International Academy of Ecology and Environmental Sciences Arthropods 2224-4255 9 1 2020 3 1 Year-round correlation between mass and copulation duration in forest millipedes 15-20 EN Mark Cooper http://www.iaees.org/publications/journals/arthropods/articles/2020-9(1)/correlation-between-mass-and-copulation-duration-in-millipedes.pdf> 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).