Box 1: The tenets of natural selection applied to
microbe-mediated adaptation
The phenotype of an organism is fundamental to local adaptation and
adaptive plasticity because natural selection acts upon traits (or
selection acts upon plasticity in traits). Evolution by natural
selection will occur when the following criteria are met (Lewontin
1970):
- Variation exists in host traits that mediate or respond to
interactions with specific microbes or microbial communities, which
leads to different host genotypes associating with or responding to
different microbes.
- Host traits that mediate interactions with microbes are heritable
- Traits mediating interactions with specific microbes or microbial
communities affect fitness.