FSD 2010 - Dung beetles

5th International Symposium-Workshop on Frugivores and Seed Dispersal (1985-2010)

Tunnell 'n' Roll Dung Beetles

Who are they ?

When frugivores of the tropical forest defecate from their sleeping site or during foraging, a large amount of fragrant dung is scattered on the ground, attracting a rich assemblage of coprophagous scarabs. It is a free-for-all where insects fight to secure a piece of dung as a personal meal or food for their larvae. An observer can easily distinguish two strategies to avoid the scramble competition. These behavioral strategies are performed by different functional groups of dung beetles.

The rollers form a ball and roll it backward out of the fray. At several meters away, they bury the ball at shallow depth. The burrowers, also called tunnellers, mostly larger than rollers and often stockier, dig a burrow right under the dung mass where they gather a large amount of dung, burying it sometimes deep into the forest topsoil. Burrowers often move a dung mass by pushing it with their heads to remove it out of the middle of the mêlée.

Tunneler

Roller

Oxysternon conspicillatum

Canthon fulgidus

Seed Dispersal by Dung Beetle

The consequence of the intense dung beetles' work is that the seeds contained in the dung are eventually dispersed both horizontally and vertically. Some of the seeds are thus protected from seed-eaters like rodents but others may be buried too deeply for successful germination. Rollers tend to move only small seeds and to bury them near the soil surface whereas some of the large burrowers bury larger seeds at greater depths.

Dung beetles are indeed the serendipitous gardeners of the tropical forests, not only by protecting and planting seeds but also by favouring seedling establishment. They loosen the topsoil, fertilise it, enhancing root growth and stimulating soil biological activity, notably the earthworms, potential dispersers of small seeds. Dung beetles are thus at the centre of a processing chain based on the organically very rich primate (and other mammal) dung and likely play a key role in shaping the soil seed bank.

Experts of Seed Dispersal by Dung Beetles

(Photo : Laurence Culot & Ellen Andresen at ATBC-GTOE2009, Marburg. © Pierre-Michel Forget)

Recent references

Andresen E. 2008. Dung beetle assemblages in primary forest and disturbed habitats in a tropical dry forest landscape in Western Mexico. J. Insect Conservation 12: 639-650.

Andresen, E, & Laurance SGW. 2007. Possible indirect effects of mammal hunting on dung beetle assemblages in Panama. Biotropica 39: 141-146. Abstract

Culot, L., Huynen, M.C., Gerard, P., et al. 2009. Short-term post-dispersal fate of seeds defecated by two small primate species (Saguinus mystax and Saguinus fuscicollis) in the Amazonian forest of Peru. J. Tropical Ecology 25: 229-238. Abstract

(Oxysternon conspicillatum © Diego Zárate)

Feer, F. 2008. Responses of dung beetle assemblages to characteristics of rain forest edges. Ecotropica 14: 49-62.

Larsen, T. H., A. Lopera, & A. Forsyth. 2008. Understanding trait-dependent community disassembly: dung beetles, density functions and forest fragmentation. Conservation Biology 22: 1288-1298. Abstract

Navarrete, D., Halffter, G. 2008. Dung beetle (Coleoptera : Scarabaeidae : Scarabaeinae) diversity in continuous forest, forest fragments and cattle pastures in a landscape of Chiapas, Mexico: the effects of anthropogenic changes. Biodiversity and Conservation 17: 2869-2898.

Nichols, E., Gardner, T.A., Peres, C.A., et al. 2009. Co-declining mammals and dung beetles: an impending ecological cascade. Oikos 118: 481-487. Abstract

(Canthon fulgidus © Carolina Santos)

Nichols, E., S. Spector, J. Louzada, T. H. Larsen, S. Amezquita, M. E. Favila. 2008. Review: Ecological functions and ecosystem services provided by Scarabaeinae dung beetles. Biological Conservation, 141(6):1461-1474. Abstract

Nyeko, P. 2009. Dung Beetle Assemblages and Seasonality in Primary Forest and Forest Fragments on Agricultural Landscapes in Budongo, Uganda. Biotropica 41: 476-484. www3.interscience.wiley.com/journal/122247061/abstract

Perez-Ramos IM, Maranon T, Lobo JM, et al. 2007. Acorn removal and dispersal by the dung beetle Thorectes lusitanicus: ecological implications. Ecological Entomology 32: 349-356. Abstract

Pouvelle, S., Feer, F., Ponge, J-F. 2008. Topsoil as Affected by Dung Deposition Under Resting Places of Red Howler Monkey (Alouatta seniculus). Pedosphere 18: 691-698. Abstract

Pouvelle, S., Jouard, S., Feer, F., Tully, T., Ponge, J-F. 2009. The latrine effect : impact of howler monkeys on the distribution of small seeds in a tropical rain-forest soil. J. Tropical Ecology 25: 239-248. Abstract

Jörn Theuerkauf, Sophie Rouys, Arno L. van Berge Henegouwen, Frank-Thorsten Krell, Sławomir Mazur, and Michael Mühlenberg. 2009. Colonization of forest Elephant dung by invertebrates in the Bossematié fForest Reserve, Ivory Coast. Zoological Studies 48(3): 343-350. pdf

Vulinec K, Lambert JE, Mellow DJ. 2006. Primate and dung beetle communities in secondary growth rain forests: Implications for conservation of seed dispersal systems. Int. J. Primatology 27 : 855-879. Abstract

Vulinec, K., Lima, A.P., Carvalho-Jr, E.A.R. & Mellow, D.J. 2007. Dung Beetles and Long-term Habitat Fragmentation in Alter do Chão, Amazônia, Brazil. Tropical Conservation Science 1: 111-121. On line version.

Vulinec, K. and Lambert, J. E. 2009. Neutral and Niche Perspectives and the Role of Primates as Seed Dispersers: A Case Study from Rio Paratari, Brazil. Pp. 321-340 In South American Primates. Comparative Perspectives in the Study of Behavior, Ecology, and Conservation. Series: Developments in Primatology: Progress and Prospects. Edited by Garber, P.A., Estrada, A., Bicca-Marques, J.C., Heymann, E.W., and Strier, K.B. Springer.

Books

Hanski, I. and Cambefort, Y. (Eds) 1991. Dung Beetle Ecology. Princeton: Princeton University Press.

Web

Wikipedia: Dung beetles

Scarabaeinae Research Network

Scarabnet

Scarab Workers

Acknowledgements

Thanks to François Feer for the text and Kevina Vulinek for editing it. Thanks to Kevina Vulinek and Ellen Andresen for sharing nice photos of these beautiful, colorful creatures that contrast with their natural background !