Dung beetles play a hugely important role in dung decomposition and nutrient cycling on pasture land. Their presence indicates good soil biology and that you have beetle-friendly soil management! In monitoring dung beetle populations, you can begin to learn how populations might vary across your farm, or see how populations progress over time.
Below we’ve suggested a couple of methods for monitoring dung beetles, so you can have a read through and decide which one works best for you!
How to identify dung beetles:
Dung beetles have ‘clubbed’ antennae, with a thickened, club like ending. They have strong paddle shaped legs, and tend to ‘play dead’ when handled, and crucially, they live in dung! If you’re not sure that what you’ve found is a dung beetle, you can have a look at this identification page on the DUMP website.
What to record
- Number of dung beetles
- Notes: Note which species of dung beetle if you know it
- Photos
Equipment
For Visual Search Method:
- Trowel
- White bag / tray
For Floatation Method:
- Bucket (& water)
- Sieve
- Collection tray
How to do the test
Method 1: Visual Search
1. Go to one of your GPS mapped soil sampling sites in a pasture field (or create a new sample site in the Soilmentor app while you’re out in the field).
2. Look around, and find a pile of dung close to your sample site, and break it apart in the tray (wearing gloves), looking for beetles. Remember to count them as you go – this is what you’ll record in your Soilmentor app. It might be helpful to put the beetles to one side in the tray.
3. Look for tunnels at the interface between soil and dung – these can be large enough to poke your thumb in to (likely a Geotrupidae tunnel) or as small as a pencil width (Onthophagus similis, Colobopterus erraticus).
4. The insects that don’t move while you’re breaking up the dung will likely be dung beetles – they are slow moving and tend to play dead!
5. You can gently dig burrowing beetles out with a trowel – it’s advisable to note the direction of the tunnel and carefully dig it out from one side to prevent collapse.
6. The more times you use this method, the better you will get at spotting beetles! Some smaller and darker species are easy to miss.
7. When you’ve finished counting, record the number you find within ‘Dung beetle count’ in the Soilmentor app.
Method 2: Floatation Method
1. Find a dung sample near your sample site (as explained above), pick it up and place it in the bucket.
2. Pour water into the sides of the bucket (avoiding pouring onto the dung as this can break the dung up and discolour the water making it harder to spot beetles).
3. You may need to weigh the dung down with something so that only the beetles float.
4. The beetles can then be scooped out with a sieve (tea strainers also work well), and placed into the tray for observation and to make it easier to count them.
5. Note that in this method you will only be finding endocoprid species – those that live within the dung itself, and not burrowing species, so it may be worth also looking for burrows underneath the dung using the methodology explained in the visual search.
6. When you’re finished sampling, enter the number of beetles you have counted into the Soilmentor app.
If you’re enjoying the search for dung beetles, there are some more advanced methods for finding them on the DUMP website here.
Resources
If you’d like to identify your beetles further, you can submit your beetle sightings to iRecord, to help scientists to map dung beetle distributions!
Download a PDF copy of Peter Skidmore’s book Insects of the British Cow-dung Community from the Field Studies Council website.
Image credits: DUMP Dung Beetle Mapping Project