Expression of subunits of an insecticide target receptor varies across tissues, life stages, castes, and species of social bees.

Global losses of insects jeopardize ecosystem stability and crop pollination. Robust evidence indicates that insecticides have contributed to these losses. Notably, insecticides targeting nicotinic acetylcholine receptors (nAChRs) have neurotoxic effects on beneficial insects. Because each nAChR consists of five subunits, the alternative arrangements of subunits could create a multitude of receptors differing in structure and function. Therefore, understanding whether the use of subunits varies is essential for evaluating and predicting the effects of insecticides targeting such receptors. To better understand how the use and composition of nAChRs differ within and between insect pollinators, we analysed RNA-seq gene expression data from tissues and castes of Apis mellifera honey bees and life stages and castes of the Bombus terrestris bumble bees. We reveal that all analysed tissues express nAChRs and that relative expression levels of nAChR subunits vary widely across almost all comparisons. Our work thus shows fine-tuned spatial and temporal expression of nAChRs. Given that coexpression of subunits underpins the compositional diversity of functional receptors and that the affinities of insecticides depend on nAChR composition, our findings provide a likely mechanism for the various damaging effects of nAChR-targeting insecticides on insects. Furthermore, our results indicate that the appraisal of insecticide risks should carefully consider variation in molecular targets.

Convergent Reversion to Single Mating in a Wasp Social Parasite.

While eusociality arose in species with single-mating females, multiple mating by queens has evolved repeatedly across the social ants, bees, and wasps. Understanding the benefits and costs of multiple mating of queens is important because polyandry results in reduced relatedness between siblings, reducing kin-selected benefits of helping while also selecting for secondary social traits that reduce intracolony conflict. The leading hypothesis for the benefits of polyandry in social insects emphasizes advantages of a genetically diverse workforce. Workerless social parasite species (inquilines) provide a unique opportunity to test this hypothesis, since they are derived from social ancestors but do not produce workers of their own. Such parasites are thus predicted to evolve single mating because they would experience the costs of multiple mating but not the benefits if such benefits accrue through the production of a genetically diverse group of workers. Here we show that the workerless social parasite Dolichovespula arctica, a derived parasite of wasps, has reverted to obligate single mating from a facultatively polyandrous ancestor, mirroring a similar reversion from obligate polyandry to approximate monandry in a social parasite of fungus-farming ants. This finding and a comparison with two other cases where inquilinism did not induce reversal to monandry support the hypothesis that facultative polyandry can be costly and may be maintained by benefits of a genetically diverse workforce.

Phylogenomic analysis of yellowjackets and hornets (Hymenoptera: Vespidae, Vespinae).

The phylogenetic relationships among genera of the subfamily Vespinae (yellowjackets and hornets) remain unclear. Yellowjackets and hornets constitute one of the only two lineages of highly eusocial wasps, and the distribution of key behavioral traits correlates closely with the current classification of the group. The potential of the Vespinae to elucidate the evolution of social life, however, remains limited due to ambiguous genus-level relationships. Here, we address the relationships among genera within the Vespinae using transcriptomic (RNA-seq) data. We sequenced the transcriptomes of six vespid wasps, including three of the four genera recognized in the Vespinae, combined our data with publicly available transcriptomes, and assembled two matrices comprising 1,507 and 3,356 putative single-copy genes. The results of our phylogenomic analyses recover Dolichovespula as more closely related to Vespa than to Vespula, therefore challenging the prevailing hypothesis of yellowjacket (Vespula+Dolichovespula) monophyly. This suggests that traits such as large colony size and high paternity arose in the genus Vespula following its early divergence from the remaining vespine genera.

Phylogeny, landmark analysis and the use of wing venation to study the evolution of social wasps (Hymenoptera: Vespidae: Vespinae).

Wing venation provides useful characters with which to classify extant and fossil insects. Recently, quantification of its shape using landmarks has increased the potential of wing venation to distinguish taxa. However, the use of wing landmarks in phylogenetic analyses remains largely unexplored. Here, we tested landmark analysis under parsimony (LAUP) to include wing shape data in a phylogenetic analysis of hornets and yellow jackets. Using 68 morphological characters, nine genes and wing landmarks, we produced the first total-evidence phylogeny of Vespinae. We also tested the influence of LAUP parameters using simulated landmarks. Our data confirmed that optimization parameters, alignment method, landmark number and, under low optimization parameters, the initial orientation of aligned shapes can influence LAUP results. Furthermore, single landmark configurations never accurately reflected the topology used for data simulation, but results were significantly close when compared to random topologies. Thus, wing landmark configurations were unreliable phylogenetic characters when treated independently, but provided some useful insights when combined with other data. Our phylogeny corroborated the monophyly of most groups proposed on the basis of morphology and showed the fossil Palaeovespa is distantly related to extant genera. Unstable relationships among genera suggest that rapid radiations occurred in the early history of the Vespinae.

Phylogenetic relationships of yellowjackets inferred from nine loci (Hymenoptera: Vespidae, Vespinae, Vespula and Dolichovespula).

Eusociality has arisen repeatedly and independently in the history of insects, often leading to evolutionary success and ecological dominance. Eusocial wasps of the genera Vespula and Dolichovespula, or yellowjackets, have developed advanced social traits in a relatively small number of species. The origin of traits such as effective paternity and colony size has been interpreted with reference to an established phylogenetic hypothesis that is based on phenotypic data, while the application of molecular evidence to phylogenetic analysis within yellowjackets has been limited. Here, we investigate the evolutionary history of yellowjackets on the basis of mitochondrial and nuclear markers (nuclear: 28S, EF1α, Pol II, and wg; mitochondrial: 12S, 16S, COI, COII, and Cytb). We use these data to test the monophyly of yellowjackets and species groups, and resolve species-level relationships within each genus using parsimony and Bayesian inference. Our results indicate that a yellowjacket clade is either weakly supported (parsimony) or rejected (Bayesian inference). However, the monophyly of each yellowjacket genus as well as species groups are strongly supported and concordant between methods. Our results agree with previous studies regarding the monophyly of the Vespula vulgaris group and the sister relationship between the V. rufa and V. squamosa groups. This suggests convergence of large colony size and high effective paternity in the vulgaris group and V. squamosa, or a single origin of both traits in the most recent common ancestor of all Vespula species and their evolutionary reversal in the rufa group.

Recurring adaptive introgression of a supergene variant that determines social organization.

Introgression has been proposed as an essential source of adaptive genetic variation. However, a key barrier to adaptive introgression is that recombination can break down combinations of alleles that underpin many traits. This barrier might be overcome in supergene regions, where suppressed recombination leads to joint inheritance across many loci. Here, we study the evolution of a large supergene region that determines a major social and ecological trait in Solenopsis fire ants: whether colonies have one queen or multiple queens. Using coalescent-based phylogenies built from the genomes of 365 haploid fire ant males, we show that the supergene variant responsible for multiple-queen colonies evolved in one species and repeatedly spread to other species through introgressive hybridization. This finding highlights how supergene architecture can enable a complex adaptive phenotype to recurrently permeate species boundaries.

A phylogenetic approach to conserving Amazonian biodiversity.

Amazonia is a highly threatened rainforest that encompasses a major proportion of Earth's biological diversity. Our main goal was to establish conservation priorities for Amazonia's areas of endemism on the basis of measures of evolutionary distinctiveness. We considered two previously identified sets of areas of endemism. The first set consisted of eight large areas used traditionally in biogeographical studies: Belém, Tapajós, Xingu, Guiana, Rondônia, Imeri, Inambari, and Napo. The second set consisted of 16 smaller areas that were subdivisions of the larger areas. We assembled a data set of 50 phylogenies that represented 16 orders and 1715 distributional records. We identified priority conservation areas for the areas of endemism according to node-based metrics of evolutionary distinctiveness. We contrasted these results with priority areas identified on the basis of raw species richness and species endemicity. For the larger areas, we identified Guiana and Inambari as the first- and second-most important areas for conservation. The remaining areas in this first group scored half (e.g., Napo) or less than Guiana and Inambari on all indices. For the smaller areas, a subdivision of Guiana (i.e., Guyana and the Brazilian states of Roraima and Amazonas) was at the top of the ranking and was followed by a subdivision of Inambari (i.e., northwestern portion of Amazonas) and then another subdivision of Guiana (i.e., Suriname, French Guiana, and the Brazilian state of Amapá). The distinctiveness-based rankings of the priority of areas correlated directly with those derived from species richness and species endemicity. Current conservation strategies in Amazonia, although they rely on many other criteria apart from phylogeny, are focusing on the most important areas for conservation we identified here.

Healthy Pollinators: Evaluating Pesticides with Molecular Medicine Approaches.

Pollinators have been declining worldwide, and pesticides have contributed to these declines. High-resolution approaches from molecular medicine can provide unparalleled insight into organismal physiology and health. Applying these approaches to pollinators can significantly improve the efficiency and sensitivity of pesticide research and evaluation, and thus the sustainability of modern agriculture.

Cone beam computed tomography: an innovative tool for airway assessment.

Improvements in airway imaging technology provide the potential for an improved understanding of airway pathology and upper airway mechanics. We present here a preliminary report on the applicability of cone beam computed tomography technology in conjunction with multidimensional digital analysis for the purposes of clinical airway management. The use of this technology for airway imaging in anesthesiology has not been reported. Traditional skeletal and soft tissue images as well as distance and volume measurements were obtained without difficulty. Three-dimensional image reconstructions as well as "virtual laryngoscopy" were achieved with resulting excellent image quality, suggesting a broad range of possibilities for upper airway examination and analysis. A modified Muller test with volumetric rendering of the airway passages under baseline and negative pressure conditions was also performed, made possible as a result of the system's short (9 s) scanning times. We believe that cone beam computed tomography technology offers an additional dimension to airway evaluation that has considerable potential.

Phylogenetic tests reject Emery's rule in the evolution of social parasitism in yellowjackets and hornets (Hymenoptera: Vespidae, Vespinae).

Social parasites exploit the brood-care behaviour and social structure of one or more host species. Within the social Hymenoptera there are different types of social parasitism. In its extreme form, species of obligate social parasites, or inquilines, do not have the worker caste and depend entirely on the workers of a host species to raise their reproductive offspring. The strict form of Emery's rule states that social parasites share immediate common ancestry with their hosts. Moreover, this rule has been linked with a sympatric origin of inquilines from their hosts. Here, we conduct phylogenetic analyses of yellowjackets and hornets based on 12 gene fragments and evaluate competing evolutionary scenarios to test Emery's rule. We find that inquilines, as well as facultative social parasites, are not the closest relatives of their hosts. Therefore, Emery's rule in its strict sense is rejected, suggesting that social parasites have not evolved sympatrically from their hosts in yellowjackets and hornets. However, the relaxed version of the rule is supported, as inquilines and their hosts belong to the same Dolichovespula clade. Furthermore, inquilinism has evolved only once in Dolichovespula.

Pericardial fat mimicking pericardial effusion on two-dimensional echocardiography.

A 78-year-old overweight woman with diabetes mellitus, bronchial asthma, and Sheehan's syndrome on chronic steroid therapy presented with mild short-lived hematemesis, significant hypotension disproportionate to the degree of bleeding and radiographic evidence of cardiomegaly. Endoscopy showed duodenal ulcer. During evaluation of the unexplained brief hypotension and cardiomegaly, 2D-echocardiogram demonstrated anterior and posterior echo-free spaces consistent with large pericardial effusion (PE). However, subsequent elective surgical pericardiotomy unexpectedly revealed large amounts of pericardial fat. Pericardial fat was also noted on magnetic resonance imaging of the chest. Our case illustrates a potential pitfall of 2D-echocardiography in the diagnosis of PE.