Wonderfully weird: the head anatomy of the armadillo ant, Tatuidris tatusia (Hymenoptera: Formicidae: Agroecomyrmecinae), with evolutionary implications

Tatuidris tatusia Brown & Kempf, 1968, the armadillo ant, is a morphologically unique species found in low to high elevation forests in regions of Central and South America. It is one of only two extant representatives of the subfamily Agroecomyrmecinae, and very little is known about the biology of these ants, which are almost exclusively collected from leaf litter and have rarely been seen alive. Here, we illuminate the functional morphology and evolution of this species via detailed anatomical documentation of their exceptionally modified head. We describe and illustrate the skeletomuscular system, digestive tract, and cephalic glands based on high-resolution micro-computed tomography scan data. We hypothesize that the modifications which produce the unusual “shield-like” head shape are the result of complex optimizations for mandibular power, physical protection, and balance. The most conspicuous cephalic features are the broadening of the frontal region and foreshortening of the postgenal region. The former characteristic is likely also associated with the lateral position of the antennal scrobe, the inverted antennal articulation, and the broad attachment surface for the mandibular adductor muscles. This head geometry also comes with a degree of internal restructuring of the tentorium and the antennal musculature, which have a unique configuration among ants studied so far. The mandibular blades, and their articulations and muscles, are highly distinctive compared with previously evaluated species. Using a 3D-printed model, we were able to hypothesize their entire range of motion as the mandibles fit tightly into the oral foramen. Finally, we compare T. tatusia across other related subfamilies and discuss the evolution of the Agroecomyrmecinae and other species-poor and phylogenetically isolated “relictual” lineages.journal articl

Extensive collection of femtoliter pad secretion droplets in beetle Leptinotarsa decemlineata allows nanoliter microrheology

Pads of beetles are covered with long, deformable setae, each ending in a micrometric terminal plate coated with secretory fluid. It was recently shown that the layer of the pad secretion covering the terminal plates is responsible for the generation of strong attractive forces. However, less is known about the fluid itself because it is produced in extremely small quantity. We here present a first experimental investigation of the rheological properties of the pad secretion in the Colorado potato beetle {\it Leptinotarsa decemlineata}. Because the secretion is produced in an extremely small amount at the level of the terminal plate, we first develop a procedure based on capillary effects to collect the secretion. We then manage to incorporate micrometric beads, initially in the form of a dry powder, and record their thermal motion to determine the mechanical properties of the surrounding medium. We achieve such a quantitative measurement within the collected volume, much smaller than the $1 {\rm \mu}$l sample volume usually required for this technique. Surprisingly, the beetle secretion was found to behave as a purely viscous liquid, of high viscosity. This suggests that no specific complex fluid behaviour is needed during beetle locomotion. We build a scenario for the contact formation between the spatula at the setal tip and a substrate, during the insect walk. We show that the attachment dynamics of the insect pad computed from the high measured viscosity is in good agreement with observed insect pace. We finally discuss the consequences of the secretion viscosity on the insect adhesion

Nuclear medicine procedures and the evaluation of male sexual organs: a short review

Sexuality consists of three aspects that are interrelated and inseparable, biological, physiological and social. The biological aspect considers the individual's capability to give and to receive pleasure. In consequence, it covers the functionality of the sexual organs and the physiology of human sexual response cycle. Diagnostic imaging modalities, such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) have been used to evaluate clinical disorders of the male reproductive system. PET and SPECT procedures basically involve the administration of a radiopharmaceutical that has a higher uptake in a specific tumor or tissue. The aim of this brief review is to present some radiopharmaceuticals that have been used in the clinical evaluation of the male sexual organs (testes, prostate, seminal vesicles, penis) related with male sexuality. This information could be useful in better understanding the male sexual response cycle, as well as the sexual disorders, when considering the male sexual organs and the pelvic floor. Moreover, the findings obtained with PET and SPECT imaging could help to evaluate the efficacy of clinical results of therapeutic procedures. In conclusion, the knowledge from these images could aid in better understanding the physiology of the different organs related with sexuality. Furthermore, they could be important tools to evaluate the physiological integrity of the involved organs, to improve clinical strategies and to accompany the patients under treatment

Author Correction: Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases.

Emmanuelle Souzeau, who contributed to analysis of data, was inadvertently omitted from the author list in the originally published version of this Article. This has now been corrected in both the PDF and HTML versions of the Article

The Beetle Tree of Life Reveals that Coleoptera Survived End-Permium Mass Extinction to Diversify During the Cretaceous Terrestrial Revolution

Here we present a phylogeny of beetles (Insecta: Coleoptera) based on DNA sequence data from eight nuclear genes, including six single-copy nuclear protein-coding genes, for 367 species representing 172 of 183 extant families. Our results refine existing knowledge of relationships among major groups of beetles. Strepsiptera was confirmed as sister to Coleoptera and each of the suborders of Coleoptera was recovered as monophyletic. Interrelationships among the suborders, namely Polyphaga (Adephaga (Archostemata, Myxophaga)), in our study differ from previous studies. Adephaga comprised two clades corresponding to Hydradephaga and Geadephaga. The series and superfamilies of Polyphaga were mostly monophyletic. The traditional Cucujoidea were recovered in three distantly related clades. Lymexyloidea was recovered within Tenebrionoidea. Several of the series and superfamilies of Polyphaga received moderate to maximal clade support in most analyses, for example Buprestoidea, Chrysomeloidea, Coccinelloidea, Cucujiformia, Curculionoidea, Dascilloidea, Elateroidea, Histeroidea and Hydrophiloidea. However, many of the relationships within Polyphaga lacked compatible resolution under maximum-likelihood and Bayesian inference, and/or lacked consistently strong nodal support. Overall, we recovered slightly younger estimated divergence times than previous studies for most groups of beetles. The ordinal split between Coleoptera and Strepsiptera was estimated to have occurred in the Early Permian. Crown Coleoptera appeared in the Late Permian, and only one or two lineages survived the end-Permian mass extinction, with stem group representatives of all four suborders appearing by the end of the Triassic. The basal split in Polyphaga was estimated to have occurred in the Triassic, with the stem groups of most series and superfamilies originating during the Triassic or Jurassic. Most extant families of beetles were estimated to have Cretaceous origins. Overall, Coleoptera experienced an increase in diversification rate compared to the rest of Neuropteroidea. Furthermore, 10 family-level clades, all in suborder Polyphaga, were identified as having experienced significant increases in diversification rate. These include most beetle species with phytophagous habits, but also several groups not typically or primarily associated with plants. Most of these groups originated in the Cretaceous, which is also when a majority of the most species-rich beetle families first appeared. An additional 12 clades showed evidence for significant decreases in diversification rate. These clades are species-poor in the Modern fauna, but collectively exhibit diverse trophic habits. The apparent success of beetles, as measured by species numbers, may result from their associations with widespread and diverse substrates – especially plants, but also including fungi, wood and leaf litter – but what facilitated these associations in the first place or has allowed these associations to flourish likely varies within and between lineages. Our results provide a uniquely well-resolved temporal and phylogenetic framework for studying patterns of innovation and diversification in Coleoptera, and a foundation for further sampling and resolution of the beetle tree of life

The Beetle Tree of Life Reveals the Order Coleoptera Survived End Permain Mass Extinction to Diversify During the Cretaceous Terrestrial Revolution

Here we present a phylogeny of beetles (Insecta: Coleoptera) based on DNA sequence data from eight nuclear genes, including six single-copy nuclear protein-coding genes, for 367 species representing 172 of 183 extant families. Our results refine existing knowledge of relationships among major groups of beetles. Strepsiptera was confirmed as sister to Coleoptera and each of the suborders of Coleoptera was recovered as monophyletic. Interrelationships among the suborders, namely Polyphaga (Adephaga (Archostemata, Myxophaga)), in our study differ from previous studies. Adephaga comprised two clades corresponding to Hydradephaga and Geadephaga. The series and superfamilies of Polyphaga were mostly monophyletic. The traditional Cucujoidea were recovered in three distantly related clades. Lymexyloidea was recovered within Tenebrionoidea. Several of the series and superfamilies of Polyphaga received moderate to maximal clade support in most analyses, for example Buprestoidea, Chrysomeloidea, Coccinelloidea, Cucujiformia, Curculionoidea, Dascilloidea, Elateroidea, Histeroidea and Hydrophiloidea. However, many of the relationships within Polyphaga lacked compatible resolution under maximum-likelihood and Bayesian inference, and/or lacked consistently strong nodal support. Overall, we recovered slightly younger estimated divergence times than previous studies for most groups of beetles. The ordinal split between Coleoptera and Strepsiptera was estimated to have occurred in the Early Permian. Crown Coleoptera appeared in the Late Permian, and only one or two lineages survived the end-Permian mass extinction, with stem group representatives of all four suborders appearing by the end of the Triassic. The basal split in Polyphaga was estimated to have occurred in the Triassic, with the stem groups of most series and superfamilies originating during the Triassic or Jurassic. Most extant families of beetles were estimated to have Cretaceous origins. Overall, Coleoptera experienced an increase in diversification rate compared to the rest of Neuropteroidea. Furthermore, 10 family-level clades, all in suborder Polyphaga, were identified as having experienced significant increases in diversification rate. These include most beetle species with phytophagous habits, but also several groups not typically or primarily associated with plants. Most of these groups originated in the Cretaceous, which is also when a majority of the most species-rich beetle families first appeared. An additional 12 clades showed evidence for significant decreases in diversification rate. These clades are species-poor in the Modern fauna, but collectively exhibit diverse trophic habits. The apparent success of beetles, as measured by species numbers, may result from their associations with widespread and diverse substrates - especially plants, but also including fungi, wood and leaf litter - but what facilitated these associations in the first place or has allowed these associations to flourish likely varies within and between lineages. Our results provide a uniquely well-resolved temporal and phylogenetic framework for studying patterns of innovation and diversification in Coleoptera, and a foundation for further sampling and resolution of the beetle tree of life.Facultad de Ciencias Naturales y Muse

Countering Extremists on Social Media:Challenges for Strategic Communication and Content Moderation

Extremist exploitation of social media platforms is an important regulatory question for civil society, government, and the private sector. Extremists exploit social media for a range of reasons-from spreading hateful narratives and propaganda to financing, recruitment, and sharing operational information. Policy responses to this question fit under two headings, strategic communication and content moderation. At the center of both of these policy responses is a calculation about how best to limit audience exposure to extremist narratives and maintain the marginality of extremist views, while being conscious of rights to free expression and the appropriateness of restrictions on speech. This special issue on "Countering Extremists on Social Media: Challenges for Strategic Communication and Content Moderation" focuses on one form of strategic communication, countering violent extremism. In this editorial we discuss the background and effectiveness of this approach, and introduce five articles which develop multiple strands of research into responses and solutions to extremist exploitation of social media. We conclude by suggesting an agenda for future research on how multistakeholder initiatives to challenge extremist exploitation of social media are conceived, designed, and implemented, and the challenges these initiatives need to surmount