Divergent Character Research Articles

Quantum Big-Bounce as a phenomenology of RQM in the Mini-superspace

We investigate the emergence of a quantum Big-Bounce in the context of an isotropic Universe, filled by a self-interacting scalar field, which plays the role of a physical clock. The bouncing cosmology is the result of a scattering process, driven by the scalar field potential, which presence breaks down the frequency separation of the Wheeler-DeWitt equation, treated in strict analogy to a relativistic quantum system. Differently from previous analyses, we consider a really perturbative self-interaction potential, affecting the dynamics in a finite range of the time labeled by the scalar clock (and in particular we remove the divergent character previously allowed). The main result of the present analysis is that, when the Relativistic Quantum Mechanics formalism is properly implemented in the Mini-superspace analogy, the probability amplitude for the bounce is, both in the standard and polymerized case, characterized by a maximum in correspondence of the quasi-classical condition of a Universe minimum volume.

Ecological character displacement among Nothobranchius annual killifishes in Tanzania.

Divergent ecological character displacement (ECD) is the competition-driven divergence in resource use-related phenotypic traits between coexisting species. It is considered one of the primary drivers of ecological diversification and adaptive radiation. We analyzed phenotypic and ecological variation in 2 African annual killifish species of the genus Nothobranchius: N. eggersi and N. melanospilus in sympatry and N. melanospilus in allopatry. Our aim was to test whether allopatric and sympatric populations of N. melanospilus differ morphologically from each other and from N. eggersi and examine whether these differences are consistent with the predictions of ECD. We find that sympatric N. melanospilus differ from allopatric N. melanospilus and differ from N. eggersi more strongly than the latter. Our data satisfy four criteria for demonstrating ECD: Differences in phenotypes between allopatric and sympatric N. melanospilus are greater than expected by chance; the divergence pattern between allopatric and sympatric N. melanospilus results from an evolutionary shift rather than from ecological sorting; morphological differences observed reflect differences in resource use; and, lastly, sites of allopatry and sympatry do not differ in food resource availability or other ecological conditions. Our results suggest that competition is the main driver of the observed divergence between two N. melanospilus populations.

Seabed morphodynamics of a coastal lagoon of the Gulf of California

A two-dimensional, vertically integrated, non-linear numerical model was applied to investigate the Urias coastal lagoon’s (URCOL) tide-driven currents, bed load sediment transport, and seabed morphodynamics. The coastal body of water, located on the eastern side of the Gulf of California, includes the Mazatlán harbour, the most important port on the Pacific Mexican coast due to the relevant activities like the heavy vessel traffic. URCOL also includes an extensive aquaculture infrastructure at the lagoon head. The tidal hydrodynamic modelling revealed the mixed character of tides predominantly semidiurnal in the lagoon. The numerical computation at the harbour entrance showed an ebb-dominant tidal distortion. The distribution patterns of the erosion and accretion rates are consistent with the convergent and divergent character of the vectors of sediment transport rates. The sediment accretion has been predicted mainly in the middle part of the channel, right where the channel starts curving, changing the alignment of the lagoon. The tidal hydrodynamics, sharp topographic gradient, and geometric features of the lagoon seem to determine the location of accretion and erosion areas.

Entropy variation of rotating BTZ black hole under Hawking radiation

An axially symmetric rotating Banados-Teitelboim-Zanelli (BTZ) black hole is considered for comprehending its interior information. The largest space-like hyper-surface is chosen to estimate its maximal interior volume as a time-dependent quantity. Similarly, the quantum mode entropy of the scalar field associated with this volume is found to increase with Eddington time. An evolution relation between the variation of quantum mode entropy and Bekenstein-Hawking entropy is obtained for an infinitesimal time interval. On comparing to higher-dimensional black holes, the characteristic feature of this evolution relation is its divergent character.

Vitality of Rubus arcticus L. in medium and southern taiga

Vitality strategies for 11 coenopopulations of arctic bramble (Rubus arcticus L.) were defined in conditions of medium and southern taiga on the edge of the species range. In studied conditions optimal habitats for R. arcticus growth, while maintaining high vitality index, are open meadows and coniferous-small-leaved forests with high level of soil moisture: Epilobium-gramineous wet meadow formed on a runway and surrounded by spruce-birch forest with pine and aspen-birch herbaceous forest with spruce. The study showed that the pedicel length, width of the central lobe of the 3rd leaf from the metamere base, and number of living leaves are the most sensitive features which react to the state of environment. R. arcticus shows 3 ontogenetic tactics near the border of its range: divergent, convergent and stabilizing tactic. Most of morphological features studied prove divergent character of ontogenetic tactic, which determines the increase in features’ variability in close-to-stress conditions. Near its southern border arctic bramble uses defensive strategies for survival allowing its successful vegetative reproduction. According to the results of the study and species’ ecological peculiarities and in order to achieve effective monitoring and prognosis of the species’ state, it is important that we apply complex estimation of variability of physiological-biological and morphological parameters of R. arcticus.

"Vojvođanska nacija" - ideološke pobude i antiistorijski narativ

The paper represents the historiographic facing with the narrative about the need to construct the "Vojvodina nation". This narrative, aware of the need for validity and historical persistence, searches for a foundation in its specific interpretation of historiography. The starting point can be found in the acceptance of the historical context of the emancipation of the Serbian national idea in the Habsburg Monarchy. Such discourse is also applied to the Yugoslav state organization, regardless of its divergent character in relation to the Austro-Hungarian Monarchy and the circumstances of the liberation and defence war, in which quite a harmonized national interest of Serbs was realized about unity in the joint state. The ideological prejudice about the meta-ethnic character of Yugoslav unity prevailing after the victory of the socialist revolution, led to the federalist concept of the state organization created on the ruins of the alleged "Great Serbian" national idea. Despite intentions, the circumstance of the socialist building of the Yugoslav society did not prevent the development of nationalist ideas of party bureaucrats. It was a prerequisite for the development of Vojvodina statism and national-building.

Relativistic time-dependent quantum dynamics across supercritical barriers for Klein-Gordon and Dirac particles

We investigate wave-packet dynamics across supercritical barriers for the Klein-Gordon and Dirac equations. Our treatment is based on a multiple scattering expansion (MSE). For spin-0 particles, the MSE diverges, rendering invalid the use of the usual connection formulas for the scattering basis functions. In a time-dependent formulation, the divergent character of the MSE naturally accounts for charge creation at the barrier boundaries. In the Dirac case, the MSE converges and no charge is created. We show that this time-dependent charge behavior dynamics can adequately explain the Klein paradox in a first-quantized setting. We further compare our semianalytical wave-packet approach to exact finite-difference solutions of the relativistic wave equations.

3D Geometric Morphometrics Reveals Convergent Character Displacement in the Central European Contact Zone between Two Species of Hedgehogs (Genus Erinaceus)

Simple SummaryHedgehogs, being insectivores with slow metabolisms, are quite sensitive to temperature and food availability. As a consequence, their ranges have oscillated in relation to past climate changes. Species that have evolved in different regions, but their ranges have shifted and overlapped subsequently, often represent intense competitors as a result of ecological similarities. The present study focuses on this phenomenon in the contact zone in central Europe and adjacent regions, using genetic determination of species and description of size and shape of skull, the morphological structure mirroring many selection pressures related to ecology. While animals living outside of the contact zone show marked differences between the two species, individuals within the contact zone are more alike with a smaller skull size and a convergent jawbone shape. Changes in skull size can be related to inter-species competition and also facilitated by selection pressure, mediated by overpopulated medium-sized predators such as foxes or badgers. Since the function of the lower jaw is mainly connected to feeding, we hypothesize that this pattern is due to the selection to size and shape related to competition for food resources. The present study helps to describe general patterns related to species formation, as well as species responses to anthropogenic environmental changes.Hedgehogs, as medium-sized plantigrade insectivores with low basal metabolic rates and related defensive anti-predator strategies, are quite sensitive to temperature and ecosystem productivity. Their ranges therefore changed dramatically due to Pleistocene climate oscillations, resulting in allopatric speciation and the subsequent formation of secondary contact zones. Such interactions between closely related species are known to generate strong evolutionary forces responsible for niche differentiation. In this connection, here, we detail the results of research on the phenotypic evolution in the two species of hedgehog present in central Europe, as based on genetics and geometric morphometrics in samples along a longitudinal transect that includes the contact zone between the species. While in allopatry, Erinaceus europaeus is found to have a larger skull than E. roumanicus and distinct cranial and mandibular shapes; the members of the two species in sympatry are smaller and more similar to each other, with a convergent shape of the mandible. The relevant data fail to reveal any major role for either hybridisation or clinal variation. We, therefore, hypothesise that competitive pressure exerted on the studied species does not generate divergent selection sufficient for divergent character displacement to evolve, instead giving rise to convergent selection in the face of resource limitation in the direction of smaller skull size. Considering the multi-factorial constraints present in the relevant adaptive landscape, reduction in size could also be facilitated by predator pressure in ecosystems characterised by mesopredator release and other anthropogenic factors. As the function of the animals’ lower jaw is mainly connected with feeding (in contrast to the cranium whose functions are obviously more complex), we interpret the similarity in shape as reflecting local adaptations to overlapping dietary resources in the two species and hence as convergent character displacement.

Selection for Rhythm as a Trigger for Recursive Evolution in the Elaborate Display System of Woodpeckers.

Evolution is never truly predictable, in part because the process of selection is recursive: it operates on its own output to generate historical contingencies, so emergent traits can reshape how others evolve in the future. Studies rarely attempt to directly trace how recursion underlies present-day phenotypic pattern on a macroevolutionary basis. To address this gap, we examined how different selection regimes-each operating on a different timescale-guide the evolution of the woodpecker drum display. Approximately 200 species drum with distinctive speed and length, which are important for territorial competition. We discovered remarkable variation in drum rhythm, with some species drumming at constant rates and others changing speed along a range of mathematical functions. Rhythm undergoes divergent character displacement among sympatric sister species, a process that wanes as other reproductive boundaries emerge over time. Tracing the recursive effects of this process, we found that modifying rhythm may then potentiate or constrain speed/length elaboration. Additionally, increased sexual size dimorphism predicts the emergence of rhythms associated with constrained evolutionary rates of speed/length, implying that selection can also constrain itself. Altogether, our findings illustrate how recursion introduces contingencies that allow diverse phenotypes to arise from similar selection regimes.

Mapping civil society: the ecology of actors in the Toronto region greenbelt

ABSTRACTCivil society’s potential as a force for solving complex societal problems – particularly those that require a challenge to the status quo – has provoked practical and theoretical interest, with its potential largely reliant on the perception that it is a ready if variable source of social capital resources. However, there are no guarantees that civil society will use its social capital for the greater good. Civil society encompasses a range of groups, some more inward-looking and oriented to private interests, and others more outward-looking and oriented to public interests. This divergent character of civil society was evident in the three campaigns for greenspace protection that eventually led to the creation of the Toronto region greenbelt, where civil society organisations (CSOs) from both growth and conservation camps contended for influence, each succeeding at different times. But over time (a time when state actors were increasingly in need of non-state partners to help solve complex governance problems), coalitions of environmental CSOs in the three campaigns – to protect the Niagara Escarpment, Oak Ridges Moraine and surrounding countryside – became more effective at influencing government to protect greenspace. A comparison of the coalitions using a framework based on key attributes of CSOs – missions and memberships – suggests that the environmental coalitions were more effective when they recruited more members with a diverse set of resources arising from both bonding and bridging social capital. In general, the more inclusive and public-interested the CSOs, the more effective the challenge to the status quo.

The Development of a Social Creativity Enhancement Program for Young Children Using Creativity Techniques - A Study on the Balanced Approach of Creativity and Social Communication -

본 연구는 창의성 기법을 활용하여 창의성과 사회적 의사소통의 균형적 발달을 도모하기 위한 사회적 창의 증진 프로그램을 개발하였다. 프로그램의 개발을 위하여 문헌 및 선행 연구 고찰이 이루어졌 으며, 프로그램에서 활용하는 창의성 기법의 선정을 위하여 창의성 전문가 1인의 자문 및 유아교사 5 인의 의견을 통하여 현장견해를 반영하였다. 또한 프로그램 개발 단계마다 이론 전문가 3인 및 현장 유아교사 5인과의 협의를 수행하여 프로그램의 타당도와 적합성을 검토하고 수정 및 보완하였다. 수정된 프로그램으로 만 5세 유아 14명에게 예비연구를 실시하였고, 프로그램에 대한 평가내용을 반영 하여 최종 프로그램을 개발하였다. 이러한 절차를 통하여 개발된 프로그램은 사회적 맥락에서 창의성과 효율적인 의사소통 능력을 발휘하는 사회적 창의를 갖춘 인재로 성장시키고자 하는데 목적을 두었 다. 목표는 창의성(확산적사고, 수렴적사고, 지식, 성향, 동기)과 사회적 의사소통능력(경청하기, 감정 조절하기, 자기 생각 느낌 표현하기, 타인 의도 이해하기, 공감과 함께 관심 갖기, 협력하여 해결하기, 사회규칙 지키기)을 증진시키고자 하였다. 이를 위하여 창의성 기법(브레인스토밍, 색다른 용도법, 자유연상법, 스캠퍼, 강제결합법, 육색모자기법, 유추법)을 활용하였다. 이러한 과정을 통하여 창의성과 사회적 의사소통의 균형을 추구하는 ‘사회적 창의 균형 모델’을 구축하였으며, 교수-학습과정을 3단계 여섯 과정으로 구성하여 프로그램을 개발하였다.This study developed a social creativity enhancement program to promote the balanced development of creativity and social communication using creativity techniques. For the development of this program, literature and previous research on creativity, social communication, creativity techniques, and the NURI Curriculum were reviewed. In selecting creativity techniques employed in the program, this study used on-the-spot opinions of one creativity expert and five preschool teachers. In addition, three experts and five preschool teachers in the child education field were consulted at each stage of the program development to review, revise and supplement the program s validity and suitability. A revised program used to conduct preliminary research on 14 children aged five years and developed the final program reflecting the evaluation of the program. The program developed through these procedures aimed to grow children into talented people with social creativity that demonstrates both creativity and effective communication skills in a social context. The specific goals are to facilitate creativity (divergent thinking, convergent thinking, knowledge, character, and motivation) and social communication skills (listening, controlling emotion, expressing feelings, understanding others intentions, sharing feelings, showing interest in others, cooperation for solutions, and abiding by social rules) through the program. For this purpose, creativity techniques (brainstorming, unusual uses, free association, SCAMPER, forced relationships , six thinking hats, and analogizing) were utilized. Through this process, this study built the social creative balance model, which seeks a balance between creativity and social communication.

Renormalization-scheme variation of a QCD perturbation expansion with tamed large-order behavior

The renormalization-scheme and scale dependence of the truncated QCD perturbative expansions is one of the main sources of theoretical error of the standard model predictions, especially at intermediate energies. Recently, a class of renormalization schemes, parametrized by a single real number $C$, has been defined and investigated in the frame of the standard perturbation expansions in powers of the coupling. In the present paper we investigate the $C$-scheme variation of a Borel-improved QCD perturbation series, which implements information about the large-order divergent character of perturbation theory by means of an optimal conformal mapping of the Borel plane. In the new expansions, the powers of the strong coupling are replaced by a set of expansion functions with properties which resemble those of the expanded correlators, having in particular a singular behavior at the origin of the complex coupling plane. On the other hand, the new expansions have a tamed increase at high orders, as demonstrated by previous studies in the $\overline{\mathrm{MS}}$ renormalization scheme. Using as examples the Adler function and the hadronic decay width of the $\ensuremath{\tau}$ lepton, we investigate the properties of the Borel-improved expansions in the $C$-scheme, in comparison with the standard expansions in the $C$-scheme and the expansions in $\overline{\mathrm{MS}}$. The variation with the renormalization scale and the prescription for the choice of an optimal value of the parameter $C$ are discussed. The good large-order behavior of the Borel-improved expansions is proved also in the $C$-scheme, which is a further argument in favor of using them in applications of perturbative QCD at intermediate energies.

Evaluation of genetic relationship between 15 bamboo species of North-East India based on ISSR marker analysis.

The classification of bamboos based on floral morphology and reproductive characters is very hard due to erratic flowering behavior and unusually long reproductive cycle. The application of reliable and effective DNA molecular markers is highly essential to address this problem. In the present investigation, inter-simple sequence repeats (ISSR) markers were employed to study phylogenetic relationship of 15 different bamboos of North-East India. The 10 ISSR primers generated 116 polymorphic loci or scorable bands with average of 11.6 bands per primer. The genetic similarity coefficient ranged from 0.41-0.76 showing high genetic polymorphism among different bamboo species. The phylogenetic tree constructed based on genetic similarity matrix revealed genetic proximity of endemic Bambusa mizorameana to other five Dendrocalamus species by clustering into a single group, while Dendrocalamus manipureanus segregated from the cluster indicating its genetic divergent character. Except for Schizotachyum fuchsianum, the three Schizotachyum species viz., S. dullooa, S. pergracile and S. munroi exhibited close genetic affinity by grouping into a single minor clade. Principal coordinates analysis (PCoA) showed distribution of different bamboos species in the plot in accordance to unweighted pair-group method with arithmetic average (UPGMA) cluster analysis. Genetic relationship of 15 different bamboos as revealed from the dendrogram and PCoA analysis reasonably conformed to traditional system of classification though slight disagreement existed. This is the first report on the successful use of ISSR markers in the phylogenetic and genetic variation studies of 15 important bamboos of the region including the endemic bamboo species of B. mizorameana, B. manipureana, D. sikkimensis and D. manipureanus.

The changing concept of work

In most countries, a standard (or core) model of employment relationship (i.e. full-time work under an open-ended employment contract) typically receives the greatest labour and social security protection, with divergent work arrangements receiving less protection in correlation to the magnitude of the differences between the former and the latter. However, recent developments concerning non-standard forms of work may question this dynamic. In this article, we examine the nature and current evolution of the standard employment relationship, then analyse how other forms of work deviate from this standard. In order to do so, we draw on the conclusions of the numerous studies recently published by scholars and international organisations in the wake of the growing public debate on the ‘new world of work’. Afterwards, we analyse the situation of non-standard workers under certain social security systems, in order to determine how those systems have approached the divergent character of these forms of work. This leads us to identify the main challenges that social security systems experience when faced with non-standard forms of work. The article concludes by addressing the need to adapt the basic principles of social security to the atypical features of non-standard work.

RELATIONSHIP BETWEEN CONVERGENT-DIVERGENT THINKING CHARACTERS AND MIND MAP

<p><em>This study aims to evaluate the mind mapping material in creativity course syllabus. The test is performed to see the students' convergent-divergent thinking characters. The treatment of the accounting mind map using numerical symbols was given to students before and after the thinking character tests. The test used paired sample t-test, Wilcoxon, and Chi-Square. The test result proves that there is an increase of students' divergent thinking character after given the material of accounting mind map using numerical symbols compared to before treatment. However, there is no difference of convergent thinking characters in class C before and after treatment</em>.</p>

The centrifugal visual system of a palaeognathous bird, the Chilean Tinamou (Nothoprocta perdicaria).

The avian centrifugal visual system, which projects from the brain to the retina, has been intensively studied in several Neognathous birds that have a distinct isthmo-optic nucleus (ION). However, birds of the order Palaeognathae seem to lack a proper ION in histologically stained brain sections. We had previously reported in the palaeognathous Chilean Tinamou (Nothoprocta perdicaria) that intraocular injections of Cholera Toxin B subunit retrogradely label a considerable number of neurons, which form a diffuse isthmo-optic complex (IOC). In order to better understand how this IOC-based centrifugal visual system is organized, we have studied its major components by means of in vivo and in vitro tracing experiments. Our results show that the IOC, though structurally less organized than an ION, possesses a dense core region consisting of multipolar neurons. It receives afferents from neurons in L10a of the optic tectum, which are distributed with a wider interneuronal spacing than in Neognathae. The tecto-IOC terminals are delicate and divergent, unlike the prominent convergent tecto-ION terminals in Neognathae. The centrifugal IOC terminals in the retina are exclusively divergent, resembling the terminals from "ectopic" centrifugal neurons in Neognathae. We conclude that the Tinamou's IOC participates in a comparable general IOC-retina-TeO-IOC circuitry as the neognathous ION. However, the connections between the components are structurally different and their divergent character suggests a lower spatial resolution. Our findings call for further comparative studies in a broad range of species for advancing our understanding of the evolution, plasticity and functional roles of the avian centrifugal visual system.

Wittgenstein’s Remarks Concerning the Accessibility of Foreign Cultures

AbstractWittgenstein (1889-1951) was highly disapproving of scholars whom he thought unable to properly acknowledge diversity amongst cultures or take due note of the enormous differences separating them from tribes living in radically heterogeneous cultural environments. The best known and paradigmatic example of his attitude to such differences is to be found in his Remarks on Frazer’s ‘Golden Bough’, where he wrote: “[…] how impossible for him [Frazer, J.B.] to understand a different way of life from the English one of his time”. But to cut a long story short, whether Wittgenstein saw this “impossibility” as an intrinsic feature of the task or not is by no means unambiguously clear. To resolve this question, I shall take as my point of departure the socio-anthropological writings of B. Malinowski (1884-1942), who spent several years amongst one of the Pacific island tribes - the Trobriands. In his “field studies”, Malinowski focused on the tribe’s “form of life”: i.e. on their belief in ritual and magic, and on how their customs interlinked with kinship and with their economy. Taking into account Malinowski’s own pragmatic conception of language and his notion of the divergent character of scientific and magical forms of belief, I then outline Wittgenstein’s notions of “language game”, “family resemblance” and “form of life”. The usage of these concepts will show in what sense Wittgenstein would have recognized the similarities within and between different cultures and human societies - but, equally, just how far we can understand a human way of life deeply different from our own.

Tests of the Role of Sexual Selection in Genitalic Divergence with Mutiple Hybrid Clines

Abstract Determining whether sexually selected characters affect reproductive isolation is key to understanding the significance of such selectively driven divergence in speciation. Divergence in the shape of male genitalia is ubiquitous in many insect taxa and can have important fitness consequences for males within a species. Yet, it is unclear whether this selectively divergent character affects gene flow among species. We test this hypothesis using explicit predictions about the clinal transition in genitalic shape across a hybrid zone between the grasshopper subspecies Barytettix humphreysii humphreysii and B. h. cochisei. Slight morphological differences in genitalic shape across their ranges raised the possibility that local processes might give misleading interpretations about sexual selection's potential contribution to reproductive isolation. Therefore, we examined multiple transects to explore the effectiveness of genitalic divergence as a barrier to gene flow on a background of potentially dif...

‘Who else would we speak to?’ National Policy Networks in post-devolution Britain: The case of spatial planning

The implementation of the devolution process that started in 1999 was frequently assumed by contemporary commentators and scholars to lead to a fractured relationship with the national centre and a fragmented state as a consequence. However, discourse analysis and policy reviews in relation to spatial planning policies demonstrates that agendas and legislation implemented by central and devolved governments since devolution are characterised by marked similarities in intention and type (albeit with some differences in name and delivery route). In investigating the potential sites and sources of these policy similarities and possible mobilities, and drawing on research data, we suggest that the British Irish Council’s spatial planning task group as one of the potential candidates to be considered as a national policy community or network. Alongside a range of other factors following devolution, this has contributed to development and delivery in one specific policy area that has taken a convergent rather than divergent character.

Species-level divergences in multiple functional traits between the two endemic subspecies of Blue Chaffinches Fringilla teydea in Canary Islands

One of the biggest challenges in avian taxonomy is the delimitation of allopatric species because their reproductive incompatibility cannot be directly studied in the wild. Instead, reproductive incompatibility has to be inferred from multiple, divergent character sets that indicate a low likelihood of allopatric populations amalgamating upon secondary contact. A set of quantitative criteria for species delimitation has been developed for avian taxonomy. Here, we report a broad multi-trait comparison of the two insular subspecies of the Blue Chaffinch Fringilla teydea, endemic to the pine forests of Tenerife (ssp. teydea) and Gran Canaria (ssp. polatzeki) in the Canary Islands. We found that the two taxa were reciprocally monophyletic in their whole mitogenomes and two Z chromosome introns. The genetic distance in mitogenomes indicates around 1 Mya of allopatric evolution. There were diagnostic differences in body morphometrics, song and plumage reflectance spectra, whose combined divergence score (=11) exceeds the threshold level (=7) set for species delimitation by Tobias et al. (Ibis 152:724–746, 2010). Moreover, we found a marked divergence in sperm lengths with little range overlap. Relatively long sperm with low intra- and intermale CV compared to other passerines suggest a mating system with high levels of sperm competition (extrapair paternity) in these taxa. The large and diagnostic divergences in multiple functional traits qualify for species rank, i.e., Tenerife Blue Chaffinch (Fringilla teydea) and Gran Canaria Blue Chaffinch (Fringilla polatzeki). We encourage a wider use of sperm traits in avian taxonomy because sperm divergences might signal reproductive incompatibility at the postcopulatory prezygotic stage, especially in species with sperm competition.