Posts Tagged ‘Beetle’

Beetles reduce methane production from cowpats

August 22, 2013

Leaving aside all the extraneous nonsense about global warming and cattle flatulence – which was not actually studied at all – this paper by an intrepid Finnish researcher does address the effect of dung beetles on methane production in dung. Perhaps someday it will not be necessary to wrap-up otherwise good research in a “global warming” cloak just to ensure publication or funding or both

 Penttilä A, Slade EM, Simojoki A, Riutta T, Minkkinen K, and Roslin T. (2013) Quantifying Beetle-Mediated Effects on Gas Fluxes from Dung Pats. PLoS ONE 8(8): e71454. doi:10.1371/journal.pone.0071454

Abstract: Agriculture is one of the largest contributors of the anthropogenic greenhouse gases (GHGs) responsible for global warming. Measurements of gas fluxes from dung pats suggest that dung is a source of GHGs, but whether these emissions are modified by arthropods has not been studied. A closed chamber system was used to measure the fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from dung pats with and without dung beetles on a grass sward. The presence of dung beetles significantly affected the fluxes of GHGs from dung pats. Most importantly, fresh dung pats emitted higher amounts of CO2 and lower amounts of CH4 per day in the presence than absence of beetles. Emissions of N2O showed a distinct peak three weeks after the start of the experiment – a pattern detected only in the presence of beetles. When summed over the main grazing season (June–July), total emissions of CH4proved significantly lower, and total emissions of N2O significantly higher in the presence than absence of beetles. While clearly conditional on the experimental conditions, the patterns observed here reveal a potential impact of dung beetles on gas fluxes realized at a small spatial scale, and thereby suggest that arthropods may have an overall effect on gas fluxes from agriculture. Dissecting the exact mechanisms behind these effects, mapping out the range of conditions under which they occur, and quantifying effect sizes under variable environmental conditions emerge as key priorities for further research.

Dung beetles like Aphodius pedellus may aerate cow pats- Drawing of beetle by Kari Heliövaara

From EurekAlert:

Atte Penttilä, who undertook the study for his Masters, explains: “Cow pats offer a prime food for a large number of organisms. In fact, there are probably as many beetle species living in dung as there are bird species on this planet.”

Of the dung beetles living in Northern Europe, most spend their entire lives within the dung pats. “We believe that these beetles exert much of their impact by simply digging around in the dung. Methane is primarily born under anaerobic conditions, and the tunneling by beetles seems to aerate the pats. This will have a major impact on how carbon escapes from cow pats into the atmosphere.”

“You see, the important thing here is not just how much carbon is released” explains Tomas Roslin, head of the research team. “The question is rather in what form it is released. If carbon is first taken up by plants as carbon dioxide, then emitted in the same format by the cows eating the plants, then the effect of plants passing through cattle will be small in terms of global warming. But if in the process the same carbon is converted from carbon dioxide to methane – a gas with a much higher impact on climate – it is then that we need to worry.”

“If the beetles can keep those methane emissions down, well then we should obviously thank them – and make sure to include them in our calculations of overall climatic effects of dairy and beef farming.”

 


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