A preliminary list of the Ant Fauna in Northeastern Sahara of Algeria ( Hymenoptera : Formicidae )

In Algeria, as in countries where it is not too cold, the ants have the advantage of being abundant. They exist everywhere, in the forest as in open areas, along the water as in dry areas, on clay as on rocks (Cagniant, 1973). Comparing with other countries of the North of Africa, Cagniant (2009) evaluate the Moroccan myrmecofauna approximately to 220 species, while both of Algeria and Tunisia include 180 in Total (Cagniant, 2006). The myrmecofauna of Algeria is known through some fragmentary studies done by: (e.g. Forel, 1890; 1894; 1902; Sanchi, 1915; 1929a; 1929b; Bernard, 1955; 1963; 1973; 1977; 1982; Cagniant, 1966a; 1966b; 1967; 1968a; 1968b; 1969; 1970a; Barech et al., 2011; 2015). Unfortunately, Abstract We present here a preliminary list of ant fauna of some study sites in the northeastern Sahara of Algeria using two methodologies, quadrat and pitfall traps (Barber-pots) methods. This work was conducted in wild and agricultural ecosystems in the basin of Ouargla, El-Oued region and Djamaa region. We record a total of 26 species of 12 genera belonging to three subfamilies Dolichoderinae, Formicinae, and Myrmicinae. Species of the Myrmicinae and Formicinae were the most abundant with 62.96% and 29.63% respectively. The most diverse genus was Monomorium Mayr, 1855 (6 species), followed by Messor Forel, 1890 (5). The highest diversity of ants was in Djamaa region (24 species), followed by Ouargla (18) and El-Oued (13). Moreover, this work shows the first record of the species Strumigenys membranifera Emery, 1869 for the Country. Finally, we observed a variation in the distribution of ant species between study sites, for why, ecological determinants such as soil need to be studied deeply to explain their influence on the repartition and richness of the Saharan myrmycofauna of Algeria. Sociobiology An international journal on social insects


Introduction
In Algeria, as in countries where it is not too cold, the ants have the advantage of being abundant.They exist everywhere, in the forest as in open areas, along the water as in dry areas, on clay as on rocks (Cagniant, 1973).Comparing with other countries of the North of Africa, Cagniant (2009) evaluate the Moroccan myrmecofauna approximately to 220 species, while both of Algeria and Tunisia include 180 in Total (Cagniant, 2006).The myrmecofauna of Algeria is known through some fragmentary studies done by: (e.g.Forel, 1890;1894;1902;Sanchi, 1915;1929a;1929b;Bernard, 1955;1963;1973;1977;1982;Cagniant, 1966a;1966b;1967;1968a;1968b;1969;1970a;Barech et al., 2011;2015).Unfortunately, no serious studies have been made on repartition of these microfauna in the Algerian territory, excepting those of (Cagniant, 1968c;1970b;1970c) who have established a list of the forest ants of Algeria with a total of 120 species.Recently, Djioua and Sadoudi-ali Ahmed (2015) listed the richness of ant fauna in some forest and agricultural areas of Kabylia.Barech et al. (2016) added a checklist of the myrmecological fauna of a saline lake area, Chott El Hodna.In northern Sahara of Algeria, the ant fauna has a significant percentage among the arthropods that inhabit this region by adapting to the conditions of the arid environment.However, the Saharan species were poorly studied.The objective of this study is to evaluate the diversity of myrmecofauna in wild and agricultural ecosystems of the northeastern Sahara of Algeria.

Study sites
This study was conducted in wild and agricultural ecosystems owns of several areas of the northeastern Sahara of Algeria.For that, three study sites were selected because of the high variation in their flora (appendix I), represented by the basin of Ouargla, El-Oued region and Djamaa region (Table 1).To represent the physiognomy of the vegetation of Table 1.Sites where ants were sampled in the northern-east Sahara of Algeria.
each study site, a transect of 500 m2 (10m x 50m) was carried out.It consists to produce an inventory of plant species found there and represent them graphically next two figures, one in vertical projection onto a plane and the other in profile.
The projected orthogonally on a plane representation allows specifying the structure of the plant community and the recovery rate.However, the profile representation provides indications on physiognomy of the milieu, showing if it is open, semi-open or closed.

Sampling methods
Data sampling was carried out on a monthly basis, between April 2012 and March 2013.For that, two standard ant collecting methods were used.Ants for quantitative study were collected using quadrat methods which consist to a manual capture onto a delimited surface, during a known time interval.In this study, ants were sampled from a surface of 10 m x 10 m, during 3min.This method allows the observation of nests and the enumeration of population of each ant species (Berville et al., 2015).A second method was added for complementary data on ant diversity by using pitfall trap (Barber pots).These interceptions traps consisted of a metallic container (7.4 cm diameter × 10.5 cm long), placed at the same level as the surrounding ground, filled one-third with a solution of water and a drop of liquid dishwashing soap to break the surface tension.Each pitfall trap distant from the other by 5 m along a transect of 50 m 2 (10 traps) for each study site.The pitfall traps were left running during 24 hours before being gathered and emptied of their contents.This method was used by several authors such as (Hernández-Ruiz & Castaño-Meneses, 2006;Berville et al., 2015).

Data analysis
Ant diversity in the study sites was expressed as species richness, Abundance and proportion.Moreover, Factorial Correspondence Analysis (FCA) was carried out using XLSTAT in order to provide a factorial map of the repartition of ant species between the three regions.Hoffman and Franke (1986) defined the Correspondence analysis as an exploratory data analysis technique for the graphical display of contingency tables and multivariate categorical data.

Richness and abundance
We recorded 26 ant species of 12 genera and three subfamilies.Myrmicinae was the most abundant subfamily (62.96 %), followed by Formicinae (29.63%) and Dolichoderinae (7.41%).The most diverse genus was Monomorium and Messor (5 species each ones), followed by Cataglyphis (4).Tapinoma, Componotus and Tetramorium, each is represented by two species.However, the genera Lepisiota, Plagiolepis, Cardiocandyla, Crematogaster, Pheidole and Strumigenys are presented by one species each one.The genus Strumigenys is recorded for the first time from Algeria by the species S. membranifera EMERY, 1869.The region of Djamaa was the most diversify with 24 ant species, followed by Ouargla (18) and El-Oued (13).Similarly, Djamaa region included the high number of restricted ant species, which are represented by: Tapinoma simrothi, Cataglyphis albicans, Plagiolepis barbara, Crematogaster inermis, Messor sanctus and Tetramorium sericeiventre.Nevertheless, both of El-Oued region and Ouargla region include one restricted ant species each ones, represented by Messor aegyptiacus tunetinus and S. membranifera respectively.According to Deyrup (1997), this species often occurs in disturbed open areas, such as lawns and pastures.Effectively, one sample of this species, identified as a queen was collected from the wild ecosystem of Ouargla region.In Saudi Arabia, it was recorded from an area of date palm trees cultivation (Sharaf et al., 2014).Wetterer (2011) considered S. membranifera as a cosmopolitan ant species which has spread around the world through human commerce, in all zoogeographical regions (Bolton, 1983;Bolton, 2000).But it was probably suggested that it has an African origin (Brown & Wilson, 1959).In the Mediterranean region, it occurs in: France, Greece, Italy, Malta, Spain, Egypt and Tunisia (Wetterer, 2011).The absence of record of this species in the adjacent countries such as Morocco, Libya, Niger and Mali allowed us to suggest a hypothesis of being introduced from Tunisia because of its localization near El Oued region and their similar ecosystems.Although its known that S. membranifera and S.emmae are a successful invasive species (Wetterer 2011), Sharaf et al. (2014) thought that S. membranifera reaches more temperate areas.So, the Sahara of Algeria presents a good area for their invasion.
The analyze of the data of table 2 shows that some ant species are common in all study sites.For example: Monomorium salomonis obscuriceps and Pheidole pallidula are the only species which occurred in all study stations.This result confirms the view of (Hernández-Ruiz & Castaño-Meneses, 2006) which stated that populations of the genus Monomorium are frequent and occupy environments with different conditions of soil (humid or dry), because they are not so highly affected by micro weather changes.In other hand, the species P. pallidula has spread through the Mediterranean regions (Bernard, 1956).The study of the abundance of ant species in different ecosystems of the northeastern Sahara of Algeria is given for the first time.Among the identified species, the most abundant ant species was Lepisiota frauenfeldi atlantis (34.02%) for Djamaa region, Messor aegyptiacus tunetinus (28.24%) for El-Oued region and Tapinoma nigerrimum (23.58%) for Ouargla region (Tables 3, 4, 5).By analyzing   the data of tables (3,4,5), we observe that most species of the genus Cataglyphis was found more abundant in the wild ecosystems.However, C. albicans was restricted to the agricultural areas.This genus is occured in open areas such as clearing and steppe in the north of Africa from the seaside to 2800m in Hoggar (Cagniant, 2009).Also, Cataglyphis bombycina was the most abundant.Its high abundance is explained by their common existence in sand-dune and other sandy areas of the south of Morocco and Algeria (Cagniant, 2009).Similarly, L. frauenfeldi atlantis occured greatly on arid zone (Cagniant, 2006).The lowest abundance is reported in the genus Cardiocondyla.According to (Cagniant, 2009), this genus appears discretely in open habitat.Generally, there is a difference and variation in the proportion of each ant species between different study sites and habitats.Some species are found in wild and agricultural ecosystems.In other hand, some species are collected just from the wild ecosystem such as, Cataglyphis rubra, Tetramorium sericeiventre and S. membranifera.Cagniant (1997) confirmed the presence of the species T. sericeiventre in the region of Biskra which is located near the region of Djamaa.In opposition, the species, Tapinoma nigerrimum, T. simrothi and Crematogaster inermis were collected only from agricultural areas.T. nigerrimum was found in pasturage milieu from the north of Algeria into the Saharan Atlas (Cagniant, 1970b).Whereas, T. simrothi is more common in pasture areas but it suffers if exposed to cold.
The same author confirmed its presence in the Saharan Atlas of Algeria above 1300 m.This variation in abundance and distribution between the two species is explained by (Cagniant, 1966a) who wrote that T. nigerrimum resists better cold, this capacity allowed it to be maintained in the north of Algeria.For the Crematogaster genus, Cagniant (2005) found C. inermis on tree (fruit and Tamarix) in Morocco and include the other species of this group to the arboreal insect, most of the time.

Factorial Correspondence Analysis (FCA)
The factorial map displays a total inertia of 100 % for both axes, F1 (60.62%) and F2 (39.38%) (Fig 1).The chart shows the existence of six grouping (A, B, C, D, E, F) distribute between the study regions.The groups A, C and E contain exclusive species for Djamaa, El-Oued and Ouargla region respectively, which are already mentioned in the text above.The group B contains one species shared between Djamaa and El-Oued region, represented by T. biskrense.The group D contains 11 species shared between the three regions represented by: Camponotus barbaricus, Camponotus thoracicus, Cataglyphis bicolor, C. bombycina, Cardiocondyla batesii, Messor arenarius, Messor foreli, Monomorium areniphilum, M. salomonis obscuriceps, Monomorium subopacum, P. pallidula.The last group F contains 6 species shared between the region of Ouargla and the region of Djamaa.This group groups the species T. nigerrimum, C. rubra, L. frauenfeldi atlantis, Messor medioruber sublaeviceps, Monomorium destructor, Monomorium salomonis obscuratum.For a better understanding of the variation in the distribution of ants species, others researches must be made in the future.This last is consistent with the study of the influence of ecological determinants such as soil parameters and vegetation cover on ant distribution.Bardgett et al. (2005) wrote that Soil characteristics are well known with their strong effects on spatial distribution of soil communities.Meanwhile, Boulton et al. (2005) concluded that overall ant species richness and abundance are more consistently associated with soil chemistry and texture than plants.Additionally, a particular change in environmental conditions may increase the diversity of one subset of organisms within a community, while decreasing the diversity of a different group of organisms (Semida et al., 2001).Also, there is a relationship between ant community abundance and altitude.Taheri and Reyes-Lo´pez (2015) stated that some approach followed in the study of myrmecofauna such as season, altitude, aridity, geology and vegetation types and animal farming practices give a better picture of the composition and distribution of the species.
This work is a contribution for the study of Algerian myrmecofauna of the northeastern Sahara.Data on ant fauna from the occidental and central Sahara stay unknown and need a great effort in sampling methods to dispatch richness and abundance of species.Finally, it is certain that other survey expanded in space and in time will enrich more this list.

Table 2 .
Occurrence and distribution of ant species collected in the northeastern Sahara of Algeria.
A: abundance, P: proportion

Table 3 .
Abundance and proportion of ant species recorded in Djamaa region.

Table 4 .
Abundance and proportion of ant species recorded in El-Oued region.

Table 5 .
Abundance and proportion of ant species recorded in Ouargla region.