ABSTRACT
The species-energy hypothesis predicts increasing biodiversity with increasing energy in ecosystems. Proxies for energy availability are often grouped into ambient energy (i.e., solar radiation) and substrate energy (i.e., non-structural carbohydrates or nutritional content). The relative importance of substrate energy is thought to decrease with increasing trophic level from primary consumers to predators, with reciprocal effects of ambient energy. Yet, empirical tests are lacking. We compiled data on 332,557 deadwood-inhabiting beetles of 901 species reared from wood of 49 tree species across Europe. Using host-phylogeny-controlled models, we show that the relative importance of substrate energy versus ambient energy decreases with increasing trophic levels: the diversity of zoophagous and mycetophagous beetles was determined by ambient energy, while non-structural carbohydrate content in woody tissues determined that of xylophagous beetles. Our study thus overall supports the species-energy hypothesis and specifies that the relative importance of ambient temperature increases with increasing trophic level with opposite effects for substrate energy.
Subject(s)
Coleoptera , Ecosystem , Animals , Trees , Wood , Biodiversity , EuropeABSTRACT
In their 2023 Nutrition and Health paper "Effects of the application of a food processing-based classification system in obese women: A randomized controlled pilot study", Giacomello et al. investigated the effects of an educational intervention based on the Dietary Guidelines for the Brazilian Population among obese women. The authors concluded that the intervention significantly improved weight loss, quality of life, components of metabolic syndrome, and pain. However, we believe the statistical analysis employed in the study was flawed. The authors used within-group changes to draw conclusions, which is known as a difference in nominal significance error. This error has the potential to inflate Type I error rates substantially. To address this issue, we re-analyzed the data obtained from the authors. We focused on body mass and hip circumference and replicated the incorrectly chosen within-group analyses, which remained significant. However, to properly evaluate the intervention's effectiveness, it is essential to compare the differences between the groups directly. Therefore, we calculated change scores for each participant and used independent samples t-tests and linear mixed models to compare between-group differences. Both methods yielded similar non-significant p-values, indicating that there is no significant effect of treatment on body mass or hip circumference. The original paper's conclusions regarding the effectiveness of the intervention are not supported by the proper statistical analysis. The data should be re-analyzed using appropriate between-group comparisons, and the corrected results should be published, or the incorrect results and original paper should be retracted.
ABSTRACT
Developmental processes transduce diverse influences during phenotype formation, thereby biasing and structuring amount and type of phenotypic variation available for evolutionary processes to act on. The causes, extent, and consequences of this bias are subject to significant debate. Here we explore the role of developmental bias in contributing to organisms' ability to innovate, to adapt to novel or stressful conditions, and to generate well integrated, resilient phenotypes in the face of perturbations. We focus our inquiry on one taxon, the horned dung beetle genus Onthophagus, and review the role developmental bias might play across several levels of biological organization: (a) gene regulatory networks that pattern specific body regions; (b) plastic developmental mechanisms that coordinate body wide responses to changing environments and; (c) developmental symbioses and niche construction that enable organisms to build teams and to actively modify their own selective environments. We posit that across all these levels developmental bias shapes the way living systems innovate, adapt, and withstand stress, in ways that can alternately limit, bias, or facilitate developmental evolution. We conclude that the structuring contribution of developmental bias in evolution deserves further study to better understand why and how developmental evolution unfolds the way it does.
Subject(s)
Adaptation, Biological , Biological Evolution , Coleoptera/physiology , Gene Regulatory Networks , Animals , Coleoptera/genetics , Coleoptera/growth & development , Life History TraitsABSTRACT
Size and shape constitute fundamental aspects in the description of morphology. Yet while the developmental-genetic underpinnings of trait size, in particular with regard to scaling relationships, are increasingly well understood, those of shape remain largely elusive. Here we investigate the potential function of the Notch signaling pathway in instructing the shape of beetle horns, a highly diversified and evolutionarily novel morphological structure. We focused on the bull-headed dung beetle Onthophagus taurus due to the wide range of horn sizes and shapes present among males in this species, in order to assess the potential function of Notch signaling in the specification of horn shape alongside the regulation of shape changes with allometry. Using RNA interference-mediated transcript depletion of Notch and its ligands, we document a highly conserved role of Notch signaling in general appendage formation. By integrating our functional genetic approach with a geometric morphometric analysis, we find that Notch signaling moderately but consistently affects horn shape, and does so differently for the horns of minor, intermediate-sized, and major males. Our results suggest that the function of Notch signaling during head horn formation may vary in a complex manner across male morphs, and highlights the power of integrating functional genetic and geometric morphometric approaches in analyzing subtle but nevertheless biologically important phenotypes in the face of significant allometric variation.
Subject(s)
Body Patterning , Coleoptera/growth & development , Coleoptera/genetics , Receptors, Notch/physiology , Serrate-Jagged Proteins/metabolism , Signal Transduction , Animals , Biological Evolution , Coleoptera/anatomy & histology , Gene Expression Regulation, Developmental , Gene Knockdown Techniques , Genes, Insect , Insect Proteins/genetics , Insect Proteins/metabolism , Male , Morphogenesis , Phenotype , RNA Interference , Serrate-Jagged Proteins/genetics , Sex CharacteristicsABSTRACT
Complex traits like limbs, brains, or eyes form through coordinated integration of diverse cell fates across developmental space and time, yet understanding how complexity and integration emerge from uniform, undifferentiated precursor tissues remains limited. Here, we use ectopic eye formation as a paradigm to investigate the emergence and integration of novel complex structures following massive ontogenetic perturbation. We show that down-regulation via RNAi of a single head patterning gene-orthodenticle-induces ectopic structures externally resembling compound eyes at the middorsal adult head of both basal and derived scarabaeid beetle species (Onthophagini and Oniticellini). Scanning electron microscopy documents ommatidial organization of these induced structures, while immunohistochemistry reveals the presence of rudimentary ommatidial lenses, crystalline cones, and associated neural-like tissue within them. Further, RNA-sequencing experiments show that after orthodenticle down-regulation, the transcriptional signature of the middorsal head-the location of ectopic eye induction-converges onto that of regular compound eyes, including up-regulation of several retina-specific genes. Finally, a light-aversion behavioral assay to assess functionality reveals that ectopic compound eyes can rescue the ability to respond to visual stimuli when wild-type eyes are surgically removed. Combined, our results show that knockdown of a single gene is sufficient for the middorsal head to acquire the competence to ectopically generate a functional compound eye-like structure. These findings highlight the buffering capacity of developmental systems, allowing massive genetic perturbations to be channeled toward orderly and functional developmental outcomes, and render ectopic eye formation a widely accessible paradigm to study the evolution of complex systems.
Subject(s)
Coleoptera/physiology , Compound Eye, Arthropod/physiology , Retina/physiology , Animals , Body Patterning/genetics , Coleoptera/genetics , Down-Regulation/genetics , Eye Proteins/genetics , Gene Expression Regulation, Developmental/genetics , Lens, Crystalline/physiology , RNA Interference/physiology , Up-Regulation/geneticsABSTRACT
Many dung beetle communities are characterized by species that share very similar morphological, ecological, and behavioral traits and requirements yet appear to be stably maintained. Here, we document that the morphologically nearly indistinguishable, sympatric, and syntopic tunneling sister species Onthophagus taurus and Onthophagus illyricus may be avoiding competitive exclusion by nesting at remarkably different soil depths. Intriguingly, we also find rapid divergence in preferred nesting depth across native and recently established O. taurus populations. Furthermore, geometric morphometric analyses reveal that both inter- and intraspecific divergences in nesting depth are paralleled by similar changes in the shape of the primary digging appendages, the fore tibiae. Collectively, our results identify preferred nesting depth and tibial shape as surprisingly evolutionarily labile and with the potential to ease interspecific competition and/or to facilitate adaptation to local climatic conditions.
Subject(s)
Coleoptera/anatomy & histology , Adaptation, Physiological , Animals , Behavior, Animal , Biological Evolution , Body Size/physiology , Coleoptera/physiology , Extremities/anatomy & histology , Female , Male , Nesting Behavior , Species SpecificityABSTRACT
Explaining the extraordinarily rapid diversification of insect copulatory structures has been a longstanding objective in evolutionary biology. However, remarkably little is known about the developmental genetic underpinnings of their formation. Furthermore, recent work has questioned whether male genitalic structures in beetles are serially homologous to appendages, or even homologous to the genitalia of other orders. Using RNA interference, we demonstrate that several cardinal appendage-patterning genes regulate the formation of copulatory structures in Onthophagus beetles of both sexes. These results are in strong disagreement with previous findings in the model beetle species Tribolium castaneum, but congruent with earlier studies in true bugs and flies. Our results support the hypotheses that genitalic development is largely conserved across insect orders, and that genitalia constitute serial appendage homologues. Moreover, we identify two patterning genes with striking phenotypic effects in both sexes. In these cases, the affected structures are known to interact functionally during copulation, but are not homologous to each other. This suggests that shared developmental regulation of male and female copulatory structures may extend beyond components related by descent to those related by function.
Subject(s)
Body Patterning , Coleoptera/growth & development , Coleoptera/genetics , Gene Expression Regulation, Developmental , Insect Proteins/genetics , Animals , Biological Evolution , Female , Genitalia, Female/growth & development , Genitalia, Male/growth & development , Insect Proteins/metabolism , Male , RNA Interference , Species SpecificityABSTRACT
BACKGROUND: Guided by Clinical Pharmacogenomic Implementation Consortium (CPIC) guidelines for >140 medications, pharmacogenomic tests inform medication selection and dosing to optimize efficacy while minimizing toxicities. PURPOSE: This study assessed pharmacogenomic self-reported curricular content, knowledge, skills, attitudes, and usage in advanced practice registered nurses (APRNs) with prescriptive privileges. METHODOLOGY: An online survey was administered assessing pharmacogenomic curricular content, knowledge, skills, attitudes, and usage. RESULTS: Data from 266 APRNs were analyzed. Most graduated with their highest nursing degree â¼10 years ago and reported pharmacogenomic curricular content ( n = 124, 48%). Pharmacogenomic curricular content was associated with pharmacogenomic familiarity ( p = .045) but not with knowledge confidence ( p = .615). Pharmacogenomic usage, defined as ordering a pharmacogenomic test within the past year, was low ( n = 76, 29%) and most ( n = 210, 84%) reported never using CPIC Guidelines. Advanced practice registered nurses ( n = 162) who did not anticipate ordering a pharmacogenomic test in the next year ( n = 77, 48%) indicated that they did not know what test to order. CONCLUSIONS: Deficits were identified in APRN pharmacogenomic knowledge and skills despite academic training. Most reported not ordering pharmacogenomic tests, did not know what test to order, and did not use CPIC guidelines. IMPLICATIONS: Pharmacogenomics is a quality and safety issue. Academic training did not result in practice integration and most reported capacity deficits. Recommendation for overcoming academic deficits include: (1) assessment of pharmacogenomics curricular content and faculty teaching capacity; (2) training addressing identified deficiencies; and (3) Commission of Collegiate Nursing Education policies that include pharmacogenomics in advanced pharmacology. Practicing APRN plans include on-the-job training and/or mandatory training at the time of relicensure.
Subject(s)
Advanced Practice Nursing , Pharmacogenetics , Humans , Advanced Practice Nursing/methods , Advanced Practice Nursing/statistics & numerical data , Advanced Practice Nursing/standards , Pharmacogenetics/methods , Pharmacogenetics/statistics & numerical data , Pharmacogenetics/education , Female , Adult , Male , Surveys and Questionnaires , Middle Aged , Curriculum/trends , Curriculum/standards , Nurse Practitioners/education , Nurse Practitioners/statistics & numerical data , Clinical Competence/statistics & numerical data , Clinical Competence/standardsABSTRACT
BACKGROUND: Nutrient availability is among the most widespread means by which environmental variability affects developmental outcomes. Because almost all cells within an individual organism share the same genome, structure-specific growth responses must result from changes in gene regulation. Earlier work suggested that histone deacetylases (HDACs) may serve as epigenetic regulators linking nutritional conditions to trait-specific development. Here we expand on this work by assessing the function of diverse HDACs in the structure-specific growth of both sex-shared and sex-specific traits including evolutionarily novel structures in the horned dung beetle Onthophagus taurus. RESULTS: We identified five HDAC members whose downregulation yielded highly variable mortality depending on which HDAC member was targeted. We then show that HDAC1, 3, and 4 operate in both a gene- and trait-specific manner in the regulation of nutrition-responsiveness of appendage size and shape. Specifically, HDAC 1, 3, or 4 knockdown diminished wing size similarly while leg development was differentially affected by RNAi targeting HDAC3 and HDAC4. In addition, depletion of HDAC3 transcript resulted in a more rounded shape of genitalia at the pupal stage and decreased the length of adult aedeagus across all body sizes. Most importantly, we find that HDAC3 and HDAC4 pattern the morphology and regulate the scaling of evolutionarily novel head and thoracic horns as a function of nutritional variation. CONCLUSION: Collectively, our results suggest that both functional overlap and division of labor among HDAC members contribute to morphological diversification of both conventional and recently evolved appendages. More generally, our work raises the possibility that HDAC-mediated scaling relationships and their evolution may underpin morphological diversification within and across insect species broadly.
ABSTRACT
Developmental and evolutionary processes underlying phenotypic variation frequently target several traits simultaneously, thereby causing covariation, or integration, among phenotypes. While phenotypic integration can be neutral, correlational selection can drive adaptive covariation. Especially, the evolution and development of exaggerated secondary sexual traits may require the adjustment of other traits that support, compensate for, or otherwise function in a concerted manner. Although phenotypic integration is ubiquitous, the interplay between genetic, developmental, and ecological conditions in shaping integration and its evolution remains poorly understood. Here, we study the evolution and plasticity of trait integration in the bull-headed dung beetle Onthophagus taurus which is characterized by the polyphenic expression of horned ('major') and hornless ('minor') male morphs. By comparing populations subject to divergent intensities of mate competition, we tested whether mating system shifts affect integration of traits predicted to function in a morph-specific manner. We focussed on fore and hind tibia morphology as these appendages are used to stabilize major males during fights, and on wings, as they are thought to contribute to morph-based differences in dispersal behavior. We found phenotypic integration between fore and hind tibia length and horn length that was stronger in major males, suggesting phenotypic plasticity in integration and potentially secondary sexual trait compensation. Similarly, we observed that fore tibia shape was also integrated with relative horn length. However, although we found population differentiation in wing and tibia shape and allometry, populations did not differ in integration. Lastly, we detected little evidence for morph differences in integration in either tibia or wing shape, although wing allometries differed between morphs. This contrasts with previous studies documenting intraspecific differentiation in morphology, behavior, and allometry as a response to varying levels of mate competition across O. taurus populations. We discuss how sexual selection may shape morph-specific integration, compensation, and allometry across populations.
ABSTRACT
Many capture-recapture studies on adult dragonflies have found male-biased sex ratios. However, few have estimated survivorship of males and females separately from data on frequency of recaptures in the field. Even when daily survival and capture probabilities are estimated separately, controversies can arise on whether sex biases in local survival are to be attributed to mortality or permanent emigration from the study site. The knowledge of male and female movements, assessed on an appropriate scale (i.e., within and outside the breeding site), can help address this issue. In this paper, we performed a 4-yr capture-recapture study of two Libellula fulva Müller populations in northwest Italy. Cormack-Jolly-Seber models were used to get unbiased estimates of demographic parameters (daily survival and capture probabilities, sex ratio, mean life span, and population size). Movement parameters were measured directly by georeferencing encounters. Moderate differences in survival, with males surviving better than females, were found in one population and not in the other, suggesting that these differences are not an inherent characteristic of the species. In the population with lower female survival, females were not more vagile than males, thus indicating their lower survival was caused by actual mortality rather than to emigration. In the population with no survival differences between males and females, marked males outnumbered females, but estimated sex ratios were approximately 1:1 or female biased. Therefore, raw field data were misleading because they led to underestimates of the more elusive sex and overestimates of the more detectable one (males). Survival and movement differences detected in the two populations are discussed in the framework of local environmental and demographic factors.
Subject(s)
Ecosystem , Insecta , Sex Ratio , Animals , Female , Italy , Male , Population DynamicsABSTRACT
Fecundity is a fundamental determinant of fitness, yet the proximate developmental and physiological mechanisms that enable its often rapid evolution in natural populations are poorly understood. Here, we investigated two populations of the dung beetle Onthophagus taurus that were established in exotic ranges in the early 1970s. These populations are subject to drastically different levels of resource competition in the field, and have diverged dramatically in female fecundity. Specifically, Western Australian O. taurus experience high levels of resource competition, and exhibit greatly elevated reproductive output compared to beetles from the Eastern US, where resource competition is minimal and female fecundity is low. We compared patterns of ovarian maturation, relative investment into and timing of egg production, and potential trade-offs between ovarian investment and the duration of larval development and adult body size between populations representative of both exotic ranges. We found that the rapid divergence in fecundity between exotic populations is associated with striking differences in several aspects of ovarian development: (1) Western Australian females exhibit accelerated ovarian development, (2) produce more eggs, (3) bigger eggs, and (4) start laying eggs earlier compared to their Eastern US counterparts. At the same time, divergence in ovarian maturation patterns occurred alongside changes in (5) larval developmental time, and (6) adult body size, and (7) mass. Western Australian females take longer to complete larval development and, surprisingly, emerge into smaller yet heavier adults than size-matched Eastern US females. We discuss our results in the context of the evolutionary developmental biology of fecundity in exotic populations.
Subject(s)
Coleoptera/growth & development , Animals , Biological Evolution , Body Size , Coleoptera/anatomy & histology , Female , Fertility , Indiana , Introduced Species , Larva/growth & development , Male , Ovary/growth & development , Oviposition , Western AustraliaABSTRACT
Genitalia are among the fastest evolving morphological traits in arthropods. Among the many hypotheses aimed at explaining this observation, some explicitly or implicitly predict concomitant male and female changes of genital traits that interact during copulation (i.e., lock and key, sexual conflict, cryptic female choice and pleiotropy). Testing these hypotheses requires insights into whether male and female copulatory structures that physically interact during mating also affect each other's evolution and patterns of diversification. Here we compare and contrast size and shape evolution of male and female structures that are known to interact tightly during copulation using two model systems: (a) the sister species O. taurus (1 native, 3 recently established populations) and O. illyricus, and (b) the species-complex O. fracticornis-similis-opacicollis. Partial Least Squares analyses indicated very little to no correlation between size and shape of copulatory structures, both in males and females. Accordingly, comparing shape and size diversification patterns of genitalia within each sex showed that the two components diversify readily--though largely independently of each other--within and between species. Similarly, comparing patterns of divergence across sexes showed that relative sizes of male and female copulatory organs diversify largely independent of each other. However, performing this analysis for genital shape revealed a signature of parallel divergence. Our results therefore suggest that male and female copulatory structures that are linked mechanically during copulation may diverge in concert with respect to their shapes. Furthermore, our results suggest that genital divergence in general, and co-divergence of male and female genital shape in particular, can evolve over an extraordinarily short time frame. Results are discussed in the framework of the hypotheses that assume or predict concomitant evolutionary changes in male and female copulatory organs.