Sizing the Knowledge Gap in Taxonomy: The Last Dozen Years of Aphidiinae Research

Simple Summary

Taxonomy is a biological discipline with the task to identify, name, and describe organisms, and as such, it provides necessary data for all other biological disciplines. The biodiversity crisis through which we are living draws attention to the crucial role of taxonomy in biology today. At the same time, the scientific community, as well as society in general, has become more aware of the difficulties associated with taxonomy, such as gaps in taxonomic knowledge, a lack of taxonomic infrastructure, and an insufficient number of taxonomic experts (“taxonomic impediment”). With this study, we tried to size this knowledge gap by analyzing the taxonomical studies on Aphidiinae (Hymenoptera: Braconidae) conducted from 2010 to 2021. Aphidiinae are endoparasitoids of aphids; a single specimen completes its development inside the living aphid host, which are used in biological control programs. Here, we summarize the knowledge gathered over the last dozen years and discuss it in a general context.

Abstract

Taxonomic impediment is one of the main roadblocks to managing the current biodiversity crisis. Insect taxonomy is the biggest contributor to the taxonomic impediment, both in terms of the knowledge gap and the lack of experts. With this study, we tried to size the knowledge gap by analyzing taxonomical studies on the subfamily Aphidiinae (Hymenoptera: Braconidae) conducted from 2010 to 2021. All available taxonomic knowledge gathered in this period is critically summarized: newly described species, detection of alien species, published identification keys, etc. All findings are discussed relative to the current state of general taxonomy. Future prospects for taxonomy are also discussed.

Phylogeny of the Subtribe Monoctonina (Hymenoptera, Braconidae, Aphidiinae)

Members of the Monoctonina subtribe have long been neglected in applied studies of the subfamily Aphidiinae, due to their low economic importance, as they do not parasitize pests of cultivated plants. Consequently, data about this group are scarce, including its taxonomy and phylogeny. In the present study, we explore inter- and intraspecific genetic variation of Monoctonina species, including genera Monoctonus Haliday 1833, Monoctonia Starý 1962, Falciconus Mackauer 1959 and Harkeria Cameron 1900. We employ two molecular markers, the barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) and the D2 region of the 28S nuclear gene (28S rDNA), to analyze genetic structuring and phylogeny of all available Monoctonina species, and combine them with morphological data for an integrative approach. We report one new species, and three potentially new species which can be formally described when further specimens are available. Analysis of phylogenetic relationships within the subtribe shows a basal position for the genera Falciconus and Monoctonia, and the close relatedness of Harkeria and Monoctonus.

Phylogenetic relationships and subgeneric classification of European Ephedrus species (Hymenoptera, Braconidae, Aphidiinae)

In this study two molecular markers were used to establish taxonomic status and phylogenetic relationships of Ephedrus subgenera and species distributed in Europe. Fifteen of the nineteen currently known species have been analysed, representing three subgenera: Breviephedrus Gärdenfors, 1986, Lysephedrus Starý, 1958 and Ephedrus Haliday, 1833. The results of analysis of COI and EF1α molecular markers and morphological studies did not support this classification. Three clades separated by the highest genetic distances reported for the subfamily Aphidiinae on intrageneric level. Ephedrusbrevis is separated from persicae and plagiator species groups with genetic distances of 19.6 % and 16.3 % respectively, while the distance between persicae and plagiator groups was 20.7 %. These results lead to the conclusion that the traditional subgeneric classification of Ephedrus needs revision. Species from persicae species group are raised to subgenus level as Fovephedrus Chen, 1986 and Lysephedrussyn. nov. is assigned as a junior synonym of subgenusEphedrus. Key for identification of Ephedrus subgenera is provided. Ephedrushyadaphidis Kocić & Tomanović sp. nov. is described and several species are confirmed as valid species for the first time. Furthermore, two species are synonymised: E.dysaphidissyn. nov. as a junior synonym of E.cerasicola and E.blattnyisyn. nov. as a junior synonym of E.plagiator.