Researchers are using computers to generate “digital organisms” that undergo evolutionary processes such as mutation and reproduction. As a result, they have overturned a long-standing assumption of evolutionary theory: that the faster a given species reproduces, the likelier it is to win a competition with another species for dominance of an ecosystem, according to an article today in the journal Nature.Wilke and his associates’ computer work suggests the opposite is sometimes the case. In some cases, a slower-reproducing organism will end up dominating the ecosystem.

This is because of the importance of “robustness,” a third factor that in addition to mutation and replication rates influences a species’ chances of survival.

A “robust” organism organizes its genetic information so efficiently — for example, by making multiple copies of a crucial gene, just in case one is damaged by mutation — that it is more likely to survive a high mutation rate.