Mating systems and relative reproductive success inferred via PBT
Outputs from parentage analysis were used to generate individual
profiles for each adult which included the number of offspring produced,
the number of unique mates, and the number of offspring produced per
mating. These data were then used to describe the mating system by
looking for evidence of monogamy (one male mates with one female or vice
versa), polygyny (one male mates with multiple females), or polyandry
(one female mates with multiple males). Because Roth et al. (2018) did
not quantify total offspring production and only a subset of offspring
were analyzed for genetic analysis, we present measures of relative
reproductive success among adults and relative production by different
sexes. We quantified the correlation between the number of mates an
adult acquired and the number of offspring produced using a Pearson’s
correlation coefficient.
Although we expected the incidence of false positive and false negative
rates for parentage assignment to be low because we used stringent
criteria to limit error (see above), we elected to use a complimentary
analysis, sibship assignment (SA), to confirm PBT results. Briefly, we
estimated full-sibling relationships among our juvenile collection using
the sibship assignment approach implemented in the software program
COLONY (Jones and Wang 2010), and compared the outputs from SA and
parentage analysis. COLONY employs a full-likelihood approach to
estimate sibship and has been shown to outperform other sibship
reconstruction methods (Lepais et al. 2010). For comparison purposes, we
determined the proportion of full sibling pairs that were identical
based on the two estimation procedures. Additionally, we examined the
number of full-sibling pairs that were detected by one program and not
the other. Lastly, we report on the number of single children families
detected via sibship assignment and parentage analysis.