New research has revealed the part evolution has played in the development of the complex and fascinating termite gut. 

Termites have a unique gut microbiome to thank for their evolutionary success. It enables them to eat wood, a food source most other animals can’t digest.

The gut microbiome, which can weigh up to two thirds of the termite’s total body weight, is made up of several thousand different species of microbe, many of which are only found in the termite gut. It has been a puzzle to researchers as to how the termite gut biome has evolved, but recent research examining the DNA of the gut microbes claims to have unraveled the answer.

The research team, which included Prof Theodore Evans and Dr Nathan Lo, concluded that the gut microbiome has developed through a mixture of vertical and horizontal transmission.

Vertical transmission is the passing of gut contents from one generation to the next. The life cycle of social insects, such as termites, allows this to happen quite readily, as gut content is passed to successful reproductive generations. Overtime, this allows the gut microbiome to co-evolve with their termite hosts to become very specialised.

Horizontal transfer is the acquisition of microbes from the environment, normally from their diet. In this regard, their findings were interesting in that they concluded that the source of most of the horizontal transmission was from other termite colonies. When colonies fight, the victor will often eat the vanquished, thus acquiring their gut bacteria. Other horizontal transmission could arise from other animal sources, through ingesting soil and faecal matter.

This study was part of ongoing work by the group to understand digestion in termites, which is poorly understood. And while understanding the digestive process and the enzymes the bacteria produce to aid in the digestion of wood are certainly academically interesting, it also has the potential for use in developing biofuels.

More information on termite evolution

Further reading: Bourguignon et al. (2018). ‘Rampant Host Switching Shaped the Termite Gut Microbiome’. Current Biology, 28(4), pp. 649-654