The eastern subterranean termite, Reticulitermes flavipes, exists in colonies, whose members share work and resources among themselves. Different castes of termite have evolved to do different jobs: worker termites dig tunnels and eat wood; soldier termites defend the colony; and reproductive termites fertilise or lay eggs. Each caste has specific features useful for their role. For example, soldier termites are larger than workers and have an enlarged head and hard black mouthparts that they use to fight ants or termites from neighbouring colonies. Interestingly, the fate of an individual is not determined until the larval stage. Little is known about how these fates are specified especially at the molecular level.
To investigate this, the research team from Purdue University searched for genes that were expressed at different levels in soldier and worker termites, and found 25 candidates.
Workers had higher levels of expression of genes involved in breaking down cellulose, perhaps not surprising given that these animals have to digest wood. These genes belonged both to the termites themselves, and to the bacteria and protozoa that live in the termites' guts. Soldiers had higher levels of expression of genes central to the formation of muscle or the cytoskeleton. These genes might be involved in making the soldiers' large mouthparts work.
Michael Scharf and collegues also discovered two genes that may be involved in directing termite development. These genes are related to two genes, called bric-a-brac and bicaudal, which regulate patterning in the fruit fly, Drosophila. Bric-a-brac works by inh
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