Sunday, April 22, 2012

Dung beetles

A pinned, adult specimen of Phanaeus vindex, the 'rainbow scarab'.
It is one of the more colorful beetles that bury dung to protect and
feed their offspring.
My lab has added poo to our list of "study subjects". Cow poo in particular. My new postdoc, Sean Whipple, has some interesting ideas regarding the role of dung beetles to provide ecosystem services. He recently completed his dung-beetle focused doctorate program at UN-L. Continuing on this work, my lab intends to explore the roles that these diminutive creatures play in such things as restoring carbon and nitrogen back into rangelands and pastures in the Great Plains. Perhaps, more importantly, what can we do in managing our pastures and range to facilitate the activities of dung beetles. The previous work that has been published has indicated that these insects can have tremendous value even in reducing particular greenhouse gases that would otherwise emanate from our rangeland and pastures. As much as ~80% of greenhouse gas emissions have been found to be sequestered by these insects on rangeland. You may these numbers surprising; however, these insects can incorporate dung back into the sod very quickly. In fact, many dung beetle species prefer fresh cattle dung and so they (particularly the dung beetle species that bury their dung or 'brood' balls) move this fresh excrement into the soil very quickly as they compete for this resource.
Some dung beetles are rather striking (e.g., the above specimen of Phanaeus vindex) and we generally think of them as rolling balls of dung across the grasslands. (Many species such as P. vindex take their brood balls directly into the ground, without rolling them around.) However, there are many species (across a couple taxonomic families) of 'dung beetle', some of which would not necessarily strike you as a dung beetle and they can be quite tiny. Nevertheless, even the smallest dung beetles (see video of some small dung beetles in the subfamily Aphodiinae) work to break down feces as the adults and their offspring carve up the resource. This process can also facilitate the entry of fungi that can further break down the dung. There will be much more on this topic appearing here in the near future.