Mark Cooper School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg 2050, South Africa Arthropods ISSN 2224-4255 http://www.iaees.org/publications/journals/arthropods/online-version.asp 2020 9 1 15 20 International Academy of Ecology and Environmental Sciences Hong Kong 14 August 2019 20 September 2019 1 March 2020 copulation Diplopoda horizontal lighter mass Correlates of diplopod size include diet, copulation duration, energy expense of copulation, oxygen consumption, precipitation, sex and temperature. Sexual Size Dimorphism (SSD) in the diplopod genus Centrobolus has a positive correlation with body size and copulation duration. Intraspecific variation in mass was calculated in forest millipedes and correlated with copulation duration (R^2=0.68, d.f.=7, p=0.01). Interspecific variation in mass was calculated in forest millipede species and correlated with copulation duration (R=0.6711, R^2=0.4504, p=0.144473, n= 3, 3). http://www.iaees.org/publications/journals/arthropods/articles/2020-9(1)/correlation-between-mass-and-copulation-duration-in-millipedes.pdf