Species are often presumed to be apparent in nature, but in practice they may be difficult to recognise, especially when viewed across continents rather than within a single site. Coalescent-based Poisson-tree-process (PTP) models applied to fast-evolving genes promise one quantitative criterion for recognising species, complete with the estimates of uncertainty that are required of a scientific method. Such methods face challenges especially in discerning between widespread polytypic species and complexes of closely related, restricted-range species. In particular, ‘over-sampling’ of many closely related individuals within one species could risk causing groups of less closely-related individuals within other species appearing relatively more distinct and consequently could risk them being interpreted falsely as separate species. Some of the most persistent taxonomic problems among bumblebees (genus Bombus Latreille, 1802) are within the subgenus Melanobombus von Dalla Torre, 1880. For a global revision of Melanobombus species, we use COI barcodes and seek to reduce the risk from localised over-sampling by filtering the data to include only unique haplotypes. Unique haplotypes give more conservative results than unfiltered data, but still increase the number of species in comparison with recent morphological treatments. After integrative assessment of COI coalescents in comparison with morphological groups, the number of accepted species shows a non-linear increase with sample size that plateaus to an increase of 47% (to 25 species) compared with a previous estimate (of 17) based on morphology alone. For the most widespread and variable species-complexes, our revised species improve the match to the patterns expected of species, both for genetic divergence-with-distance and for sympatry, leading to three main inferences. (1) The particularly widespread polytypic Bombus sichelii Radoszkowski, 1859, is a single species. (2) We detect two candidates for species within previous broad concepts of each of the former B. lapidarius (Linnaeus, 1758), B. miniatus Bingham, 1897, and B. rufofasciatus Smith, 1852. Within B. lapidarius s. lat. we find insufficient evidence to corroborate the candidate species, with no coalescent or morphological support for a recent claim for a separate species, B. bisiculus Lecocq, Biella, Martinet & Rasmont, 2019 described from southern Italy, but rather we find a weak and uncorroborated coalescent for a different and much broader group of samples from across southeastern Europe but excluding Turkey. Within the former broad concepts of B. miniatus s. lat. and B. rufofasciatus s. lat. the coalescent evidence is stronger and subtle evidence from morphology corroborates recognising B. miniatus s. str. and B. eurythorax Wang, 1892 stat. rev. as separate species as well as B. rufofasciatus s. str. and B. prshewalskyi Morawitz, 1880 stat. rev. as separate species. (3) Our coalescent and morphological results ‘split’ more clearly what has long been interpreted as a single polytypic B. keriensis Morawitz, 1887, s. lat., by supporting novel concepts of the restricted-range species: B. alagesianus Reinig, 1930 stat. rev., B. incertoides Vogt, 1911 stat. rev., B. keriensis s. str., B. qilianensis sp. nov., B. separandus Vogt, 1909 stat. rev., and B. tibeticus sp. nov. A lectotype is designated for the name B. keriensis and a neotype is designated for the name B. alagesianus. We estimate the phylogeny of Melanobombus species by including three slower-evolving genes to provide more evidence for deeper relationships, to estimate the time calibration of this phylogeny, and to estimate ancestral distributions, all within a Bayesian framework. We provide the first keys for identifying all of the species of Melanobombus.

In the largest systematic spider collection effort in a single location in the Caucasus Ecoregion, across several altitudinal zones and throughout the entire vegetation period of one year, 426 juvenile and 359 adult spiders belonging to 69 species from 48 genera and 19 families were collected in the Lagodekhi Reserve, Georgia, in 2014, using Malaise traps on a transect with seven study plots between 666 and 2559 m a.s.l. in the montane, subalpine, and alpine vegetation zones. Phoroncidia pilula (Karsch, 1879) is recorded in the Western Palaearctic for the first time. Thirty-eight species are recorded in the Lagodekhi Reserve for the first time, raising the number of spider species of this reserve to 202, five additions are first records for the Caucasus Ecoregion and ten species are first records for Georgia. Diagnostic drawings and analyses are provided for 13 species, including Megalepthyphantes pseudocollinus Saaristo, 1997, Phoroncidia paradoxa (Lucas, 1846), P. pilula (Karsch, 1879), and Trochosa cachetiensis Mcheidze, 1997. An updated checklist of the spiders in the Lagodekhi Reserve is provided.

In fragmented farmland landscapes structural complexity and low agricultural intensification should decrease the abundance of crop aphids due to increased abundances and species diversity of aphid enemies, including hymenopteran parasitoids. Here we study the effects of landscape structure and agricultural intensification on parasitism rates, abundances, and species richness of aphids and their parasitoids in five different regions in Europe. While total aphid numbers did not differ significantly among regions, we observed marked differences between Scandinavian and central European sites with respect to the species composition of aphids and their parasitoids and parasitism rates. In the cross country comparison landscape complexity and agricultural intensification did not significantly affect total aphid densities, although we observed species-specific reactions to land use. We also observed a tendency towards increased parasitoid species richness at low agricultural intensification but not at high landscape structure.

A list of Iranian Encyrtidae (Hymenoptera: Chalcidoidea) is given for the first time. It includes 93 species representing 32 genera. Host information from Iran and distributional data are also provided. Three genera and 7 species are first recorded from Iran. New host records are provided for three species. Two new species, Gyranusoidea iranica sp. n. and Microterys iranicus sp. n., are described and diagnostic characters are provided for them.