There is a hole in my litterbag….

Submitted by editor on 27 November 2018.Get the paper!

Disaster. A ruined experiment. Returning after a year to find half of the experiment eaten! Usually plant material, or litter, rots when buried outside, so we were expecting some of the litter to have disappeared through decomposition. But eaten? What would eat plant litter? And not only that, what would eat through a nylon meshed litterbag? One creature: a termite.  

Waste management is an important feature of many ecosystems around the world. Prodigious amounts of plant litter either rots, burns or is consumed. In tropical ecosystems, termites are the primary consumers of plant litter. Termites are so-called catholic consumers, eating a variety of material from dead wood – including people’s houses! – animal dung, animal horns, leaf litter to even nylon mesh litterbags. Generally, termites prefer dry, porous and recalcitrant material, but would termites eat plant roots too?

Photo by: Per Harald Olsen

Roots comprise approximately half of all plant litter, but surprisingly little work has explored to what extent termites contribute to root litter removal. So, we buried hundreds of fine-meshed litterbags containing roots of different plant species as an offering to microbes and termites in protected areas and pasturelands surrounding the Serengeti National Park in Tanzania. We also set up a complimentary mini-cafeteria of leaf and root litter near termite mounds to see what species and litter-types termites preferred. Then rescuing our experiment from the disaster of discovering nylon eating termites, we made note of any termite visual clues, such as soil debris, and scanned all the meshed litterbags to determine whether termites had visited a litterbag or not.

After a year of decomposing and after collecting several well eaten litterbags, we found that termites do in fact eat root litter, but that there are some plant species they prefer over others. Interestingly, termites avoided roots and leaves of the grass Themeda triandra (Red oat grass/Kangaroo grass). This was surprising to us as the Red oat grass dominates inside Serengeti protected areas. On the other hand, termites really liked roots and leaves of common pastural grasses such as Cynodon dactylon (Bermuda grass) as well as maize.

Although problematic for ecologists, not to mention for houses and crops, it is worth remembering not all termites are pests. By altering the plant species available to termites involved in decomposition, humans may be increasingly relying upon termites to recycle litter and manage ecosystem waste in tropical ecosystems.

Photo: Per Harald Olsen

The paper ‘Litter type and termites regulate root decomposition across contrasting savanna land-uses’ was a collaborative effort between researchers from the Norwegian University of Science and Technology, Tanzanian Wildlife Research Institute and Sokoine University of Agriculture and was part of the AficanBioServices  project funded by EU Horizon 2020 (grant 641918).

 

Stuart W. Smith on behalf of all co-authors

 

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