Putting the springtail back on the biological map

Year of Soils column by Nico van Straalen, February

Soil animals tend to be appreciated for what they do, not what they are. Just think of earthworms, woodlice, millipedes, mites and springtails: the whole shooting match of detritivores and microbivores that help break down organic matter and complete the nutrient cycle. As long as you’re talking about their role in the ecosystem, people will nod in agreement: well sure, aren’t those little critters important! And so just about every scientific article about earthworms, woodlice, mites and springtails starts with some phrase stressing how enormously useful they are to the ecosystem.

I’ve increasingly come to dislike this utilitarian approach. I refuse to make my own research into springtails dependent on their role in the ecosystem. What if the role of a particular species appears less than clear at a certain moment? Does it mean doing research into that species is no longer useful? And how about rare species, which by definition have little impact on waste streams and the process of breaking down organic matter?

Springtails, too, have long been regarded as animals that merely “did something” in the soil. But they have managed to get their own back against such one-sided views. My colleague Dick Roelofs has demonstrated that the genome of the soil-living springtail Folsomia candida contains a whole panoply of laterally transferred genes. These include all the genes necessary for the biosynthesis of β-lactam antibiotics.

That’s right: antibiotics such as penicillin are derived from certain fungi (which is where Alexander Fleming discovered them in 1928) and bacteria, and no animal has ever been known to produce them or even possess the right genes to do so…except Folsomia candida! This discovery has suddenly made Folsomia a fascinating poster child for genetic research: how did those genes get there? What other animals may have them? And what is the purpose of these antibiotics?

It means the springtail is now back on the biological map.

Keywords: year of soil columns