Midwinter Madness – The Snow flea

Between 1982 and 1992 I worked as a research and advisory entomologist for the UK Forestry Commission based at their Northern Research Station just outside Edinburgh. For the first five years of my time there I worked almost exclusively on the pine beauty moth, Panolis flammea. The pine beauty moth is

a native insect that became a pest of a non-native tree, Pinus contorta, then a tree that was widely planted over northern Britain. The majority of planting in Scotland was in the north and this meant that my study sites were in Sutherland and Caithness and Aberdeenshire. My main experimental forest was west of Aberdeen in the Spey valley (very handy for the whisky trail) in the Elchies block of Criagellalchie Forest.

My experimental forest with nearby distillery marked 😉

In Mid-January 1984, I headed north to do some maintenance on my head capsule collecting funnel traps.

In those days, snow was a perennial hazard, even in the south of Scotland and as I progressed northwards the drifts at the side of the road became increasingly higher. When I reached the forest gates, it was obvious that I was not going to be able to drive to my site. The sun was shining, the sky was blue and the snow glistened. A perfect day for a walk, albeit one of 10 km. Luckily, the weather had been sunny for the last couple of days so the snow was mostly hard enough to walk on. Only in a few places did I break the surface and find that I was standing on about a metre depth of snow. Two hours later as I was approaching my field site, squinting against the sun bouncing off the white untouched snow, I saw black spots moving on the surface. My immediate thought was that I was suffering the first stages of snow-blindness, but as I got nearer I saw that the black dots were actually insects. At first sight I thought I was hallucinating, was this some strange bizarre form of life perhaps an aphid-fly hybridization experiment gone wrong? On closer examination I realised that I was looking at wingless Mecopterans.

Male snow flea, Boreus hyemalis http://mecoptera.free.fr/Boreus-hyemalis.html

 

Female Boreus hyemalis, note the sting-like ovipositor. http://www.wbrc.org.uk/WORCRECD/32/Bingham–John–Snow_Flea_Boreus_hyemalis.html

Although I was familiar with Scorpion-flies, I had never seen these critters before.

The aptly named Scorpion fly Panorpa communis : https://commons.wikimedia.org/wiki/File:Scorpion_Fly._Panorpa_communis._Mecoptera_(7837166610).jpg

I collected a few to send off for identification and confirmation and carried on into the depths of the forest to check on my funnels. On returning to civilization a day or so later I sent my specimens off to the Natural History Museum and shortly after was informed that I had they were the snow flea, Boreus hyemalis and that I had extended the recorded range of this particular species, albeit only by a few miles.

My record – it lasted 10 years as the furthest north before M.S.C. Elliott recorded it in February 1994 in Easter Fearn in the north-west Highlands.

Distribution of Boreus hyemalis in 1994; my record, then the furthest North.

 

Current recorded distribution of Boreus hyemalis – obviously widespread – just lacking people willing to go and look for it in the winter 🙂

So what is a snow flea. It is of course, not a flea, being a Mecopteran or Scorpion fly, albeit non-winged.  In Britain there are three species with wings (in the genus Panorpa), the larvae and adults both being predatory on other insects. The adult snow flea is about 5mm long, and lives among moss on which it feeds as both a larva and adult (Withycombe, 1922, 1926). Interestingly, the BugLife site states that they are predatory in both the larval and adult stage. I am not sure where they got this information as they do not cite a reference and all the published literature I have seen indicates that they are moss feeders (Withycombe, 1922, 1926; Fraser, 1943; Hågvar, 2010). Indeed, Wthycombe (1922) conducted a series of experiments on the larvae and conclusively demonstrated that they were unable to complete their development unless fed on moss, although the adults will apparently also feed on dead insects.

These are true winter-active insects, adults emerging in October and November when they mate and lay their eggs the eggs at the base of moss plants), Polytrichium commune being the preferred host (Fraser, 1943). The eggs start to hatch in November and the larvae forage within the moss clumps, pupating towards the end of the summer, emerging as adults after 6-8 weeks.  The adults, which are wingless, thus come out in the coldest months of the year, usually between October and April.  They are most easily seen when walking or jumping on the snow surface. Considering that the adults are winter-active they have a surprisingly high super-cooling point (-6.5^oC) (Sömme & Östbye, 1969), especially when compared with the cereal aphid, Sitobion avenae, which has a super-cooling point of -24^oC but rarely survives English winters (Knight & Bale, 1986). The BugLife site wonders “how they (snow fleas) manage to jump up to 5 cm without muscular hind legs” but Burrows (2011) found that their jumping prowess is by virtue of large depressor muscles within the thorax which enables them to jump distances of up to 10 cm with a take-off velocity of 1 m s^-1, indicating a force of about 16 times their body weight.  So aptly named in this respect too.

The Snow flea is not found (or at least has not been recorded) in the mild south-west of Britain, seeming to prefer areas with a harsher winter. Climate warming may thus pose a threat for this intriguing and little studied insect. Perhaps it is time for us all to venture out in mid-winter and start scanning the surface of snow drifts in heathland areas for these elusive creatures before it is too late.

 

References

Burrows, M (2011) Jumping mechanism and performance of snow fleas (Mecoptera, Boreidae). Journal of Experimental Biology, 214, 2362-2374.

Fraser, F.C. (1943) Ecological and biological notes on Boreus hyemalis (L.) (Mecopt., Boreidae). Journal of the Society for British Entomology, 2, 125-129

Knight, J. D. & Bale, J. S. (1986). Cold hardiness and overwintering of the grain aphid Sitobion avenae. Ecological Entomology 11, 189-197.

Sömme, L. & Östbye, O. (1969) Cold-hardiness in some winter active isnects. Norsk Entomologisk Tidsskrift, 16, 45-48

Withycombe, C. L. (1922). On the life history of Boreus hyemalis L. Transactions of the Entomological Society of London, 1921, 312-318.

Withycombe, C. L. (1926). Additional remarks upon Boreus hyemalis L. Entomologist’s Monthly Magazine, 62, 81-83.

 

Useful link

For more images and observations see http://www.wbrc.org.uk/WORCRECD/32/Bingham–John–Snow_Flea_Boreus_hyemalis.html

 

By the side of the River Liffey – ENTO’15 Dublin

This year, the Royal Entomological Society’s biennial symposium was held at Trinity College, Dublin (September 2nd-4th). This was the first time that the Society has held its symposium meeting outside the UK. The symposium theme this year was Insect Ecosystem Services, whilst the Annual Meeting which ran alongside the symposium meeting this year, was divided into nine themes, Biocontrol, Conservation, Decomposition, Insect Diversity and Services, Multiple Ecosystem Services, Outreach, Plant-Insect Interactions, Pollination and just in case anyone was feeling left out, Open.

The meeting convenors, Archie Murchie, Jane Stout, Olaf Schmidt, Stephen Jess, Brian Nelson, and Catherine Bertrand, came from both sides of the border so that the whole of Ireland was represented.

As a number of us were going from Harper Adams University we decided to use the Sail-rail option (any mainline station in the UK to Dublin for £78 return). We were thus able to feel smug on two levels, economically and ecologically 🙂 We set out on the morning of Tuesday 1^st September from Stafford Railway Station, changing at Crewe for the longer journey to Holyhead.

Andy Cherrill, Tom Pope, Joe Roberts, Charlotte Rowley and Fran Sconce look after the luggage.

Just over two hours later we arrived at Holyhead to join the queue for the ferry to Dublin.

In the queue at Holyhead.

Two of my former students were supposed to join us on the ferry but due to a broken down train, only one of them made it in time, Mark Ramsden being the last passenger to board whilst Mike Garratt had to wait for the next ferry.

Tom Pope and Mark Ramsden relaxing on board the ferry.

We arrived at Trinity College in the pouring rain, but still got a feel for some of the impressive architecture on campus.

                           

I never quite worked out what this piece of art was about, although the added extra made me smile.

The bedrooms were very self-contained – the bed was rather neatly built into the storage although it did make me feel like I was sleeping on a shelf.

After settling in we found a pleasant pub and sampled some of the local beverages.

Despite the beverage intake, I was up bright and early on Wednesday morning, in fact so early, that I was not only first at the Registration Desk, but beat the Royal Entomological Society Staff there.

After setting up our stand we were able to enjoy the programme of excellent plenary talks and those in the National Meeting themes. There was a great deal of live tweeting taking place so I thought I would give you a flavour of those rather than describing the talks in detail.  For the full conference experience use Twitter #ento15

Dave Goulson from Sussex University,  was the first of the plenary speakers and lead off with a thought-provoking talk about the global threats to insect pollination services.

I was a bit disappointed that John Pickett, who was chairing the session cut short a possibly lively debate between Lin Field and Dave Goulson about pesticide usage.

The next plenary speaker was Akexandra-Maria Klein from Freiburg speaking about biodiversity and pollination services.

The third plenary speaker was Lynn Dicks from Cambridge asking how much flower-rich habitat is enough for wild pollinators?

I was the fourth plenary speaker, talking about how entomology and entomologist have influenced the world. I deliberately avoided crop protection and pollination services.

I was very pleased that my talk was on the first day as this allowed me to enjoy the rest of the meeting, including the social events to the full.

The following day, Jan Bengtsson from SLU in Sweden spoke about biological ontrol in a landscape context and the pros and cons of valuing ecosystem services.

Jan was followed by Sarina Macfadyne from CSIRO, Australia, who spoke about temporal patterns in plant growth and pest populations across agricultural landscapes and astounded us with the list of pesticides that are still able to be used by farmers in Australia.

The next plenary speaker, Charles Midega – icipe spoke about the use of companion cropping for sustainable pest management in Africa and extolled the virtues of ‘push-pull’ agriculture.

The last plenary of Day Two was Jerry Cross of East Malling Research who enlightened us about the arthropod ecosystem services in apple orchards and their economic benefits. He also highlighted the problems faced by organic growers trying to produce ‘perfect’ fruit for the supermarkets.

The third day of the conference plenaries was kicked off by Michael Ulyshen from the USDA Forest Service – who reviewed the role of insects in wood decomposition and nutrient cycling. My take-home image form his talk was the picture of how a box of woodchips was converted to soil by a stage beetle larvae completing its life cycle.

The last plenary of the morning was Craig Macadam from BugLife who explained to us that aquatic insects are much than just fish food and play cultural role as well as an ecological one.

The afternoon session of the last day was Sarah Beynon, the Queen of Dung Beetles who enthralled us with her stories of research and outreach . It was a testament to the interest people had in what Sarah had to say, that the audience was till well over a hundred, despite it being the last afternoon.

The final plenary lecture, and last lecture of the conference, was given by Tom Bolger from the other university in Dublin, UCD. Hi subject was soil organisms and their role in agricultural productivity.

I know that I have only given you a minimal survey of the plenary lectures, but you can access the written text of all the talks in the special issue of Ecological Entomology for free.

I did of course attend a number of the other talks, and had to miss many that I wanted to see but which clashed with the ones that I did see.

Eugenie Regan gave a great talk on her dream of setting up a Global Butterfly Index.

One of my PhD students, Joe Roberts, gave an excellent talk on his first year of research into developing an artificial diet for predatory mites.

Katie Murray, a fomer MREs student of mine, now doing a PhD at the University of Stirling, gave a lively talk on Harlequin ladybirds and the problems they may be having with STDs.

Rudi Verspoor, yet another former MRes student gave us an overview of a project that he and Laura Riggi, have developed on entomophagy in Benin.

Peter Smithers from Plymouth University gave an amusing and revelatory talk the ways in which Insects are perceived and portrayed. Some excellent material for my planned book on influential entomology 😉

Chris Jeffs, yet another former MRes student gave an excellent presentation about climate warming and host-parasitoid interactions.

My colleague (and former MSc student) Tom Pope bravely volunteered to step into a gap in the programme and gave an excellent talk about how understanding vine weevil behaviour can help improve biological control programmes.

Jasmine Parkinson from the University of Sussex, and incidentally a student of a former student of mine, gave an excellent and well-timed talk about mealybugs and their symbionts.

Charlotte Rowley from Harper Adams gave an excellent talk about saddle-gall midge pheromones.

Another former student, Mike Garratt, now at Reading University, gave an overview of his work on hedgerows and their dual roles as habitats for pollinators and natural enemies.

There were also excellent talks by Jessica Scrivens on niche partitioning in cryptic bumblebees, Relena Ribbons on ants and their roles as ecological indicators, Rosalind Shaw on biodiversity and multiple services in farmland from David George on how to convince farmers and growers that field margins are a worthwhile investment. My apologies to all those whose talks I missed, I wanted to see them but parallel sessions got in the way.

Richard Comont, whose talk I missed, very recognisable from the back 😉

 

I leave you with a selection of photographs from the social parts of the programme including our last morning in Dublin before catching the ferry home on Saturday morning.

 

The Conference Dinner – former and current students gathering.

Tom Pope signs the Obligations Book – his signature now joins those of Darwin and Wallace.

Archie Murchie with RES Librarian Val McAtear.

The youngest delegate and his father; I hope to see him at Harper Adams learning entomology in the near future.

Entomologists learning how to dance a ceilidh.

Moving much too fast for my camera to capture them.

Academic toilets – note the shelf on which books can be placed whilst hands are otherwise occupied.

On site history.

Impressive doorway in the Museum café.

The Natural History Museum was very vertebrate biased.

They certainly didn’t way know the best way to mount aphids.

I was, however, pleased to see a historical Pooter.

 

On our final day the sun actually made an appearance so our farewell to Ireland was stunning.

And finally, many thanks to the conference organizers and the Royal Entomological Society for giving us such a good experience.  A lot to live up to for ENTO’16 which will be at Harper Adams University.  We hope to see you there.

Postscript

As a result of being tourists on Saturday morning we were exposed to a lot of gift shops and in one I impulsively bought a souvenir 😉

Ten papers that shook my world – Way & Banks (1964) – counting aphid eggs to protect crops

The previous papers in this series (Southwood, 1961; Haukioja & Niemelä 1976; Owen & Weigert, 1976), were all ones that had an influence on my post-PhD career. This one in contrast, had a direct effect on my PhD as well as on my subsequent career, and was, I guess, greatly influential in the publication of the first book to deal with the ecology of insect overwintering (Leather, Walters & Bale, 1993). In 1964 Mike Way, one of the early proponents of Integrated Pest Management (in fact considered to be the father of UK IPM), was working on control methods for the black bean aphid, Aphis fabae.

Mike had recently joined Imperial College from Rothamsted Research Station where he had been leading research on ways to reduce pesticide use by farmers and growers.   During his time at Rothamsted he had worked closely with a colleague, C.J. Banks on the black bean aphid including studies on the overwintering eggs. As they said in the introduction to their paper, published four years after their experiments; “During the British winter A. fabae survives almost exclusively in the egg stage. Egg mortality might therefore be important in affecting size of populations of this species and in predicting outbreaks”. They investigated the effects of temperature and predators on the mortality of the eggs on the primary host, spindle, Euonymus europaeus, and concluded that the levels of mortality seen would not affect the success of the aphids the following spring. By 1968 (Way & Banks, 1968) they had followed up on the idea and began to feel confident that aphid populations on field beans could be predicted from the number of eggs on the winter host; spindle bushes. The publication of this paper stimulated the setting up of a long-term collaborative project monitoring Aphis fabae eggs on spindle bushes at over 300 locations throughout England south of the River Humber, and monitoring aphid numbers in about 100 bean fields per year.   In 1977 the results were finally published (Way et al., 1977) and the highly successful black bean aphid forecasting system was born. This was further refined by using the Rothamsted aphid suction trap data (Way et al., 1981).

This was also the year that I began my PhD at the University of East Anglia, working on the bird cherry-oat aphid, Rhopalosiphum padi. In the course of my preparatory reading I came across Way & Banks (1964) just in time to set up a plot of bird cherry saplings which I monitored for the next three winters, the first winter’s work resulting in my first publication (Leather, 1980). I subsequently went on to develop the bird cherry aphid forecasting system still used in Finland today (Leather & Lehti, 1981; Leather, 1983; Kurppa, 1989).

Sadly, despite the great success of these two systems there has not been a huge take-up of the idea, although the concept has been looked at for predicting pea aphid numbers in Sweden (Bommarco & Ekbom, 1995) and rosy apple aphids in Switzerland (Graf et al., 2006). Nevertheless, for me this paper was hugely influential and resulted in me counting aphid eggs for over 30 years!

References

Bommarco, R. & Ekbom, B. (1995) Phenology and prediction of pea aphid infestations on pas. International Journal of Pest Management, 41, 101-113

Graf, B., Höpli, H.U., Höhn, H. and Samietz, J. (2006) Temperature effects on egg development of the rosy apple aphid and forecasting of egg hatch. Entomologia Experimentalis et applicata, 119, 207-211

Haukioja, E. & Niemela, P. (1976) Does birch defend itself actively against herbivores? Report of the Kevo Subarctic Research Station, 13, 44-47.

Kurppa, S. (1989) Predicting outbreaks of Rhopalosiphum padi in Finland. Annales Agriculturae Fenniae 28: 333-348.

Leather, S. R. (1983) Forecasting aphid outbreaks using winter egg counts: an assessment of its feasibility and an example of its application. Zeitschrift fur Angewandte Entomolgie 96: 282-287.

Leather, S. R. & Lehti, J. P. (1981) Abundance and survival of eggs of the bird cherry-oat aphid, Rhopalosiphum padi in southern Finland. Annales entomologici Fennici 47;: 125-130.

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

Owen, D.F. & Wiegert, R.G. (1976) Do consumers maximise plant fitness? Oikos, 27, 488-492.

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

Way, M.J. & Banks, C.J. (1964) Natural mortality of eggs of the black bean aphid Aphis fabae on the spindle tree, Euonymus europaeus L. Annals of Applied Biology, 54, 255-267.

Way, M. J. & Banks, C. J. (1968). Population studies on the active stages of the black bean aphid, Aphis fabae Scop., on its winter Euonymus europaeus L. Annals of Applied Biology 62, 177-197.

Way, M. J., Cammel, M. E., Taylor, L. R. &Woiwod, I., P. (1981). The use of egg counts and suction trap samples to forecast the infestation of spring sown field beansVicia faba by the black bean aphid, Aphis fabae. Annals of Applied Biology 98: 21-34.

Way, M.J., Cammell, M.E., Alford, D.V., Gould, H.J., Graham, C.W., & Lane, A. (1977) Use of forecasting in chemical control of black bean aphid, Aphis fabae Scop., on spring-sown field beans, Vicia faba L. Plant Pathology, 26, 1-7.

 

Post script

Michael Way died in 2011 and is greatly missed by all those who knew him well. He examined my PhD thesis, and to my delight and relief, was very complimentary about it and passed it without the need for corrections. I was greatly honoured that a decade or so later I became one of his colleagues and worked alongside him at Silwood Park. He was a very modest and self-deprecating man and never had a bad word to say about anyone. He had a remarkable career, his first paper published in 1948 dealing the effect of DDT on bees (Way & Synge, 1948) and his last paper published in 2011 dealing with ants and biological control (Seguni et al., 2011), a remarkable 63 year span. His obituary can be found here http://www.telegraph.co.uk/news/obituaries/science-obituaries/8427667/Michael-Way.html