Fire millipedes obey the female sooner norm in cross mating <em>Centrobolus</em> (Myriapoda)

Abstract

Sexual mediation of copulation duration is reviewed in arthropods. Copulation duration and ejaculate volume were recorded in cross mating Centrobolus to test species' mediation differences. Conspecific C. inscriptus copulation durations were long (170.0 ± 49.3 min, n = 46), C. annulatus copulation durations were short (39.4 ± 18.6 min, n = 8), while mating between heterospecifics (C. inscriptus X C. annulatus) had the shortest copulation durations (12.4 ± 10.6 min, n = 6); when re-mating interval, sexual size dimorphism, sex ratio and ejaculate volume were controlled. ⺠(the female sooner norm) suggests size-assortative mating without a size based preference in these mate-guarding millipedes.