The results were subjected to exploratory analysis to test for normality and independence of the residuals (Shapiro & Wilk 1965), homogeneity of variance of errors in the treatments (Burr & Foster 1972), and non-additivity of the model (Tukey 1949). Where necessary, **data** were transformed in order to meet the assumptions of the analysis of variance (ANOVA) (SAS Institute 2009). Thus, sex ratio was transformed by  X + 0.5 . Treatment means were compared using Tukey's test (P ≤ 0.05) with the SAS statistical analysis program (SAS Institute 2009).