Bioclimatic Stages Research Articles

Phlebotominae (Diptera: Psychodidae) of human leishmaniosis sites in Tunisia

In order to identify the phlebotomine sandfly populations in Tunisian leishmaniosis foci, an entomological survey was carried out through three entomological seasons (2002-2003-2004) in 19 visceral and cutaneous leishmaniosis areas, located in six bioclimatic zones. Sandfly collections were based on light and sticky traps placed around human leishmaniosis cases. 8,722 phlebotomine sandflies belonging to 12 species were collected. The dominance of subgenus Larroussius species in northern foci, Phlebotomus papatasi in south-western foci and their co-dominance in the centre of the country is in accordance with the distribution of Leishmania infantum and L. major in Tunisia. The low density found in the historical zoonotic cutaneous leishmaniosis focus of Metlaoui in the south-west may indicate the high competence of the local populations. Studied phlebotomine settlements have showed a low specific diversity in most of the studied sites. In L. infantum areas, the dominant species were respectively: P. perfiliewi in the cutaneous leishmaniosis site of the humid bioclimatic stage, P. perniciosus in the cutaneous and visceral leishmaniosis foci of semi-arid and arid bioclimatic stages and P. longicuspis in the visceral leishmaniosis focus of saharan bioclimate. In the zoonotic cutaneous leishmaniosis foci, P. papatasi was a dominant species. In the well-known south-eastern foci of cutaneous leishmaniosis due to L. killicki, P. sergenti was a dominant species with P. perniciosus. In the central emerging foci of L. killicki, P. perniciosus was a dominant species in some sites whereas it was very rare in others. In these sites, the subgenus Paraphlebotomus was always present with a higher abundance of P. alexandri than P. sergenti.

Oil composition variability among populations in relationship with their ecological areas in TunisianRosmarinus officinalis L.

The essential oil of Rosmarinus officinalis L. (Lamiaceae) from 14 wild Tunisian populations, sampled in three ecological areas (sub-humid, semi-arid superior and arid superior bioclimatic stages), was analysed by GC and GC–MS. According to populations, 25 constituents, representing 93.68–98.77% of the total components, were identified. 1,8-cineole (20.34–45.79%), camphor (8.5–30.17%), α-pinene (6.53–13.1%) and borneol (3.73–25%) represent the major compounds. However, the mean percentages of compounds varied significantly among populations; α-pinene, 1,8-cineole were the main constituents which differentiated the populations. In addition, the proportion and nature of the constituents varied according to population bioclimatic stage, showing large differences between the ecological groups considered. Populations from arid superior bioclimate, represented by Rosmarinus officinalis var. troglodytorum, were characterized by high proportions of α-pinene, camphor and a relatively low content of 1,8-cineole. Copyright © 2005 John Wiley & Sons, Ltd.

Myrtus communis in Tunisia: variability of the essential oil composition in natural populations

The essential oil of 12 Tunisian natural populations of Myrtus communis L. (Myrtacea), prospected in three bioclimatic stages (humid inferior, sub-humid and semi-arid superior) were analyzed. Oil was extracted by n-hexane from crushed leaves and analysed by GC and GC-MS. Twenty-four components, representing approximately 79.10% of the oil, were identified. The major constituents were α-pinene (19.20%) and 1,8-cineole (15.96%). The other important constituents were linalool (7.66%), α-terpineol (7.51%) and limonene (5.75%). The percentage of all components varied within and among populations according to their bioclimatic appurtenance. α-Pinene, camphene and 1,8-cineole were the main compounds to differentiate the populations according to the bioclimate. Copyright © 2005 John Wiley & Sons, Ltd.

Genetic diversity in wild Tunisian populations of Mentha pulegium L. (Lamiaceae)

The allozyme variation of 15 Tunisian wild populations of Mentha pulegium L. threatened by human activities (clearing, hard-grazing, ploughing, traditional uses) was surveyed by the analysis of 14 isozyme loci using horizontal gel starch electrophoresis. The species exhibited a high level of genetic variation within populations (the mean Ap = 2.20, P = 72%, Ho = 0.349 and He = 0.229), which indicates a predominately outcrossing mating system and the recruitment of new genotypes via dispersal seeds. The genetic structure analysis of the populations using F statistics indicates no inbreeding, and showed an excess of heterozygosity for few loci. The moderate differentiation of populations (FST = 0.110) and the low rate of gene flow between them (Nm = 2.02) might been caused by recent isolation of the populations through biotope disturbances. The value of Nei's genetic identity varied from 0.839 to 0.999 reflecting a relatively low genetic divergence between populations. Cluster analysis using UPGMA method and Nei's genetic identity values, showed that populations geographically close didn't always cluster together. However, populations within the same bioclimatic stage generally subclustered together indicating that differentiation between bioclimatic regions occurred.