Tag Archives: Malaise trap

Entomological classics – the Window (pane) Flight Intercept Trap

A couple of years ago I received a paper to review in which the authors detailed how they had invented a new trap for sampling and collecting beetles in tropical forests. I was astounded to see that they were describing a window pane trap, something that I had known about since I was a student and which has been used by entomologists worldwide for many years.  I quite politely pointed this out in my review and directed the authors to Southwood ‘s Ecological Methods (1966).  The other referee was less tolerant, her/his report simply read “see Southwood page 193”.  At the time I wrote the review it was firmly stuck in my mind that the technique was as old as the hills, or at least as old the invention of cucumber frames 🙂  I certainly thought of it as a Victorian or Edwardian invention.  To my surprise when I started delving into the literature all the Victorian references to window traps turned out to be ways to protect households from invasion from houseflies and other unwanted flying insects; nothing to do with entomological sampling or collecting. E.g. this patent from 1856 where the inventor describes its operation as follows “The flies enter the trap through the passage B, as illustrated, and after satisfying their wants from the baitboard seek to escape, and being attracted by strong light from the glass back they fly in that direction and being headed out crawl up the glass back until they nearly reach the upper edge of the same, when, being still attracted and deluded by light from the glass top, they attempt to fly upward or through the same and in doing so instead of rising, are, owing to the inclination of the glass top, precipitated into the trough of soap suds and drowned, as illustrated in the drawing.

This fly trap is exceedingly simple, quite cheap, and only costs about twenty-five cents, and has been tried and found to answer well the purpose intended.”

1

Unfortunately not what I was looking for 🙂

Despite scouring Google and Google Scholar, to the lengths of even getting to page 30, which apparently no-one does, it seems that the earliest reference to what we think of as a Window (pane) trap was not invented until 1954 (Chapman & Kinghorn, 1955)  to sample Ambrosia beetles (Trypodendron spp.) and other scolytids in Canadian forests.  There is unfortunately no picture to illustrate the trap, but the written description is fairly clear “ a piece of window glass (2 X 2 ft) set in a three-sided wooden frame from which a sheet metal trough is hung. The trough is filled with fuel oil or water….Traps are hung from various types of pole framework  depending on their location, and guy wires are used to keep them from swinging.”  I am pretty certain that this 1954 date is the earliest record as even that vade mecum of the entomologist, Instructions for Collectors No. 4a (Smart, 1949) has no mention of it.

The theory behind the window (pane) trap is that flying insects are unable to see the clear glass (or Perspex), bang into it, and stunned, fall into the collecting trough where they drown to be collected and identified later. A fantastically simple idea, which is why I was surprised that it took entomologists so long to invent it. As far as I can tell from the written description given by Chapman & Kinghorn (1955), the trap was suspended from a ground based framework.  I think that this version I found in Chapman (1962) is probably the original design or at least very close to it.

2

Chapman & Kinghorn’s original window flight trap? Chapman (1962).

They also used this is a much more ambitious way as shown below.

3

Multiple Chapman & Kinghorn Window traps in operation (Chapman & Kinghorn, 1958).

This design in a slightly modified version  is shown in Lundberg (1979) and designs very

4

Ground based window trap in use in a Swedish forest (Lundberg, 1979).

similar to these are still in use.

5

A modern ground-based window(pane) flight intercept trap. http://www.qm.qld.gov.au/Find+out+about/Animals+of+Queensland/Insects/Collecting+insects/~/media/51C96B0159AF463C9E11CC1B100244DE.jpg?w=400&h=260&as=1

 

Despite its efficiency the ‘classic’ windowpane trap has perhaps not been used as much as it deserves, instead, a plethora of alternative designs have been described since the mid-1970s. So for example we have a small-scale tree hanging version, with a four-way window being used to catch forest coleoptera (Hines & Heikkenen, 1977).  Although the small area flight intercept traps were

6 6a

The Hines & Heikkenen (1977) small area window flight intercept trap.

relatively easy to deploy, they obviously just weren’t big enough for some people. In 1980, Peck & Davies, described a large-area window trap used to catch small beetles. This used the central panel of a Malaise trap as the window under which they placed a large metal collecting trough.  Unlike the Hines & Heikkenen trap, this like the original Chapman & Kinghorn trap, was ground-based.  The

7

The Peck & Davies(1980) large-area “window” trap.

authors, in an attempt to impose order on to the entomological collecting world, urge other coleopterists to adopt a similar trap design.  In 1981 we see a modification to the Hines & Heikkenen

8

The Omnidirectional flight trap (Wilkening et al., 1981).

trap to improve its efficiency (Wilkening et al., 1981).  Despite the name omnidirectional, implying that it catches insects from all directions,  this trap catches large fast-flying insects in the lower chamber, into which they fall stunned on bumping into the window pane and slow upwards flying insects in the upper chamber.  The authors argue that the original version of the trap did not catch slow-flying insects as they were able to detect the pane early enough to avoid being stunned and then took evasive action by flying up and away from the collecting bottle.  The new improved version takes advantage of this behaviour and traps them in the upper bottle into which they inadvertently fly.

In 1988, my fellow editor, Yves Basset, then at Griffiths University in Australia, now at the Smithsonian Tropical Research Institute in Panama, decided to combine a Malaise trap with a Hines & Heikkenen trap to produce what he called a composite interception trap (Basset, 1988),

9

The Basset composite interception trap (Basset, 1988).

10

The Basset composite trap in action. http://web.uvic.ca/~canopy/sampling.html

 

Despite this ingenious trap, trapping forest canopy insects obviously continued to occupy the minds of forest entomologists and in 1997 another pair of entomologists working in Australia came up with yet another design for a flight intercept trap, this time one that could be suspended at different heights in the canopy and left for long periods of time (Hill & Cermak, 1997). The novelty of this trap

11

The Hill & Cermak modified Window trap

 

as far as I can make out is the use of multiple collecting chambers (ice cream tubs) and a plastic instead of a Perspex, ‘window’.

Entomologists are forever tinkering and ‘improving’ with sampling methods, so it should not be a surprise to find a group of entomologsist from the USA describing the ultimate in a composite trap,  this time a combination of four different traps, the cone, the Malaise, the yellow pan trap and the flight intercept trap (Russo et al., 2011). Interestingly, the authors describe this as a passive trap,

x

The ultimate composite insect trap (Russo et al., 2011).

but as it incorporates a yellow pan trap, which actively attracts insects, this is not strictly true.

Returning to the more conventional flight intercept trap design, Lamarre et al (2012) compared their very slightly modified window pane trap with Malaise traps in tropical forests in French Guiana and

13

According to the paper, the first attempt to develop a standardised Window pane trap. https://commons.wikimedia.org/wiki/File%3AA_modified_windowpane_trap.jpeg

concluded that their model was more efficient and “should be used as an alternative and standardised method for future empirical studies”  a bold statement indeed, as they did not compare their trap with any of the other traditionally used window pane traps described above.

And finally and right up to date, and in the best entomological tradition of using cheap easily obtainable materials, yet another variant on the flight intercept trap; this time using plastic bottles – pop, soda, water, cider, beer, take your pick J (Steininger et al., 2015).

14

The simple, effective and accessible bottle window intercept trap. http://jee.oxfordjournals.org/content/108/3/1115

I am sure, however, that as I write, some ingenious entomologist out in the field somewhere, is thinking of yet another modification to the window (pane) flight intercept trap to make my post out of date!

 

References

Basset, Y. (1988) A composite interception trap for sampling arthropods in tree canopies.  Journal of the Australian Entomological Society, 27, 213-219

Chapman, J.A. (1962) Field studies on attack flight and log selection by the ambrosia beetle Trypodendron lineatum (Oliv.) (Coleoptera: Scolytidae). Canadian Entomologist, 94, 74-92

Chapman, J.A. & Kinghorn, J.M. (1955) Window flight traps for insects.  Canadian Entomologist, 87, 46-47.

Chapman, J.A. & Kinghorn, J.M. (1958) Studies of flight and attack activity of the ambrosia beetle, Trypodendron lineatum (Oliv.) and other Scolytids. Canadian Entomologist, 90, 362-372

Hill, C.J. & Cermak, M. (1997) A new design and some preliminary results for a flight intercept trap to sample forest canopy arthropods.  Australian Journal of Entomology, 36, 51-55

Hines, J.W. & Heikkenen, H.J. (1977) Beetles attracted to severed Virgina pine (Pinus virginiana Mill.). Environmental Entomology, 6, 123-127

Lamarre, G.P.A., Molto, Q., Fine, P.V.A. & Baraloto, C. (2012) A comparison of two common flight interception traps to survey tropical arthropods.  ZooKeys, 216, 43-55

Lundberg, S. (1979) Fångst av skallbaggar med hjälp av fönsterfällor. Entomologisk Tidskrift (Stockolm), 100, 29-32

Peck, S.B. & Davies, A.E. (1980) Collecting small beetles with large-area “window” traps.  Coleopterists Bulletin, 34, 237-239

Russo, L., Stehouwer, R., Heberling, J.M. & Shea, K. (2011) The composite insectrrap: an innovative combination trap for biologically diverse sampling.  PLoS ONE, 6, e21079.doi:10.1371/journal.pone.0021079

Wilkening, A.J., Foltz, J.L., Atkinson, T.H. & Connor, M.D. (1981) An omnidirectional flight trap for ascending and descending insects.  Canadian Entomologist, 113, 453-455

 

Postscript

Apropos of the ultimate composite trap, I came across this combination four-way window-yellow pan trap combination some years ago, but have not been able to find a published inventor of it.  I should also add that flight intercept traps are also sometimes known as impact traps.

15

*Vade mecum, a handbook or guide that is kept constantly at hand for consultation.

 

Advertisements

3 Comments

Filed under Entomological classics, EntoNotes

Entomological classics – The Malaise Trap

More years ago than I care to remember, my friends and I were playing the now, very non-PC game of Cowboys and Indians, when we saw through the trees, what we thought was a tent. On sneaking up to it we found that, if it was a tent, it wasn’t very watertight!  There were no sides, instead there was a central panel and the whole thing was made of netting.  What we had actually found, was of course a Malaise trap, although of course we did not know this at the time.  It was only later as an undergraduate that I realised what we had found all those years before.

So exactly what is a Malaise trap and how did it come into being? The Malaise Trap is a relatively new invention.  It was invented by the Swedish entomologist, Dr René Malaise in the 1930s (hence the name) and revealed to a more general entomological audience in 1937 (Malaise, 1937).  It was actually designed as a replacement for the traditional hand-held collecting net, which as Malaise states in the introduction to his paper ‘”Since the time of Linneaus, the technique of catching insects has not improved very much, and we are to-day using the same kind of net as then for our main instrument”.

I was amused, when reading on further, to find that my childhood gaffe of confusing a Malaise Trap with a net was fully justified. Malaise, later in the same paper writes, ”During my extensive travels I have repeatedly found that insects happened to enter my tent, and that they always accumulated at the ceiling-corners in vain efforts to escape at that place without paying any attention to the open tent door”. He then goes on to describe how he conjectured that “a trap made as invisible as possible and put up at a place where insect are wont to patrol back and forth, might catch them much better than any tent, and perhaps better than a man with a net, as a trap could catch them all the time, by night as by day, and never be forced to quit catching when it was best because dinner-time was at hand”.

He thus set about constructing a trap based on the idea of an open tent with a collecting device attached to the central end pole to take advantage of the fact that most insects when encountering an obstacle tend to fly upwards. On reaching the apex of the tent, the only way out is into the collecting device which is filled with a killing agent.  It is in effect, a flight intercept trap, but unlike window traps (subject of a later post), the insects instead of falling into a collecting device, head upwards and collect themselves. Malaise tested his first version of the trap on an expedition to Burma and found them to be a great success “every day’s catch from the traps grew larger and larger, and sorting it required more and more time”. He found the traps particularly good for Diptera and Hymenoptera but also very good for Coleoptera and Noctuid and Sphingid moths.  He also mentions catching Hemiptera.

In outward form, the Malaise Trap has remained fairly unchanged since its invention. The first versions were apparently fairly heavy, having a brass insect collecting cylinder and also only had one opening.  Malaise recognised the disadvantages of the single entrance version and suggested in the 1937 paper that a bilateral model would be more effective.  These followed in due course. Modified versions using plastic cylinders and different netting material were  invented in the 1960s (Gressit & Gressit, 1962; Townes, 1962; Butler, 1965).  Townes’s paper gives a very detailed description of the construction and use of modified Malaise traps (90 pages) in contrast to Butler’s three page description of a cheap and cheerful version made from a modified bed-net.

Nowadays, entomologists world-wide, particularly Dipterists and Hymenopterists, use Malaise traps of various designs and colours, and cost.  In the UK they are available from commercial outlets at prices ranging from £60 to £165. They are extremely effective and we use them to collect insects for our practical classes in the Entomology MSc based at Harper Adams University.

    Malaise traps

Malaise trap in operation, Harper Adams University, Shropshire, UK.

 

References

Butler, G.D. 91965) A modified Malaise insect trap. The Pan-Pacific Entomologist, 41, 51-53

Gressitt, J.L. & Gressitt, M.K. (1962) An improved Malaise Trap. Pacific Insects, 4, 87-90

Malaise, R. (1937) A new insect-trap.  Entomologisk Tidskrift, Stockholm, 58, 148-160

Townes, H. (1962) Design for a Malaise trap. Proceedings of the Entomological Society of  Washington, 64, 162-253

 

Post script

Malaise was not just an entomologist; he was an explorer and a passionate believer in the existence of Atlantis. A detailed biography of this extraordinary character can be found here, including a photograph of the original Malaise trap.

 

Post post script

I was amused to find in the 1949 edition of Instructions for Collectors No. 4a, Insects (Smart, 1949), this somewhat dismissive comment about the Malaise Trap “It is a very novel idea and captures large numbers of insects, but as at present designed is rather cumbersome, and since its design will probably be modified with experience it is not described here

2 Comments

Filed under Entomological classics, EntoNotes, Uncategorized