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

It's time for Africa - hidden diversity of the Aphidius colemani species group (Hymenoptera, Braconidae, Aphidiinae) south of the Sahara

Aphidius colemani is an important biological control agent, used in greenhouses and open fields against aphid pests. Despite this economical importance, A. colemani, along with A. transcaspicus and A. platensis, has gone through a complex taxonomical history. The three species have only recently gained status as separate species again, comprising the morphologically defined Aphidius colemani species group. Other than sporadic records probably as a consequence of escape from greenhouses, the A. colemani species group members prefer warmer regions and there are numerous records from South America, Southern Europe and Asia. Based on slide-mounted material collected in the period 1964-2001 in Africa, we describe five new species belonging to this group, and report A. colemani, A. transcaspicus and A. platensis from several African countries. This data opens questions about the origin of the group and presents potential for the diversification of biological control agents against aphid pests.

Dyscrituluseuropaeus sp. nov. (Hymenoptera, Braconidae, Aphidiinae): description of a new aphid parasitoid species with an identification key for species of the genus

The braconid genus Dyscritulus Hincks is a small member of the subfamily Aphidiinae, distributed in Europe and Central Asia. All its species are highly specialized parasitoids of aphids of the genera Drepanosiphum Koch and, probably, Periphyllus van der Hoeven which are mostly associated with maple and sycamore trees (genus Acer). Upon examination of specimens from the Naturalis Biodiversity Center, Leiden, we unexpectedly noted unusual variability in morphological characters compared to other known Dyscritulus species. Further inspection of other material previously identified as Dyscritulusplaniceps Marshall, 1896 revealed additional specimens with the same morphological variability. Here we describe a new species of the genus, Dyscrituluseuropaeussp. nov., associated with Drepanosiphum aphids on Acer.

Cereal Aphid Parasitoids in Europe (Hymenoptera: Braconidae: Aphidiinae): Taxonomy, Biodiversity, and Ecology

Cereals are very common and widespread crops in Europe. Aphids are a diverse group of herbivorous pests on cereals and one of the most important limiting factors of cereal production. Here, we present an overview of knowledge about the taxonomy, biodiversity, and ecology of cereal aphid parasitoids in Europe, an important group of natural enemies contributing to cereal aphid control. We review the knowledge obtained from the integrative taxonomy of 26 cereal aphid primary parasitoid species, including two allochthonous species (Lysiphlebus testaceipes and Trioxys sunnysidensis) and two recently described species (Lipolexis labialis and Paralipsis brachycaudi). We further review 28 hyperparasitoid species belonging to three hymenopteran superfamilies and four families (Ceraphronoidea: Megaspillidae; Chalcidoidea: Pteromalidae, Encyrtidae; Cynipoidea: Figitidae). We also compile knowledge on the presence of secondary endosymbionts in cereal aphids, as these are expected to influence the community composition and biocontrol efficiency of cereal aphid parasitoids. To study aphid-parasitoid-hyperparasitoid food webs more effectively, we present two kinds of DNA-based approach: (i) diagnostic PCR (mainly multiplex PCR), and (ii) DNA sequence-based methods. Finally, we also review the effects of landscape complexity on the different trophic levels in the food webs of cereal aphids and their associated parasitoids, as well as the impacts of agricultural practices and environmental variation.

Special Issue: Selected Papers from the 1st International Electronic Conference on Entomology

The 1st International Electronic Conference on Entomology (1IECE) was held between 1 and 15 July 2021 on the MDPI Sciforum platform organized and funded by the international journal Insects [...].

Biodiversity and Distribution of Reticulitermes in the Southeastern USA

Simple Summary

Describing global biodiversity involves identifying species and describing their distributions. The subterranean termite genus Reticulitermes represents an important group of wood-destroying organisms; however, little is known about their species-specific distribution across the three northern hemisphere continents where they are endemic. We combined several taxonomic methods to identify the species of over 4000 specimens in the first statewide survey of subterranean termites from Georgia, USA. The area surveyed, 153,900 km², represents eco-regions typical of most of the southeast and eastern seaboard of the United States. There were three species, R. flavipes, R. virginicus, and R. nelsonae, found throughout Georgia. R. malletei was predominantly collected in the northern Piedmont soil province, while R. hageni, the least encountered species, was not collected from South Georgia. Our findings support the need for a taxonomic revision of the genus Reticulitermes, agreement on an appropriate integrated taxonomic approach for species determination, and should stimulate future research on diverse topics such as biodiversity, monitoring for these structural pests, and identifying their role in forest ecosystems.

Abstract

Reticulitermes subterranean termites are widely distributed ecosystem engineers and structural pests, yet describing their species distribution worldwide or regionally has been hindered by taxonomic uncertainties. Morphological plasticity confounds the use of taxonomic keys, while recent species descriptions and molecular techniques lacking taxonomic support have caused a muddle in interpreting the literature on Reticulitermes species distributions. We employed an integrative taxonomic approach combining behavioral, morphological, and molecular techniques to identify 4371 Reticulitermes samples to species. Five Reticulitermes species were collected from wood-on-ground at 1570 sites covering 153,900 km² in the state of Georgia, USA. Three species were collected throughout Georgia, with R. flavipes identified from every one of the 159 counties. R. nelsonae was the second most frequently collected species, found in 128 counties, with R. virginicus third with 122. Two species had distributions confined to the northern part of the state. R. malletei was collected from 73 counties, while the least collected species, R. hageni, was found in 16. Results show that the most recently described species (R. nelsonae, 2012) is widely distributed and the second-most frequently encountered termite, representing 23% of all samples. The invasive species R. flavipes represented half of all the samples collected, while R. hageni, the least at less than 1%. A search of GenBank identified a number of accessions mismatched to a species designation resulting in the literature under-reporting the biodiversity of the genus. We, therefore, outline a path to standardize methods for species identification using an integrated taxonomic approach with appropriate barcodes for consistent identification across research teams worldwide. The data also illuminate new opportunities to examine questions related to the ecology, evolution, dispersal, and resource partitioning behaviors of these sympatric species across distinct geographical regions.