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2 Posts tagged with the pitfall_trap tag
1

Dung, fog and more dung in Borneo

Posted by Blaps Mar 25, 2013

This blog is from one of our excellent specimen preparators and research assistants,  Lucia Chmurova who was lucky enough to spend some time on one of the Museum expeditions to Borneo. Here she gives us an insight into beetle collecting in the tropics!

 

'I was very lucky to join a big NHM expedition to Borneo in August 2012. I was extremely excited because I have missed Borneo ever since I returned from my first trip there in 2010. Upon Max Barclay's advice I agreed to sample dung beetles as my project (and unwittingly I agreed to everything that comes with it…). I followed a set protocol developed for dung beetle trapping in order for future comparison with already sampled sites by other scientists. The protocol consists of 10 dung, and 2 carrion-baited pitfall traps and 2 flight interception traps. The Malaysian dung beetle fauna is well known, well represented in the museum's collection, and there are specialists that are able to identify them. Fulfilling these three criteria suggests a promising and achievable project. With my project chosen and kit assembled I was ready to go!

 

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A quick teaser for invertebrate fauna of Borneo; a predatory land flatworm or a ‘hammerhead worm’.

© Tim Cockerill

 

Our expedition started in the Danum Valley, perhaps one of the busiest research stations in the world. Located in the middle of a conservation area in Sabah, Malaysian Borneo, the Danum Valley field station is very well equipped and has housed hundreds of scientists from around the world. The timing of our arrival was somewhat comical, coinciding with a visit from Prince William and The Duchess of Cambridge on a leg of their Southeast Asian tour. As the couple emerged, perfectly dressed, from their helicopter, our team covered in mud and sweat looked a bit less royal in comparison.

 

Some readers might not know that traps for catching dung beetles must first be baited by … well … dung. This involves preparing wrapped packages of dung and hanging them above the trap to lure beetles in. I thought to myself that I should be perhaps a bit more selective about where I would go and prepare my perfumed 'dung packages' so I don't put off potential future patrons of the station. As for the perfume, I was quite well-equipped and so the highly dreaded preparation of tens of dung packages wasn't so bad after all! I have to admit I opted out from Max's tip to use a plastic bag with a hole in its corner and squeeze dung out like I would do with icing for a cake! I used a fork instead.

 

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Me and THE package.

© Tim Cockerill

 

I am not going to go into much detail about what trapping techniques we used while in the field as these are already nicely described in the Tanzania blog , perhaps with the exceptions of water pan traps and fogging. Although not so much used by Coleopterists, water pan traps are very popular when trapping for wasps and bugs. These are simply plastic bowls of various colours (most commonly yellow or blue) filled with water and a few drops of detergent. Its smell in combination with yellow colour attracts insects that are eventually drawn inside the traps.

 

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Although the contents of this pan trap might not look like much, what looks like dust to our eyes, might in fact be hundreds of tiny Hymenoptera trapped inside.

© Tim Cockerill

 

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I could not resist showing you this sophisticated upgrade to a pitfall trap: chopsticks and a plate instead of a usual leaf to stop the trap filling with rainwater! (to find out what exactly a pitfall trap is, read …)

© Tim Cockerill

 

Fogging is perhaps the most efficient sampling method for insects - it collects vast amounts of all kinds of insects in a short period of time. A selective insecticide (which doesn't affect birds or mammals and evaporates quickly) is sprayed into a tree, under which collecting trays are placed to catch all falling insects.

 

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A fogger being hoisted up the tree.

© Neil Greenwood

 

 

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Collecting trays ready to collect falling insects.

© Tim Cockerill

 

This must be done in perfectly windless and rainless conditions, to avoid the insecticide being spread out into surrounding trees and insects sticking to the leaves once they are dead. As the name ‘RAIN’ forest hints, these conditions do not happen very often. All fogging kit assembled together is quite bulky so we were happy when a group of Oxford University students volunteered to help with carrying all the heavy kit for us. After a few attempts of waking up at 5 in the morning (as this is unfortunately the 'windlessest' hour of the day) and trekking to the field site only to discover that leaves are once again wet, we eventually managed to fog at least once!

 

At the start, the lucky chosen individual (in this case a professional fogger, Timothy), tries to start the fogger by moving the engine rod quickly in and out, looking comical and failing repeatedly. Eventually the fogger trembles vigorously and a sound similar to a lawn mower spreads through the forest. After this amusing start, thick fog starts spreading up the tree and the whole situation suddenly looks nothing but impressive. One has to wonder what insects live up 40m tall trees. It was amazing to realise that even my help and research could help to be a step closer to discovering diversity of one of the earth's least known faunas - that of tree canopies. 

 

Some of the joys of field work:

 

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Coleopterist Peter Hammond and lichenologist Pat Wolseley forgot their waterproofs, bin bags did well enough.

© Neil Greenwood

 

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#Hymenopterist Andy Polaszek after a sword fight (or leech fight?!).

© Neil Greenwood

 

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Some serious work after a successful fogging day. In case you don't recognise us, from left:

Neil Greenwood, Andrew Polaszek, Lucia Chmurova and Tim Cockerill.

© Neil Greenwood

 

 

 

Our last stop was Maliau Basin. The forest here looked a bit different to that in the Danum Valley; here there were many more old growth trees present with open spaces between them in comparison to vine and rattan-entwined trees in the first field station. It felt a bit less disturbed, and even the bearded pigs looked attractively slimmer here. My pitfall traps were getting so full after one day of collecting that beetles started literally spilling over and escaping from them. A picture below shows the contents of a single pit-fall trap!

 

 

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The contents of a single dung pitfall trap.

© Tim Cockerill

 

 

After a few days in the Maliau Basin, and collecting kilos of dung beetles, our trip came to an end. Although very sad when leaving Borneo, I was happy about my successful trapping. At the moment, my collected material is still in Malaysia but will hopefully be sent to London soon so I can have a look at the wonderful diversity of beetles that scientific trapping reveals'.

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A tenebrionid couple.

© Tim Cockerill


 

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Some moths (notably members of the Arctiidae family) pupate in a woven basket of the caterpillar’s body hairs rather than silk.

© Tim Cockerill

 

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Coccinellidae

© Lucia Chmurova


 

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A cockroach shedding its skin.

© Lucia Chmurova

0

Dear Beetlers,

 

Come to Science Uncovered this Friday 28th September to hear more about this:

 

We have returned safe and well from our recent fieldwork trip to Tanzania (we are into our second year of collecting!) and really want to share with you some of the techniques employed in the field. This trip was undertaken in the months of July and August - the dry season, where ordinarily there is not much beetle activity; however, one of the aims of this series of collecting trips is to map Tanzania's beetle and butterfly and moth fauna through all of the seasons. Eventually we will have a really useful data set from many (and remote) localities; and hopefully this will yield some very interesting new species...but until we get everything identified (we are still identifying material from 2010 - there's soooo much of it!) here is how we found our specimens in the first place...

 

Given we were heading to some really remote localities it was really important to inform local officials and indeed local people who we were and why this pair of crazy western 'researchers' had just appeared from nowhere. Here is our 4x4 vehicle with its very official notice!

 

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U Tafiti is 'research' in Swahili; 'wadudu' is insect! So we were entitled 'U Tafiti wawadudu'!

 

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Here is HT having quite a giggle with the Mama and farmer at Mount Hanang where we camped (Tanzania's fourth highest mountain at 3417m)

 

Once we had set up camp after a five hour drive from the city of Arusha; it was time to um, relax!

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The beautiful Mount Hanang in the background.


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HT and some cows; overseeing unpacking proceedings!

 

But, whilst some of us lounge about taking it easy, others are hard at work keeping the camp in order...

 

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BG working hard whilst HT 'relaxes'! This is our 'science table' where all the processing of specimens: labelling, cleaning, filling up tubes with IMS happens.

 

And so into the field. Here at Mount Hanang there is diverse habitats: mid altitude grassland, farmed countryside, ericaceous forest and sub-montane and montane forest all a happy hunting ground for the intrepid entomologist...

 

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HT, our local guide Isaiah and Jembe our Masai guide all erecting a butterfly trap on the forest edge at Hanang. This will be elevated high up in to the canopy and baited with some delicious rotting fruit.

 

Whilst HT was busy butterfly trapping I was off in another direction beating for beetles!

 

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BG, our camp expert Saleem and Jembe all looking for SBJs (small brown jobs, such as Phalacrids, Shining Flower Beetles) and weevils by  beating vegetation with a big stick onto a big umbrella-like white sheet!

 

Winkler Traps

 

Then it was into the forest edge to collect some leaf litter for sieving (again SBJs live in leaf litter, we are hoping to find things like fungus beetles (Lathridiidae) and Pselaphinae, and all manner of Cucujoidea)!

 

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And the prize for the most boring photo...


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Here's HT and Jembe sorting through leaf litter with a series of sieves

 

As most creatures that live in leaf litter are small and secretive there is another very effective method we use to collect them by, which is known as the Winkler trap! Once we have sieved the litter to remove all the big stuff the remaining topsoil and litter is placed inside mesh bags within the cotton bag and basically hung up to dry. Eventually the small organisms will start moving about and head to the bottom of the trap where they fall into a waiting pot of IMS.

 

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Me with my Winkler! A very cold early morning at Mount Hanang!

 

We took samples of leaf litter at all three sites we collected from. The final site at Hasama Forest in Mbulu district was again at high altitude (c.2000m); as far as we know the last person to collect in this area was Kielland in 1990 and he was looking for butterflies...

 

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Sieving litter for Winkler traps at Hasama forest, Mbulu. It was soo cold and windy that the only way to do it was to seek refuge by the truck!

 

Dung Traps

 

We can't have a blog without mentioning poo it would seem so, onto dung trapping! We were very lucky at Mount Hanang to have the employ of a team of able and willing young entomologists who worked very hard searching for dung beetles (so we didnt have to!) and were amply rewarded with 500 Tanzania shillings and a packet of sweeties! Our  'snacky time' was around 5pm and the children soon learned that the office would be open once the hard fieldworkers had taken off their boots and had time for a G&T before supper (very civilised!). Here's HT 'negotiating' prices with the children.

 

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'Snacky time' at Hasama Forest! Of course a freshly pressed newspaper was always made available!

 

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Driving a hard bargain! Our terms: one full tube (no padding with extra dung) and no repetition for 500 Shillings and a packet of jellies!

 

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Team dung beetle! (I'm the one on the left...).

 

As our dung beetle workers would never reveal their sources, (very good business!) we did employ other methods. The classic dung pitfal trap where little pre-made knapsacks of dung (this time buffalo!) are suspended above pitfal traps work really well. These were placed every one hundred meters into and along the forest at Hanang.

 

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HT and Isaiah preparing dung pitfal traps

 

On to Longido, about 50 km from the Tanzanian / Kenyan border to a very different habitat: the bush! Very very dry and surrounded by Masai, goats and Acacia trees...we had to work very hard to find beetles here!

 

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Longido bush setting traps: dung knapsack - tick! Soap-laced water for pitfall traps - tick! This entomologist is good to go!

 

Sometimes less sophisticated methods can also be employed given one has the time and the inclination to look hard enough...

 

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Yes, I am literally grubbing about in fresh buffalo dung; here I found some interesting Hydrophilid beetles especially adapted to living in poo!

 

Water Beetles

 

That takes us on nicely to collecting for water beetles. Whilst having a dreamy ride through the Eastern Rift mountains on our way to Mbulu, HT exclaims rather excitedly 'Stop the truck! Water!' I was less enthusiastic and stayed in the truck observing from a safe distance whilst HT sank up to his knees in a stagnant no doubt disease ridden puddle of water in the pursuit of water beetles and their ilk (Dytiscidae). And what better way to catch them than with a household sieve!

 

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NOT allowed back in the truck!

 

Once at Longido, our Masia guide (we are not permitted to enter any forest reserve without a local guide) promised there was water in the mountains. After an arduous trek to approx 2500m, and at times loosing what path there was, not to mention the searing heat, we eventually came to a mountain stream...

 

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Here we found not only some curious looking Dytiscids (predacious diving beetles) but also some whirligig beetles (Gyrinidae), leeches (yuk!) and a fresh water crab!

 

Water beetles are really hard to catch, being predacious they are really fast swimmers and also the bigger ones can give you a nasty nip if you're not careful; we found some big ones...

 

SLAM and Malaise trapping

 

Trapping using nets is the most common method but can often times be difficult in challenging terrain, not to mention remote environments where local people are overtly curious about what on earth you are up to! In Longido, where Masai children would appear as if by magic (We hold them entirely responsible for our missing pitfal traps!) we decided that the SLAM trap was too enticing for curious minds so we erected it as high up in the canopy as we could! This type of trap is very versatile as it can be erected anywhere but is especially good for wood piles where emerging beetles will fly into the net and become trapped.

 

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Hoisting the trap with BG and Saleem

 

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The entomologists demonstrate their good work!

 

Malaise traps are more precise in where they should be placed. Ideally they should be in the way of an insect flight path so that insects fly into the net, instinctually fly upwards and just like the SLAM trap, become, um, trapped!

 

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The very important job of holding a piece of string; erecting the Malaise trap, Mount Hanag

 

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But oh no! It's all gone wrong  - in an ironic twist of fate it is the entomologists that have become trapped...

 

Finally to end on a 'lighter note' we must mention light trapping! Light trapping might be commonly employed for trapping butterflies and moths but it is actually very effective for catching beetles too. So, each night at dusk we would start up the generator and the mercury vapour light would work its magic! One night at the Longido camp an unexpected downpour somehow broke the light and so we lost a nights trapping; at Hasama forest the winds were so high that the light was smashed; another nights trapping lost. But, on a good night, it's possible to stay up for as long as you can, say until 3pm gradually picking off the insects that come to the light. At longido I found a prize Carabid, an Anthia, or more commonly known as a Domino beetle, that was more attracted to the sausage flies than the light!

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The downpour at Longido; luckily we had enough tarpaulins but failed to secure the storm flaps on one of the tens = wet sleeping bag!

 

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The entomologist (still apparently in her pyjama bottoms), demonstrates the light trap!

 

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And we leave you for now with a beautiful view!

 

Next time the hardships and hiccups of fieldwork; and after that, fashion, fieldwork and friviolity...watch this space!

 

So the intrepid entomologists say farewell; and hope that you will join us and our wonderful colleagues on Friday night at Science Uncovered to hear more about collecting in the field, all over the world! http://www.nhm.ac.uk/visit-us/whats-on/after-hours/science-uncovered/index.html