Sanghvi, KrishShandilya, SuchetaBrown, AlanaTodorova, BilianaJahn, MartinGascoigne, Samuel J LCamilleri, Tara-LynPizzari, TommasoSepil, Irem2025-08-212025-08-212025-04Sanghvi, K, Shandilya, S, Brown, A, Todorova, B, Jahn, M, Gascoigne, S J L, Camilleri, T-L, Pizzari, T & Sepil, I 2025, 'Reproductive output of old males is limited by seminal fluid, not sperm number', Evolution Letters, vol. 9, no. 2, pp. 282-291. https://doi.org/10.1093/evlett/qrae0712056-3744crossref: 10.1093/evlett/qrae071ORCID: /0000-0002-2984-1810/work/190476700https://hdl.handle.net/2164/25889We are grateful to Ellie Bath, Ben Hopkins, Stu Wigby, Alex Kacelnik, and members of the fly lab for helpful suggestions. We also thank Mariana Wolfner, Claudia Fricke, Bahar Patlar, and Ina Lindenbaum for providing us with Tudor flies and associated crossing details, and Michael Thom for giving us gfp flies. We thank attendees of the Biology of Sperm Conference, 2023, for helpful discussions, and Kevin Foster for allowing us to use his lab’s confocal microscope.101394779engagingcryptic female choiceDrosophilaejaculatesenescencesexual selectionQH301 BiologySupplementary DataDASLinkDryadQH301Journal article10.1093/evlett/qrae071https://academic.oup.com/evlett/article/9/2/282/794358992