Morphometrical and histological studies of dissected female reproductive system of the red palm weevil, rhynchophoros ferrugineus (Olivier) (Coleoptera: Curculionidae) [electronic resource].

Includes references.

Using light microscopy, the ovarian structure and oogenesis in the red palm weevil, Rhynchophorus ferrugineus (Olivier) were described. Reproductive system consists of two ovaries, lateral oviduct, common oviduct, the vagina, the bursa copulatrix and spermatheca. Ovarioles are of polytrophic type and each ovariole is long and divided into three regions: the germarium, the vitellarium (early previtellogenic zone and vitellogenic zone) and the stalk or calyx. Study describes the morphological differentiation in the structure of the ovarioles in different ages of female ( 4, 6, 10, 20, 30, 40, 50 and 60 days-old weevils). The mean length of previtellogenic zone showed the highest value (9.89 ± 0.77 mm) in 30 days-old weevils while the lowest value (4.22±1.65 mm} was recorded in 60 days-old weevils. Vitellogenic zone mean length reached its maximum value (32.17±0.43 mm) in 20 days-old weevils, then decreased until reached its minimum one (18.11±4.55 mm) in 60 days-old weevils. Calyx showed stable length (3.00 mm) from 4th day to 60th day, while the mean width increased gradually until the 60th day (l.82±0.03 mm). The highest mean number of oocytes in previtellogenic zone/ 2 ovaries (32.44±0.77 oocytes) was recorded in 20 days-old weevils. While the lowest mean number of oocytes (11.55±4.29 oocytes) was recorded in 60 days-old weevils. In vitellogenic zone, mean number of immature oocytes/ 2 ovaries reached its maximum values in 20 days-old weevils with values of 62.66±3.53 oocytes, then decreased to record its minimum value (20.44±5.55 oocytes) in 60 days-old weevils. The highest period of mature ova production (calyx/ 2 ovaries) was 30-40 days post weevils emergence with mean of 21.66± 4.71 and 10.11±1.07 ova, respectively, then the number of mature ova decreased in calyx as it recorded minimum number of ova (4.33 ± 0.33) at the age of 60 days. The total mean of mature ova and immature oocytes production inside the reproductive system reached its maximum ( 118. 77 oocytes) at age of 30 days. This method could be of a useful help in determining the age of female captured in traps in the fields.

Summary in Arabic.

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