Reproductive traits of Porcellio variabilis Lucas, 1946 (Isopoda, Oniscidea) from Tunisia

Abstract

Abstract:The breeding phenology and reproductive strategies of Porcellio variabilis were investigated, both in field and laboratory, in the population of Béja (North of Tunisia). P. variabilis Lucas, 1946 is characterized by a seasonal reproduction period followed by a sexual rest phase during November, December and January. Mean fecundity showed a great seasonal variation ranging between 29.612 eggs for females caught in the late summer, and 125.920 eggs for those collected in the spring. P. variabilis is an iteroparous species; females were able to produce one (95% of females), two (40% of females) or three broods (20% of females) during their reproduction period. The duration of the gestation period ranged from 34 days in the first brood to 14 days in the third one. Energy allocated to reproduction decreased from the first brood (26.29%) to the last one (4.618%). During the sampling period, eight cohorts were identified, each exhibiting a variable life span estimated around 6 months for cohorts born in early spring, and 12 months for those born in the fall. According to our present results and previous studies in another population of P. variabilis in Tunisia, we discuss factors of variability in breeding phenology in this species.

Comparison of terrestrial isopod (Crustacea: Oniscidea) assemblages from two preserved areas (Bouhedma and Chambi) in arid regions

“…Leptotrichus panzerii and P. variabilis were the most common species, collected in five and six habitats from the two parks, respectively. The presence of P. variabilis in both parks suggests that this species is able to use a variety of habitats, as previously reported (Medini & Charfi-Cheikhrouha 1998;Medini-Bouaziz et al 2015). Armadillidium sulcatum, collected in all habitats in Bouhedma and in the second habitat of Chambi, characterized by morphological and ecological variability in Tunisia (Hamaied-Melki 2008), was capable of adapting to habitats with harsh conditions.…”

Reproductive Patterns of Terrestrial Isopods (Crustacea, Isopoda, Oniscidea) from Uruguay

“…According to that reported for most terrestrial isopods from different world regions (Cuartas & Petriella, 2001;Glazier, Wolf & Kelly, 2003;Quadros, Caubet & Araujo, 2009;Achouri et al, 2008;Kight, 2008;Ivanov, 2011;Achouri, 2012;Montesanto et al, 2012;Medini-Bouaziz, El-Gtari & Charfi-Cheikhrouha, 2015), Armadillidium vulgare showed a positive correlation between fecundity and fertility and the body length of ovigerous females. Fecundity in Armadillidium nasatum also showed this positive correlation, this result is in agreement with the observer by Glazier et al (2003) for a population of the same species in central Pennsylvania.…”

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

“…The reproduction of these two iteroparous Porcellio was characterized by two breeding seasons: the most important one in spring and the other in autumn distinctly separated by a sexual rest phase [22,24]. This reproductive phenology differs from that of (1) mesic species such as P. variabilis [33,82], which generally shows a breeding period spread over several months followed by a sexual rest and (2) H. reaumurii and other desert species from the Middle East characterized by a single spring or autumn breeding season [45,72,83]. Our results about reproductive traits of both species showed that P. buddelundi exhibited a set of characteristics corresponding to those of the r-strategists: a shorter life span, a smaller size, early sexual maturity, higher fertility, and a reproductive allocation to maximize brood size.…”