Table 2 Contemporary evolution of human commensals in urban environments.

Columns show species’ common and scientific names, the evolutionary processes studied, and corresponding references

Common nameScientific nameEvolutionary processesReferences
German cockroachBlatella germanicaSelection: Sugar-baited pesticides impose selection that
causes evolution of glucose aversion.
Genetic drift: Pesticide treatment and founder events cause
Gene flow: Genetic differentiation increases with spatial scale,
being lowest within buildings, higher between buildings,
and greatest between cities and continents.
(93, 100, 139, 140)
Bed bugCimex lectulariusSelection: Insecticide application drives evolution of resistance.
Genetic drift: Population bottlenecks cause a loss of genetic
diversity within populations.
Gene flow: Limited dispersal contributes to high genetic
differentiation between populations.
(56, 94, 123, 141144)
Northern house mosquitoCulex pipiens (molestus)Selection: Underground populations do not require a blood
meal to lay eggs, lack a winter diapause and are reproductively
isolated from aboveground populations.
Genetic drift: Underground populations have less
genetic diversity and are genetically differentiated from
aboveground populations.
(52, 53, 145, 146)
Rock dove (aka “pigeon”)Columba liviaSelection: Darker morphs (with white rumps) exhibit lower
predation to falcons, higher survival as young when exposed to
lead, and greater defense against parasites.
House mouseMus musculusGene flow: Populations exhibit patterns of early dispersal and
population expansion, followed by patterns that mirror
human migration and settlement patterns.
Head and body licePediculus humanusSelection: Increased frequency of resistance to pesticides
through time, which is related to mutations in
the VSSC α-subunit gene.
Norway ratRattus norvegicusSelection: Evolve resistance to warfarin pesticides through
mutations in VKORCI.
Genetic drift: Populations exhibit little evidence of inbreeding.
Gene flow: There is moderate genetic differentiation
and genetic clustering of populations, which is attributed to limited
dispersal and natural barriers to gene flow.
(92, 95, 98, 151, 152)
Black ratRattus rattusGene flow: Populations exhibit substantial genetic clustering
and patterns of dispersal and population expansion that reflect
human dispersal and settlement.