Molecular analyses reveal consistent food web structure with elevation in rainforest Drosophila – parasitoid communities

The analysis of interaction networks across spatial environmental gradients is a powerful approach to investigate the responses of communities to global change. Using a combination of DNA metabarcoding and traditional molecular methods we built bipartite Drosophila-parasitoid food webs from six Australian rainforest sites across gradients spanning 850 m in elevation and 5° Celsius in mean temperature. Our cost-effective hierarchical approach to network reconstruction separated the determination of host frequencies from the detection and quantification of interactions. The food webs comprised 5-9 host and 5-11 parasitoid species at each site, and showed a lower incidence of parasitism at high elevation. Despite considerable turnover in the relative abundance of host Drosophila species, and contrary to some previous results, we did not detect significant changes to fundamental metrics of network structure including nestedness and specialisation with elevation. Advances in community ecology depend on data from a combination of methodological approaches. It is therefore especially valuable to develop model study systems for sets of closely-interacting species that are diverse enough to be representative, yet still amenable to field and laboratory experiments

Wolbachia and DNA barcoding insects: patterns, potential and problems

Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein – wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor – for which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region

The global change of species interactions

A recommendation of the preprint: Mennerat A, Charmantier A, Hurtrez-Bousses S, Perret P, and Lambrechts MM. 2019. Parasite intensity is driven by temperature in a wild bird. bioRxiv 323311, ver 4 peer-reviewed and recommended by Peer Community in Ecology. doi: 10.1101/32331

Axial stiffness for large-scale ball slewing rings with four-point contact

This article deals with the design of slewing rings (slewing bearings). A fully parametric, 3D virtual model of a ball slewing ring with four-point contact was created in the PTC/Creo Parametric CAD system. This model was subsequently used for finite-element analysis using Ansys/Workbench CAE software. The purpose of the FEM analysis was to determine the axial stiffness characteristics. Results of FEM analysis were experimentally verified using a test bench. At the end of the article, we present the nomograms of the deformation constant for different pitch diameters, rolling element diameters and contact angles

DROP: Molecular voucher database for identification of Drosophila parasitoids

A curated open-access molecular reference database for Drosophila parasitoids (DROP). Identifying Drosophila parasitoids is challenging and poses major impediment to realize the full potential of this model system in studies ranging from molecular mechanisms to food webs, and in biological control of Drosophila suzukii. In DROP, genetic data are linked to voucher specimens and, where possible, the voucher specimens are identified by taxonomists and vetted through direct comparison with primary type material. An updated taxonomic catalogue for the research community is also part of DROP. DROP offers accurate molecular identification and improves cross-referencing between individual studies that we hope will catalyze research on this diverse and fascinating model system. Our effort should also serve as an example for researchers facing similar molecular identification problems in other groups of organisms.Please primarily cite the following paper which introduces this database: Lue et al (2021). DROP: Molecular voucher database for identification of Drosophila parasitoids. Molecular Ecology Resources, 21, 2437–2454. https://doi.org/10.1111/1755-0998.1343

Cystomastacoides van Achterberg (Braconidae, Rogadinae): first host record and descriptions of three new species from Thailand and Papua New Guinea

A new species of Cystomastacoides van Achterberg, C. asotaphaga Quicke sp. n., is described and illustrated based on a series of specimens reared from caterpillars of the erebid moth Asota plana Walker from Papua New Guinea. Two other new species without biological data are also described, C. nicolepeelerae Quicke & Butcher sp. n. also from Papua New Guinea, and C. kiddo Quicke & Butcher sp. n. from Thailand. A key is provided to the four known species. The new species extend the known range of the genus considerably, itpreviously been known only from a single species from mainland China (Yunnan), and additionally provides the first host record for the genus. Other related genera are parasitoids of Sphingidae, Lymantriidae and Crambidae

High hymenopteran parasitoid infestation rates in Czech populations of the Euphydryas aurinia butterfly inferred using a new molecular marker

We apply a molecular approach to quantify the level of hymenopteran parasitoids infestation in the larvae of the marsh fritillary (Euphydryas aurinia), a declining butterfly species, in western Bohemia, Czech Republic, in two subsequent years. We used the novel primer HymR157 in combination with known universal 28SD1F to establish a PCR detection system which amplifies hymenopteran parasitoids, but not the lepidopteran host. In the 14 sampled E. aurinia colonies, the infestation rates per individuum were 33.3% and 40.2%; whereas per sampled larval colony, these were on average 38.5% (range 0–100) and 40.1% (0–78). The per-colony infestation rates correlated with the numbers of larval webs censused per colony the year prior to sampling the parasitoids, pointing to a time lag in parasitoid infestation rates. The levels of the hymenopteran parasitoid prevalence are thus relatively high, supporting the importance of parasitoids for the population dynamics of the threatened host. The detection primers we developed can detect a range of hymenopteran parasitoids on other butterfly hosts

High hymenopteran parasitoid infestation rates in Czech populations of the Euphydryas aurinia butterfly inferred using a new molecular marker

We apply a molecular approach to quantify the level of hymenopteran parasitoids infestation in the larvae of the marsh fritillary (Euphydryas aurinia), a declining butterfly species, in western Bohemia, Czech Republic, in two subsequent years. We used the novel primer HymR157 in combination with known universal 28SD1F to establish a PCR detection system which amplifies hymenopteran parasitoids, but not the lepidopteran host. In the 14 sampled E. aurinia colonies, the infestation rates per individuum were 33.3% and 40.2%; whereas per sampled larval colony, these were on average 38.5% (range 0–100) and 40.1% (0–78). The per-colony infestation rates correlated with the numbers of larval webs censused per colony the year prior to sampling the parasitoids, pointing to a time lag in parasitoid infestation rates. The levels of the hymenopteran parasitoid prevalence are thus relatively high, supporting the importance of parasitoids for the population dynamics of the threatened host. The detection primers we developed can detect a range of hymenopteran parasitoids on other butterfly hosts

Colastomion Baker (Braconidae, Rogadinae): nine new species from Papua New Guinea reared from Crambidae

Nine new species of Colastomion Baker are described, illustrated and keyed based on series of specimens reared from caterpillars of crambid moths from lowland Papua New Guinea plus one additional field collected specimen, viz. C. cheesmanae Quicke sp. n., C. crambidiphagus Quicke sp. n., C. gregarius Quicke sp. n., C. maclayi Quicke sp. n., C. madangensis Quicke sp. n., C. masalaii Quicke sp. n., C. parotiphagus Quicke sp. n., C. pukpuk Quicke sp. n. and C. wanang Quicke sp. n. Most species are morphologically easily distinguished but DNA barcoding additionally reveals a pair of exceedingly similar species (C. pukpuk sp. n. and C. maclayi sp. n.) that might otherwise have gone unrecognised. The new species each appear to be relatively specialised on their host species and all parasitize only caterpillars of Lepidoptera: Crambidae: Spilomelinae