The Rollercoaster Ride of a Dung Beetle

beetle

E. flagellatus, a dung beetle

by Hinal Kharva – I must admit that after joining the NICE lab I am learning a lot about the amazing world of Insects.  Today I will tell you something interesting about one of my favourite insects, the dung beetle.  Why it is my favourite?  First, they are not a pest, and second, they play really important roles in ecosystems by maintaining the nutrient cycle. As the name suggests, dung beetles feed partly or exclusively on the dung of herbivores and faeces of other omnivorous animals.  Some of them also feed on fruits, mushrooms and decaying leaves.  Dung beetles are also known as “rollers”, as they roll and bury dung balls either for food or for making a brooding ball.  When they are making a brooding ball, males and females both take part in the rolling process. (Check out the appended video below that I recorded while trekking at Rayakottai hill.)  When an appropriate place of soft soil is found, they bury the ball, mate underground, and the female then lays eggs inside the dung ball.  Dung beetles can roll up to 10 times their weight.  In an extreme example, male Onthophagus taurus beetles can pull 1000 times of their own body weight. [1]

Here is another fascinating fact.  A species of dung beetle (the African Scarabaeus zambesianus) navigates by polarization patterns in the moonlight, the first animal known to do so[2] [3] . Dung beetles can also navigate when only the Milky way or clusters of bright stars are visible[4], making them the only insects known to orient themselves by the galaxy[2] !

How often do you see a dung beetle in your surroundings?  They are found almost every place except Antarctica. They are present from tropical forests to savannas and even deserts.  How do they find their food? They use a sense of smell to search for dung.  Now here is an example of how a plant exploits the dung beetle’s sense of smell and habit of burying dung balls.  The seeds of the plant Ceratocaryum argenteum (Restionaceae), found in South Africa, release many volatile compounds similar to the dung of herbivores.  These stinky seeds attract dung beetles that roll and bury them.  In return, beetle does not get any reward.  This phenomenon is also an example of deception (bluffing) for plant seed dispersal[5].

seed

A seed of Ceratocaryum

Dung beetles are widely used in ecological research as a good bioindicator. They play an important role in agriculture.  By burying and consuming dung, they improve nutrient recycling and soil structure [6] [7]. Therefore, many countries like New Zealand, North and South America, Mexico, Argentina have introduced these creatures for the benefit of animal husbandry.

One of the best examples is the Australian Dung Beetle Project (1965–1985), which was led by George Bornemisszaan, an entomologist and ecologist.  He found that Australian farmland was covered in a large number of cattle dung pads. Cattle were recently introduced to Australia by Europeans in the 1880s, which produce large, soft, moist dung pads.  Native beetles were not adapted to utilize this type of dung as a food source or breeding ground. Thus, without such fauna, the dung pads took months to decompose, and became the primary breeding ground for several pestilent species of flies and parasitic worms.  George suggested to introduce species of dung beetles which are found in the same area where cattle were being reared in South Africa and Europe.  The introduction of 23 species of beetles turned out to be successful, which improved the quality and fertility of Australian cattle pastures, as well as reduced the number of flies[8].

So next time when you spot a dung beetle, give it a moment and think of how important these creatures are in the web of nutrition and at the same time keeping our surroundings dung free!

References

  1. Khaleeli, Homa ( 2010). “Just how strong is a dung beetle?” The Guardian. London.
  2. Wits University (2013)”. Dung Beetles Follow the Milky way: Insects found to use stars for orientation”. Science Daily.
  3. Dell’Amore, Christine. (2013).”Dung Beetles Navigate Via the Milky way, First know in the Animal Kingdom”. News Watch. National Geographic Society.
  4. Dacke, M, Nilsson, D. E, Scholtz, C. H, Byrne, M, Warrant, E. J. (2003). “Animal behaviour: Insect orientation to polarized moonlight”. Nature. 424(6944): 33. doi:1038/424033a.
  5. Jeremy J. Midgley, Joseph D. M, Gary N. Bronner (2015). “Faecal mimicry by seeds ensures dispersal by dung beetles”. Nature plants brief communication. DOI: 10.1038/NPLANTS.2015.141
  6. Brown J, Scholtz, C. H, Janeau, J. L, Grellier, S, Podwojewski, P. (2010). “Dung beetles (Coleoptera: Scarabaeidae) can improve soil hydrological properties”. Applied Soil Ecology. 46: 9. doi:1016/j.apsoil.2010.05.010.
  7. Nichols, E, Spector, S, Louzada, J, Larsen, T, Amezquita, S, Favila, M.E.(2008). “Ecological funtions and ecosystem services provided by Scarabainew dung beetles”. Biological Conservation. 141(6): 1461–1474. doi:1016/j.biocon.2008.04.011.
  8. Collis B (2002).Fields of Discovery: Australia’s CSIRO. Australia:Allen & Unwin.p.46.ISBN 1-865-08602-9

  One thought on “The Rollercoaster Ride of a Dung Beetle

  1. Bhavik Patel
    December 11, 2017 at 9:48 am

    I didn’t know about it Hinal…quite informative..next time I’ll look at those tiny insects with your provided perspective. Good Job.

    Like

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