Data from: A cost for high levels of sperm competition in rodents: increased sperm DNA fragmentation

Sperm competition, a prevalent evolutionary process in which the
spermatozoa of two or more males compete for the fertilization of the same
ovum, leads to morphological and physiological adaptations, including
increases in energetic metabolism that may serve to propel sperm faster
but that may have negative effects on DNA integrity. Sperm DNA damage is
associated with reduced rates of fertilization, embryo and foetal loss,
offspring mortality, and mutations leading to genetic disease. We tested
whether high levels of sperm competition affect sperm DNA integrity. We
evaluated sperm DNA integrity in 18 species of rodents that differ in
their levels of sperm competition using the sperm chromatin structure
assay (SCSA). DNA integrity was assessed upon sperm collection, in
response to incubation under capacitating or non-capacitating conditions,
and after exposure to physical and chemical stressors. Sperm DNA was very
resistant to physical and chemical stressors, whereas incubation in
non-capacitating and capacitating conditions resulted in only a small
increase in sperm DNA damage. Importantly, levels of sperm competition
were positively associated with sperm DNA fragmentation across rodent
species. This is the first evidence showing that high levels of sperm
competition lead to an important cost in the form of increased sperm DNA
damage.