Latitudinal pattern of Enicospilus species richness across Japan. Coloured bars indicate observed species number and extended non-coloured bars indicate saturation species richness, estimated by individual-based extrapolation methods based on Chao1 richness estimator in EstimateS v.9.1.0 software application. Enicospilus species richness across Japan significantly decreases towards the north (Spearman’s rank correlation coefficient = -0.89, p-value = 0.03).