Tag Archives: feeding

Thrip, thrips, thripses – A thrips by any other name

As well as the more well-known EntoPub*, the Harper Adams entomologists also indulge in Entolunch**, when we gather in one of our larger offices to eat our packed lunches and keep up to date with what we are doing, covering research, teaching and day-to-day life. This is not because we are anti-social or are averse to mixing with other disciplines, but because our offices are almost 500 m away from the Staff Common Room and nearest food outlet.  Last week our conversation turned to the Thysanoptera, more commonly known as thrips or thunder bugs.

Thrips1

Some fine examples of thrips, including the common thunder bug.

According to Lewis (1997) they were first described by DeGeer in 1744 under the name Physapus, but in 1758, Linneaus, ignoring this, placed the then four known species in a genus Thrips, later elevated to Order by Haliday in 1836.  Why Linneaus decided to call them thrips is a bit of a mystery, as according to the Oxford English Dictionary, thrips is derived from the Latin via Greek, meaning woodworm!

Thrips are tiny little insects, the giants among them, (mainly tropical) can reach lengths of up to 15 mm but most are round about 1-2 mm long (Kirk, 1996; Moritz, 1997).  Although they are not bugs, their feeding process can be described as “piercing-sucking or punch and suck” (Kirk, 1997).

Thrips2

 

There are about 8000 species of thrips worldwide (Lewis, 1997), although probably less than 200 in the UK (Kirk, 1996). Although many are important plant pests (Lewis, 1997), they can also be pollinators and fungivores (Kirk, 1996) or even very effective biological control agents (Gilstrap, 1995).    Some are gall-formers, and these, like some galling aphids, also have fights to the death with their rivals (Crespi, 1988).  All in all, almost as wonderful as aphids 🙂

But I digress, our conversation that lunchtime was not about the biology of thrips, but about the singularity (or plurality) of their name. Thrips are (in)famous for being like sheep, they are thrips whether you are speaking of one or of many, which has, and does, cause some debate among entomologists and others.

Thrips3

http://mxplx.com/memelist/keyword=end

We quite liked thripses although it does conjure visions of Gollum and his precious.

Thrips4

Who knew that Gollum was an entomologist?

Intrigued by the linguistic puzzle of thrips I wondered what it was in other languages. Using Google Translate, and possibly risking a Tolkienesque mistranslation, I found that in most cases, even French, it was boringly enough, thrips.

There were some languages where thrips was not thrips, but not many:

German               thripse

Swedish               trips

Italian                  tripidi

Catalan                 els trips

Estonian               ripslased

Polish                    wciornastki

Czech                    třásněnka

 

Perhaps my favourite was the Afrikaans, blaaspootjies. On breaking it down into parts it turns out that blaas means bladder and pootjies, legs, which doesn’t seem to make a lot of sense.

Bengali, Chinese and Japanese, were quite picturesque.

 

Bengali              থ্রিপস্ (thripas)

Chinese             牧草虫 (mùcǎo chóng)

Japanese          アザミウマ (azamiuma)

 

But the most ornate was Tamil

Thrips5

(llaippēṉ)

Which is quite a long word for such small insects, but very pretty all the same.  If anyone has any more suggestions for the naming of thrips, do feel free to comment.

 

References

Crespi, B.J. (1988) Risks and benefits of lethal male fighting in the colonial, polygynous thrips Hoplothrips karnyi (Insecta: Thysanoptera).  Behavorial Ecology & Sociobiology, 22, 293-301.

Gilstrap, F.E. (1995) Six-spotted thrips: a gift from nature that controls spider mites. [In] Thrips Biology and Management, pp 305-316, (ed. B.L. Parker, M. Skinner & T. Lewis),  Plenum Press, New York.

Kirk, W.D.J. (1996)  Thrips,  Naturalist’s Handbooks, Richmond Publishing Co. Ltd., Slough UK. [A very nice and simple introduction to the wonderful world of thrips]

Kirk, W.D.J. (1997) Feeding, [In] Thrips as Crop Pests, pp 119-174 (ed T Lewis), CAB International, Wallingford Oxford

Lewis, T. (1997) Pest thrips in perspective, [In] Thrips as Crop Pests, pp 1-13 (ed T Lewis), CAB International, Wallingford Oxford

Moritz, G. (1997) Structure, growth and development.  [In] Thrips as Crop Pests, pp 15-63 (ed T Lewis), CAB International, Wallingford Oxford

 

Post script

Slapped wrist for me – Elina Mäntylä has pointed out that in Finnish, thrips is ripsiäinen, probably to do with the wing structure.  I should have known that having lived and worked in Finland at the Pest Investigation Department.  interestingly, Google Translate thinks it is Thrips in Finnish – but if you do Finnish to English it does indeed translate ripsiäinen to thrips.

 

Glossary

*EntoPub            Drinks and a meal in a local hostelry organised by one of the Harper Adams Entomologists but not confined solely to entomologists.  We do like to mix with non-entomologists occasionally 🙂  Held at approximately 10 day intervals.

**EntoLunch     A communal occasion when the Harper Adams entomologists get together in office AY02 and eat their packed lunches whilst chatting, usually with some entomological connection.  Again this is not entirely confined to entomologists, we are usually joined by a couple of soil and water scientists who share our exile on the edge of the campus 🙂  A daily event during the working week.

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The Curious Case of the Shark-finned Aphid

The large (giant) willow aphid, Tuberlolachnus salignus, is, in my opinion, one of the world’s greatest unsolved mysteries.  This aphid is sometimes regarded as being the largest aphid in the world.  It can reach a length of 5 mm, can weigh up to 13 mg as an adult and the new-born nymphs weigh about 0.25 mg (Hargreaves & Llewellyn, 1978).  You can get an idea of how big it is from the picture below.

willow aphid on finger

http://www.rothamsted.ac.uk/PressReleases.php?PRID=100

This is pretty big for an aphid, although not quite as big as one of my former PhD students (Tilly Collins) liked to pretend!  The picture below used to appear on her website and was the envy of a number of Texan entomologists.  Tuberolachnus salignus, as you might expect, since it feeds through the bark and not on leaves, has rather a long set of stylets, up to  1.8 mm, more than a third of it’s body length (Mittler, 1957).

tilly on aphid

This picture emphasises the first mystery: what is the function of the dorsal tubercle, which so closely resembles a rose thorn, or to me, a shark’s fin.  Nobody knows.  Is it defensive? Unlikely, since T. salignus being a willow feeder is stuffed full of nasty chemicals and very few predators seem to want, or be able to feed on it.  They feed in large aggregations on the stems of their willow tree hosts and can have serious effects on tree growth (Collins et al., 2001).  As the aphids produce a lot of honeydew, they are often ant-attended  (Collins & Leather, 2002) and these also deter potential predators.  In fact the aphid colonies produce so much honeydew in the summer that they attract huge numbers of vespid wasps that are in search of energy-rich sugar sources at that time of year.  These too are likely to make potential predators and parasitoids think twice about approaching the aphids.

Tuberolachnus

Photograph courtesy Dr Tilly Collins

The wasps also cause a problem for researchers and when Tilly was doing her PhD, she used to have to confine her fieldwork to those times of day when the wasps were not around.   In addition, if you crush one of the aphids you will discover that it stains your fingers bright orange and that this stain will last several days if you don’t try too hard to wash it off.  If you get this aphid ‘blood’ on your clothes they will be permanently marked and Tilly used to say that she ought to be paid an extra clothing allowance.

Tuberolachnus salignus, is as far as we can tell, anholocyclic, no males have been recorded and no matter how hard people have tried to induce the formation of males and sexual females, they have not been successful.  This is however, not the second mystery.  The mystery is that every year, in about February, it does a disappearing act and for about four months its whereabouts remain a mystery (Collins et al., 2001).  So we have an aphid that spends a substantial period of the year feeding on willow trees without leaves and then in the spring when most aphids are hatching from their eggs to take advantage of the spring flush, T. salignus disappears!  Does it go underground?  If so, what plant is it feeding on and why leave the willows when their sap is rising and soluble nitrogen is readily available?

So here is a challenge for all entomological detectives out there.  What is the function of the dorsal tubercle and where does T. salignus go for the spring break?

Truly a remarkable aphid and two mysteries that I would dearly love to know the answers to and yet another reason why I love aphids so much.

Collins, C.M. & Leather, S.R. (2002) Ant-mediated dispersal of the black willow aphid Pterocomma salicis L.; does the ant Lasius niger L. judge aphid-host quality. Ecological Entomology, 27, 238-241. http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2311.2002.00390.x/full

Collins, C. M., Rosado, R. G. & Leather, S. R. (2001). The impact of the aphids Tuberloachnus salignus and Pterocomma salicis on willow trees. Annals of Applied Biology 138, 133-140 http://onlinelibrary.wiley.com/doi/10.1111/j.1744-7348.2001.tb00095.x/abstract.

Hargreaves, C. E. M. & Llewellyn, M. (1978). The ecological energetics of the willow aphid, Tuberolachnus salignus:the influence of aphid Journal of Animal Ecology, 47, 605-613. http://www.jstor.org/discover/10.2307/3804?uid=3738032&uid=2&uid=4&sid=21101920521473

Mittler, T. E. (1957). Studies on the feeding and nutrition of Tuberolachnus salignus (Gmehn) (Homoptera, Aphididae). I. The uptake of phloem sap. Journal of  Experimental Biology, 34, 334-341  http://jeb.biologists.org/content/34/3/334.full.pdf

Other resources

http://influentialpoints.com/Gallery/Tuberolachnus_salignus.htm

http://www.nhm.ac.uk/nature-online/life/insects-spiders/common-bugs/aphid-watch/

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