Monthly Archives: June 2021

Professor Emeritus – the final instar?

Six years ago, I celebrated my 60th birthday by writing a light hearted survey of my life to then under the title of The Seven Ages of an Entomologist, in which I likened each stage of my career to  an insect life cycle, from egg hatch through to adulthood, with full Professor being the seventh and final stage.  I have from my detailed field observations, realised that there is a rare super-imago stage, the Emeritus Professor 🙂

I unofficially (my letter of appointment didn’t arrive until mid-June) entered this stage on April 1st this year (2021), the occasion of which I had announced via Twitter on March 31st  when I tweeted

Today is my last day as a salaried academic as I officially ‘retire’ – tomorrow (yes April 1st – don’t snigger) I officially join the ranks of the old fogey/greybeards and become Professor Emeritus – I must admit I have mixed feelings about this stage of my academic career

A number of my colleagues and academic friends elsewhere, on achieving Emeritus status, pretty much continue as before, teaching, researching and writing papers and coming into the office almost every day. As a PhD student, at the University of East Anglia, the sight of Professor Emeritus Jack Kitching, then in his seventies, striding across the grass from the lake with a bucket of water, was a familiar sight. My former colleague, Graham Matthews at Imperial College, was still, aged 80, a regular visitor to his office and my PhD supervisor, Tony Dixon, now 84, is still writing papers, although mainly from his home office. 

What are these mixed feelings of which I wrote? Now I may be an exception among academics of my generation, but almost all my social life, such as it is, has with the exception of my best friend from school*, and old school and undergraduate university friends on Facebook, come about through my work.  There was a phase when our children were at school, and my wife and I were stalwarts of the PTA, that I attended Quiz Nights and other fundraising activities, but that is now long in the past and my non-academic socialising is now interactions with our neighbours, and until lockdown, social events run by the band of which my wife is the Manager. I am thus one of those sad people whose work and other life are pretty much inextricably linked. The prospect of leaving my academic setting was not something I viewed with any degree of sanguinity, despite the fact that originally our retirement plan was to spend our sunset years basking in the sun of the Pyrénées-Orientales cosily ensconced in our French house with a mountain view and easy access to the local wines and food and a suitably equipped study- cum- library in which to write all the books that I have had planned for years, but not yet had the time to write.

The aspect of retirement that worried me most was the loss of daily contact with students, (unlike a lot of research active academics, I really enjoy teaching) and the chance to chat with colleagues of all disciplines at coffee time.  The Harper Adams coffee culture, prior to the pandemic, was second to none. These two factors weighed very heavily against the prospect of gently pickling myself in France 🙂

Then along came two life changing events, the lunacy of Brexit which threw a spanner in the works regarding our retirement plans and oesophageal cancer which was an even bigger problem. On top of all this, add Covid and lockdown!  The two latter events made a huge change to my working life, in that I was physically isolated from my campus office, colleagues and students. Luckily, I am a bit of an introvert so the solitude was not too big a problem, country walks and plenty to read have kept me sane (discounting the post-operative paranoia) over the past year and our coffee mornings via Teams with the Entogroup have been a fairly good surrogate for keeping in touch with gossip and work, although virtual reality will never, in my opinion, be as good as the real thing, but it has been a help. It has also made me more able to pull away from the campus than if I had been working full-time on site, as I have no doubt that I would have found the physical and psychological separation much more difficult. Frankly, I think I would have been terrified. As it is I am just apprehensive. As Emeritus I will still get the opportunity to teach, but can now avoid all the bits I dislike about the job, administration and marking 🙂  I will also have more time to write up some of the back-log of papers that have been sitting patiently on my desk; some for more than twenty years.  More importantly, and hopefully, more financially rewarding, I hope to get all the books I have had planned for the last thirty years, finally written! I am very grateful to the University for granting me this honour and opportunity.

Looking back at the last nine years I have been Professor of Entomology at Harper Adams University I think it is apposite to quote from my 60th birthday post in which I wrote

My hope is that in five years time when I become a retired Professor and my hair and beard colour are the same, that entomology will be taught at more than one university in the UK and not just at postgraduate level.”

I am very pleased to point out that there are now three universities in the UK that run postgraduate courses in entomology (none as good as ours of course) and Harper Adams University now offers a very successful entomology undergraduate degree.

Another quote from the same post “A small point of personal satisfaction, is that, despite my elevation, I still do not own a suit “.  Guess what, I still don’t 🙂

Professor not-emeritus in lockdown, before chemotherapy and Professor Emeritus, complete with post-chemotherapy hair growth.

Post script

Somewhat disconcertingly I found on attempting to log on to my email and other accounts after the end of my last working day as a salaried employee, I found that all my accounts had been closed down. Our HR Department obviously have no idea how academia works. It would seem that in HR World, once you retire, you no longer exist. As you can imagine this caused a certain amount of panic on my part. Luckily after contacting my Head of Department via my Google account, I was readmitted to the system by mid-morning the following day, and to my great relief found that all my files were intact.

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Unsolved mysteries or unasked questions? The mysterious case of the bumbling bibionids

Some years ago, Ole Heie published a paper discussing what he called aphid mysteries not yet solved (Heie, 2009).  These included such gems as the shark’s fin on the giant willow aphid and why are aphids so fussy about their host plants? I could add a few of my own; of the three very common aphids that feed on sycamore, one, Periphyllus testudinaceus, is commonly attended  by ants another P. acericola, is sometimes attended by ants and the third, Drepanosiphum platanoidis is attacked by ants. The question that one would ask is why this gradation when all three aphids live on the same tree and all produce lots of honeydew, the ant’s reward. People have pointed out that those ants that are obligately ant-attended have evolved a specific structure, the trophiobiotic organ (Heie, 1980) and that the siphunculi in non-ant attended aphids are longer than those of ant-attended species, which presumably enhances their defensive function (Way, 1963). These observations do not, however, answer the question as to why the association or lack of association arose, they just allow us to speculate about how the association has shaped the aphid, in essence an example of a circular argument.  Although I have raised the question, and you might respond and say that the question has been asked by voicing it, in my opinion, the question remains unasked (untested) and the mystery unsolved.  

There are plenty more aphid examples I could throw into the mix, but given the time of year when I started to write this, I thought I’d do a more topical unsolved mystery.  Why are St Mark’s flies (Bibio marci) so easy to catch? A simplistic answer is they are so easy to catch because they fly very slowly and appear to make no effort to avoid being caught.  I can literally grab them out of the air.  

One that I caught earlier -)

The real question is how come they are so easy to catch? Why, unlike the ubiquitous housefly, Musca domestica, which is nigh on impossible to sneak up on, (well by me at any rate, but perhaps you are better at it than me), has evolution produced such a dozy animal?  

Dipteran phylogeny (after Yeates et al., 2007). 

Bibionids appeared earlier in the evolution of flies than the Muscids and if you look at the phylogeny above you can see that as new Orders of flies arose, they moved from being long-legged, relatively clumsy fliers, such as the crane flies and Bibionids to the much more agile species we see in the Empids (dagger flies), Asilids (robber flies) and blue bottles and house flies.  Bibio marci is found across most of Europe while the housefly is found everywhere that humans are to be found, a truly global beast.  Based on distribution alone we could argue that M. domestica  is the more successful of the two. 

Their structure apart, are there any differences in their life history traits that might explain why natural selection has shaped adult Bibionids into being such easily caught organisms when compared with houseflies? Given the big differences in their flight agility we might expect their respective predators to be markedly different.  The eyes of a typical housefly have about 3400 ommatida (Sukontason et al., 2008) and process visual information around seven times more quickly than humans, enabling them to identify, and easily avoid attempts to catch or swat them, since they effectively see the human’s movements in slow motion. The eyes of bibionids on the other hand are divided into two halves, with one half pointing upwards, the other downwards.  The upward pointing half is used to locate mates while the downward pointing half is used for positioning (Zeil, 1983), so they are good at hovering (Ennos,1989), but not very agile in comparison with other flies, including, in my experience anyway, crane flies, which although looking clumsy are surpassingly good at not being caught*.  Despite these differences in flight ability, their predators are not very different.  Adult houseflies have many predators, including birds, reptiles, amphibians, various insects, and spiders which is pretty similar to St Mark’s flies, the adults of which form a substantial proportion of the diet of birds, such as starlings and chaffinches and are eaten by spiders and attacked by Empids (dagger flies) (D’Arcy-Burt & Blackshaw, 1991). 

What about their diets then? You might not realise it but we can describe adult houseflies as being mainly carnivorous; their primary food is animal matter, carrion, and faeces, but they also consume milk, sugary substances, and rotting fruit and vegetables. Although they don’t have jaws per se, they deal with solid foods by liquefying them with saliva before sucking it up.  Given their food preferences they are great at moving bacteria around the environment, hence their bad reputation as public health pests. Adult bibionids on the other hand are nectar feeders (Lewis & Smith, 1969; Smith & Lewis, 1972), so can be classified as beneficals due to their pollinating ability (Lewis & Smith 1969). As larvae, B. marci feed on leaf litter, both coniferous (von Schremer, 1958) and deciduous (Pobozsny, 1982), so again have a very important role in humification and soil formation (Pobozsny, 1982).  House fly larvae feed primarily on muck, dead and decaying material, animal faeces, pig manure being a particular favourite (Larrain & Salas, 2008; Pastor et al., 2011), which, like B. marci, makes them important components of the ecosystem. We are, however, concerned with the adults and their exposure to predators, and looking at their respective life styles it seems odd that B. marci is such a lethargic flyer as it would seem to be just as, or even more so, exposed to predators as the house fly.

That leaves us with the life cycle.  Is there something about B. marci’s life history traits that enables it shrug off the possibility of predation?  The adult has a short life cycle, one week, there is only one generation a year and the typical female lays 3330 eggs (Skartveit, 2002), so pretty prolific. The house fly has a longer adult life, and at 25oC lays just over 700 eggs (Fletcher et al, 1990), so although fecund, nowhere near as productive as B. marci.   They do however, whip through the generations, in temperate regions of the world getting through 10-12 generations in a year, so their multiplication rate is massive compared with that of our bumbling bibionid.

Given all the evidence, I would have thought that B. marci would benefit greatly by being a faster flyer and less conspicuous and/or unpalatable.  It is none of these things. It might be spatially aware, but its predator avoidance mechanisms seem to leave a lot to be desired and birds love to eat it. That said, it has been remarkably successful and was, in the past, regarded as an agricultural pest (Morris, 1921).  There does, however, seem to be growing evidence, that B. marci is not as numerous as it once was, (Grabener et al., 2020), so given the close association that the house fly has with humans and the current direction of global heating, I would bet that the former will, over the next few years decline in numbers and the latter become an even bigger pest. Sadly, this seems to be the direction we are heading with regard to insect numbers, those we love are threatened, those we hate are doing well ☹

References 

 D’Arcy-Burt, S. & Blackshaw, R.P. (1991) Bibionids (Diptera: Bibionidae) in agricultural land: a review of damage, benefits, natural enemies and control. Annals of Applied Biology, 118, 695-708

Ennos, A.R. (1989) The kinematics and aerodynamics of the free flight of some Diptera. Journal of Experimental Biology,142, 49-85. 

Fletcher, M.G., Axtell, R.C., & Stinner, R.E. (1990) Longevity and fecundity of Musca domestica (Diptera: Muscidae) as a function of temperature. Journal of Medical Entomology, 27, 922–926.  

Grabener, S., Oldeland, J., Shortall, C.R. & Harrington, R. (2020) Changes in phenology and abundance of suction-trapped Diptera from a farmland site in the UK over four decadesEcological Entomology, 45, 1215-1219.

Healy K, McNally L, Ruxton GD, Cooper N, Jackson AL (2013). Metabolic rate and body size are linked with perception of temporal information. Animal Behaviour. 86, 685–696.  

Heie, O. (1980)  The Aphdioidea (Hemiptera) of Fennoscandia and Denmark. 1. Fauna Entomologica Scandinavica 9.Scandinavian Science Press, Klampenborg, Denmark. 

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

Larrain, P.S. & Salas, C.F. (2008) House fly (Musca domestica L.) (Diptera: Muscidae) development in different types of manure. Chilean Journal of Agricultural Research, 68, 192-197.

Lewis, T. & Smith, B.D. (1969) The insect faunas of pear and apple orchards and the effect of windbreaks on their distribution. Annals of Applied Biology, 64, 11-20.

Morris, H.M. (1921) The larval and pupal stages of the Bibionidae.  Bulletin of Entomological Research, 12, 221-232.

Skartveit, J. (2002) Variation in fecundity in relation to female size and altitude in Palaearctic Bibioninae (Diptera, Bibionidae). Studia Dipterologica9, 113-127

Smith, B.D. & Lewis, T. (1972) The effects of windbreaks on the blossom-visiting fauna of apple orchards and on yield. Annals of Applied Biology, 72, 229-238.

Sukontason, K.L., Chaiwong, T., Piangjai, S. et al. (2008) Ommatidia of blow fly, house fly, and flesh fly: implication of their vision efficiency. Parasitology Research, 103, 123–131

Pastor, B., Cickova, H., Kozanek, M., Martinez-Sanchez, A., Takac, P. & Rojo, S. (2011) Effect of the size of the pupae, adult diet, oviposition substrate and adult population density on egg production in Musca domestica (Diptera: Muscidae). European Journal of Entomology, 108, 587-596.

Pobozsny, M. (1982) The feeding biology of larval St Mark’s fly Bibio marci (Diptera: Bibionidae). Acta Zoologica Academie Scientiarum Hungariaicae, 28, 355-360.

von Schremer, F. (1958) Bibio larvae as utilisers of litter of dead needles. Anziger Schadlingskunde, 31, 151-153.

Way, M.J. (1963) Mutualism between ants and honeydew-producing Homoptera.  Annual Review of Entomology, 3, 307-344. 

Yeates, D.K., Wiegmann, B.M., Courtney, G.W., Meier, R., Lambkin, C., & Pape, T. (2007) Phylogeny and systematics of Diptera: Two decades of progress and prospects. Zootaxa1668, 565-590

Zeil, J. (1983) Sexual dimorphism in the visual system of flies: the compound eyes and neural superposition in bibionidae (Diptera). Journal of Comparative Physiology, 150, 379-393.  

*I speak from bitter experience; my second-year undergraduate insect collection was Tipulids, which turned out to be a lot more difficult to catch than I had anticipated.

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Green islands for the third and final time?

I have regaled you with tales of green islands twice before, first in relation to trees miraculously surviving mass defoliation events, and second, in terms of leaf miners and their exploitation of cytokinins.  This time it is the turn of the cowpat islets to make their appearance.  Those of you who are lucky enough to be able to walk in the countryside will probably have noticed that some of the fields you walk through are dotted with lots of clumps of longer grass and perhaps wondered what they are and why they are there.

A recently grazed pasture, showing very clear cowpat islets (Sutton, Staffordshire May 2021).

 If you look early enough or carefully later on, you will see that these clumps are associated with cowpats.  There have been a lot of theories about why these clumps arise, ranging from increased plant nutrition (Taylor & Rudman, 1966), after all we put manure on our gardens to improve plant growth, to unpalatability of the grass due to raised sugar levels (Plice, 1951).  This latter idea has since been dismissed, although the fact that cattle avoid feeding on these clumps has been well documented (Merten & Donker, 1964).  There is another explanation for why cattle avoid grazing near cowpats. You may not know it, but despite the fact that cattle don’t seem to have much control (or perhaps they just don’t care) over when and where they deposit their excreta, but cattle, despite the behaviour of bullocks, aren’t stupid. Just like you and me, they aren’t that keen on eating their own and other people’s sh*t.  A good reason for avoiding eating excreta, whether your own or someone else’s, is that areas contaminated with dung are associated with higher numbers of gastro-intestinal parasites (Boom & Sheath, 2008; Gethings et al., 2015), so it makes very good sense to avoid eating contaminated grass.  Whatever the reason, be it increased nutrition or distastefulness, the result is clumps of longer grass dotted around the pasture taking up between 20 and 30% of the field (Taylor & Rudman, 1966).

You may, by now, be wondering why an entomologist is going on about cowpats and grass clumps. Well, as you all know, in my world, everything comes round to entomology 🙂 It has been known for some time that hedges and hedgerows provide refuges for insects, admittedly, not all beneficial ones (Lewis, 1969; D’Hulster, M. & Desender, 1982), but nevertheless, an observation that led to the development of beetle banks and conservation headlands (Sotherton et al., 1989; Thomas et al., 1991). It is, however, not just field boundaries that can provide habitats for insects. Belgian coloepterist, the late Konjev Desender and colleagues, found that the sward islets provided extra overwintering sites for staphylinid beetles, which provide an important role in natural pest regulation (D’Hulster & Desender, 1984).  Strangely, well to me anyway, interest in the entomological role of sward islets died a death.  It wasn’t until almost thirty years later that a former colleague of mine, keen hemipterist Alvin Helden (now at Anglia Ruskin University), and colleagues, found that sward islets were also proving very important refugia for grassland Hemiptera and lycosid and linyphid spiders (Helden et al., 2010: Dittrich & Helden, 2012). Before the grazed sward recovered the islets, which in their study occupied 24% of the pasture, hosted about 50% of the total arthropod community.  So a very important role in conserving biodiversity within agroecosystems, but despite this very important finding, sward islet entomology has yet again fallen off the entomological radar 😦

Less recently grazed pasture, but cowpat islets still visible within the recovering sward (Sutton, Staffordshire, May 2021) but still, according to Alvin Helden, containing a higher density of arthropods than the surrounding grazed area (Helden et al., 2010).

I think that revisiting the ecology of sward islets would prove very rewarding for both MSc and PhD projects.  Off the top of my head I can come up with a couple of projects; for a PhD, given that the fertilisation level and type affected the relative abundance of two of the Hemipteran families, Delphacids and Cicadellids (Dittrich & Helden, 2012), a comparison of the fauna and flora of sward islets on conventional and organic farms would make a really rewarding project. Harking back to my interests in island biogeography a study of the size, floral composition, structure and distribution of sward islets and how this affects arthropod communities would make a neat MSc project or perhaps even another PhD.

I am sure that with a little bit of thought, many more projects, not just entomological could be devised. Over to you dear readers.

References

Boom, C.J. & Sheath G.W. (2008) Migration of gastrointestinal nematode larvae from cattle faecal pats onto grazable herbage. Veterinary Parasitology, 157, 260-266.

D’Hulster, M. & Desender, K. (1982) Ecological and faunal studies on Coleoptera in agricultural land III. Seasonal abundance and hibernation of Staphylinidae in the grassy edge of a pasture. Pedobiologia, 23, 403–414.

D’Hulster, M. & Desender, K. (1984) Ecological and faunal studies of Coleoptera in agricultural land IV. Hibernation of Staphylinidae in agro-ecosystems. Pedobiologia, 26, 65–73.

Dittrich , A.D.K. & Helden, A.J. (2012) Experimental sward islets: the effect of dung and fertilisation on Hemiptera and Araneae. Insect Conservation and Diversity, 5, 46–56.

Gethings, O.J., Sage, R.B. & Leather, S.R. (2015) Spatio-temporal factors influencing the occurrence of Syngamus trachea within release pens in the south West of England. Veterinary Parasitology, 207, 64-71.

Helden, A.J., Anderson, A., Sheridan, H. & Purvis, G. (2010) The role of grassland sward islets in the distribution of arthropods in cattle pastures. Insect Conservation and Diversity, 3, 291–301.

Lewis, T. (1969) The diversity of the insect fauna in a hedgerow and neighbouring fields. Journal of Applied Ecology, 6, 453-458.

Marten, G.C. &  Donker, J.D. (1964) Selective grazing induced by animal excreta. II. Investigation of a causal theory. Journal of Dairy Science, 47, 871-874.

Plice, M. J. (1951) Sugar versus the intuitive choice of foods by livestock. Agronomy Journal, 43, 341-342.

Sotherton, N.W., Boatman, N.D. & Rands, M.R.W. (1989) The ‘conservation headland’ experiment in cereal ecosystems. The Entomologist, 108, 135-143.

Taylor, J.C. & Rudman, J.E. (1966) The distribution of herbage at different heights in ‘grazed’ and ‘dung patch’ areas of a sward under two methods of grazing management. The Journal of Agricultural Science, 66, 29-39.

Thomas, M.B., Wratten, S.D. & Sotherton, N.W. (1991) Creation of ‘island’ habitats in farmland to manipulate populations of beneficial arthropods: Predator densities and emigration. Journal of Applied Ecology, 28, 906-917.

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