Genetic diversity and efficacy of natural selection in spiders with pre-copulatory sexual cannibalism

These factors include sexual cannibalism, offspring investment, and mating system. Pre-copulatory sexual cannibalism where the female consumes the male prior to mating exacerbates this effect.

We performed comparative transcriptomics in two spider species, the cannibalistic Trechaleoides biocellata and the non-cannibalistic T. keyserlingi, to generate genomic evidence to support these predictions. First, we estimated heterozygosity and found that genetic diversity is relatively lower in the cannibalistic species. Second, we calculated dN/dS ratios as a measure of purifying selection, higher dN/dS ratio indicated relaxed purifying selection in the cannibalistic species.