Instantaneous insemination in the millipede Centrobolus inscriptus (Spirobolida: Trigoniulidae) determined by artificially-terminated mating

Abstract

Male millipedes may control the duration of copulation and maintain genital contact with females in relation to the intensity of sperm competition. Post-insemination associations were considered in arthropods and the timing of insemination in the millipede Centrobolus inscriptus calculated by artificially-terminated radiolabelled mating. Copula pairs were separated after 1, 2, 3, 4, 5, 10, 20, and 30 minutes of copulation. Ejaculate volumes inseminated did not correlate significantly with the manipulated copulation durations (r = -0.35, df = 8, P = 0.35). High (ca. 2500 dpm) and low values in the first 5 minutes evidenced