Comparative morphology of male genital skeletomusculature in the Leptanillinae (Hymenoptera: Formicidae), with a standardized muscular terminology for the male genitalia of Hymenoptera

The male genitalia of the Insecta are famed for structural and functional diversity. Variation in this anatomical region shows ample phylogenetic signal, and this variation has proven indispensable for classification across the insects at multiple taxonomic ranks. However, in the ants (Hymenoptera: Formicidae) the male genital phenotype is ancillary to the morphology of the worker caste for systematic purposes. Ants of the enigmatic subfamily Leptanillinae are an exception, as males are easier to collect than workers. Ongoing systematic revision of the Leptanillinae must therefore rely upon the male phenotype – particularly the spectacular morphological profusion of the male genitalia. To thoroughly illuminate this anatomical region and aid comparative morphological research on ant male genitalia, we present a comparative morphological study of the male genitalia in nine exemplar lineages spanning the Leptanillinae, plus three outgroups representing other major clades of the Formicidae. We use micro-computed tomography (micro-CT) to generate 3D volumetric reconstructions of male genital skeletomusculature in these specimens. Our descriptions use new muscular terminology compatible with topographic main-group systems for the rest of the pterygote soma, and applicable to all Hymenoptera. We find that male genitalia in the Leptanillinae show an overall trend towards skeletomuscular simplification, with muscular reduction in some cases being unprecedented in ants, or even hymenopterans in general. In several lineages of the Leptanillinae we describe derivations of the male genitalia that are bizarre and unparalleled among the Hymenoptera. We conclude by discussing the functional implications of the often-extreme morphologies here observed

Capturing the essence of folding and functions of biomolecules using Coarse-Grained Models

The distances over which biological molecules and their complexes can function range from a few nanometres, in the case of folded structures, to millimetres, for example during chromosome organization. Describing phenomena that cover such diverse length, and also time scales, requires models that capture the underlying physics for the particular length scale of interest. Theoretical ideas, in particular, concepts from polymer physics, have guided the development of coarse-grained models to study folding of DNA, RNA, and proteins. More recently, such models and their variants have been applied to the functions of biological nanomachines. Simulations using coarse-grained models are now poised to address a wide range of problems in biology.Comment: 37 pages, 8 figure

Parents' assessment of parent-child interaction interventions – a longitudinal study in 101 families

<p>Abstract</p> <p>Background</p> <p>The aim of the study was to describe families with small children who participated in parent-child interaction interventions at four centres in Sweden, and to examine long term and short term changes regarding the parents' experience of parental stress, parental attachment patterns, the parents' mental health and life satisfaction, the parents' social support and the children's problems.</p> <p>Methods</p> <p>In this longitudinal study a consecutive sample of 101 families (94 mothers and 54 fathers) with 118 children (median age 3 years) was assessed, using self-reports, at the outset of the treatment (T1), six months later (T2) and 18 months after the beginning of treatment (T3). Analysis of the observed differences was carried out using Wilcoxon's Signed-Rank test and Cohen's d.</p> <p>Results</p> <p>The results from commencement of treatment showed that the parents had considerable problems in all areas examined. At the outset of treatment (T1) the mothers showed a higher level of problem load than the fathers on almost all scales. In the families where the children's problems have also been measured (children from the age of four) it appeared that they had problems of a nature and degree otherwise found in psychiatric populations. We found a clear general trend towards a positive development from T1 to T2 and this development was also reinforced from T2 to T3. Aggression in the child was one of the most common causes for contact. There were few undesired or unplanned interruptions of the treatment, and the attrition from the study was low.</p> <p>Conclusion</p> <p>This study has shown that it is possible to reach mothers as well as fathers with parenting problems and to create an intervention program with very low dropout levels – which is of special importance for families with small children displaying aggressive behaviour. The parents taking part in this study showed clear improvement trends after six months and this development was reinforced a year later. This study suggests the necessity of clinical development and future research concerning the role of fathers in parent-child interaction interventions.</p

Comparative morphology of male genital skeletomusculature in the Leptanillinae (Hymenoptera: Formicidae), with a standardized muscular terminology for the male genitalia of Hymenoptera

The male genitalia of the Insecta are famed for structural and functional diversity. Variation in this anatomical region shows ample phylogenetic signal, and this variation has proven indispensable for classification across the insects at multiple taxonomic ranks. However, in the ants (Hymenoptera: Formicidae) the male genital phenotype is ancillary to the morphology of the worker caste for systematic purposes. Ants of the enigmatic subfamily Leptanillinae are an exception, as males are easier to collect than workers. Ongoing systematic revision of the Leptanillinae must therefore rely upon the male phenotype – particularly the spectacular morphological profusion of the male genitalia. To thoroughly illuminate this anatomical region and aid comparative morphological research on ant male genitalia, we present a comparative morphological study of the male genitalia in nine exemplar lineages spanning the Leptanillinae, plus three outgroups representing other major clades of the Formicidae. We use micro-computed tomography (micro-CT) to generate 3D volumetric reconstructions of male genital skeletomusculature in these specimens. Our descriptions use new muscular terminology compatible with topographic main-group systems for the rest of the pterygote soma, and applicable to all Hymenoptera. We find that male genitalia in the Leptanillinae show an overall trend towards skeletomuscular simplification, with muscular reduction in some cases being unprecedented in ants, or even hymenopterans in general. In several lineages of the Leptanillinae we describe derivations of the male genitalia that are bizarre and unparalleled among the Hymenoptera. We conclude by discussing the functional implications of the often-extreme morphologies here observed

Systematic bias and the phylogeny of Coleoptera—A response to Cai et al. (2022) following the responses to Cai et al. (2020)

Systematic bias is one of the major phylogenetic issues arising over the last two decades. Using methods designed to reduce compositional and rate heterogeneity, hence systematic bias, Cai and co-workers (2022) (= CEA22) reanalyzed the DNA sequence dataset for Coleoptera of Zhang et al. (2018) (= ZEA). CEA22 suggest that their phylogenetic results and major evolutionary hypotheses about the Coleoptera should be favoured over other recently published studies. Here, we discuss the methodology of CEA22 with particular attention to how their perfunctory reanalysis of ZEA obfuscates rather than illuminates beetle phylogeny. Similar to published rebuttals of an earlier study of theirs, we specifically find that many of their claims are misleading, unsupported, or false. Critically, CEA22 fail to establish the stated premise for their reanalysis. They fail to demonstrate how composition or rate heterogeneity supposedly impacted the phylogeny estimate of ZEA, let alone the results of other recent studies. Moreover, despite their claim of comprehensive sampling of Coleoptera, their dataset is neither the most diverse with respect to species and higher taxa included, nor anywhere near the largest in terms of sequence data and sampled loci. Although CEA22 does contribute additional fossils for calibration, those seeking the best available estimate for Coleoptera phylogeny and evolution based on molecular data are advised to look elsewhere