**2. Desert** *Porcellio* **species and their geographical distribution**

Despite its small size (163,610 km<sup>2</sup> ), Tunisia has 1300 km of coast on the Mediterranean Sea and is characterized by climatic, geological, and relief diversity. It is comprised of wetlands (5%), cultivated land (32%), nearly 13% forests, and about 40% desert lands. The arid regions

**Figure 1.** Geographical distribution of *Porcellio simulator* and *Porcellio albicornis* in Tunisia.

extend south of the Tunisian Dorsal from Sfax to Douiret in Tataouine. The climate of pre-Saharan Tunisia is located in the Mediterranean isoclimatic zone which can be defined, from an ecological point of view, as a climate of temperate zone, thus with seasonal and daily photoperiodism and with rainfall concentrated during the cold or relatively cold season (less than 200 mm/year), summer being dry [64].

[44]. Based on the results obtained by the different studies carried out on the reproductive phenology of the desert species of the Middle East and based on the knowledge acquired

• To closely study the reproductive model of the semidesert species *P. buddelundi* and desert

• To verify the hypothesis of a single breeding season observed in Middle East desert species. • To analyze the burrowing behavior of *P. albinus* and to identify its locomotor activity rhythm, in order to understand the behavioral mechanisms of adaptations of this species

and is characterized by climatic, geological, and relief diversity. It is comprised of wetlands (5%), cultivated land (32%), nearly 13% forests, and about 40% desert lands. The arid regions

), Tunisia has 1300 km of coast on the Mediterranean Sea

**2. Desert** *Porcellio* **species and their geographical distribution**

**Figure 1.** Geographical distribution of *Porcellio simulator* and *Porcellio albicornis* in Tunisia.

in the *H. reaumurii* model terrestrial species, it is envisaged:

*P. albinus*.

to the xeric conditions.

32 Community and Global Ecology of Deserts

Despite its small size (163,610 km<sup>2</sup>

This great ecosystem diversity has allowed the installation of several species of terrestrial Isopods, and the most recent assessments point to more than 40 species of oniscoids (Charfi-Cheikhrouha et al., unpublished). The *Porcellio* list, assessed by Medini-Bouaziz as 12 species in 2002 (*P. laevis*, *P. variabilis*, *P. dominici*, *P. marginenotatus*, *P. spatulatus*, *P. albicornis*, *P. lamellatus*, *P. djahizi*, *P. simulator*, *P. buddelundi*, *P. olivieri*, and *P. albinus*), was enlarged by the discovery of a 13th species *Porcellio wagneri*, which was first reported in Tunisia by Hamaied et al. (unpublished). The high species richness of *Porcellio* is reached in arid bioclimatic stages (eight species). The xeric species are quite numerous, representing more than a third of all *Porcellio* reported in Tunisia. These pre-desert and desert species belong to two distinct geographical groups of *Porcellio*: the North African group or laevis group and the group bético-rifain or group Hoffmanseggi. The former is represented by four of the five species reported in Tunisia (*P. simulator*, *P. olivieri*, *P. albicornis*, and *P. albinus*) and the last one by species *P. buddelundi* [64].

**Figure 2.** Geographical distribution of *Porcellio buddelundi* in Tunisia.

## **2.1. Geographical distribution in the world and in Tunisia**

Xeric species, confined to the pre-Saharan Tunisia, are spread south of the Tunisian Dorsal corresponding to the eastern extension of the Saharan Atlas, as follows:


**Figure 4.** Geographical distribution of *Porcellio albinus* in Tunisia.

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**Figure 5.** *Porcellio buddelundi.*

**Figure 3.** Geographical distribution of *Porcellio olivieri* in Tunisia.

Behavioral and Reproductive Strategies of *Porcellio* Species (Oniscidea) in Tunisian Pre-Desert… http://dx.doi.org/10.5772/intechopen.76191 35

**Figure 4.** Geographical distribution of *Porcellio albinus* in Tunisia.

**Figure 5.** *Porcellio buddelundi.*

**2.1. Geographical distribution in the world and in Tunisia**

**Figure 3.** Geographical distribution of *Porcellio olivieri* in Tunisia.

(**Figure 1**).

34 Community and Global Ecology of Deserts

Kebili (**Figure 2**).

(**Figure 3**).

corresponding to the eastern extension of the Saharan Atlas, as follows:

Xeric species, confined to the pre-Saharan Tunisia, are spread south of the Tunisian Dorsal

• *Porcellio simulator* is a North African species; its populations cover the center of Algeria [50] and occupy the center-west sector in the region of the high steppes in Tunisia [57]

• *Porcellio buddelundi* and *Porcellio albicornis* show a narrow distribution area that is restricted to Sicily and circum-Sicilian islands in Italy [62] and in Tunisia [23, 64]. In Tunisia, the distribution of *P. buddelundi* covers Jeffara, the plains of Kairouan, and the high Tunisian steppes, while the presence *of P. albicornis* has been reported in the regions of Gabes and

• *Porcellio olivieri* has a wide geographical distribution area that covers North Africa including Morocco [63], Algeria [65, 66], Libya [63, 67] as well as Egypt [49, 63, 65], and the Middle East [65, 68]. Described as an eastern desert species, *Porcellio olivieri* is found in Tunisia, in the Jeffara regions, in the southern lowlands, and in the southern Sahel

**Figure 6.** *Porcellio albinus.*

• The distribution area of *P. albinus*, the only burrowing species of the genus in Tunisia, is less extensive than that of *P. olivieri*. Its geographical distribution covers the North African Sahara, the Canary Islands [67], and the Niger Sahara [44]. In Tunisia, *P. albinus* occupies the regions of Jeffara and Nefzaoua and the southern lowlands. The expansion of this species to the north stops south of the Gafsa region (**Figure 4**). *Porcellio albinus* as *P. albicornis* is one of the rare species adapted to arid and Saharan habitats [64, 69].

### **2.2. Biotopes**

The distribution of the xeric species correlates to stone coverage with the exception of both species *Porcellio albicornis* and *Porcellio albinus*, which live in sandy soil irrespective of stone coverage. The three pre-desert species *P. simulator*, *P. buddelundi*, and *P. olivieri* dwell in rocky areas (reg) which is home to various types of garrigue vegetation, including *Artemisia, Rosmarinus, Stipa,* and *Lygeum*; they rarely share the same habitat. The other two species, *P. albinus* and *P. albicornis*, were found in sandy nebkhas covered by desert vegetation species such as *Stipagrostis pungens, Astragalus armatus*, *Zygophyllum album*, and *Calicotome villosa*. However, *P. albicornis* may occupy another type of biotope that corresponds to a dry wadi rich in *Limoniastrum monopetalum* and *Peganum harmala* where he lives in sympatry with *Hemilepistus reaumurii*.

retention capacity and consequently high residual moisture content. In fact this criterion and the slightly alkaline pH of the soil (pH = 7.83) favor the survival of this species in a desert environment. Oued El Jir homes various types of garrigue vegetation, including *Artemisia*, *Rosmarinus*, *Stipa*, and *Lygeum*. The Köppen-Geiger climate map classified Matmata climate as BSh type. The climate in this area is characterized by an annual mean temperature of 18.9°C and a moderate annual temperature range (9–28.6°C) (**Table 1**). The total annual rainfall is 209 mm, and the variation in the precipitation between the driest and the wettest month is 34 mm (**Table 1**).

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**Figure 7.** Sampling sites.

For *P. albinus*, the sampling site was the coastal area of Zarat, South of Gabes, Tunisia (33°40′N, 10°21′E (DMS)) (**Figure 7**); it corresponds to a marine sebkha environment [70]. The habitat is dominated by nebkhas corresponding to an accumulation of sand brought by the wind and trapped by vegetation (**Figure 9**). The vegetation was mainly composed of desert-adapted species

The two *Porcellio* we investigated in this chapter are *P. buddelundi* and *P. albinus* (**Figures 5** and **6**). Both species were collected at two different sites.

The population of *P. buddelundi* was collected at Oued El Jir, Matmata (Gabès), in the southeast of Tunisia (33°31′34′′N, 10°7′19′′ E (DMS)) (**Figure 7**). The habitat corresponds to a bare stony "reg" (**Figure 8**), and the soil is silt-clay type. This silt-clay structure is characterized by its high water Behavioral and Reproductive Strategies of *Porcellio* Species (Oniscidea) in Tunisian Pre-Desert… http://dx.doi.org/10.5772/intechopen.76191 37

**Figure 7.** Sampling sites.

• The distribution area of *P. albinus*, the only burrowing species of the genus in Tunisia, is less extensive than that of *P. olivieri*. Its geographical distribution covers the North African Sahara, the Canary Islands [67], and the Niger Sahara [44]. In Tunisia, *P. albinus* occupies the regions of Jeffara and Nefzaoua and the southern lowlands. The expansion of this species to the north stops south of the Gafsa region (**Figure 4**). *Porcellio albinus* as *P. albicornis* is

The distribution of the xeric species correlates to stone coverage with the exception of both species *Porcellio albicornis* and *Porcellio albinus*, which live in sandy soil irrespective of stone coverage. The three pre-desert species *P. simulator*, *P. buddelundi*, and *P. olivieri* dwell in rocky areas (reg) which is home to various types of garrigue vegetation, including *Artemisia, Rosmarinus, Stipa,* and *Lygeum*; they rarely share the same habitat. The other two species, *P. albinus* and *P. albicornis*, were found in sandy nebkhas covered by desert vegetation species such as *Stipagrostis pungens, Astragalus armatus*, *Zygophyllum album*, and *Calicotome villosa*. However, *P. albicornis* may occupy another type of biotope that corresponds to a dry wadi rich in *Limoniastrum monopetalum* and *Peganum harmala* where he lives in sympatry with *Hemilepistus reaumurii*.

The two *Porcellio* we investigated in this chapter are *P. buddelundi* and *P. albinus* (**Figures 5** and **6**).

The population of *P. buddelundi* was collected at Oued El Jir, Matmata (Gabès), in the southeast of Tunisia (33°31′34′′N, 10°7′19′′ E (DMS)) (**Figure 7**). The habitat corresponds to a bare stony "reg" (**Figure 8**), and the soil is silt-clay type. This silt-clay structure is characterized by its high water

one of the rare species adapted to arid and Saharan habitats [64, 69].

Both species were collected at two different sites.

**2.2. Biotopes**

**Figure 6.** *Porcellio albinus.*

36 Community and Global Ecology of Deserts

retention capacity and consequently high residual moisture content. In fact this criterion and the slightly alkaline pH of the soil (pH = 7.83) favor the survival of this species in a desert environment. Oued El Jir homes various types of garrigue vegetation, including *Artemisia*, *Rosmarinus*, *Stipa*, and *Lygeum*. The Köppen-Geiger climate map classified Matmata climate as BSh type. The climate in this area is characterized by an annual mean temperature of 18.9°C and a moderate annual temperature range (9–28.6°C) (**Table 1**). The total annual rainfall is 209 mm, and the variation in the precipitation between the driest and the wettest month is 34 mm (**Table 1**).

For *P. albinus*, the sampling site was the coastal area of Zarat, South of Gabes, Tunisia (33°40′N, 10°21′E (DMS)) (**Figure 7**); it corresponds to a marine sebkha environment [70]. The habitat is dominated by nebkhas corresponding to an accumulation of sand brought by the wind and trapped by vegetation (**Figure 9**). The vegetation was mainly composed of desert-adapted species

restricted to arid areas such as *Stipagrostis pungens*, *Astragalus armatus*, *Zygophyllum album*, and *Calicotome villosa*. The climate at Zarat is considered to be BWh by the Köppen-Geiger climate classification. Zarat climate is characterized by an annual rainfall of 178 mm and a difference in precipitation between the driest and the wettest month of 35 mm (**Table 2**). The average annual

Rainfall 19 17 20 15 7 2 0 1 16 35 23 23

**Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.**

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11.7 12.9 15.3 18.3 21.8 25.1 27.7 28.1 26.3 22.2 16.9 12.8

7 7.7 9.9 12.8 16.2 19.6 21.6 22.1 20.7 17 11.8 8.1

16.4 18.1 20.8 23.9 27.4 30.6 33.9 34.2 31.9 27.6 22.1 17.6

temperature is 19.9°C, and the annual temperature range is about 16.4°C (**Table 2**).

on studies of reproductive phenology performed on temperate oniscoids.

*buddelundi* **in pre-desert habitats**

**Table 2.** Zarat temperature and precipitation.

**3.1. Breeding phenology**

Mean temperature

(°C)

Minimum temperature (°C)

Maximum temperature (°C)

70 mg body mass.

**3. Reproductive traits comparison of** *Porcellio albinus* **and** *Porcellio* 

In North Africa, only the xeric species *Armadillo officinalis* from Libya [71] and *Hemilepistus reaumurii* from Tunisia [72, 73] have been the subject of study on reproductive phenology. These studies confirmed seasonal reproduction of temperate region species. Considering this element and what has been reported for the xeric Oniscidea of the Middle East in the introduction, two *Porcellio* species from the arid regions (*P. buddelundi* and *P. albinus*) were chosen on the basis of their geographical distribution in Tunisia (quite large in the case of *P. buddelundi* and more restricted in *P. albinus*) and their burrow digging (non-burrow digging *P. buddelundi* and *P. albinus* burrowing species). Both species are expected to have seasonal breeding, based

The two *Porcellio* we investigated on Tunisia area were studied in the field. 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.

Sexual maturity was reached at about 14 mm in size during the first year of life (9 months) in females *of P. albinus* and at 41.1 mg of body mass in those of *P. buddelundi*. Considering this and the mean ovigerous female size (17.38 ± 1.8 mm), females of *P. albinus* cannot reproduce until the second year of their life. Those of *P. buddelundi* reproduce when they reach or exceed

**Figure 8.** Biotope (Reg) of *Porcellio buddelundi.*


**Table 1.** Matmata temperature and precipitation.

**Figure 9.** Biotope (nebkhas) of *Porcellio albinus.*


**Table 2.** Zarat temperature and precipitation.

**Figure 8.** Biotope (Reg) of *Porcellio buddelundi.*

38 Community and Global Ecology of Deserts

**Table 1.** Matmata temperature and precipitation.

**Figure 9.** Biotope (nebkhas) of *Porcellio albinus.*

Mean temperature

(°C)

Minimum temperature (°C)

Maximum temperature (°C) **Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.**

9 10.6 13.7 17.7 21.2 25.3 28.6 28.4 25.9 21.1 15.3 10.2

4.2 5.2 8 11.7 15.1 19.2 21.8 21.7 19.8 15.5 9.9 5.3

13.9 16.1 19.5 23.7 27.3 31.4 35.4 35.1 32.1 26.7 20.7 15.2

Rainfall 28 24 35 16 11 3 1 3 13 24 28 23

restricted to arid areas such as *Stipagrostis pungens*, *Astragalus armatus*, *Zygophyllum album*, and *Calicotome villosa*. The climate at Zarat is considered to be BWh by the Köppen-Geiger climate classification. Zarat climate is characterized by an annual rainfall of 178 mm and a difference in precipitation between the driest and the wettest month of 35 mm (**Table 2**). The average annual temperature is 19.9°C, and the annual temperature range is about 16.4°C (**Table 2**).
