The melittology research in Northern Africa and the Middle East: past and present situations

Background: More than 20,000 species in the superfamily Apoidea have been identified worldwide. This superfamily includes the most important group of insect pollinators that contribute to the integrity of ecosystems. Main body: We have gathered in this paper data from many previous works in Northern Africa and Middle East regions. Some of these data are date from many years ago and others are recent. We present here a nonexhaustive list of some common Apoid species. In addition, certain previous studies that were published and other current research opportunities were suggested. Conclusion: Although there are many bee experts in the Arab world, i.e., in apiculture, however, a few researchers are interested in melittology even though it seems that this region represents a large bee diversity.


Background
The sexual reproduction of over 90% of approximately 250,000 species of Angiosperms is depending on animal-pollination (Kearns & Oliveras, 2009). This plant-animal interaction maintains the world's biodiversity and contributes to the integrity of ecosystems. Crops often depend on honeybee colonies for their productivity, partially on wild bee pollinators also (Klein et al., 2006;Potts et al., 2016). Actually, among 107 global crops, 90 are visited by bees, being the most important group of pollinators (Klein et al., 2006). However, the economic, ecological, and biodiversity importances of pollinators are acknowledged for few systems (Delaplane & Mayer, 2000) and there is a considerable extent for studying the characteristics of pollinators in Northern Africa and the Middle East (MENA) which moderates the value of pollinator communities. Although over 20,000 bee species have been globally reported (Ascher & Pickering, 2020), in most of Northen African and Arab countries, the total number of bee species is unclear and there are no published keys for species identification or even there is no updated checklist of bees for each country or the whole region (Grace, 2010;Shebl, Kamel, & Mahfouz, 2013). According to Rasmont (1995), the Maghreb and North Africa probably represent a bee diversity comparable or even larger than that of California where 1200 species were counted (Moldenke & Neff, 1974). Some studies show that the Maghreb and the Nile delta are remarkably rich in bee species and Morocco constitutes a hotspot for bee species richness. In contrast, in the area between western Egypt and southeastern Tunisia, the species richness is considered in a very low level (Michez & Patiny, 2007;Patiny, Michez, Kuhlmann, Pauly, & Barbier, 2009). Dours (1872); Benoist (1941Benoist ( , 1949Benoist ( , 1950; Guiglia (1942); Priesner (1957); and Schulthess (1924) were among the first entomologists who were interested in the study of bee fauna in The Mediterranean and Northen Africa regions. More recent works include those of Daly (1983); Ebmer (1985); Ebmer and Grünwaldt (1976); Gusenleitner and Schwarz (2002); (Zanden, 1991(Zanden, , 1994(Zanden, , 1996. Melittology research was done extensively in Algeria, Egypt, Morocco, and Saudi Arabia, in the last four decades probably with the beginning of the 70s. On the other hand, some works were carried out in Tunisia and Libya and probably in other countries (Bendifallah et al., 2010a).

Main text
In Egypt, the first study was carried out in the late 1950s by Priesner (1957) who was interested in species of the genus Anthophora in the region. Suez Canal University is the hub center of melittology research in Egypt now. Several research projects of bee diversity and conservation have been started in the last two decades (Osman & Shebl, 2020;Shebl et al., 2013). Grace (2010) recorded around 370 bee species in Egypt. In 2020, 466 bee species were recorded by Ascher and Pickering (2020) representing 15 subfamilies and seven families of Apoidea. The first research with solitary bees started in the seventies at the Agriculture Research Center, Ministry of Agriculture. Some papers were published in local and international journals (Ibrahim, Nassib, & El-Sherbeeny, 1978;Moustafa, El-Hefny, Abd El-Salam, & Salem, 1979;Moustafa & El Berry, 1976;Rashad, 1978;Rashad, 1985). Extensive field expeditions were done in the Canal region, 62 species were listed in addition to some newly recorded species (Shebl et al., 2013;Shebl & Farag, 2015) (Table 1). At the beginning of this century, Suez Canal University was collaborated with Idaho University (USA) and received grants for initiating leafcutting-bee cell management for alfalfa pollination (Shebl, Kamel, Abu Hashesh, & Osman, 2009). Some species were successfully nested in artificial nests (Kamel et al., 2019;Shebl, Hassan, Kamel, Osman, & Engel, 2018). Since there is no accurate number of native bee species in the country and still more species to be found and discovered (Abu Zeid, Shebl, & Metwali, 2019), more research is needed to be conducted.
In 2020, a preliminary study conducted in a semi-arid environment in Tunisia concerned the distribution of insect visitors, in addition to honey bees hives, revealed the presence of three superfamilies: the Apoidea (represented mainly by the Apidae and Megachilidea families), the Ichneumonoidea, and the Vespoidea (Ben Abdelkader, Ounisi, Barbouche, & Ammar, 2020).
Although research on the conservation of wild bees is common in the Mediterranean area, little is known about their status in the Libyan ecosystem. Libya as all other countries of the Mediterranean Basin contains many non-Apis species that spread all over the country. Among the works carried out in the Maghreb region during the first half of the twentieth century, we found the work of Guiglia (1942) who studied the Hymenoptera of Libya. Recently, about 151 bee species were recorded by Grace (2010) and 276 species were reported by Ascher and Pickering (2020) in Libya (Table 1).
The melittology research in Libya based on a teamwork at Faculty of Science, Omar Al-Mukhtar University. Currently, there are some ongoing studies focused on wild bee's diversity of the Al-Jabal Al-Akhder that is a dense in east Libya, covered with agricultural and wild plants. Also, some basic ecological studies such as species distribution and their interaction with wild plant flowers are in progress. Surely, the results of these studies will encourage other researchers to get involved and explore the country's native bee diversity and its great impact on the ecosystem.
In Morocco, the bee fauna was studied by Benoist (1941Benoist ( , 1949Benoist ( , 1950. Ebmer and Grünwaldt (1976) and Ebmer (1985) (14) were reported in Morocco (Ascher & Pickering, 2020) (Table 1). Currently, there is a great funded project by ICARDA to evaluate the role of solitary bees in crop pollination. This project extended to other countries, e.g., Algeria represented in the National Institute of Agronomic Research (Algiers and Touggourt) whose work began in 2020. Patiny et al. (2009) evaluated the distribution of some bee species within a region including the Sahara and Arabian deserts and their adjacent areas. They found that the Hoplitis mucida (Dours, 1873) was presented in Maghreb region (Morocco, Algeria, and Tunisia). The Melitturga albescens was the only palaearctic species found in Atlas Mountains and Tafilalt in Morocco. Panurgus dentatus was reported in Morocco along the southern slopes of the Atlas Mountains and in Egypt (Nile Valley) (Shebl, Patiny, & Michez, 2015), the mountains south of Tripoli and westwards into Tunisia. Dasypoda oraniensis was restricted to Morocco and western Algeria and was not existed in the eastern part of North Africa.
The first information concerning the bees of Syria dates from 1890. Thirty-four species were recorded from Damascus. Later in 1908, 20 new species of bees, mostly from Damascus and Homs, were recorded. In 1956, the list of the bees described and recorded was about 55 species (Mavromoustakis, 1956b). In 2010, Grace (2010) cited 266 species from Syria, while (Ascher & Pickering, 2020) reported the presence of 440 species (Table 1).
In Lebanon, bee fauna is not well documented. The first works were from Mavromoustakis (1955Mavromoustakis ( , 1956aMavromoustakis ( , 1962 who collected extensively bees of Anthidiini and Osminii. About 163 species were cited by Grace (2010), but 260 species were listed byAscher and Pickering (2020). Boustani et al. (2020) listed four species of bumblebees with different foraging ranges.
In Iraq, studies in this concern were very few also. Augul (2018) investigated the fauna of bees (Hymenoptera, Apoidea) from different regions of Iraq. A total of 16 species from 13 genera belonging to four families was found. The same author revised all the species that were recorded in previous investigations and reported the presence of 110 species, 32 genera belonging to five families: Apidae, Andernidae, Colletidae, Halictidae, and Megachilidae. In 2019, a revision about the Sphecidae was done, 41 species belonging to 12 genera, and four subfamilies of the family Sphecidae were found in Iraq (Augul, 2019).
Unfortunately, we were unable to find any literature about the bee fauna of Yemen and Oman except those cited by Baker (2004). Some genera were recorded by Alqarni et al. (2014c) and Engel (2011). According to Ascher and Pickering (2020), 67 species recorded in Yemen representing five families and 83 species were recorded in Oman, considered very low number compared to those of other regions (Table 1).
This work describes the situation of mellitology research in North Africa and the Middle East. It also cites the most common species present in the region. According to the literature, the bee fauna is very rich in MENA region with the presence of the six families in all the countries. The diversity of species is variable according to the countries geography, topography, and floral diversity. There are many common bee species, for each family, exist in MENA region, Apidea with almost 549 species, followed by the Megachilidae with 555 species. The Andrenidae and the Halictidae families came third place with almost 326 and 330 species respectively. Finally, the Colletidiae and the Mellittidae presented 148 and 25 species respectively. This review forms the basis for further studies involving the identification and beeplant interactions in MENA regions. The continuous surveys will add more information about the bees in the region. Those efforts will be made to seek out further material in the field, obtain observations on their floral visitation behaviors, nesting biology, and locate immature stages.

Conclusions
Bees have great economic and ecological value. Recently, their continuous global loss requires the urgent development of specific conservation strategies. However, the difficulty of estimating the loss of bees and/or their preservation is due to lack of information (e.g., databases, not updating previous findings, etc.) concerning their worldwide diversity. Nevertheless, very little work has so far aimed to study the diversity of bees in the Arab world and Northen Africa although studies on bee diversity are abundant in many countries. One of the major problems facing scientists especially in Northen Africa is the lack of funding and collaboration for conducting several research expeditions across the countries. Moreover, upcoming researches in these countries need to focus on taxonomy, diversity, ecology, and biology of native bees. Our utmost goal of such initiative and consortium is to show the great impact of native bees on the pollination services of wild and cultivated plants that are requesting continuous protection and conservation.
Abbreviations UAE: United Arab Emirates; MENA: Middle East and North Africa