Comparison of some reproductive characteristics of farmed and wild white shrimp males Litopenaeus vannamei (Decapoda: Penaeidae)

We rated some reproductive characteristics of white shrimp Litopenaeus vannamei (Boone, 1931) males using 46 farmed individuals (weighing 21.42 +/- 0.56 g) and 40 wild individuals (weighing 36.10 +/- 0.72 g). In farmed shrimps, spermatophore mean weight was 8.94 +/- 0.51 mg; total mean sperm count was 3.90 +/- 0.27 x 10(6) in each spermatophore; and mean percentage of normal sperm was 86.9 +/- 0.37%. In wild individuals, the respective values were 30.68 +/- 2.32 mg; 6.22 +/- 1.09 x 10(6); and 62.1 +/- 3.56%. In both groups, the differences between right and left spermatophore were not significant (p < 0.01). There were significant differences in spermatophore weight and percentage of normal sperm between farmed and wild shrimps; sperm counts differences, however, were not significant (p < 0.01). The relationship between spermatophore weight (Ws) and individual weight (Wo) was Ws (mg)=1.23 (Wo)-17.34 (r2=0.89), in farmed shrimps; and Ws (mg) = 2.57 (Wo)-60.04 (r2 = 0.64), in wild ones. In cultivated organisms, the relationship between sperm counts (Cs) and individual weight (Wo) was Cs (x 10(6)) = 1.13 * 10(-4*) (Wo) 3.361 (r2 = 0.85); and versus spermatophores weight was Cs (x 10(6)) = 0.439* (Ws) 0.984 (r2 = 0.90). In wild organisms, there was no correlation. The proportion of normal sperm ranged from 79.8 to 95.2 % (86.9 +/- 0.37%) and from 14.0 to 91.5% (62.1 +/- 2.52%), in farmed and wild shrimps, respectively. The most frequent abnormalities in both farm and wild animals were sperm without spike (49.3% and 76.6%, respectively) and irregular shape (35.8 % and 17.7 %). The less frequent occurrences were those of bent (10.2 % and 4.29%) and double spike (4.7% and 1.41%).

Juvenile hormone III and nutrition effects on spermatogenesis in the 4th instar nymphs of Panstrongylus megistus (Hemiptera: Reduviidae)

When 4th instar nymphs of Panstrongylus megistus are fed eith a saturant blood meal, there is an intense proliferation of the spermatogonia. At the end of the intermoult, the older spermatogonial cysts differentiate into 1st primary spermatocyte cysts. In the nymphs deprived of the blood meal this evolution is not observed, but a small growth of the testicular follicles occurs, due to a few mitotic divisions. This growth is observed at least, until 25 days after ecdysis. Since day 15, an autolytic process starts in the older spermatogonial cysts. The presence of exogenous juvenile hormone III (JH III) does not promote the development of the germ cells in the fasting insects. There is only a small growth of the testicular follicles and the autolytic process is also observed. In the precocious adults obtained by allatectomy or prcocene II treatment, germ cells are observed in all development stages, except packed and elongated spermatozoa bundels