New data on the hoverflies of Morocco (Diptera, Syrphidae) with faunistic and bibliographical inventories

Abstract All published records of 148 species of hoverflies from Morocco are reviewed and appropriate literature references, new locality records, and relevant comments are provided for each species. The list is supplemented with records from new field surveys. Two species, Eumerus obliquus (Fabricius, 1805) and Orthonevra brevicornis Loew, 1843 are recorded for the first time in Morocco. The new checklist comprises 150 nominal species from three subfamilies, 14 tribes, and 49 genera.


Introduction
Syrphidae (Diptera: Brachycera), commonly named hoverflies, constitute, among the order Diptera, a taxonomically well-characterised family. Most adults feed on pollen and nectar and thus are potentially important pollinators and their conservation is essential to sustain the productivity of natural and agricultural landscapes (Moquet et al. 2018). The larvae of Syrphidae have various food habits; certain species are predators while others are phytophagous, mycophagous or saprophytophagous (Rotheray and Gilbert 1999, Rotheray 1993, Büchs 2003.
Syrphidae were collected from 79 localities across the main regions in Morocco, mostly in the Rif Mountains, including the Eastern region, the High Atlas, Middle Atlas and Anti Atlas. Additional material and databases indicated in the text are provided by other researchers.
Collecting was mainly carried out by sweep netting and Malaise trapping adults and/or rearing larvae and puparia in the laboratory from collected substrates in aquatic ecosystems following the technique used by Afzan and Belqat (2016). The majority of the Moroccan hoverflies were identified from external characteristics, except for some species for which male genital morphology was used to confirm their identity. Identifications were done with specific keys (Verlinden 1991, Kassebeer 1995a, Hauser and Kassebeer 1998, Kassebeer 1998b, Kassebeer 1999b, van Veen 2004, Marcos-García et al. 2007, Speight and Sarthou 2013. Fourty-six of the species were identified with the help of Bastiaan Wakkie (Brussels, Belgium).
Distribution. Western and Central Palaearctic.
Comments. New to Morocco. E. obliquus was recorded from Egypt (Steyskal andEl-Bialy 1967, Peck 1988). The species is found in open ground, thinly vegetated, semi-arid dry grassland, often along the margins of seasonal rivers; it feeds from the juice of ripe, fallen fruits of Opuntia (Speight 2018). In Morocco, we collected adults by sweeping the vegetation around lotic habitats. As stated in the literature, we found the species in the margins of a temporary river. The wet section was reduced to a thin layer of water. Riparian vegetation consisted primarily of Opuntia ficus indica (Fig. 5), of Nerium oleander, and herbaceous vegetation. The second habitat was also a river flowing towards oued Moulouya with predominant vegetation consisted of Olea europea, Citrus sinensis, Citrus reticulata, Punica granatum, and Eucalyptus.
Distribution. Mediterranean Europe, southern Russia, Lebanon, and Morocco.

Merodon sophron Hurkmans, 1993
Literature records. Middle Atlas (Hurkmans 1993: 168, Vujic et al. 2020. Comment. Endemic to Morocco. Merodon sophron is one of the 13 species belonging to the Merodon serrulatus species group. It is redefined and redescribed by Vujic et al. (2020) on the material from the type locality of Azrou.
Merodon unguicornis Strobl 1909 (Fig. 7) Literature record. Middle Atlas (Ebejer et al. 2019: 150). New site. Rif: Forest house, 17/V/2014, 1♀, sweep net, leg. Sahib and Belqat. Comment. New record for the Rif. M. unguicornis was cited for the first time in Morocco by Ebejer et al. (2019). In the present work, the female was collected at the locality of Forest house environment (Fig. 8), crossed by a spring and a brook and where the most predominant vegetation was formed by Abies marocana, Pinus negra, Pinus pinaster, Cedrus atlantica and Berberis hispanica. Collected on a misty day, as visualized in Figure 8.
Distribution. Spain and Morocco.

Discussion
The present work provides an important contribution to the Moroccan hoverfly fauna with two species recorded for the first time for Morocco: Eumerus obliquus (Fabricius, 1805) and Orthonevra brevicornis (Loew, 1843); nine new records are provided for the Rif, five for the Middle Atlas, and seven species are recorded for the first time for the Hight Atlas, the Anti Atlas, and the Eastern Region for which we have enlarged the distribution area. The 150 Moroccan species belong to three subfamilies, 14 tribes, and 49 genera (30 genera of Eristalinae, 16 of Syrphinae, and 3 of Pipizinae). Knowledge of the hoverfly diversity of Morocco is unequal among regions. For instance, the Middle Atlas and the High Atlas have the same number of species (69), the Rif has 68 species, the Anti Atlas has 18 species, while the Eastern region has only seven species.
Morocco is home to 12 endemic species: two are endemic to the Rif, four to the Middle Atlas (including both an endemic genus and species (Ighbouloumia atlasi)), three to the High Atlas, one to the central plateau, and two species, Platycheirus atlasi and Melanogaster lindbergi, to the Middle Atlas plus the High Atlas, and to the Rif plus the Middle Atlas, respectively.
Morocco with the greatest number of total species (150), has 75% of the North African syrphid fauna. Algeria, with 91 species, has 46% of the total fauna. Tunisia, with 69, has 35% of the fauna, whereas Egypt and Libya have 51 species (26%) and 34 species (17%), respectively.
Algeria, Tunisia, Libya, and Egypt share with Morocco 71, 55, 25, and 30 species, respectively, but these numbers are likely to change and a detailed comparison must await a systematic sampling of the whole region.
Of the two Iberian Peninsula countries, Spain has the best known Syrphiidae fauna with 417 species whereas Portugal has only 195 species (Marcos-Garcia et al. 2002, Speight 2015, van Eck 2011, 2016.
These new data on the Moroccan hoverfly fauna reflect the variety of suitable habitats and suggest that many more species can yet be found in Morocco, that provides a wide variety of geographical and climatic properties. New species are also likely to be discovered by genomic prospecting using molecular approaches.