moth eggs or pine sawfly eggs laid on them than those without.  Another question that could be easily looked at is whether pine trees in areas that have had outbreaks have more speckled needles than those in non-outbreak areas.  I always meant to do some formal sampling and a proper experiment to back up my feelings, but never found the time to do it.  I am pretty certain that I am unlikely to get round to doing this in the near future (if ever), but I would like to know if this is indeed another example of  a plant mimicking insect eggs.  I would be very happy indeed if any of you feel like testing my hypothesis and look forward to seeing the results in print.

 

References

MacDougal, J.M. (2003)  Passiflora boenderi (Passifloraceae): a new egg mimic passionflower from Costa Rica.  Novon, 13, 454-458

Mappes. J. & Mäkelä, I. (1993)  Egg and larval load assessment and its influence on oviposition behaviour of the leaf beetle Galerucella nymphaeae.  Oecologia, 93, 38-41

Nomakuchi, S., Masumoto, T., Sawada, K., Sunahra, T., Itakura, N. & Suzuki, N. (2001) Possible Age-Dependent Variation in Egg-Loaded Host Selectivity of the Pierid Butterfly, Anthocharis scolymus (Lepidoptera: Pieridae): A Field Observation .  Journal of Insect Behavior, 14, 451-458.

Rothschild, M. & Schoonhoven, L.M. (1977) Assessment of egg load by Pieris brassicae (Lepidoptera: Pieridae). Nature, 266, 352-355.

Williams, K.S. & Gilbert, L.E. (1981) Insects as selective agents on plant vegetative morphology: egg mimicry reduces egg laying by butterflies. Science, 212, 467-469.