Reproductive Biology of Invertebrates : fertilization Development and Parental Care Volume 4

xxiii,527 hal,;ill,;21 c

Reproductive Biology of Invertebrates : Progress in development Endocrinology Volume X

x,316 hal,;ill,;21 c

Reproductive Biology of Invertebrates Volume IV

xxiii,527 hal,;ill,;24 c

Reproductive Biology of Invertebrates Volume 1

xxv,770 hal,;ill,;27c

Estrutura populacional e biologia reprodutiva de Parastacus defossus (Crustacea: Decapoda: Parastacidae)

Este trabalho descreve a estrutura populacional e aspectos da biologia reprodutiva de Parastacus defossus Faxon, 1898, uma espécie com hábito fossorial que passa sua vida no interior de galerias subterrâneas. Aproximadamente 30 exemplares foram coletados mensalmente, de janeiro de 2003 a agosto de 2005 na região do Lami, Município de Porto Alegre, Rio Grande do Sul, Brasil. Registrou-se o comprimento mínimo, máximo e médio da carapaça de machos, fêmeas, juvenis e animais com ootestículo. Analisou-se a distribuição de freqüência por classes de tamanho, a proporção sexual, o recrutamento e o período reprodutivo. Foram amostrados um total de 766 exemplares, 315 machos (41,12%), 278 fêmeas (36,30%), 166 juvenis (21,67%) e sete animais com ootestículo (0,91%). Machos e fêmeas estiveram presentes durante todos os meses de amostragem e em todas as classes de tamanho, sendo que a maior freqüência de indivíduos foi registrada nas classes de tamanho ente 24 a 30 mm. A maior freqüência de juvenis foi observada na primavera/2003 e verão/2005. Diferenças significativas no tamanho de machos e fêmeas foram registradas apenas nas classes de tamanho entre 26-30 mm. A proporção sexual no período amostral foi de 1:0,88 (x² = 2,3; p > 0,05) e entre as classes de tamanho foram constatadas diferenças significativas nas classes de tamanho 26-28 mm (x² = 5,43; p < 0,05) e 28-30 mm (x² = 4,77; p < 0,05) de comprimento de carapaça, nas quais os machos foram mais freqüentes. Das 278 fêmeas coletadas, apenas 17 estavam ovígeras (6,11%), sendo a estação reprodutiva bem definida na primavera.<br>This study investigates the population structure and the reproductive biology of Parastacus defossus Faxon, 1898, a fossorial species that spends its life inside subterranean tunnels. Around 30 specimens were collected each month in the region of Lami, municipality of Porto Alegre, state of Rio Grande do Sul, Brazil, from January, 2003 to August, 2005. The minimum, the maximum, and the mean carapace length of males, females, juveniles and individuals with ootestis were recorded. The frequency distribution by size classes, the sexual proportion, the recruitment, and the reproductive period were analyzed. A total of 766 specimens were collected, from which 315 were males (41.12%), 278 were females (36.30%), 166 were juveniles (21.67%), and seven individuals had ootestis (0.91%). Males and females were present in all months and in all size classes. The highest frequency of individuals matched the size classes from 24 to 30 mm. The highest frequency of juveniles was recorded during the spring of 2003 and the summer 2005. Significant differences in the size of males and females were recorded in the size classes between 26 and 30 mm. The sex ratio between all males and females was 1:0.88 (x² = 2.3, p > 0.05). The proportion between males and females showed significant differences between the size classes 26-28 mm (x² = 5.43, p < 0.05) and 28-30 mm (x² = 4.77, p < 0.05) carapace length, were the number of males was highest. Of the 278 females, only 17 were ovigerous (6.11%) and the reproductive period was clearly restricted to the spring