02957naa a2200133 a 450000100080000000500110000800800410001910000220006024501050008226000090018752022850019670000210248177303210250213148202008-09-16       2008    bl uuuu     u00u1 u    #d1 aSOKOLOWICZ, C. C.  aPopulation biology of a species of terrestrial isopod, Benthana sp. (Crustacea, Isopoda, Oniscidea).  c2008  aTerrestrial isopods are crustaceans adapted to live on land. They play an important role on terrestrial habitats, participating on soil formation, nutrient recycling and also as a source of food to several organisms. The aim of this study was to provide information on the population biology of a new species of the genus Benthana. Sampling was done in Taquara, Rio Grande do Sul, Brazil (29°46?S, 50°50? W). Samples of leaf litter were taken randomly monthly from March/2006 to August/2007. Animals were separated by sex and sex-differentiation stages (adult and mancas) and had the cephalothorax width (CW) measured. To identify the existence of significant differences in sex ratio a ÷2 test was performed (á=0.05). Three types of ovigerous females were recognized: females bearing eggs, those with embryos and with mancas inside de marsupium and were used in the analysis of fecundity correlating with CW. After eighteen months of sampling, 2.016 individuals of Benthana sp. were found, 881 males, 1034 females (90 ovigerous and 32 post-ovigerous) and 101 mancas. Reproductive females (ovigerous and post-ovigerous) were present in all months, except June/2006, January and July/2007. Mancas were present from March/2006-May/2006, September/2006 and from November/2006 to April/ 2007. The mean cephalothorax width of males varied from 0.55 to 1.59mm (mean=1.18; SD=0.19), females from 0.57 to 2.02mm (mean=1.24; SD=0.34), reproductive females from 1.32 to 2.02mm (mean=1.68; SD=0.18) and mancas from 0.57 to 0.71 (mean=0.64; SD=0.03). The sex ratio favored significantly females with the proportion 1:1.17 (p&lt0.05). The correlation of fecundity with CW were significantly positive (r=0.60, p&lt0.001) and mean fecundity was 10, SD=2.3. The results found in this study follow a certain pattern among the species of terrestrial isopods studied on tropical and subtropical regions: sex ratio favoring one sex, ovigerous females absent during winter and a correlation in number of eggs and female size. As for other neotropical philosciid, Atlantoscia floridana, mean fecundity is about 10-11 eggs. The minimum number of eggs is five for both species, while the maximum is 23 for A. floridana and only 18 for Benthana sp., a species that in comparison, reaches larger sizes.1 aARAUJO, P. B. de  tIn: INTERNATIONAL COLLOQUIUM ON SOIL ZOOLOGY, 15; INTERNATIONAL COLLOQUIUM ON APTERYGOTA, 12., 2008, Curitiba. Biodiversity, conservation and sustainabele management of soil animal: abstracts. Colombo: Embrapa Florestas. Editors: George Gardner Brown; Klaus Dieter Sautter; Renato Marques; Amarildo Pasini. 1 CD-ROM.