The relationship between neutral genetic diversity and performance in wild arthropod populations

Larger effective populations (Ne) are characterized by higher genetic diversity, which is expected to predict population performance (average individual performance that influences fitness). Empirical studies of the relationship between neutral diversity and performance mostly represent species with small Ne, while there is limited data from the species-rich and ecologically important arthropods that are assumed to have large Ne but are threatened by massive declines. We performed a systematic literature search and used meta-analytical models to test the prediction of a positive association between neutral genetic diversity and performance in wild arthropods. From 14 relevant studies of 286 populations, we detected a weak (r = 0.15) but nonsignificant positive association both in the full data set (121 effect sizes) and a reduced data set accounting for dependency (14 effect sizes). Theory predicts that traits closely associated with fitness show a relatively stronger correlation with neutral diversity; this relationship was upheld for longevity and marginally for reproduction. Our analyses point to major knowledge gaps in our understanding of relationships between neutral diversity and performance. Future studies using genome-wide data sets across populations could guide more powerful designs to evaluate relationships between adaptive, deleterious and neutral diversity and performance. Graphical Abstract Based on a systematic literature search and meta-analytical models, we tested the prediction of a positive association between neutral genetic diversity and performance in wild arthropod populations and found a weak (r = 0.15) but nonsignificant positive association (121 effect sizes from 286 populations). We propose future use of genome-wide data sets across populations of different Ne for evaluating relationships between adaptive, deleterious, and neutral diversity and performance.