Click for information on how toIDENTIFY A DUNG BEETLEor SUBMIT A DUNG BEETLE RECORD.
Finding Dung beetles
There are a few different sampling techniques that you can useto find dung beetles and these are outlined below. Team DUMP uses the visual search, sieving and pitfalltraps most often.
Visual Search
This is pretty straight forward. It simply involves finding a pile of dung andbreaking it apart to look inside and find the beetles. Also look for tunnelsat the soil interfaceunder the dung. These can belarge enough to poke in your thumb (Geotrupidae tunnel) or as small as the width of a pencil (Onthophagus similis, Colobopterus erraticus). The beetle can be very carefully dug out with a small trowel. Often the best approach is to feel the direction of the tunnel by poking in a finger, then place a ‘marker’ such as a pea stick in the tunnel and dig from one side as tunnels can easily collapse.
This method can beapplied to all dung types and the more you do it, the better you will become at spotting the beetles. Some of the small dark coloured ones, such as Esymus pusillus are easy to miss. The use of disposal gloves is recommended.
Sieving
Lumps of dung are placed in a sieve and vigorouslyshaken over a pale coloured tray. The dung beetles will drop through the holes of the sieve into the tray below. After a few moments the beetles will start to move around and be easier to spot. In hot weather though, beware that they canquickly fly away.It is useful to rest the sieve and contents on a second tray whilst looking for beetles in the firstas some may continue to fall from the dung.
This method works best on may also be used to sieve other organicmatter such as flood debrisfound around the edges ofponds and streamsto look for Liothorax niger and L. plagiatus or mixed straw and dung from animal shelters forOxyomous sylvestris.
We use a round garden sieve with 1cm holes and a white lab style tray butacat litter tray work equally as well.
Pitfall trap
A pitfall fall trap is a container dug into the ground so that the top is level with or just below the ground surface. When used to catch dung beetles, a mesh grid can be placed over the aperture and a lump of fresh dung rested on top. Alternatively, some dung can be wrapped in muslin and hung above the container. Dung beetles will beattracted by the smell, fly in, land nearby, walk towards the dung and dropinto the container below.
There is theoption of adding a killing fluid such as water with a drop of detergent to break the surface tension to have a lethal trap. Please bear in mind the decomposition time depending on which killing fluid is used and check the trap accordingly. With water and detergent, beetles will start to decompose in 4-7 days depending on temperature.Alternatively, maintain a live trap by adding a littleloose soil anda small amount of dung in the base of the container.In this instance the trap would need to be checked very regularly, possibly as much as twice daily as predatory beetles such as rove beetles may eat the smaller species. The latter is certainlyrecommended ifa rare species is active in the area.
A rain shield can be added to prevent the container filling with water. This is simply an upturned plastic or good quality paperplate with three or foursupports (disposable meat skewers are quite effective and cheap to buy) that is placed over the pitfall trap. Providing the shield is placed at areasonableheight above the trap (10-15cm), it should not reduce efficiency.
Winkler extraction
Dung beetles bury themselves to escape predation from birds and we can use this ‘dig down’mechanism to our advantage. A Winkler extractor is more often used to sample leaf litter invertebrates but works really well with sieved dung samples too. In the Winkler method, sieved samples are placed in small mesh sacks which are suspended inside a funnel shaped outer sack, usually of cotton/canvas material. A collecting bottle is situated at the base of the funnel. The whole contraption is hung from a tree branch orframeso that the base of the collecting bottle is held off the ground. Over time thedung sievingsdryout and this further encourages the beetles tobury through thesubstrate and drop into the bottle below. This can be a slow process and may take 2-3 days to collect all the beetles especially if the ambientairtemperature is cool but the majority will fall through within the first 12-18 hours. It is amazing how many beetles can be collected in this way and it is therefore essential to keep an eye on the collecting bottle and empty it if required.
Floatation
The dung to be sampled can be immersed in water and the beetles will, quite quickly, float to the surface. The dung may also float and require weighting –especially applicable to horse dung. This can be achieved by placing some wire mesh over the dung before adding the water (sort of the reverse action for sieving!). The water should poured against the side of the bucket to avoid fragmenting the dung and reduce water discolouration. Beetles can be scooped out with a tea strainer or fine gauge kitchen sieve.
With this method, you willgenerally be sampling the endocoprid species i.e. those thatlive directly in the dung and will usuallynot find any that burrow beneath the soil.
Flight intercept
Although some tropicaldung beetlesare flightless, most speciesarevery good at flying as this is how theylocateand quickly colonise suitable dung. A flight intercept trap can be used to catch beetles on the wing. This is a fine gaugenet sheet that isstretched taught between two posts or trees. Trays are placed on the ground below the netting to catch falling beetles after they have hit the netting. A solution is placed in the trays to prevent the beetles flying away again. It is very important to think about the placement of the net sheet to maximise efficiency.This method is moreoften used in tropical rather than temperate environments.
Light trap
Some British dung beetles such as Acrossus rufipes and chafers e.g. Melolontha melolontha fly at dusk and are attracted to light. These beetles are regularly reported by moth enthusiasts and moth traps can be used to the dung beetlers advantage. There are a variety of light traps on the market (Watkins and Doncaster), some are quite expensive but you can build your own too.
Images on this page with thanks to Darren J. Mann and Ceri Watkins
