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Genetics and ecological studies on honeybee’s population in Sudan

The honeybee Apis mellifera L. has been classified   morphologically to 24 subspecies, and grouped into four branches according to their geographical distribution (Ruttner 1988). Recently two lineages were added by molecular approaches one called O which includes the Near and Middle Eastern subspecies and another lineage called Y including the A. m. yemenitica subspecies from Ethiopia (Franck et al. 2001).The latest new lineage will be the subject of this study.

Mogbel El-Niweiri

Mogbel El-Niweiri

The native honeybees in Sudan were first classified as Apis mellifera nubica and reclassified to Apis mellifera  yemenitica (Rutnure 1976). However, morphometrical studies which were carried out to differentiate between honeybees population in Sudan showed  more than one subspecies. El-Sarrag et al. (1992) reported that there at least two subspecies of honeybees in Sudan: a yellow banded group Apis mellifera sudanensis nov subsp and a mixed group of Apis mellifera nubica Ruttner. Apis mellifera sudanensis is a small honeybee distributed all over the Sudan between latitudes 3 N and 16 20’N whereas Apis mellifera nubica is distributed along the international borders of Sudan with Ethiopia and Uganda. The clusters of the Sudanese bees were also classified morphometrically by Mogga (1988) and divided into three sub-clusters; the smallest bee, Apis mellifera yemenitica, (Ruttner), The medium bee Apis mellifera sudanensis, (Rashad) and the largest bee Apis mellifera bandasii .

Because of the deliberate introduction and the accidental introduction of non-native species, there are two kinds of non-native honeybees in Sudan: the European (Italian & Carniolan) bees and the Asian bees (A. florea ). The first recorded import of non-native honeybees in Sudan was made in 1928 when Italian, Carniolan and F1 Carnio-Egyptian honeybees were imported from Egypt for education purposes (Anonymous 1969). However, more recently thousands of Carniolan honeybee colonies have been imported for commercial purposes in order to improve honey production in Sudan. During this expansion they might have had ample opportunities to competitively displace or hybridized with native Sudanese honeybees.

The dwarf honeybee, A. florea, was introduced to Sudan in 1985 (Lord and Nagi 1987 & Mogga and Ruttner 1988). It is spreading rapidly however, until today there are no negative reports about the affect of this non-native bees on Sudanese ecosystems or on beekeeping operations (El Shafie et al., 2002).
Beekeeping in Sudan is still practiced in a very primitive way. There are about 200.000 honeybee hives in Sudan with a total number of about 50.000 beekeepers. The vast majority of these are using traditional beekeeping technology and only ~1% use modern beekeeping equipment and technology (El-Sarrag et al.1988).
In spite of the great interest that has been given during recent years to study the Sudanese honeybee, much more work is needed in that field. Very little information has been obtained or published on the genetic structure of honeybee populations in Sudan.
The genetic diversity in populations of honey bees has assessed with allozymes like Malate dehydrogenase (Mdh-1) and hexokinase (Hk-1) to characterize A. mellifera populations or determine their racial composition (Badino et al., 1983; Sheppard and McPheron, 1986; Spivak et al., 1988; Lobo et al., 1989; Del Lama et al., 1988, 1990; Lobo, 1995). Also nuclear and mitochondrial DNA polymorphisms have been used to characterize African honeybees primarily aiming to classify the the various subspecies (Hall, 1986, 1990; Smith and Brown, 1988; Hall and Muralidharan, 1989; Oldroyd et al., 1992; Sheppard et al., 1991a,b; Clarke et al., 2001.

These techniques are however often to crude for detecting the impacts of introgression and competition at the population level. Bottlenecks, recent population declines and measuring gene flow can however be excellently analysed with microsatellite DNA loci in honeybees (Estoup et al., 1993, 1994, Franck et al., 1998).
Microsatellites were also used to show that African populations have high genetic variability and high effective population sizes (Franck et al. 2001). Moreover African honeybees were found to be have the highest degree of multiple mating (polyandry) in comparison to other subspecies (Moritz et al 1996, Franck et al. 2000).
The repeated introduction of non-native honeybees may form a serious threat to both native honeybee populations and beekeeping in Sudan. Apart for the introduction of novel diseases, the risk stems from competitive displacement and the loss of indigenous honeybee populations.
Whereas the introduction of A. florea might primarily operate through competition for food sources, the introduction on non-native Apis mellifera colonies may cause undesired hybridization with native populations.
The field work of this research will be therefore focus on sampling A. mellifera populations in Sudan including a study area, which  roughly extending from about 3 N to 22 N and from 22 E to 38 E with total of 2.5 million km². This area covers all kinds of habitat ranging from desert to tropical rainforest allowing detecting potential interactions between habitat conditions and competition between imported and native populations.   In addition to the impact of environmental factors we also want to: (1) study the impact of beekeeping (both modern and traditional) on the structure of native honeybee populations. This socio-economic aspect is of particular importance because it directly aims at the sustainability of beekeeping techniques in Sudan,(2) determine the distribution of different kinds of honeybees in Sudan to establish a data base for further ecological and genetics studies(3) find out the genetic structure of native and non-native Apis mellifera populations in Sudan(4) screen the genetic variance of these populations and test for introgression and population decline(5) characterize bee populations in Sudan to conserve the native honeybee biodiversity.

Due to the diverse arrangement of morphotyes and behavior, in addition to the previous morphmetric studies that classified Sudan- native honeybees to at least two or three sub species of (El-Sarrag et al.1992, Mogga 1988), we hypothesize that more than one subspecies will  be found in Sudan.
Due to the ongoing importations of European Apis mellifera, which started in 1928 and the overlapping of honeybee’s population along the international boundaries of Sudan, Ethiopia and Uganda we expect to see extensive hybridization in both managed and wild colonies of honeybees in Sudan.
Sudan is a tropical country and the activity of the honeybee and their distribution are greatly affected by the environmental factors such as climate, thus the native honeybees and the dwarf honeybee Apis florea are expected to be have wide distribution.
Since African honeybee queens are characterized by high degrees of multiple mating (Franck et al. 2000), we expect to find adaptations of polyandry to the large variety in ecosystems in Sudanese.
The population size and the genetic diversity of the Sudanese honeybees are expected to be high, because all the African populations display higher genetic variability than European populations at all microsatellite loci studied and that has been suggested as consequences of larger effective populations sizes of African compared to European ones (Franck et al. 2001).