Do copulation duration and sexual size dimorphism vary with relative abundance in red millipedes Centrobolus Cook, 1897?

Abstract

Copulation duration, Sexual Size Dimorphism (SSD), and relative abundance (evenness) were checked for correlations in the red millipede genus Centrobolus. There was no significant relationship between SSD and relative abundance among the two species (r=0.47, Z score=1.13, n=8, p=0.13). There was a significant relationship between relative abundance in the trees pooled with an early and late relative abundance and SSD (r=0.84, Z score=2.10, n=6, p=0.02). Greater SSD was related to the higher abundance of one species (C. inscriptus) recorded in the trees but there was no absolute difference (T-score=1.29, n=4, 4, p=0.12) or relative difference (T-score=1.29, n=4, 4, p=0.12) in relative abundances of the two species (C. anulatus and C. inscriptus). There was a relative difference in relative abundances on the ground (0.50) and the trees (17) (T-score=-429.749622, d.f.=10, p=0). There was no relative difference between relative abundances early (17) and late (17) in the season (T-score=0, d.f.=10, p=0.50). Copulation duration was positively related to relative abundance (r=0.97, Z score=4.80, n=8, p< 0.01).