Methane Production by Terrestrial Arthropods

Conclusions

Little is known about the function of the methanogenic archaea in the guts of arthropods, besides their role in lowering the H₂ partial pressure by producing methane. This lowering of the H₂ partial pressure might have similar consequences for the fermentation patterns of the gut microbiota similar to the situation known from mammalian guts and rumen (Hobson 1988). In addition, it may be speculated as to whether intestinal methanogens can contribute also to the nitrogen-carbon balance in the hindgut by the fixation of atmospheric nitrogen, since methanogenic archaea possess the whole set of genes required for nitrogen fixation (Raymond et al. 2004). Recently, it has been shown that the detrivorous and humivorous insects or their larvae have a much greater importance in the mineralization of organic compounds and the supplementation of soil with nitrogen than anticipated by earlier investigators (Nardi et al. 2002; Lemke et al. 2003; Ndiaye et al. 2004; Zhang and Brune 2004). Thus, the role of methanogenic arthropods exceeds their role as methane-emitters and potential contributors to global warming. Future studies will provide further information about their complex role in terrestrial ecosystems.