**3.2. Fecundity, fertility and reproductive allocation**

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].

Based on the study of fertility (number of mancae released from the marsupium) and the energy allocated to reproduction for each of the two species (**Table 3**), different tradeoffs were highlighted. The pre-desert species *P. buddelundi* generates a large number of small progeny (53.13 ± 3.2 mancae; newborn body mass = 0.44 ± 0.21 mg), whereas *P. albinus* produces few large offspring (19 ± 9 mancae; newborn body mass = 1.44 ± 0.75 mg).

#### **3.3. Care of progeny**

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. During this sensitive period, they depend on their brood-caring mother who provides

**Figure 10.** Reproductive activities of *Porcellio albinus* and *Porcellio buddelundi.*

them with food and defends them against predators. At the age of 2 months (size 8 mm), the young emerge for the first time from the burrow to forage.

Besides these results, the digging of about 30 burrows during the spring breeding season, carried out during the day when the animals are inside their burrows, revealed that these burrows contain either adults over 14 mm in size (one or two males/burrow, one female/burrow, a couple/burrow) or an adult female with several mancae or juveniles less than 12.5 mm in size. The number of these young in the burrows ranges between 3 and 35 individuals with an average number of 15 ± 10 pulli or juveniles/burrow. This indicates that the young of *P. albinus* remain in their natal burrow and do not disperse until they reach sexual maturity.
