Monthly Archives: September 2020

Pick & Mix 52 – conservation, farming, coral reefs, Erasmus Darwin, resilient forestry, thanotosis, seasonality in blogs, orchids, teaching on line and arachnophobic entomologists

Interesting article from James Rebank – We need to change the way we see and think about farming.

Trees aren’t living as long as they used to and this threatens their role in capturing carbon

Resilient, conservation facing forestry?

If you want to know how to move an entomology course on line, Steve Heard shares his with us all – fantastic and innovative – a great example to us all

I recently posted a somewhat tongue in cheek spoof paper blogpost about seasonal views of my blogturns out that someone has done this for real!

Did you know that many entomologists are afraid of spiders?

Biodiversity is not just in the Amazon – equally endangered and just as biodiverse – Scotland’s coastal gem, but climate change could wipe it all out L

How playing dead can save your life – great post from Ray Cannon on thanotosis

Most of us when we hear the name Darwin automatically think of Charles, but his grandfather, Erasmus Darwin, was also a naturalist and in his day, just as famous. I am pleased, that thanks to the free service offered by the Biodiversity Heritage Library, to give yoy the chance to read his book, published in 1800, Phytologia or The Philosophy of Agriculture and Gardening, in which he attempts to dispel plant blindness, a thing even then and puts forward the idea of biological control using parasitic wasps.

If you like orchids or even if you are not a huge fan this might appeal to you.





Filed under Pick and mix

Time of year determines some, but not all, views of my blog posts

I was going to format this post as a spoof Nature communication, but not being as skilled as our students, who turn out excellently formatted mock papers for their assignments, decided not to. I did, however, go for a typical Nature title 🙂

The other day when I was looking at my blog stats I clicked on the view post stats button next to my most read post of the day, Not all aphids are vegans*, and was amused enough by the strong seasonal dynamics shown to post it on Twitter.

Not all aphids are vegans – strong seasonal dynamics

As you can see, the peaks and troughs of views strongly follow the times of year that aphids are present and absent.

As regular readers of my blog will know, I am a bit of an aphidophile. It is kind of hard to miss if I’m honest, but then aphids are fantastic and awesome, so you will get no apologies from me for loving them and writing, or talking about them whenever I get the chance to do so.

That said, not all my posts are about aphids, insects yes, but I do write about other things too, including entomological equipment, classic papers and teaching matters, and sometimes about my holidays 🙂

Given the strong correlation between aphid life cycle timing and visits to the post about biting aphids, I wondered how my other aphid posts stacked up in terms of seasonal viewing.

Aphid life cycles – bizarre, complex or what?

Somewhat surprisingly, well to me at least, the post about aphid life cycles did not show very strong seasonal dynamics, although April, when aphids start to become active, did, at the beginning of the post’s life, show a bit of a peak of interest, but has since broken down completely.  Another season aspect of aphid biology is wing formation. This is usually associated with late spring and early summer (Dixon, 1973, 1976), and in this case, the viewing history fitted appropriately.

Not all aphids have wings – seasonally appropriate


What about the other end of the year, autumn and winter?  As expected, my post about aphid overwintering showed the reverse pattern to the other aphid posts, people wanted to read about aphid overwintering as winter appraoched.

A Winter’s Tale – aphid overwintering

Aphid posts, as predicted, show a correlation (OK, not tested) with the time of year associated with the appropriate part of the life cycle.  We would therefore expect that posts that are more general would show no marked seasonality in their popularity. To test this I looked at first, my posts that deal with entomological equipment, pan traps, clip cages and the poster and then at two posts that fit into the teaching category.  Staring with the Pan trap, a very basic and commonly used piece of field equipment, despite a slight expectation on my part that there might be a spring peak (after all, that is when insects start flying) there was no pattern that I could see.

The pan trap – disappointingly no pattern


Nest I looked at the Pooter, an essential bit of general entomological kit (Leather, 2015) used by entomologists of all types. Given that this is used in both the laboratory and the field, I didn’t really expect to see any pattern jumping out at me.  I wasn’t disappointed although if you look very quickly, and not too closely, it is just about possible top convince yourself that there is an increase in views during the summer, which would fit with the general increase in insects caught in nets.

The Pooter – perhaps a slight tendency for views to increase in mid-summer


Next, back to aphids, this time a piece of kit that is almost, but not entirely, confined to aphidologists (Macgillivray & Anderson, 1957).  My expectation here, was that given that clip cages are almost always used in laboratories or glasshouses, that there would be absolutely no pattern in the viewing figures. Sure enough, that was the outcome.

The clip cage – no discernible patterns

Finally, the two teaching posts, first my tribute to Southwood’s classic species-area paper (Southwood, 1961).  I know that this post is used for undergraduate teaching at one university, so given the regularity of university timetabling, might have a chance of  showing a pattern;  It didn’t.

Southwood (1961) – the number of insect species associated with various trees – no pattern

Finally, a post that has attracted a modicum of attention over the years, all about what to expect in a PhD viva.  My hypothesis for this, given that most PhD projects start at the beginning of the academic year and run for four or five years before submission, was that if there was going to be an annual peak in views that it would be between October and January.  To save you the troubkle of squinting at the graph, there was no pattern.

Are PhD examiners really ogres? – no consistent peak

In conclusion, aphid posts tend to show viewing patterns consistent with the time of year and life cycle stage, other, more general posts show absolutely no pattern.



Dixon, A.F.G. (1973) Biology of Aphids. Edward Arnold, London.

Dixon, A.F.G. (1976) Reproductive strategies of the alate morphs of the bird cherry-oat aphid Rhopalosiphum padi. Journal of Animal Ecology, 45, 817-830.

Leather, S.R. (2015) An entomological classic – the Pooter or insect aspirator. British Journal of Entomology & Natural History, 28, 52-54.

MacGillivray, M.E. & Anderson, G.B. (1957) Three useful insect cages. Canadian Entomologist, 89, 43-46.

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






Filed under Uncategorized

Paper reviewers are a valuable resource – Editors, please treat them with respect

Maybe I’m getting grumpy in my old age, but I think not.  In fact, I think I am now seen as the go to nice Referee 3 for when the Editor wants a sympathetic split decision breaker; something on the lines of he is a bit of an old-fashioned grammar pedant, but he is always willing to see the positive side of a study so long as the methodology is sound :-). I know what of I speak. As an Editor myself, I have a mental list of which Referee 3 to approach to help me soften the blow, put in the knife or contradict what I consider an overly harsh Referee 2.

Referees, or reviewers as we now tend to call them, are the life-blood of a successful journal; as I have written before, good reviewers are worth their weight in gold and should be treasured and encouraged.  A major problem is that with what seems to be an exponential increase in the number of journals and papers submitted, reviewers of any sort, good, bad or average, are in short supply.  The problem is exacerbated by a misguided notion held by many potential reviewers of how many reviews they should do a year (Didham et al., 2017).

As someone who does far more than my fair share of paper reviewing, I average about three to four papers a month, I think this puts me way ahead of the pack. To back this up, Publons tells me that over the last twelve months, I have reviewed 42 papers, 1.4 reviews for every paper that I have published.  I think that by any criteria this makes me a good citizen, if not a saint :-).

I was thus somewhat miffed*  the day before yesterday, when, with one week to go before the agreed due date for a review of a paper I had, against my better judgement, agreed to do, the following email arrived.


“Dear Dr Leather:

Recently, I asked you to review Manuscript XX-XXX-000 entitled “How to annoy a reviewer”

It has since become apparent that I will not need you to review at this time. If you have already put some work into it and are near completion, you could send it along to us, just email to: inconsderateditor@journalwhichjustlostmygoodwill

If you have not started the review, then you can relax and cross it off your “to do” list.

Many thanks for your good intentions and I hope you will be able to review other manuscripts in the near future.”



I’m not a great fan of the late Mr Morrison, especially his politics, but this reverse quote sums my feelings exactly.

Gritting my teeth, I very politely replied, to the Editor, thanking him for letting me know that my services were no longer needed. In reality, I was fuming and almost instantly posted an anonymised Tweet to let off a bit of steam.  Now, I don’t know about you, but as an Editor I would never do this.  If you have, as all Editors do, invited more than two potential reviewers at the same time, it is extremely poor editorial practice, ten days later, to tell a reviewer they were superfluous to requirements.  As it happened, I was, when the email arrived, just about to write the review.

Now, as an Editor, I would have no compunction in sending a similar email to a reviewer who was showing up as overdue on the system.  To someone who was well within the specified return date, I would never ever consider dumping them at this stage, even if by some miracle, I had already received three reviews, not just the magical two.  I don’t think any author would begrudge an extra day or two to hear back from the journal.  In my judgement, this is an extremely effective way to antagonise reviewers, and I, for one, will no longer be willing to review for this particular journal.


What do you think?


Some editors may try to blame the automated system for the email, but that is a very poor excuse.  The system tells you when the required number of reviews (usually two) has been achieved.  As an Editor, if you still have a reviewer listed as awaiting review, you just change the number of reviews required to three, thus preempting the automatic email. Easy peasy, and very importantly, you have not lost the good will of your reviewer.


Didham, R.K., Leather, S.R. & Basset, Y. (2017) Don’t be a zero-sum reviewer. Insect Conservation & Diversity, 10, 1-4.



Filed under Bugbears, Science writing

Pick & Mix 51 – permafrost, shifting baselines, insect pests, carrion beetles, a history of chocolate, double flowers, wasps and the most beautiful springtail you have ever seen

Very worrying news from the frozen North

You will have seen Extinction Rebellion in the news a lot complaining about lack of progress on slowing down climate change, but do they care about Nature as a whole?

Help prevent shifting baseline syndrome by talking to your grandchildren

Social media isn’t just funny cat videos – The next invasion of insect pests will be discovered via social media

Nice article on carrion beetles – and incidentally emphasising the importance of citizen science projects and social media

If you like chocolate and want an excuse to eat more, then this article might be of interest J

Did you know that flowers can grow out of flowers? Unravelling the mystery of double flowers

Professor Sierian Sunmer of University College London, explains why wasps like to join you on your picnic as summer comes to an end

Will we add a new butterfly to the British list – is the Camberwell Beauty on the way to join us?

Springtails – ubiquitous, beautiful, incredibly useful and totally overlooked by almost everyone




Filed under Pick and mix

Large, complex, beautiful and multi-chambered – Robin’s pincushion, rose bedeguar gall, mossy rose gall

As I wrote a little while ago, thanks to the Covid-19 lockdown I have been roaming the countryside around my rural retreat a lot more than I normally do. One of the things that I have noticed is that there seem to be a lot more of the spectacular galls caused by the gall wasp, Diplolepis rosae, than I can remember seeing in previous years. I have absolutely no empirical evidence for this observation, so it could all be down to shifting baselines (Jones et al., 2020). Nevertheless, to me they have been much more noticeable this year, perhaps confounding the insect apocalypse narrative (Leather, 2018), but then again, perhaps not.

I am, when it comes to galls, more of an expert on those caused by aphids, than on those induced by Hymenoptera, although, as it happens I am a co-author on an oak gall wasp paper (Walker et al., 2002).  Of course, that does not make me an expert. One the rose bushes in our front garden always has at least one of Robin’s spectacular pincushions clamouring for attention.  The others rarely have one and I have idly wondered about the host preferences of the wasp and the suitability of different roses for the development of the larvae.

Our front garden Diplolepis rosae gall

Having noticed that despite the relative abundance of the galls in the hedgerow roses, some bushes were totally gall-free while others supported several, sometimes in close proximity to each other, my thoughts immediately turned to possible student project.

Multiple infestations of Diplolepis rosae on hedgerow roses in the environs of Sutton, Staffordshire

A preliminary bit of research with the aid of Google Scholar quickly disabused me of that idea, but, as is the way with the internet, soon had me delving deep into the past in search of the history of this fascinating manifestation of insect activity.

My first discovery was that is also known as the rose bedeguar gall, something that had, until now, totally passed me by. According to my favourite dictionary (Gordh & Headrich, 2001),

“Bedeguar, Bedegar or Bedequar’ comes from a French word, bédégar, and is ultimately from the Persian, bād-āwar, meaning ‘wind-brought’”.

I’m guessing this meant that the first people to see them had no idea what caused them.

Not just complex galls

My next discovery was that D. rosae and the parasitoids that share its gall is a fairly well studied system (Randolph, 2005; Urban, 2018), although I am sure that it would still be possible to come up with some sort of project.  Diploelpis rosae is a member of the order Hymenoptera, so related to the larger and much more obvious bees, wasps and ants. It belongs to a family of wasps, the Cynipidae, commonly known as gall wasps.  Considering how small they are, 3.8 mm (Urban, 2018), the galls they make are spectacularly huge as are those that their relatives on oak form. Interestingly* more than 80% of gall wasps are associated with oaks, with most of the rest forming galls on members of the rose family (Shorthouse, 1973).  That in itself is, at least to me, an interesting fact; why such a restricted host range?  It is univoltine (one generation a year), overwinters as mature larva or pre-pupa in the galls, and emerges as adults in the spring when it seeks out suitable egg-laying sites. It is mainly parthenogenetic, although males are occasionally found (Callan, 1940; Stille, 1984). Despite being tiny, each wasp has the potential to lay about 500 eggs (Stille & Dävring, 1980). The adults are not very adventurous, usually laying eggs in the developing buds or flowers of the bush they emerged on, or on another close by (Bronner, 1985: Urban, 2018). That said, there must be some sort of host preference and selection going on, as in Sweden and the Czech Republic most galls are found on Rosa canina (Stille, 1984; Urban 2018). They also seem to favour younger bushes, or those that produce long vigorous stems (Stille, 1984).  The potentially high fecundity is presumably an adaptation to the high rates of parasitism that the larvae of D. rosae can experience, up to 70% in some cases (Stille, 1984).  In fact, so varied and numerous are the parasites, that many of the early papers about D. rosae pay more attention to the other inhabitants of the galls than they do the architects (Osten Sacken, 1870; Blair, 1945; Bugbee, 1951).  Females that lay a lot of eggs in the same developing bud produce bigger galls and a greater proportion of the larvae survive (Stille, 1984).

Survival of D. rosae in relation to gall weight (after Stille, 1984)

 It also appears that the closer to the ground the galls are, the lower the parasitism rate (Laszló, 2001).

The ideal strategy would then be for female D. rosae to lay big galls as low down on the plants as possible, but from personal observation this is not always the case , so as is often the case with the “Mother knows best” hypothesis there is something we humans are missing that the insects aren’t (Awmack & Leather, 2002).

Those darned taxonomists!

So, as so much is already known about this tiny wasp and its spectacular gall, I thought I would do a little bit of entomological archaeology and trace the entomological history of this little insect. Now I think taxonomists are wonderful people and have a huge respect for the very often unacknowledged work that they do, and am a great supporter of the campaign to make sure that people cite them in their papers (Packer et al., 2018), but they are a contentious bunch :-).  I mention this because inputting Diplolepis rosae into Google Scholar didn’t get me very far back in time, 1951 to be precise (Bugbee, 1951).  This paper justifies my good-natured jibe at the argumentative nature of taxonomists as he explains his renaming of what was then Rhodites rosae, by citing a 1917 paper (Rohwer & Fagan, 1917) who argued that the French entomologist Étienne Geoffroy (1725-1810) who raised the Genus Diplolepis in 1762, should take precedence over Theodor Hartig’s (1805-1880) 1840 Genus Rhodites. This pointed me back to the 1940s and the discovery that the mossy rose gall was then known as Rhodites rosae and I quote “I have recently published an epitome of  my own experience e in rearing from galls of R. rosae” (Blair, 1945). A bit more delving and I found that in France in the 1930s and in the USA in the 1920s, it was still known as R. rosae (Weld, 1926; da Silva  Tavares, 1930). Wending my back via citations I arrived in 1903 to find it listed as Cynips rosae (Ashmead, 1903).

Historical insights – Monsieur Wirey was ahead of his time

Armed with this knowledge, my journey back into the history of D. roase was much simplified and introduced me to a gem of a book, Insect Architecture by James Rennie  (1787-1867) (Rennie, 1851). Here I found an interesting account of galls in general but a detailed exposition of the Bedeguar gall of rose as he described it, including this rather nice drawing.

Professor Rennie presents some hypotheses on the formation of insect galls in general;

Many of the processes which we have detailed bear some resemblance to our own operations of building with materials cemented together; but we shall now turn our attention to a class of insect-architects, and who cannot, so far as we know, be matched in prospective skill by any of the higher orders of animals. We refer to the numerous family which have received the name of gall-flies,

  1. Wirey says, the gall tubercle is produced by irritation, in the same way as an inflamed tumor in an animal body, by the swelling of the cellular tissue and the flow of liquid matter, which changes the organization, and alters the natural external form. This seems to be the received doctrine at present in France. “

As you can see from the above he has little time for the French explanation (typical English exceptionalism) and puts forward his own idea that the galls are formed because the egg laying process blocks the vessels of the plant and the fluid that would normally flow unimpeded blows up the tissue surrounding the egg like a balloon.  Of course he was wrong and M. Wirey was correct :-).  Considering that he had no access to the sophisticated techniques we have he pretty much hit the nail on the head.

That aside, his book introduced me to an entomologist I had never heard of, Priscilla Wakefield (1751-1832), yet another overlooked and forgotten female scientist.

Possible projects?

Although my plans for lots of great MSc projects were reduced somewhat I have had a lot of educational fun and I think that there are still some things that could usefully be looked at, long term recording across multiple sites which I hope the British Plant Gall Society is doing would be interesting.  On my walks I noticed a lot of variability in size and phenology of gall formation.  At the end of August I was coming across small very fresh looking galls at the same time as I was seeing larger more advanced galls.

A very fresh looking Bedeguar gall, August 26th 2020, Sutton

As far as I can tell, the timing of gall formation and its effect on final size of the galls has not been looked at in detail; do early galls enter winter larger than later formed galls, or is it entirely due to the number of eggs laid?  Given the huge number of other inhabitants of the galls, at least fourteen different species (Laszló, 2001, there is probably a viable project in looking at the timing of invasion by the different gall parasites and the outcome this may or may not have on the final composition of the gall fauna.

Feel free to suggest additional projects in the comments.


Ashmead, W.H. (1903) Classification of the gall-wasps and the parasitic cynipoids, or the superfamily Cynipoidea. IV, Psyche, 10, 210-216.

Awmack, C.S. & Leather, S.R. (2002) Host plant quality and fecundity in herbivorous insects. Annual Review of Entomology, 47, 817-844.

Blair, K.G. (1945) Notes on the economy of the rose‐galls formed by Rhodites (Hymenoptera, Cynipidae). Proceedings of the Royal Entomological Society, Series A, 20, 26-31.

Bronner, R. (1985) Anatomy of the ovipositor and oviposition behavior of the gall wasp Diplolepis rosae (Hymenoptera: Cynipidae). Canadian Entomologist, 117, 849-858.

Bugbee, R. E. (1951). New and described parasites of the genus Eurytoma illiger from rose galls caused by species of the cynipid genus Diplolepis Geoffrey Hymenoptera: Eurytomidae). Annals of the Entomological Society of America, 44, 213–261

Callan, E.Mc. (1940) On the occurrence of males of Rhodites rosae (l.) (Hymenoptera, Cynipidae). Proceedings of the Royal Entomological Society of London, Series A., 15, 21-26.

Da Silva Tavares, J. (1930) Quelques Cécidies du Centre de la France, Publications de la Société Linnéenne de Lyon75, 145-167.

Gordh, G & Headrick, D.H. (2001) A Dictionary of Entomology, CABI, Wallingford

Jones, L.P., Turvey, S.T.,  Massimino, D. & Papworth, S. K.(2020) Investigating the implications of shifting baseline syndrome on conservation. People & Nature,

Laszló, Z. (2001) The parasitic complex of Diplolepis rosae (LinnaeuS, 1758) (Hymenoptera, Cynipidae): influencing factors and interspecific relationships. Entomologica Romanica, 6, 133–140.

Leather, S.R. (2018) “Ecological Armageddon” – more evidence for the drastic decline in insect numbers. Annals of Applied Biology, 172, 1-3.

Osten Sacken, R. (1870) Contributions to the natural hstory of the Cynipidæ of the United State and their galls.  Transactions of the American Entomological Society, 3, 54-64.

Packer, L., Monckton, S.K., Onuferko, T.M. & Ferrari, R.R. (2018) Validating taxonomic identifications in entomological research. Insect Conservation & Diversity, 11, 1-12.

Randolph, S. (2005) The Natural History of the Rose Bedeguar Gall and its Insect Community, The British Plant Gall Society.

Rennie, J. (1857) Insect Architecture. John Murray, London.

Rohwer, S. A. & Fagan, M. M. (1917) The type-species of the genera of the Cynipidea, or the gall wasps and parasitic cynipoids. Proceedings of the U.S. National Museum, 53, 357-380.

Shorthouse, J.D. (1973) The insect community associated with rose galls of Diplolepis polita (Cynipidae, Hymenoptera). Quaestiones Entomologicae, 9, 55-98.

Stille, B. (1984) The effect of hosptlant and parasitoids on the reproductive success of the parthenogenetic gall wasp Diplolepis rosae (Hymenoptera, Cynipidae). Oecologia, 63, 364-369.

Stille, B. & Dävring, L. (1980) Meiosis and reproductive strategy in the parthenogenetic gall wasp Diplolepis rosae (L.) (Hymenoptera, Cynipidae), Heriditas, 92, 353-362.

Urban, J. (2018). Diplolepis rosae (L.) Hymenoptera: Cynipidae): development, ecology and galls in the Brno region. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 66, 905-925.

Wakefield, P. (1816) An Introduction to the Natural History and Classification of Insects in a series of Familiar Letters with Illustrative Engravings. Darton, Harvey & Darton, London.

Walker, P., Leather, S.R. & Crawley, M.J. (2002) Differential rates of invasion in three related alien oak gall wasps (Cynipidae: Hymenoptera). Diversity & Distributions, 8, 335-349.

Weld, L. H. (1926) Field notes on gall-inhabiting cynipid wasps with descriptions of new species. Proceedings of the United States National Museum, 68, 1-131.




Filed under EntoNotes