(1986), the relative penis length index
(RPL) can be used to describe the severity of imposex.
(1987) and indices of imposex of Gibbs were estimated as follows: Vas Deferens Stages Index (VDSI) = ([SIGMA] of degrees of VDS/total number of females analyzed), Relative Penis Length Index
(RPLI) = (average pseudopenis length in females/average penis length in males)x100 and Relative Penis Size Index (RPSI) = (average pseudopenis length in females /average penis length in males)3x100 (Gibbs et al., 1987).
Uncubed relative penis length index
(RPLI) cubed relative penis length index
(RPSI) and vas deference index (VDSI) were calculated as described previously (Afsar et al., 2012a,c) The RPLI was 8.35 and RPSI 0.06.
1987), and the relative penis length index. For statistical purposes, the relative penis length index was calculated for each female by dividing the female penis length by the average male penis length.
trunculus from Bizerta Channel were severely affected by this deformity (incidence = 100%, relative penis length index = 57.6, vas deferens sequence index = 4.3), with an annual average of 7.8 % sterile females (Table 2).
The frequency and intensity of imposex in various species of gastropods were expressed according to (Fioroni et al., 1991; Gibbs and Bryan, 1994; Vishwakiran and Anil, 1999) as follow: (i) uncubed relative penis length index (RPLI); (ii) cubed relative penis size index (RPSI); (iii) vas deferens sequence index (VDSI).
RPLI, relative penis length index; RPSI, relative penis size index; VDSI, vas deferens sequence index.
Penis length of males and imposexed females was measured under a stereoscopic microscope and the Relative Penis Length Index
(RPLI) and Relative Penis Size Index (RPSI) were calculated according to Gibbs and Bryan (1987).