Phylogenomic analysis of Stylops reveals the evolutionary history of a Holarctic Strepsiptera radiation parasitizing wild bees.

Holarctic Stylops is the largest genus of the enigmatic insect order Strepsiptera, twisted winged parasites. Members of Stylops are obligate endoparasites of Andrena mining bees and exhibit extreme sexual dimorphism typical of Strepsiptera. So far, molecular studies on Stylops have focused on questions on species delimitation. Here, we utilize the power of whole genome sequencing to infer the phylogeny of this morphologically challenging genus from thousands of loci. We use a species tree method, concatenated maximum likelihood analysis and Bayesian analysis with a relaxed clock model to reconstruct the phylogeny of 46 Stylops species, estimate divergence times, evaluate topological consistency across methods and infer the root position. Furthermore, the biogeographical history and coevolutionary patterns with host species are assessed. All methods recovered a well resolved topology with close to all nodes maximally supported and only a handful of minor topological variations. Based on the result, we find that included species can be divided into 12 species groups, seven of them including only Palaearctic species, three Nearctic and two were geographically mixed. We find a strongly supported root position between a clade formed by the spreta, thwaitesi and gwynanae species groups and the remaining species and that the sister group of Stylops is Eurystylops or Eurystylops + Kinzelbachus. Our results indicate that Stylops originated in the Western Palaearctic or Western Palaearctic and Nearctic in the early Neogene or late Paleogene, with four independent dispersal events to the Nearctic. Cophylogenetic analyses indicate that the diversification of Stylops has been shaped by both significant coevolution with the mining bee hosts and host-shifting. The well resolved and strongly supported phylogeny will provide a valuable phylogenetic basis for further studies into the fascinating world of Strepsipterans.

MuTr: Multi-Stage Transformer for Hand Pose Estimation from Full-Scene Depth Image.

This work presents a novel transformer-based method for hand pose estimation-DePOTR. We test the DePOTR method on four benchmark datasets, where DePOTR outperforms other transformer-based methods while achieving results on par with other state-of-the-art methods. To further demonstrate the strength of DePOTR, we propose a novel multi-stage approach from full-scene depth image-MuTr. MuTr removes the necessity of having two different models in the hand pose estimation pipeline-one for hand localization and one for pose estimation-while maintaining promising results. To the best of our knowledge, this is the first successful attempt to use the same model architecture in standard and simultaneously in full-scene image setup while achieving competitive results in both of them. On the NYU dataset, DePOTR and MuTr reach precision equal to 7.85 mm and 8.71 mm, respectively.

Phylogenetic relationships and the evolution of host preferences in the largest clade of brood parasitic bees (Apidae: Nomadinae).

Brood parasites (also known as cleptoparasites) represent a substantial fraction of global bee diversity. Rather than constructing their own nests, these species instead invade those of host bees to lay their eggs. Larvae then hatch and consume the food provisions intended for the host's offspring. While this life history strategy has evolved numerous times across the phylogeny of bees, the oldest and most speciose parasitic clade is the subfamily Nomadinae (Apidae). However, the phylogenetic relationships among brood parasitic apids both within and outside the Nomadinae have not been fully resolved. Here, we present new findings on the phylogeny of this diverse group of brood parasites based on ultraconserved element (UCE) sequence data and extensive taxon sampling with 114 nomadine species representing all tribes. We suggest a broader definition of the subfamily Nomadinae to describe a clade that includes almost all parasitic members of the family Apidae. The tribe Melectini forms the sister group to all other Nomadinae, while the remainder of the subfamily is composed of two sister clades: a "nomadine line" representing the former Nomadinae sensu stricto, and an "ericrocidine line" that unites several mostly Neotropical lineages. We find the tribe Osirini Handlirsch to be polyphyletic, and divide it into three lineages, including the newly described Parepeolini trib. nov. In addition to our taxonomic findings, we use our phylogeny to explore the evolution of different modes of parasitism, detecting two independent transitions from closed-cell to open-cell parasitism. Finally, we examine how nomadine host-parasite associations have evolved over time. In support of Emery's rule, which suggests close relationships between hosts and parasites, we confirm that the earliest nomadines were parasites of their close free-living relatives within the family Apidae, but that over time their host range broadened to include more distantly related hosts spanning the diversity of bees. This expanded breadth of host taxa may also be associated with the transition to open-cell parasitism.

Polyandrous bee provides extended offspring care biparentally as an alternative to monandry based eusociality.

Parental care behavior evolves to increase the survival of offspring. When offspring care becomes complicated for ecological reasons, cooperation of multiple individuals can be beneficial. There are two types of cooperative care: biparental care and worker (helper)-based care (e.g., eusociality). Although biparental care is common in several groups of vertebrates, it is generally rare in arthropods. Conversely, eusociality is widespread in insects, especially the aculeate Hymenoptera. Here, we present a case of biparental care in bees, in Ceratina nigrolabiata (Apidae, Xylocopinae). Similar to eusocial behavior, biparental care leads to greater brood protection in this species. Male guarding increases provisioning of nests because females are liberated from the tradeoff between provisioning and nest protection. The main benefit of parental care for males should be increased paternity. Interestingly though, we found that paternity of offspring by guard males is extraordinarily low (10% of offspring). Generally, we found that nests were not guarded by the same male for the whole provisioning season, meaning that males arrive to nests as stepfathers. However, we show that long-term guarding performed by a single male does increase paternity. We suggest that the multiple-mating strategy of these bees increased the amount of time for interactions between the sexes, and this longer period of potential interaction supported the origin of biparental care. Eusociality based on monandry was thought to be the main type of extended brood protection in bees. We show that biparental care based on polyandry provides an interesting evolutionary alternative.

Frozen Antarctic path for dispersal initiated parallel host-parasite evolution on different continents.

After the break-up of Gondwana dispersal of organisms between America, Australia and Africa became more complicated. One of the possible remaining paths led through Antarctica, that was not yet glaciated and it remained habitable for many organisms. This favourable climate made Antarctica an important migration corridor for organisms with good dispersal ability, such as Aculeata (Hymenoptera), till the Oligocene cooling. Here we tested how cooling of Antarctica impacted global dispersal of Aculeata parasites (Strepsiptera: Xenidae). Our data set comprising six nuclear genes from a broad sample of Xenidae. Bayesian dating was used to estimate divergence times in phylogenetic reconstruction. Biogeography was investigated using event-based analytical methods: likelihood-based dispersal-extinction-cladogenesis and Bayesian models. The Bayesian model was used for reconstruction of ancestral host groups. Biogeographical methods indicate that multiple lineages were exchanged between the New World and the Old World + Australia until the Antarctica became completely frozen over. During the late Paleogene and Neogene periods, several lineages spread from the Afrotropics to other Old World regions and Australia. The original hosts of Xenidae were most likely social wasps. Within one lineage of solitary wasp parasites, parallel switch to digger wasps (Sphecidae) occurred independently in the New World and Old World regions. The biogeography and macroevolutionary history of Xenidae can be explained by the combination of dispersal, lineage extinction and climatic changes during the Cenozoic era. A habitable Antarctica and the presence of now-submerged islands and plateaus that acted as a connection between the New World and Old World + Australia provided the possibility for biotic exchanges of parasites along with their hymenopteran hosts. Although Xenidae are generally host specialists, there were significant host switches to unrelated but ecologically similar hosts during their evolution. There is little or no evidence for cophylogeny between strepsipteran parasites and hymenopteran lineages.

The interplay of climate and land use change affects the distribution of EU bumblebees.

Bumblebees in Europe have been in steady decline since the 1900s. This decline is expected to continue with climate change as the main driver. However, at the local scale, land use and land cover (LULC) change strongly affects the occurrence of bumblebees. At present, LULC change is rarely included in models of future distributions of species. This study's objective is to compare the roles of dynamic LULC change and climate change on the projected distribution patterns of 48 European bumblebee species for three change scenarios until 2100 at the scales of Europe, and Belgium, Netherlands and Luxembourg (BENELUX). We compared three types of models: (1) only climate covariates, (2) climate and static LULC covariates and (3) climate and dynamic LULC covariates. The climate and LULC change scenarios used in the models include, extreme growth applied strategy (GRAS), business as might be usual and sustainable European development goals. We analysed model performance, range gain/loss and the shift in range limits for all bumblebees. Overall, model performance improved with the introduction of LULC covariates. Dynamic models projected less range loss and gain than climate-only projections, and greater range loss and gain than static models. Overall, there is considerable variation in species responses and effects were most pronounced at the BENELUX scale. The majority of species were predicted to lose considerable range, particularly under the extreme growth scenario (GRAS; overall mean: 64% ± 34). Model simulations project a number of local extinctions and considerable range loss at the BENELUX scale (overall mean: 56% ± 39). Therefore, we recommend species-specific modelling to understand how LULC and climate interact in future modelling. The efficacy of dynamic LULC change should improve with higher thematic and spatial resolution. Nevertheless, current broad scale representations of change in major land use classes impact modelled future distribution patterns.

Antimicrobial Peptide from the Wild Bee Hylaeus signatus Venom and Its Analogues: Structure-Activity Study and Synergistic Effect with Antibiotics.

Venoms of hymenopteran insects have attracted considerable interest as a source of cationic antimicrobial peptides (AMPs). In the venom of the solitary bee Hylaeus signatus (Hymenoptera: Colletidae), we identified a new hexadecapeptide of sequence Gly-Ile-Met-Ser-Ser-Leu-Met-Lys-Lys-Leu-Ala-Ala-His-Ile-Ala-Lys-NH2. Named HYL, it belongs to the category of α-helical amphipathic AMPs. HYL exhibited weak antimicrobial activity against several strains of pathogenic bacteria and moderate activity against Candida albicans, but its hemolytic activity against human red blood cells was low. We prepared a set of HYL analogues to evaluate the effects of structural modifications on its biological activity and to increase its potency against pathogenic bacteria. This produced several analogues exhibiting significantly greater activity compared to HYL against strains of both Staphylococcus aureus and Pseudomonas aeruginosa even as their hemolytic activity remained low. Studying synergism of HYL peptides and conventional antibiotics showed the peptides act synergistically and preferentially in combination with rifampicin. Fluorescent dye propidium iodide uptake showed the tested peptides were able to facilitate entrance of antibiotics into the cytoplasm by permeabilization of the outer and inner bacterial cell membrane of P. aeruginosa. Transmission electron microscopy revealed that treatment of P. aeruginosa with one of the HYL analogues caused total disintegration of bacterial cells. NMR spectroscopy was used to elucidate the structure-activity relationship for the effect of amino acid residue substitution in HYL.

Interaction of a novel antimicrobial peptide isolated from the venom of solitary bee Colletes daviesanus with phospholipid vesicles and Escherichia coli cells.

The peptide named codesane (COD), consisting of 18 amino acid residues and isolated from the venom of wild bee Colletes daviesanus (Hymenoptera : Colletidae), falls into the category of cationic α-helical amphipathic antimicrobial peptides. In our investigations, synthetic COD exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria and Candida albicans but also noticeable hemolytic activity. COD and its analogs (collectively referred to as CODs) were studied for the mechanism of their action. The interaction of CODs with liposomes led to significant leakage of calcein entrapped in bacterial membrane-mimicking large unilamellar vesicles made preferentially from anionic phospholipids while no calcein leakage was observed from zwitterionic liposomes mimicking membranes of erythrocytes. The preference of CODs for anionic phospholipids was also established by the blue shift in the tryptophan emission spectra maxima when the interactions of tryptophan-containing COD analogs with liposomes were examined. Those results were in agreement with the antimicrobial and hemolytic activities of CODs. Moreover, we found that the studied peptides permeated both the outer and inner cytoplasmic membranes of Escherichia coli. This was determined by measuring changes in the fluorescence of probe N-phenyl-1-naphthylamine and detecting cytoplasmic ß-galactosidase released during the interaction of peptides with E. coli cells. Transmission electron microscopy revealed that treatment of E. coli with one of the COD analogs caused leakage of bacterial content mainly from the septal areas of the cells.

Structure-activity study of macropin, a novel antimicrobial peptide from the venom of solitary bee Macropis fulvipes (Hymenoptera: Melittidae).

A novel antimicrobial peptide, designated macropin (MAC-1) with sequence Gly-Phe-Gly-Met-Ala-Leu-Lys-Leu-Leu-Lys-Lys-Val-Leu-NH2 , was isolated from the venom of the solitary bee Macropis fulvipes. MAC-1 exhibited antimicrobial activity against both Gram-positive and Gram-negative bacteria, antifungal activity, and moderate hemolytic activity against human red blood cells. A series of macropin analogs were prepared to further evaluate the effect of structural alterations on antimicrobial and hemolytic activities and stability in human serum. The antimicrobial activities of several analogs against pathogenic Pseudomonas aeruginosa were significantly increased while their toxicity against human red blood cells was decreased. The activity enhancement is related to the introduction of either l- or d-lysine in selected positions. Furthermore, all-d analog and analogs with d-amino acid residues introduced at the N-terminal part of the peptide chain exhibited better serum stability than did natural macropin. Data obtained by CD spectroscopy suggest a propensity of the peptide to adopt an amphipathic α-helical secondary structure in the presence of trifluoroethanol or membrane-mimicking sodium dodecyl sulfate. In addition, the study elucidates the structure-activity relationship for the effect of d-amino acid substitutions in MAC-1 using NMR spectroscopy.

Total synthesis, proof of absolute configuration, and biosynthetic origin of stylopsal, the first isolated sex pheromone of strepsiptera.

The asymmetric total synthesis of the diastereomers of stylopsal establishes the absolute configuration of the first reported sex pheromone of the twisted-wing parasite Stylops muelleri as (3R,5R,9R)-trimethyldodecanal. The key steps for the diastereo- and enantiodivergent introduction of the methyl groups are two different types of asymmetric conjugate addition reactions of organocopper reagents to α,ß-unsaturated esters, whereas the dodecanal skeleton is assembled by Wittig reactions. The structure of the natural product was confirmed by chiral gas chromatography (GC) techniques, GC/MS and GC/electroantennography (EAD) as well as field tests. An investigation into the biosynthesis of the pheromone revealed that it is likely to be produced by decarboxylation of a 4,6,10-trimethyltridecanoic acid derivative, which was found in substantial amounts in the fat body of the female, but not in the host bee Andrena vaga. This triple-branched fatty acid precursor thus seems to be biosynthesized de novo through a polyketide pathway with two consecutive propionate-propionate-acetate assemblies to form the complete skeleton. The simplified, motionless and fully host-dependent female exploits a remarkable strategy to maximize its reproductive success by employing a relatively complex and potent sex pheromone.

Panurgines, novel antimicrobial peptides from the venom of communal bee Panurgus calcaratus (Hymenoptera: Andrenidae).

Three novel antimicrobial peptides (AMPs), named panurgines (PNGs), were isolated from the venom of the wild bee Panurgus calcaratus. The dodecapeptide of the sequence LNWGAILKHIIK-NH2 (PNG-1) belongs to the category of α-helical amphipathic AMPs. The other two cyclic peptides containing 25 amino acid residues and two intramolecular disulfide bridges of the pattern Cys8-Cys23 and Cys11-Cys19 have almost identical sequence established as LDVKKIICVACKIXPNPACKKICPK-OH (X=K, PNG-K and X=R, PNG-R). All three peptides exhibited antimicrobial activity against Gram-positive bacteria and Gram-negative bacteria, antifungal activity, and low hemolytic activity against human erythrocytes. We prepared a series of PNG-1 analogs to study the effects of cationicity, amphipathicity, and hydrophobicity on the biological activity. Several of them exhibited improved antimicrobial potency, particularly those with increased net positive charge. The linear analogs of PNG-K and PNG-R having all Cys residues substituted by α-amino butyric acid were inactive, thus indicating the importance of disulfide bridges for the antimicrobial activity. However, the linear PNG-K with all four cysteine residues unpaired, exhibited antimicrobial activity. PNG-1 and its analogs induced a significant leakage of fluorescent dye entrapped in bacterial membrane-mimicking large unilamellar vesicles as well as in vesicles mimicking eukaryotic cell membrane. On the other hand, PNG-K and PNG-R exhibited dye-leakage activity only from vesicles mimicking bacterial cell membrane.

Comprehensive phylogeny of apid bees reveals the evolutionary origins and antiquity of cleptoparasitism.

Apidae is the most speciose and behaviorally diverse family of bees. It includes solitary, eusocial, socially parasitic, and an exceptionally high proportion of cleptoparasitic species. Cleptoparasitic bees, which are brood parasites in the nests of other bees, have long caused problems in resolving the phylogenetic relationships within Apidae based on morphological data because of the tendency for parasites to converge on a suite of traits, making it difficult to differentiate similarity caused by common ancestry from convergence. Here, we resolve the evolutionary history of apid cleptoparasitism by conducting a detailed, comprehensive molecular phylogenetic analysis of all 33 apid tribes (based on 190 species), including representatives from every hypothesized origin of cleptoparasitism. Based on Bayesian ancestral state reconstruction, we show that cleptoparasitism has arisen just four times in Apidae, which is fewer times than previously estimated. Our results indicate that 99% of cleptoparasitic apid bees form a monophyletic group. Divergence time estimates reveal that cleptoparasitism is an ancient behavior in bees that first evolved in the late Cretaceous 95 Mya [95% highest posterior density (HPD) = 87-103]. Our phylogenetic analysis of the Apidae sheds light on the macroevolution of a bee family that is of evolutionary, ecological, and economic importance.

Stylopsal: the first identified female-produced sex pheromone of strepsiptera.

A female-produced sex pheromone of Stylops muelleri was identified as an unusually branched saturated aldehyde (9R)-3,5-syn-3,5,9-trimethyldodecanal. We named it stylopsal. Its structure was established by using mass spectrometry, infrared spectroscopy, and organic synthesis of candidate compounds. The synthetic standard of (9R)-3,5-syn-3,5,9-trimethyldodecanal gave identical chromatographic and mass spectrometric data as the natural pheromone and also was active in electroantennographic and behavioral assays. The female fat body lipids contained the corresponding fatty acid, indicating a possible link between lipid metabolism and the pheromone biosynthesis.

A generic classification of Xenidae (Strepsiptera) based on the morphology of the female cephalothorax and male cephalotheca with a preliminary checklist of species.

The generic taxonomy and host specialization of Xenidae have been understood differently by previous authors. Although the recent generic classification has implied a specialization on the level of host families or subfamilies, the hypothesis that each xenid genus is specialized to a single host genus was also previously postulated. A critical evaluation of the classification of the genera of Xenidae is provided here based on morphology in accordance with results of recent molecular phylogenetic studies. External features of the female cephalothoraces and male cephalothecae were documented in detail with different techniques. Diagnoses and descriptions are presented for all 13 delimited genera. The earliest diverging genera are usually well characterized by unique features, whereas deeply nested genera are usually characterized by combinations of characters. Three new genera are described: Sphecixenos gen. nov., Tuberoxenos gen. nov., and Deltoxenos gen. nov. Five previously described genera are removed from synonymy: Tachytixenos Pierce, 1911, stat. res.; Brasixenos Kogan & Oliveira, 1966, stat. res.; Leionotoxenos Pierce, 1909, stat. res.; Eupathocera Pierce, 1908, stat. res.; and Macroxenos Schultze, 1925, stat. res. One former subgenus is elevated to generic rank: Nipponoxenos Kifune & Maeta, 1975, stat. res. Monobiaphila Pierce, 1909, syn. nov. and Montezumiaphila Brèthes, 1923, syn. nov. are recognized as junior synonyms of Leionotoxenos Pierce, 1909, stat. res. Ophthalmochlus Pierce, 1908, syn. nov., Homilops Pierce, 1908, syn. nov., Sceliphronechthrus Pierce, 1909, syn. nov., and Ophthalmochlus (Isodontiphila) Pierce, 1919, syn. nov. are recognized as junior synonyms of Eupathocera Pierce, 1908, stat. res. A preliminary checklist of 119 described species of Xenidae with information on their hosts and distribution is provided. The following 14 species are recognized as valid and restituted from synonymy: Tachytixenosindicus Pierce, 1911, stat. res.; Brasixenosacinctus Kogan & Oliveira, 1966, stat. res.; Brasixenosaraujoi (Oliveira & Kogan, 1962), stat. res.; Brasixenosbahiensis Kogan & Oliveira, 1966, stat. res.; Brasixenosbrasiliensis Kogan & Oliveira, 1966, stat. res.; Brasixenosfluminensis Kogan & Oliveria, 1966, stat. res.; Brasixenosmyrapetrus Trois, 1988, stat. res.; Brasixenoszikani Kogan & Oliveira, 1966, stat. res.; Leionotoxenoshookeri Pierce, 1909, stat. res.; Leionotoxenosjonesi Pierce, 1909, stat. res.; Leionotoxenoslouisianae Pierce, 1909, stat. res.; Eupathoceraluctuosae Pierce, 1911, stat. res.; Eupathoceralugubris Pierce, 1909, stat. res.; Macroxenospiercei Schultze, 1925, stat. res. New generic combinations are proposed for 51 species: Leionotoxenosarvensidis (Pierce, 1911), comb. nov.; Leionotoxenosbishoppi (Pierce, 1909), comb. nov.; Leionotoxenosforaminati (Pierce, 1911), comb. nov.; Leionotoxenosfundati (Pierce, 1911), comb. nov.; Leionotoxenoshuastecae (Székessy, 1965), comb. nov.; Leionotoxenositatiaiae (Trois, 1984), comb. nov.; Leionotoxenosneomexicanus (Pierce, 1919), comb. nov.; Leionotoxenosprolificum (Teson & Remes Lenicov, 1979), comb. nov.; Leionotoxenosrobertsoni (Pierce, 1911), comb. nov.; Leionotoxenostigridis (Pierce, 1911), comb. nov.; Leionotoxenosvigili (Brèthes, 1923), comb. nov.; Eupathoceraargentina (Brèthes, 1923), comb. nov.; Eupathoceraauripedis (Pierce, 1911), comb. nov.; Eupathocerabucki (Trois, 1984), comb. nov.; Eupathoceraduryi (Pierce, 1909), comb. nov.; Eupathoceraerynnidis (Pierce, 1911), comb. nov.; Eupathocerafasciati (Pierce, 1909), comb. nov.; Eupathocerafuliginosi (Brèthes, 1923), comb. nov.; Eupathocerainclusa (Oliveira & Kogan, 1963), comb. nov.; Eupathocerainsularis (Kifune, 1983), comb. nov.; Eupathoceramendozae (Brèthes, 1923), comb. nov.; Eupathocerapiercei (Brèthes, 1923), comb. nov.; Eupathocerastriati (Brèthes, 1923), comb. nov.; Eupathocerataschenbergi (Brèthes, 1923), comb. nov.; Eupathocerawestwoodii (Templeton, 1841), comb. nov.; Macroxenospapuanus (Székessy, 1956), comb. nov.; Sphecixenosabbotti (Pierce, 1909), comb. nov.; Sphecixenosastrolabensis (Székessy, 1956), comb. nov.; Sphecixenosdorae (Luna de Carvalho, 1956), comb. nov.; Sphecixenoserimae (Székessy, 1956), comb. nov.; Sphecixenosesakii (Hirashima & Kifune, 1962), comb. nov.; Sphecixenosgigas (Pasteels, 1950), comb. nov.; Sphecixenoskurosawai (Kifune, 1984), comb. nov.; Sphecixenoslaetum (Ogloblin, 1926), comb. nov.; Sphecixenosorientalis (Kifune, 1985), comb. nov.; Sphecixenosreticulatus (Luna de Carvalho, 1972), comb. nov.; Sphecixenossimplex (Székessy, 1956), comb. nov.; Sphecixenosvanderiisti (Pasteels, 1952), comb. nov.; Tuberoxenosaltozambeziensis (Luna de Carvalho, 1959), comb. nov.; Tuberoxenossinuatus (Pasteels, 1956), comb. nov.; Tuberoxenossphecidarum (Siebold, 1839), comb. nov.; Tuberoxenosteres (Pasteels, 1950), comb. nov.; Tuberoxenostibetanus (Yang, 1981), comb. nov.; Deltoxenosbequaerti (Luna de Carvalho, 1956), comb. nov.; Deltoxenosbidentatus (Pasteels, 1950), comb. nov.; Deltoxenoshirokoae (Kifune & Yamane, 1992), comb. nov.; Deltoxenosiwatai (Esaki, 1931), comb. nov.; Deltoxenoslusitanicus (Luna de Carvalho, 1960), comb. nov.; Deltoxenosminor (Kifune & Maeta, 1978), comb. nov.; Deltoxenosrueppelli (Kinzelbach, 1971a), comb. nov.; Xenosropalidiae (Kinzelbach, 1975), comb. nov. Xenosminor Kinzelbach, 1971a, syn. nov. is recognized as a junior synonym of X.vesparum Rossi, 1793. Ophthalmochlusduryi Pierce, 1908, nomen nudum and Eupathoceralugubris Pierce, 1908, nomen nudum are recognized as nomina nuda and therefore unavailable in zoological nomenclature. The species diversity of Xenidae probably remains poorly known: the expected number of species is at least twice as high as the number presently described.

Individual-level specialisation and interspecific resource partitioning in bees revealed by pollen DNA metabarcoding.

It is increasingly recognised that intraspecific variation in traits, such as morphology, behaviour, or diet is both ubiquitous and ecologically important. While many species of predators and herbivores are known to display high levels of between-individual diet variation, there is a lack of studies on pollinators. It is important to fill in this gap because individual-level specialisation of flower-visiting insects is expected to affect their efficiency as pollinators with consequences for plant reproduction. Accordingly, the aim of our study was to quantify the level of individual-level specialisation and foraging preferences, as well as interspecific resource partitioning, in three co-occurring species of bees of the genus Ceratina (Hymenoptera: Apidae: Xylocopinae), C. chalybea, C. nigrolabiata, and C. cucurbitina. We conducted a field experiment where we provided artificial nesting opportunities for the bees and combined a short-term mark-recapture study with the dissection of the bees' nests to obtain repeated samples from individual foraging females and complete pollen provisions from their nests. We used DNA metabarcoding based on the ITS2 locus to identify the composition of the pollen samples. We found that the composition of pollen carried on the bodies of female bees and stored in the brood provisions in their nests significantly differed among the three co-occurring species. At the intraspecific level, individual females consistently differed in their level of specialisation and in the composition of pollen carried on their bodies and stored in their nests. We also demonstrate that higher generalisation at the species level stemmed from larger among-individual variation in diets, as observed in other types of consumers, such as predators. Our study thus reveals how specialisation and foraging preferences of bees change from the scale of individual foraging bouts to complete pollen provisions accumulated in their nests over many days. Such a multi-scale view of foraging behaviour is necessary to improve our understanding of the functioning of plant-flower visitor communities.

Signals of adaptation to agricultural stress in the genomes of two European bumblebees.

Human-induced environmental impacts on wildlife are widespread, causing major biodiversity losses. One major threat is agricultural intensification, typically characterised by large areas of monoculture, mechanical tillage, and the use of agrochemicals. Intensification leads to the fragmentation and loss of natural habitats, native vegetation, and nesting and breeding sites. Understanding the adaptability of insects to these changing environmental conditions is critical to predicting their survival. Bumblebees, key pollinators of wild and cultivated plants, are used as model species to assess insect adaptation to anthropogenic stressors. We investigated the effects of agricultural pressures on two common European bumblebees, Bombus pascuorum and B. lapidarius. Restriction-site Associated DNA Sequencing was used to identify loci under selective pressure across agricultural-natural gradients over 97 locations in Europe. 191 unique loci in B. pascuorum and 260 in B. lapidarius were identified as under selective pressure, and associated with agricultural stressors. Further investigation suggested several candidate proteins including several neurodevelopment, muscle, and detoxification proteins, but these have yet to be validated. These results provide insights into agriculture as a stressor for bumblebees, and signal for conservation action in light of ongoing anthropogenic changes.

Nesting of Ceratina nigrolabiata, a biparental bee.

Biparental care is very rare in insects, and it was well-documented in only one bee species to this date - Ceratina nigrolabiata. However, biparental care was only recently discovered in this species, and detailed description of natural history of this species is missing. Here, we describe the nesting cycle of C. nigrolabiata. Pairs of C. nigrolabiata are established before female starts offspring provisioning. After provisioning is finished (when youngest offspring reached larval stage), the male abandons the nest. Males which are present in nests where female already finished provisioning brood cells, are probably mainly temporary visitors. The female can perform long-time offspring guarding, but only 22% of completely provisioned nests are guarded by a female. Most nests (54%) are closed and abandoned, when provisioning is completed, and other (24%) are orphaned before provisioning is finished. Guarded nests have statistically higher number of brood cells provisioned than unguarded nests. Generally, C. nigrolabiata is unique among bees due to its biparental behavior, but it has also uncommon traits of nesting biology among Ceratina bees, e.g. fast offspring development in comparison with provisioning rate, and high proportion of nests which are closed and abandoned by mother.

Female calling, life cycle, and microstructures of the parasitic beetle Ripidius quadriceps Abeille de Perrin.

The precopulatory behaviour of the larviform females of Ripidius quadriceps Abeille de Perrin, 1872 is described. The calling posture of virgin females is documented. The cephalic morphology and microstructures are visualised using scanning electron microscopy, in particular the secretory pores in the cuticle of inflatable maxillary palps. An exhaustive overview of relevant publications revealed that the location of secretory pores on the head of females is unique within the order Coleoptera. Compared to other beetles with sedentary calling females, the calling phase of the short-lived and non-feeding female of Ripidius is exceptionally short. For bioassays, various traps using virgin females of Ripidius were tested. It is likely that the sedentary behaviour of the short-lived female combined with a unique morphology and priority for investing in reproduction is compensated for by the actively flying males with remarkably flabellate antennae. The life cycle of this species, including some of the exceptions recorded at the individual level, is discussed. Perspectives for a biological and morphological survey of this rarely collected western Palaearctic species are outlined. In addition, the calling behaviour, secretory sites and location of pheromone glands in females of Coleoptera producing long range pheromones is reviewed.

The spread of Colletes hederae Schmidt & Westrich, 1993 continues - first records of this plasterer bee species from Slovakia and the Czech Republic.

Colletes hederae Schmidt & Westrich, 1993 is a cryptic bee species from the C. succinctus species-group. The previous occurrence and spreading of this species were predominantly in south-western Europe. To determine if the species was spreading in Slovak territory, Hedera helix was monitored from autumn 2015. The ivy-bee was first recorded in Slovakia during autumn 2017. This species is widespread inside and around Bratislava; however, it was not recorded under this study in any sites located eastwards. In the Czech Republic, it was not recorded in the south-east part of the country in 2017-2019. In 2020, the occurrence of this species was confirmed in many localities in the south of the country and strong populations were discovered, especially in the towns Znojmo and Mikulov. The populations likely originated from neighbouring Austria, where this species was discovered in 2006 and the localities are usually less than 100 km away from Czech and Slovak localities. A further survey could map a route of the northwards spread of this species.