Data from: An empirical test of Baker’s law: Dispersal favors increased rates of self-fertilization

Baker’s law is the observation that recently dispersed populations are
more likely to be self-fertilizing than populations at the range core. The
explanatory hypothesis is that dispersal favors self-fertilization due to
reproductive assurance. Caenorhabditis elegans nematodes reproduce via
either self-fertilization or outcrossing and frequently disperse in small
numbers to new bacterial food sources. While C. elegans males facilitate
outcrossing, males and outcrossing are rare in natural C. elegans
populations. Here, we use experimental evolution to test if frequent
dispersal selects for the invasion of self-fertilization into
predominantly outcrossing populations. C. elegans dispersal often occurs
in the dauer alternative life stage. Therefore, we tested the effects of
dispersal on rates of self-fertilization in populations exposed to
dauer-inducing conditions and populations maintained under standard lab
conditions. Overall, we found that populations required to disperse to new
food sources rapidly evolved substantially elevated rates of
self-fertilization compared to populations that were not required to
disperse in both dauer and non-dauer populations. Our results demonstrate
that frequent dispersal can readily favor the evolution of increased
selfing rates in C. elegans populations, regardless of life stage. These
data provide a potential mechanism to explain the dearth of outcrossing in
natural populations of C. elegans.