>So, you agree that mites and viruses adapt more quickly than their host?

No, that's not what I said. More rapid generation allows for more rapid
adaptation, but there is no guarantee that adaptation will take place, or
that it is necessary. 

Hmm. It seems to me that we talk about trying to increase mite resistance in bees but meanwhile lamenting miticide resistance in mites and rapid evolution in viruses. 

¶

Insects often evolve resistance within about a decade after introduction of a new pesticide, and many species are resistant to so many pesticides that they are difficult or impossible to control. Similar trajectories are known for resistant weeds, which typically evolve resistance within 10 to 25 years of deployment of an herbicide. 

Bacterial diseases have evolved strong and devastating resistance to many antibiotics. This occurs at low levels in natural populations but can become common within a few years of the commercial adoption of a new drug. Retroviruses with RNA genomes evolve even more quickly than bacteria. Every year, vaccinations against influenza must be reformulated, making prediction of next year’s viral fashion one of preventative medicine’s chief challenges .

In most cases, the causes of this evolutionary pattern are clear: if a species is variable for a trait, and that trait confers a difference in survival or production of offspring, and the trait difference is heritable by offspring, then all three requirements of evolution by natural selection are present. In such cases, the evolutionary engine can turn, although evolutionary directions and speed can be influenced by factors such as drift, conflicting selection pressure, etc.

Mathematical models of evolutionary engineering provide some guidance about practical field methods, but this exchange between prediction and practice has only been common in pest management and antibiotic resistance. Most important, it is seldom realized that a pivotal goal is slowing the evolution of resistance and that, without this, all successful pest and disease control strategies are temporary.

Stephen R. Palumbi. Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138

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