Can epigenetic changes affect reproductive success?
This article deals with the effect of phenotypic variation brought on by epigenetic patterns, and how these are inherited to the next generation. Their conclusions?

Our results show that epigenetic variation is inherited in chickens, and we suggest that selection of
favourable epigenomes, either by selection of genotypes affecting epigenetic states, or by selection of methylation
states which are inherited independently of sequence differences, may have been an important aspect of chicken
domestication.

However, I personally prefer this article, as it has a more profound implication on reproductive success and addresses your question specifically. They found the there is a species-level difference in DNA methylation between humans and chimps, but more importantly that this difference is responsible for the causation of numerous lethal diseases/conditions, which has a direct impact of the fitness of the species as a whole.

Finally, we found that differentially methylated genes are strikingly enriched with loci associated with neurological disorders, psychological disorders, and cancers. Our results demonstrate that differential DNA methylation might be an important molecular mechanism driving gene-expression divergence between human and chimpanzee brains and might potentially contribute to the evolution of disease vulnerabilities. Thus, comparative studies of humans and chimpanzees stand to identify key epigenomic modifications underlying the evolution of human-specific traits.

In summary, evidence has shown that epigenetics does seem to play an active role in the evolution of species, although the exact mode of inheritance of DNA methylation from generation to generation is unknown.

References

Nätt, Daniel, Carl-Johan Rubin, Dominic Wright, Martin Johnsson, Johan Beltéky, Leif Andersson, and Per Jensen. “Heritable Genome-wide Variation of Gene Expression and Promoter Methylation Between Wild and Domesticated Chickens.” BMC Genomics 13, no. 1 (February 4, 2012): 59.

Zeng, Jia, Genevieve Konopka, Brendan G. Hunt, Todd M. Preuss, Dan Geschwind, and Soojin V. Yi. “Divergent Whole-Genome Methylation Maps of Human and Chimpanzee Brains Reveal Epigenetic Basis of Human Regulatory Evolution.” The American Journal of Human Genetics 91, no. 3 (September 7, 2012): 455–465.