Fig. 3

Effects of C. conanobrieni adults on fecundity of P. argus (a) and on reproductive output and embryo mortality of P. argus (b). A The abundance of adult C. conanobrieni is significantly and negatively correlated with fecundity and reproductive output. Redundancy analysis (RDA) biplot showing first and second ordination axes (eigenvalues 0.266 and 0.044, respectively) of adults, cysts and egg abundances of C. conanobrieni (blue arrows) with respect to host stages (triangles), host characteristics (red arrows): CL (cephalothorax length) and Fec (fecundity). Length of arrows indicate the direction and rate of increase of the variables, angles between vectors indicate close correlations. B The presence of adult C. conanobrieni in females carrying late-stage embryos resulted in lower reproductive output and higher embryo mortality compared to females carrying early-stage embryos. Redundancy analysis (RDA) biplot showing first and second ordination axes (eigenvalues 0.417 and 0.009, respectively) of the death that occurred among P. argus embryos in the different pleopods (blue arrows) and reproductive output (RO) with respect to abundances of adult C. conanobrieni in the different pairs of pleopods (red arrows) and host stages (triangles). A-B: first pair; C-D: second pair; E–F: third pair and G-H: fourth pair. The two graphs show the ordination of predictive and dependent variables. In red arrows, predictive variables: abundance of adult nemerteans per pleopod pair (from anterior to posterior: A-B, C-D, E–F, and G-H), early (ED1, ED2) and late (LD3, LD4) development stages of lobster eggs. In blue arrows, dependent variables: number dead lobster embryos per pleopod pair (Mab; Mcd; Mef; Mgh) and reproductive output (RO) of female lobsters. Each arrow (representing a quantitate variable) points in the direction of the steepest increase of their values. The angle between arrows (red/blue) indicates the correlation between individual predictive variables and/or predictive and dependent variables. The angle between arrows indicates the sign of the correlation between variables. The approximated correlation is positive when the angle is sharp and negative when the angle is greater than 90 degrees. Symbols (triangle) represent levels of a factor, specifically, development stage of lobster eggs (DS). Thus, the distance between these symbols represents the average dissimilarity between the classes (DS) being compared. Closely located symbols and arrows represent an association between levels of a factor and quantitative variables