The richness, frequency and relatedness components of mate diversity and mate portfolios

Sexual reproduction produces genetically diverse families, especially when individuals mate with multiple partners. During mating, an individual accumulates a mate portfolio, the diversity of which depends on the number of mates, their relative mating contributions and characteristics. Nevertheless, studies of mate diversity generally focus on mate number or correlated mating, the probability that pairs of offspring are full siblings. Furthermore, mate diversity is usually quantified for incomplete samples that underestimate diversity because rare mates are underrepresented. Here, we demonstrate the application of methods developed in the context of species diversity to quantify and compare mate diversity. These methods are based on Hill numbers, which represent the spectrum of mate diversity from mate number (richness), through proportional representation of relative mate contributions (Shannon diversity), to emphasis on dominant mates (including Simpson diversity and the inverse of correlated mating). Hill-number estimates can also be extrapolated to a common sample coverage, enabling standardized comparisons among portfolios, populations and species. In addition to comprehensive quantification, these methods expose new perspectives on mate diversity and provide means for their future analysis.