Data from: Sex, size and timing: sampling design for reliable population genetics analyses using microsatellite data

1. Population genetics is used in a wide variety of fields such as ecology
and biodiversity conservation. How estimated genetic characteristics of
natural populations can be influenced by the sampling design has been a
long-standing concern. Multiple simulation and empirical studies
illustrated the influence of both sample size and polymorphism of markers.
However, our review of studies on butterfly population genetics indicates
no consensus on sample size for the estimation of genetic diversity or
differentiation. Furthermore, other aspects of sampling design (sex ratio
and timing of sampling) were not addressed and their potential impact on
genetic parameter estimates rarely explored. 2. Using a large empirical
dataset (with spatial and temporal replicates) collected on a butterfly
species, Boloria aquilonaris, as well as simulated datasets reflecting (1)
three scenarios of migration-genetic drift equilibrium and (2) one
scenario of parameter stabilization after 100,000 generations, we
quantified the impacts of three aspects of genetic sampling design (namely
sample size, sex ratio, and timing of sampling) on the estimation of
allele frequencies and its potential downstream impact on the estimation
of genetic parameters. 3. With empirical data, we found that sample size
and timing of sampling strongly affected the accuracy of allele
frequencies and the downstream analyses, while sex ratio did not. Our
results were consistent across spatial and temporal replicates. Also, with
simulated data, we showed that the genetic sampling design had limited
effect in systems where dispersal outweighs genetic drift, while it can
have major consequences on our understanding of the genetic diversity and
population differentiation in systems dominated by genetic drift (such as
most study systems with conservation concerns). 4. We advocate for careful
consideration of all aspects of the sampling design in population genetics
studies, i.e. a sufficient number of samples, while ensuring similar sex
ratio among sampling locations and collecting with timing appropriate to
the question under study. This is particularly important when the study
aims at species conservation.