Tinker, Tailor, Soldier Aphid!

As a follow-up to my earlier article about biting aphids https://simonleather.wordpress.com/2013/01/25/not-all-aphids-are-vegans/, I thought it would be fun to draw people’s attention to a little-known aspect of aphid biology and ecology and yet another reason for why I love aphids so much.  Tree leaves are only really good food sources for aphids in spring and autumn, when the levels of soluble nitrogen are at their highest levels in the phloem sap (Dixon, 1973).

To get around this, a number of aphid species modify the leaf tissues by forming galls.  The galls, which are induced by chemicals in the saliva of the aphid, contain cells which are higher in nitrogen than the surrounding tissues and ensure that the nutritional quality of the leaves remains high throughout the year.

Those tree-feeding aphids, such as the sycamore aphid, Drepanosiphum platanoidis, which are unable to form galls, enter summer aestivation (reduce their metabolic rates) as an adaptation to the low nitrogen levels found in summer leaves.  Amongst aphids, the Pemphigine aphids are renowned for their gall forming activities, many of which are formed along the leaf petiole.  The position of the gall along the petiole is very important, the closer the gall is to the base of a leaf, the better the quality of the food that the gall inhabitants experience.  There is thus a premium to be gained by either being first to form a gall, or, if in second place, to usurp the aphid stem mother that got there first and push her further up the leaf petiole.   We thus see two strategies.  In the first strategy, newly emerged first instar nymphs, (such as Pemphigus betae) fight each other  for the best position on the petiole (Whitham, 1979). These fights are serious affairs, and incredibly, can last for up to two days.

In the second strategy, as seen in a related species, Epipemphigus niisimae, where a gall has already been formed by an earlier arrival, the first instar nymphs fight to gain possession of this premium dwelling place.  These fights are even more vicious and protracted and can actually result in the death of the loser (Aoki & Makino, 1982).

As a further development, a number of gall-forming aphids, such as Ceratoglypnia styracicola and Hamamelistes cristafolaie, have a specially adapted nymphal morph, with thicker and broader front legs, whose function is to defend gall usurpation by other aphid stem mothers, so-called soldier aphids (Akimoto et al, 1996; Aoki & Kurosu, 2010).  These stay outside the gall and repel possible invaders.  It should thus not come as a surprise to find that in some species, the soldiers don’t just fight other aphids, but actually defend their siblings against predators, even being able to kill lacewing larvae (Kutsukake et al., 2004).

Truly a force to be reckoned with and of course why I love aphids so much.

Akimoto, S., Ozaki, K. &Matsumoto, Y. (1996). Production of first-instar defenders by the Hormaphidid gall-forming aphid Hamamelsites cristafoliae living anholocyclically on Betula maximowicziana. Japanese Journal of Entomology 64, 879-888.

Aoki, S. &Makino, S. (1982). Gall usurpation and lethal fighting among fundatrices of the aphid Epipemphigus niisimae. Kontyu 50, 365-376.

Aoki, S. & Kurosu, U. (2010) A review of the biology of Cerataphidini (Hemiptera, Aphididae, Hormaphidinae), focusing mainly on their life cycles, gall formation, and soldiers. Psyche, 2010, http://connection.ebscohost.com/c/articles/60639059/

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

Kutsukake, M., Shibao, H., Nikoh, N., Morioka M., Tamura, T., Hoshino, T., Ohgiya, S, & Fukatsu, T. (2004) Venomous protease of aphid soldier for colony defense,  Proceedings of the National Academy of Sciences USA, 101,11338-11343. http://www.pnas.org/content/101/31/11338.full.pdf+html

Whitham, T. G. (1979). Territorial behaviour of Pemphigus gall aphids. Nature 279, 324-325.

http://www.nature.com/nature/journal/v279/n5711/abs/279324a0.html

Woolly bear postscript – where have all the young entomologists gone?

On Saturday (16^th February) I attended the Shropshire Entomology Day at Preston Montford http://www.field-studies-council.org/centres/prestonmontford.aspx organised by Peter Boardman of the Field Studies Council http://www.field-studies-council.org/. The day was very well attended, about 75 people in total, and the talks ranged from detailed discourses on how to tell aquatic bugs apart to more general talks such as that by Peter Boardman  (my personal favourite) about the genealogy of a box of insects once owned by the remarkable Dipterist and blackfly expert, Lewis Davies http://www.blackfly.org.uk/downloadable/bsgbull28.pdf and that by Richard Becker showing us how he has made his organic Welsh hill farm into a haven for a wide variety of insects from dung-flies to butterflies.  I was there with my Professorial hat on, and incidentally my entomological t-shirt, to spread the word about the MSc in Entomology that we run at Harper Adams University http://www.harper-adams.ac.uk/postgraduate/201004/entomology and to foster links between us and other like-minded individuals and organisations.  We also heard about plans for a new Dragonfly Atlas for Shropshire and the forthcoming Cranefly Distribution Atlas for Shropshire, as well as the herculean efforts of the Wrekin Forest Volunteers http://wrekinforestvolunteers.blogspot.co.uk/ to ensure that every tetrad in the count at least one invertebrate record associated with it.

All in all it was a very enjoyable and informative day.  The thing that struck me most however, and I have made this observation before http://www.harper-adams.ac.uk/staff/profile/files/uploaded/Leather_&_Quicke_2010.pdf, was that the age range of the speakers and audience was heavily skewed towards the grey end of the spectrum, me included.  There were some relative youngsters present, but the overwhelming majority of the participants present, and those pictured in the talk by Paul Watts about the Wrekin Forest Volunteers, were heading towards retirement age or definitely past it.  I have noticed this phenomenon many times when giving talks to local Natural History Societies, most markedly at the Crowthorne Natural History Society, http://cnhg.org.uk/meetings.html where I was the youngest person present by at least 15 years!

So where were all the youngsters, and in this case I mean the 20-30 age group.  Volunteering to work abroad at great expense on projects involving charismatic mega-fauna or sat in front of their computer screens playing games or engaging with their peers on Face Book?  That said, one young man I spoke with, was planning to go to university to study ecology, an ambition that had been stimulated by volunteering in India, but the impression I got was that once qualified, he intended to return to India to continue on similar projects rather than get involved with small local projects as I advocated in a previous article https://simonleather.wordpress.com/2013/02/01/think-small-and-local-focus-on-large-charismatic-mega-fauna-threatens-conservation-efforts/ .

Yes I had an enjoyable day, yes I made some great contacts and yes, I even stimulated interest in the courses we offer, but Houston, we have a problem. There is enthusiasm at primary school level and the Bug Club http://www.amentsoc.org/bug-club/ do a great job at fostering this enthusiasm, but secondary school teaching (with some rare exceptions) and sadly, biology, zoology and ecology degrees at undergraduate level in the UK, largely relegate entomological teaching to a handful of lectures, concentrating instead on molecular biology or, when whole organisms are mentioned, my pet bugbear, charismatic mega-fauna.  My greatest fear is, that unless we can get secondary schools and universities to provide teaching that encompasses the invertebrate world, we will not only see the continued lack of engagement with invertebrates by the young, but we will also lose the older end of the spectrum as the endangered entomologically enthusiastic youngsters become extinct and no longer provide us with the next generation of grey entophiles who maintain sites such as this http://www.insects.org/entophiles. I find it hard to imagine that there are people who can fail to love or be thrilled by organisms such as this giant water bug, once they have them drawn to their attention.

http://beneficialbugs.org/bugs/Giant_Water_Bug/giant_water_bug.htm

At the risk of sounding alarmist I really feel that it is imperative that we get the message of how important entomology is out  to all levels of society and government before it is too late.  How we do this is another matter, but do it we must.

Where have all the woolly bears gone? Woolly bears what are they?

Just a brief thought this week, mainly about shifting baselines and changing perceptions.  I attended the launch of the State of Britain’s Larger Moth’s Report   http://www.mothscount.org/uploads/State%20of%20Britain’s%20Larger%20Moths%202013%20report.pdf last week (February 1^st) which as well as giving me the chance to catch up with a number of old friends, also enabled me to hear Chris Packham http://www.chrispackham.co.uk/  giving a lively and very entertaining talk about why moths are important and how he got hooked by ‘natural history’.  He cited as one of the main factors,  his childhood experiences of rearing (or attempting to rear) woolly bear caterpillars, the larvae of the Garden Tiger moth Arctia caja,  a widespread and common species when I was a child and teenager in the 1960s and early 1970s.

http://www.wildlifeinsight.com/Insight/?p=3468

When I was earning extra money working as a postman in the Vale of York during my student years, it was one of the insects that I could guarantee I would encounter on my round.   Despite its wide range and great abundance, this moth has suffered a huge decline in numbers and I have hardly seen one since I was a long-haired, flares wearing student.  Like Chris Packham, it was the opportunity to interact with such a striking insect, which kept me interested in the natural world despite the competing interests of girls and beer.  As I write, I am teaching on a module (Ecological Entomology) of our MSc Entomology course http://www.harper-adams.ac.uk/postgraduate/201004/entomology (incidentally the only one in the UK).  Having been reminded of the Garden Tiger by Chris Packham, I quickly substituted my population simulation modelling exercise on the Speckled Wood Butterfly, with one on the Garden Tiger.  After I had finished introducing the subject to the students, Kevin, a mature student said that it was collecting and rearing woolly bear caterpillars as a child that had led to him to be sitting in front of me now.  One of the other students, a recent graduate, piped up and asked “what is a woolly bear?  I have never heard of them”.   He was there because he had been inspired by his project supervisor.

I guess the point that I am trying to make, is that whilst Kevin and I were inspired to become entomologists by our childhood experiences, Craig had to wait until he was exposed to the wonder and awe of working with insects as an undergraduate.  So what’s the problem you may ask?  Both students have ended up in my class. There is a problem however; the last BSc in Entomology in the UK stopped running in 1995, there are no Entomology Departments in UK universities , there are as far as I can ascertain, very few academic entomologists who describe themselves as entomologists in their job title e.g. as Professor of Entomology.  As far as I know, there is only me, http://www.harper-adams.ac.uk/staff/profile.cfm?id=201220 and then there is Francis Ratnieks at Sussex who proudly describes himself as the UK’s only Professor of Apiculture http://www.sussex.ac.uk/profiles/128567.  Others who I regard as mainstream entomologists are not described as such as in their job titles, e.g. Richard Wall at Bristol, Professor of Zoology; Jane Memmott also at Bristol,  Professor of Ecology; Bill Hughes at Sussex , Professor of Evolutionary Biology; Charles Godfray at Oxford (Hope Professor of Zoology) and the list goes on.  Even Mike Siva-Jothy who describes himself as an angry old entomologist on Twitter is just listed as Professor. Unlike arachnologists in Canada who are extremely rare organisms as outlined in Chris Buddles’ great blog article http://arthropodecology.com/2013/02/06/where-are-all-the-arachnologists-and-why-you-should-care/  we are still around in fairly respectable numbers.  We do, however, seem to be making it difficult for potential students to find and identify us.  The reasons for why I think this has happened will be the subject of another blog.  The point is, that if we are hard to find and identify, then the pool of potential future entomologists is going to become smaller as fewer and fewer undergraduates are exposed to basic entomological teaching and thus fewer and fewer entomologists will make it through to academia and our profile will become even lower and therefore even fewer students will be able to be inspired and so on and so on.  As a result, we too are likely to become as endangered as Canadian arachnologists.

So, if you are an academic who works mainly with insects and you are able to identify more species than just those you work on, then why not identify yourself in your job title as an entomologist and stand tall and proud and countable.

Think small and local – focus on large charismatic mega-fauna threatens conservation efforts

What’s the problem?

Mention conservation to most people and they immediately think of tropical rainforests, tigers, polar bears and elephants.  But high profile so called “conservationists” are no different from the general public; for example, Robin Hanbury-Tenison whose dream job is Ranger in an African national park (Daily Telegraph, July 2^nd 2009).  His writings focus on South America and Africa, and his thoughts concern saving rhinos etc.  The small essential organisms that run the world are beneath his ken.  This focus on the large and charismatic organisms fostered by TV programmes is having a harmful effect on our children’s perception of nature; a future generation of conservation scientists are receiving a highly biased view of the world.  For example, when I talk to ‘A’ Level Biology students and show them the following slide, they are all able to answer the questions posed in the middle.

When, however, I show them the following slide of common British invertebrates they are almost always at a complete loss, although some students are able to name the aphid,

although not of course, to species.  When I show them the next slide of rare

animals and an internationally rare habitat, they fail dramatically, except sometimes one will guess the dormouse correctly.

Funding bodies are no less biased (Leather, 2009).  The Darwin Initiative, a UK Government fund for international nature conservation projects, has a less than enviable record when it comes to funding entomological research; since 2003 they have awarded 154 grants, 9 that specifically name invertebrates, but 50 that name vertebrates, and did not fund any invertebrate research in 2010, despite Darwin’s well known love of invertebrates, especially beetles, and his extensive research into barnacles, insect pollinators and earthworms.  Nature conservation is also internationally biased, with less and less focus placed on the UK and an ever-increasing number of TV programmes about exotic mega-fauna.  Large areas of the UK, such as towns and ex-industrial areas are often considered wastelands in terms of nature conservation but actually, may be rich in diversity.  To remain this way, however, they need not only to be protected but also to be managed.

 Why are insects important?  Are they endangered?

Most of the world’s animals are invertebrates: insects and allied invertebrates comprise approximately 78% of the world’s macro-biodiversity, whereas vertebrates, even using the most generous estimates, make up less than 3% (Clark & May, 2002). Invertebrates have more species than all other groups put together and are an important food source for other, more popular, animals. They also carry out vital roles for us, including cleaning our air and soil, breaking down decaying material and pollination.  If these groups are not looked after and protected from extinction then not only will the favoured charismatic animals not continue but we are at risk also!   About 250 species of beetle have not been seen in the UK for 35 years, bees are in decline,  and we have no idea if earthworm and Collembolan populations are coping with modern, intensive agriculture.  Only a tiny amount of money gets channelled into nature conservation, and only a minute fraction of this then finds its way into conserving invertebrates, the majority is siphoned off to conserve the much smaller numbers of the furry, feathery and flowery.  As a result, whilst we have detailed lists of the endangered vertebrates worldwide, we don’t even know how many invertebrates there are, let alone if they are endangered or not. As Papworth et al. (2009) point out, how can we expect people to care about the environment and conserve it, if they do not perceive it in its entirety?

Why is local important?

The only places suitable for nature are considered to be untouched areas in the open countryside.  While these areas are protected, local nature reserves or patches of green space are discarded and become more and more fragmented and degraded in quality.  The biodiversity of urban gardens has been intensively researched in previous studies in Sheffield (the BUGS project) demonstrating surprisingly high invertebrate diversity (Smith et al., 2006) as have the roundabouts of Bracknell (Helden & Leather, 2004; Helden et al., 2012).  Some focus should be shifted to these sorts of sites and not just the isolated big patches, and this will allow us to support the greatest amount of habitat for British wildlife.

 What can we do?

Regardless of what exotic animal you hear about as being greatly endangered, try to look a bit closer to home and down by your feet.  You’re more likely to encounter something there which would actually make a difference if you cared about it and protected it.  And for those contemplating conservation gap years overseas, why not save money and make a difference at home.  It might not be as exotic, but your efforts will be just as valuable.

 

Clark, J.A. and May, R.M. (2002) Taxonomic bias in conservation research. Science 297, 191–192.

Helden, A.J. & Leather, S.R. (2004)  Biodiversity on urban roundabouts:  Hemiptera, management and the species-area relationship.  Basic & Applied Ecology, 5, 367-377 http://www.harper-adams.ac.uk/staff/profile/files/uploaded/Helden&Leather2004.pdf

Helden, A.J., Stamp, G.C. & Leather, S.R. (2012)  Urban biodiversity: comparison of insect assemblages on native and non-native trees.  Urban Ecosystems,  15, 611-624 http://www.harper-adams.ac.uk/staff/profile/files/uploaded/Helden_et_al_2012.pdf

Leather, S. R. (2009). Institutional vertebratism threatens UK food security. Trends in Ecology & Evolution 24: 413-414. http://www.harper-adams.ac.uk/staff/profile/files/uploaded/Leather_2009_Trends-in-Ecology-&-Evolution.pdf

Papworth, S.J., Coad, L., Rist, J., Miller-Gulland, E.J. (2009) Shifting baseline syndrome as a concept in conservation. Conservation Letters 2, 93-100. http://www.iee.unibe.ch/cb/content/e7117/e7118/e8764/e9981/e9990/Papworth_ConLet2009.pdf

Smith, R.M., Gaston, K.J., Warren, P.H., Thompson, K. (2006) Urban domestic gardens (VIII): environmental correlates of invertebrate abundance. Biodiversity & Conservation 15, 2515-2545. http://bugs.group.shef.ac.uk/BUGS1/sources/bugs-reprint8.pdf

 

Notes:

Although this article is written from an entirely UK-centric viewpoint, I would be very much surprised if what I have described is confined to the British Isles.

The UK Government commemorates Darwin with the ‘Darwin Initiative’ a fund for international nature conservation. But the little animals he loved are not well catered for. In 2009 only one project specifically relating to invertebrates was included in the 74 projects short-listed by the ‘Darwin Initiative’.

Matt Shardlow, Director of Buglife – The Invertebrate Conservation Trust said “Darwin loved bugs and understood their critical importance supporting life on earth. Currently society invests a pathetic amount of money into conserving these natural riches; without sufficient Government funding we have to depend on the generosity of individuals to save the small things that run the world.”

 

(DEFRA funding to The Darwin Initiative assists countries that are rich in biodiversity but poor in financial resources to meet their objectives under one or more of the three major biodiversity conventions: the Convention on Biological Diversity (CBD); the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES); and the Convention on the Conservation of Migratory Species of Wild Animals (CMS), through the funding of collaborative projects which draw on UK biodiversity expertise). http://darwin.defra.gov.uk/