Population dynamics and reproductive aspects ofPorcellio albinus(Isopoda, Oniscidea) of Zarat (Gabes, Tunisia)

Behavioral and Reproductive Strategies of Porcellio Species (Oniscidea) in Tunisian Pre-Desert Ecosystems

“…Of the two species studied, only P. albinus is able to provide care to his offspring. As reported by Medini-Bouaziz et al [22], the study of the population dynamics of P. albinus in Zarat revealed, in all samples taken at night outside the burrows, predominance of larger specimens due to the absence of individuals whose size is smaller than 8 mm. Indeed, after the mancae release and during the first 2 months of life, newborns do not leave the family burrow.…”

“…Nocturnal activity of P. albinus was correlated to a lower evaporation rate. In burrows, P. albinus breed and take care of their offspring for about 2 months [22]. Given the importance of a burrow for this species, the sand, scraped from the burrow and piled outside, when the member of a family started their activity, was used to close the burrow during the day probably as an antipredatory strategy.…”

“…Fecundity estimated by the number of marsupial eggs was lower in P. albinus (36.3 ± 13.8 eggs) than that in the P. buddelundi species (60.9 ± 3.5 eggs). In the latter species, Medini-Bouaziz et al [22] have shown that fecundity increases more with increasing ovigerous female body mass in spring than in autumn. A positive correlation between ovigerous female size and fecundity is noted in both species [22,24].…”

“…To study the breeding pattern of both species, a sampling of almost 100 specimens of P. buddelundi and about 60 specimens of P. albinus took place during 12 consecutive months for the former and 17 months for the latter. See Medini-Bouaziz et al [22,23] for further details on material and methods. For both species, breeding starts in March and two breeding activities are defined (Figure 10).…”

“…These Oniscidae originally arising from the aquatic environment became terrestrial during the second half of the Paleozoic era [19]. They have evolved into a wide diversity of terrestrial species that have successfully colonized a wide range of habitats ranging from supralittoral levels (Ligia [20]) to mountains (Porcellio djahizi [21]) and desert ecosystems [22][23][24].…”