Genetic researchers led by Dr Jürgen Liebig of Arizona State University have sequenced the genome of the Nevada dampwood termite (Zootermopsis nevadensis).
Simplified developmental pathway of the Nevada dampwood termite, Zootermopsis nevadensis, with sequenced castes and life stages. Image credit: Nicolas Terrapon et al.
Termites are major pests of human structures, costing an estimated USD 40 billion in damage and control treatment each year.
While Nevada dampwood termites do not cause significant damage to buildings, they are closely related to key pests such as the Eastern subterranean termite (Reticulitermes flavipes).
Having the termite genome in hand will enable researchers to look for common features expressed across termite species to find control targets effective for all types of termites. Current termite control measures consist largely of synthetic chemical-based products, some of which are toxic to vertebrates.
“While current pesticides are very effective products, the problem is that you’re injecting large volumes of them into the soil around the house. It would be nice to move to a greener technology, and that’s what the genome sequence could enable us to do,” said Dr Michael Scharf of Purdue University, a co-author of the study published in the journal Nature Communications.
The scientists examined whether the evolution of sociality in dampwood termites and other groups of insects was based on the same molecular mechanisms. They found not only differences, but also things these groups had in common.
One difference they found was in groups of genes involved in the maturing of sperm in male animals. In the case of dampwood termites that live in wood, some of these genes occur more actively or in greater numbers than in the species of ants and bees that were examined.
This reflects a unique feature of their lifestyle – that while male ants and bees, for example, produce a large number of sperm just once and then die shortly after mating, male termites mate with the queen of their nest several times during their life.
“Generally, ant males deliver sperm and then die. But sperm production goes on for life in the dampwood termite male,” explained co-author Prof Edward Vargo of North Carolina State University.
Another difference is that in comparison with highly social insects, the dampwood termites have only a few olfactory receptors.
“There’s a lot of social strife in a termite colony, and it’s got to stay cohesive to survive. Chemical communication is crucial to keeping the labor force in place,” Dr Scharf said.
The termite genome could also help researchers better understand the symbiosis between termites and the more than 4,000 species of bacteria that thrive in their guts, aiding in processes such as digestion and defense.
Previous studies of the termite gut were hampered by the inability to distinguish between termite and microbe genes.
“The genome provides a well-defined roadmap that could help us find the right cocktail of enzymes to break wood down into its simple sugars. It takes a lot of the guesswork out,” Dr Scharf explained.
The team also found proteins that might play an important role in the development of caste-specific features in dampwood termites – just like a similar system in honey bees.
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Nicolas Terrapon et al. 2014. Molecular traces of alternative social organization in a termite genome. Nature Communications 5, article number: 3636; doi: 10.1038/ncomms4636
