| Abstrakt: |
Simple Summary: Hoverflies are regarded as the second most important pollinators after bees. They also provide important environmental services including the biodegradation of organic wastes, as well as the predation of pests. Hoverflies are usually divided into several groups or regions including the Holarctic, the Oriental, the Australasian and the Afrotropical. The latter is considered one of the most diverse groups but is still poorly studied due to the unavailability of complete and detailed identification keys for numerous genera and/or species. Published taxonomy studies on hoverflies in South Africa were published in the 1980s. This study aimed to investigate the barcoding of hoverfly species found in the Free State province of South Africa in order to ascertain their taxonomy and establish their genetic richness and differentiation. From 78 specimens of hoverflies sampled in the eastern Free State of South Africa, DNA barcodes helped to confirm the taxonomy of 15 hoverfly species from nine genera. With the barcodes generated in this study, the identification of Afrotropical species can be improved, but about 40% of the known species cannot be identified using the available identification keys. The Afrotropical hoverflies remain an understudied group of hoverflies. One of the reasons for the lack of studies on this group resides in the difficulties to delimit the species using the available identification keys. DNA barcoding has been found useful in such cases of taxonomical uncertainty. Here, we present a molecular study of hoverfly species from the eastern Free State of South Africa using the mitochondrial cytochrome-c oxidase subunit I gene (COI). The identification of 78 specimens was achieved through three analytical approaches: genetic distances analysis, species delimitation models and phylogenetic reconstructions. In this study, 15 nominal species from nine genera were recorded. Of these species, five had not been previously reported to occur in South Africa, namely, Betasyrphus inflaticornis Bezzi, 1915, Mesembrius strigilatus Bezzi, 1912, Eristalinus tabanoides Jaennicke, 1876, Eristalinus vicarians Bezzi, 1915 and Eristalinus fuscicornis Karsch, 1887. Intra- and interspecific variations were found and were congruent between neighbour-joining and maximum likelihood analyses, except for the genus Allograpta Osten Sacken, 1875, where identification seemed problematic, with a relatively high (1.56%) intraspecific LogDet distance observed in Allograpta nasuta Macquart, 1842. Within the 78 specimens analysed, the assembled species by automatic partitioning (ASAP) estimated the presence of 14–17 species, while the Poisson tree processes based on the MPTP and SPTP models estimated 15 and 16 species. The three models showed similar results (10 species) for the Eristalinae subfamily, while for the Syrphinae subfamily, 5 and 6 species were suggested through MPTP and SPTP, respectively. Our results highlight the necessity of using different species delimitation models in DNA barcoding for species diagnoses. [ABSTRACT FROM AUTHOR] |
