Species Concept Research Articles

Seeking the first phylogenetic method-Edvard A. Vainio (1853-1929) and his troubled endeavour towards a natural lichen classification in the late nineteenth century Finland.

Edvard August Vainio was a world-renowned Finnish lichenologist. In Finland, however, he was a controversial person due to his strong pro-Finnish political views. Equally disputed was his opinion that systematics should be based on evolutionary theory and phylogenetic thinking. Vainio was familiar with the ideas of the early German phylogeneticists-especially those of Carl Wilhelm von Nägeli - and, applying them, aimed to create an exact method for building a natural classification of lichens already at the end of the nineteenth century. In this respect, Vainio was a true pioneer, as no actual phylogenetic method had yet been developed. In the general spirit of the time, Vainio focused on finding the ancestors of species and other taxa by comparing primitive and derived features of homologous characters. However, Vainio already understood the concept of sister groups in 1880, the identification of which is the basis of all modern phylogenetic research. Nevertheless, the distinctive method developed by Vainio was not so much focused on the construction of a phylogenetic tree, but on revealing the origin of species through the differentiation and fixation of their polymorphic variation. Indeed, Vainio's species concept is surprisingly similar to the phylogenetic species concepts presented a hundred years later. Although in many ways progressive, Vainio's views did not influence the development of phylogenetics more widely, but his discussions are nevertheless a valuable source to understanding the early development of phylogenetic theory.

Understanding species limits through the formation of phylogeographic lineages.

The outcomes of speciation across organismal dimensions (e.g., ecological, genetic, phenotypic) are often assessed using phylogeographic methods. At one extreme, reproductively isolated lineages represent easily delimitable species differing in many or all dimensions, and at the other, geographically distinct genetic segments introgress across broad environmental gradients with limited phenotypic disparity. In the ambiguous gray zone of speciation, where lineages are genetically delimitable but still interacting ecologically, it is expected that these lineages represent species in the context of ontology and the evolutionary species concept when they are maintained over time with geographically well-defined hybrid zones, particularly at the intersection of distinct environments. As a result, genetic structure is correlated with environmental differences and not space alone, and a subset of genes fail to introgress across these zones as underlying genomic differences accumulate. We present a set of tests that synthesize species delimitation with the speciation process. We can thereby assess historical demographics and diversification processes while understanding how lineages are maintained through space and time by exploring spatial and genome clines, genotype-environment interactions, and genome scans for selected loci. Employing these tests in eight lineage-pairs of snakes in North America, we show that six pairs represent 12 "good" species and that two pairs represent local adaptation and regional population structure. The distinct species pairs all have the signature of divergence before or near the mid-Pleistocene, often with low migration, stable hybrid zones of varying size, and a subset of loci showing selection on alleles at the hybrid zone corresponding to transitions between distinct ecoregions. Locally adapted populations are younger, exhibit higher migration, and less ecological differentiation. Our results demonstrate that interacting lineages can be delimited using phylogeographic and population genetic methods that properly integrate spatial, temporal, and environmental data.

Host-driven phenotypic and phenological differentiation in sympatric races of a parasitic plant

Host specificity is a key factor influencing the ecology and evolutionary diversification of parasitic organisms. Host specialisation and geographic isolation are known to lead to the genetic differentiation of allopatric races in parasitic plants. However, how divergence can co-occur in sympatry remains largely unknown. We investigated phenological and phenotypic differentiation and potential reproductive isolation among three sympatric genetic races of Cytinus hypocistis (Cytinaceae) - an extreme endophytic holoparasite with a high degree of host specialisation. We compared spatio-temporal variations in flowering phenology, flower production, floral longevity, floral rewards, and morphology, and conducted inter-race pollinations among three races parasitising Cistus ladanifer, C. salviifolius, and Halimium halimifolium (Cistaceae) in six co-occurring populations. We found that host-defined genetic races differed significantly across multiple phenotypic and phenological aspects – a phenomenon previously overlooked due to the plants’ cryptic morphology. The race parasitising H. halimifolium showed earlier blooming, higher floral display, longer flowers, and higher pollen production and nectar concentration; the race on C. salviifolius showed later flowering, significantly lower floral display and smaller flowers with lower floral rewards; the race on C. ladanifer had intermediate characteristics. Genetic races were interfertile yet may remain differentiated by restricted gene flow and host-driven selection pressures. Together, our data point to a rare case of sympatric divergent evolution hiding in plain sight: apparently morphologically similar co-occurring parasite races can be genetically, phenotypically, and phenologically distinct. This hitherto unreported example of host-driven sympatric diversification challenges how species concepts are applied to cryptic parasitic plant races.

Description of three widespread new Peronospora species parasitising Caryophyllales

Downy mildews are cosmopolitan obligate biotrophic parasites of flowering plants. They are fungus-like eukaryotes of the kingdom Straminipila, and most species are highly specialised, often parasitising only a single host species. Due to the prevalence of a broad species concept before the advent of molecular phylogenetics and the paucity of differentiating characteristics in some groups, many widespread species are still undescribed. This is also the case for some downy mildews in the clade containing the type species of Peronospora, Peronospora rumicis. Spurred by the discovery of the undescribed species parasitising Rumex acetosa at the Blávík research station in East Iceland, three new widespread species of Peronospora are introduced in this article: Peronospora blauvikensis parasitic to Rumex acetosa, P. boylei parasitic to Rumex thyrsiflorus, and P. spergulariae parasitic to Spergula marina. As the species are morphologically highly similar, a set of diagnostic bases is given for each species, allowing a quick identification via molecular barcoding.

Studies on type material from Kützing’s diatom collection VIII. Species assigned to the genera Epithemia Brébisson ex Kützing and Rhopalodia O. Müller

We detail the diatom taxa described by F.T. Kützing across three of his publications that have been referred to the diatom genera Epithemia and Rhopalodia. Taxa considered include Frustulia adnata, F. picta, E. alpestris, E. musculus, E. porcellus, E. proboscidea, E. sorex, E. ventricosa, E. vertagus, E. ventricosa β. gregaria and E. reticulata. For these 12 taxa, this represents the first time Kützing’s specimens have been illustrated with light microscopy. Most of the material consulted here is from the Natural History Museum, London, though we also reviewed material from the Academy of Natural Sciences for E. adnata. We present light microscope images of the Kützing taxa and complement these observations with images of the type slides, material packets and both herbarium (unpublished) and published drawings. In some cases, modern concepts of Kützing species are supported, but in others it is likely that species concepts will be changed by the specimens in the type material. Lectotypes are designated for Epithemia adnata and Epithemia reticulata.

The White-backed Woodpecker (Dendrocopos leucotos) as an umbrella species for threatened saproxylic beetle communities in Central European beech forests

The umbrella species concept is a popular conservation planning tool which postulates that conservation schemes targeting a specific species will indirectly benefit many other sympatric species. In Scandinavia and Central Europe, the White-backed Woodpecker (Dendrocopos leucotos) is considered an umbrella species for woodland birds and cryptogam species of conservation concern. Whether this also applies to saproxylic beetles, a group of high conservation concern, remains open. Therefore, we tested that umbrella function in Central European beech forests that are currently recolonized by this woodpecker. Relying on radiotracking data, we compared saproxylic beetle communities within the breeding home ranges of White-backed Woodpeckers (high and low activity of the bird) against forests with ascertained absence of the bird (control). Bayesian inference for linear regressions identified that species richness of threatened saproxylic beetles was 1.51 (lower and upper 5 % PPCrI=[1.09; 2.01]) times higher in sites with high White-backed Woodpecker activity compared to the control. Community composition analyses on threatened saproxylic beetles showed a reduced β-diversity at low and high White-backed Woodpecker sites compared to the control. Finally, an indicator species analysis showed that 17 saproxylic beetle species, including 4 threatened species, were positively associated with White-backed Woodpecker’s breeding home ranges, while only 3 species, but no threatened species, were associated with the control sites. Overall, our results suggest that the White-backed Woodpecker plays the role of an umbrella species for threatened saproxylic beetle communities, opening new opportunities for conservation planning in European beech forests.

Using integrative taxonomy to delimit species in the plant bug genus Pseudoloxops (Hemiptera: Miridae) in French Polynesia

Abstract We use integrative taxonomy to elucidate species boundaries of the plant bug genus Pseudoloxops (Kirkaldy 1905) in the Austral and Society archipelagos of French Polynesia. We operationalize the unified species concept by treating each individual as a potential species and then establish initial groupings (putative species) following statistically highly-supported reciprocal monophyly of individuals in a phylogenetic analysis of CO1, 16S, and 28S gene fragments. We then test our species hypotheses against additional lines of evidence from geometric morphometrics, genetic distance, discrete genitalic morphology, plant association, and geographic distribution partitions. Twenty species endemic to French Polynesia are recognized as follows: Pseudoloxops aama Balukjian & Van Dam, sp. nov., Pseudoloxops anaana Balukjian & Van Dam, sp. nov., Pseudoloxops baileyi Balukjian & Van Dam, sp. nov., Pseudoloxops chastaoliancai Balukjian & Van Dam, sp. nov., Pseudoloxops harrisonfordi Balukjian & Van Dam, sp. nov., Pseudoloxops kamalaharrisae Balukjian & Van Dam, sp. nov., Pseudoloxops oboyskii Balukjian & Van Dam, sp. nov., Pseudoloxops papepihaa Balukjian & Van Dam, sp. nov., Pseudoloxops puarata Balukjian & Van Dam, sp. nov., Pseudoloxops raimana Balukjian & Van Dam, sp. nov., Pseudoloxops ravataputuarai Balukjian & Van Dam, sp. nov., Pseudoloxops simberloffi Balukjian & Van Dam, sp. nov., Pseudoloxops tairoto Balukjian & Van Dam, sp. nov., Pseudoloxops temehanirahi Balukjian & Van Dam, sp. nov., Pseudoloxops tiapai Balukjian & Van Dam, sp. nov., Pseudoloxops toparaamahana Balukjian & Van Dam, sp. nov., Pseudoloxops tupapaau Balukjian & Van Dam, sp. nov. New synonyms are proposed for Pseudoloxops flavus (Knight, 1937) [=Pseudoloxops rubrocuneatus (Knight, 1937)] and Pseudoloxops adamsoni (Knight, 1937) [= Pseudoloxops nigribasicornis (Knight, 1937) and = Pseudoloxops tahiticus (Knight, 1937)]. Pseudoloxops rubroclavus (Knight, 1937) is redescribed.

Trofim Lysenko’s “New doctrine of the species”: an attempt at close reading

One of the core themes in the Soviet Michurinist biology was pointing out Darwin’s “errors” and a plea for a revision of classical Darwinism, allegedly based on “flat evolutionism” (= gradualism) and misinterpretation of the dialectics of the organic evolution. The result was the so-called “Soviet creative Darwinism” that promoted fundamentally new concepts of the biological species and speciation, and was coined the “new doctrine of the species” (NDS) during the 1952–1955 discussion. Even though Lysenkoism has been thoroughly studied, the basic postulates of the NDS, its logical structure and genesis remained outside the scope of attention of the historians of science. Based on primary sources, principally on T. D. Lysenko’s own publications, this article is an attempt at presenting a holistic view of the NDS and identifying its conceptual origins. The content of the NDS is shown to be closely associated with the postulates of dialectical materialism used as the philosophical grounding for the new theory. Most of its biological content is not original and was borrowed by Lysenko from other sources. The more or less original elements of the “new doctrine” were the rejection of the intraspecific struggle for existence and the “physiological” concept of speciation, based on the belief that the most important mechanism of evolutionary transformations is changes in species-specific metabolism. Both of these elements were rejected by biology in the course of its further advancement while some others (inheritance of acquired traits, speciation by leaps) find their supporters today. However, modern ideas of saltational evolution have no continuity with the NDS, as they are based on the mutational paradigm rejected by Lysenko.

Synopsis of the genus <i>Polystemma</i> (Apocynaceae, Asclepiadoideae) and recognition of three new species

Background: Polystemma is characterized by a mixed indumentum of glandular trichomes that turn white, rotate to rotate-campanulate corollas, a gynostegial corona with filiform appendages, and fusiform follicles. The taxon has undergone numerous taxonomic changes in recent years. In current phylogenies, Polystemma has been recovered as paraphyletic and many of its species require a new combination. In this study, we propose the corresponding changes and describe, map, and illustrate three new species within this genus. Questions: Do morphological data support the transfer of Matelea species to Polystemma? Are the plants of Polystemma collected in Durango, Jalisco, and Sinaloa different species? Studied species: Polystemma. Study site and dates: United States, Mexico, Guatemala, El Salvador, Honduras, Nicaragua y Costa Rica, between 2022 and 2024. Methods: More than 3,000 specimens from 20 herbaria and virtual databases were reviewed. Distribution maps were generated, and risk categories were proposed. The cohesive species concept was proposed as an explanatory hypothesis for taxon recognition. Results: A total of 27 species of the genus were recognized, these distributed from the southeastern United States of America to Costa Rica. Eleven new combinations and three lectotypifications are made, and three new species for science are proposed. Identification key, nomenclatural type information, synonyms, habitat, images of all species and distribution maps are also included. Conclusions: The review of this genus allowed for updating and improving the systematics within the subtribe Gonolobinae. Likewise, it highlights Mexico as the center of diversity and endemism for Polystemma.

Extinct or Not? Confirming the “Extinct” Status of Hieracium tolstoii (Asteraceae) with Integrated Taxonomic Investigation

Hieracium is one of the largest flowering plant genera that has recently experienced a rapid evolutionary radiation. Due to the massive morphological variation among species, frequent hybridization, and polyploidization events, combined with apomictic reproduction in polyploids, the concept of species in Hieracium is widely debated, and species identification is incredibly challenging. Taxonomic investigation can lead to changes in conservation status or, in some cases, to de-extinctions of species. Taxa with doubtful classification are particularly sensitive to this kind of problem. Hieracium tolstoii was a narrow Italian endemic species that is nowadays considered extinct. Described as a morphological intermediate form between two other species, no further investigations were conducted after its first description. To clarify H. tolstoii’s origin and ensure the validity of its current conservation status, we conducted a taxonomic investigation on herbaria specimens of the early XX century. Specimens were studied using a morphometric analysis that compared H. tolstoii with other closely related taxa. Moreover, we performed phylogenetic investigations using three plastid intergenic spacers to evaluate the relationship between species. Plastid markers revealed the presence of indels and SNPs in H. tolstoii sequences that differ from sequences of the supposed parental species. Morphometry revealed differences among species that led us to confirm the validity of H. tolstoii as an independent apomictic species and, therefore, unfortunately, its extinction.

Invasive Studies of Dandelion and other Alien Species Based on Predictive Models

Taraxacum officinale is a plant commonly known as the dandelion. It is a perennial herb native to Eurasia but has been introduced to other parts of the world and is now considered a weed in many areas. Dandelions are used in traditional medicine to treat various ailments and are also used as a food source in some cultures. However, some people regard it as an invasive species, which is a species that is harmful to the biological chain. Some suggest a reason: the dandelion's reproductive rate and ability to survive are so strong that it can easily encroach on the territory of other species, causing their numbers to decline.To protect the whole ecosystem, we need to protect other species from being invaded by dandelions. Therefore, the first problem analyzed is the spread of dandelions, and the main idea for the first problem is the Sprawl prediction-based model. The influence of different environmental factors on the spread of dandelions was considered to predict the number of dandelions after a certain time.The second model is the Logistic model, which considers the competition relationship and also uses MATLAB to draw the image. Showing the relationship between the number of dandelions and that of another species. With some knowledge of the spread and a detailed analysis of the danger of dandelions to other species, we hypothesized two main species and counted their numbers to determine the impact of dandelions. Finally, our group inquired about the concept of invasive species to further analyze whether dandelions fit.

Unique findings of <i>Phoma</i>-like fungi associated with soybean

Ascochyta leaf blight of soybean is a widespread disease caused by several closely related Phoma-like species, this disease often leads to significant crop losses. Among Phoma-like species from Didymellaceae family, the most frequently associated with symptomatic soybean tissues are species of the genera Boeremia and Didymella. Currently reliable species identification in Didymellaceae relies on polyphasic approach based on consolidated species concept and combined molecular phylogenetic, micromorphological and cultural features. At least three loci are commonly used for reconstruction of the molecular phylogeny of Didymellaceae: internal transcribed spacer (ITS) of the ribosomal DNA, partial RNA-polymerase II gene (rpb2), and β-tubulin (tub2). As a result of long-term phytosanitary monitoring of soybean crops, soybean leaves with symptoms of Ascochyta blight were collected from major soybean producing areas of Russia. From surface sterilized plant tissues more than 100 isolates of Phoma-like fungi were obtained and stored in the collection of pure cultures of the Laboratory of Mycology and Phytopathology (MF, All-Russian Institute of Plant Protection). Most of them, as a result of multilocus phylogenetic analysis, were identified as Boeremia and Didymella species. Eight isolates were identified as species of other genera, suspected to be rare findings. The aim of this study was to identify these eight isolates based on multilocus phylogenetic analysis, as well micromorphological, cultural, and pathogenicity data. Multilocus phylogenetic analysis has resulted in identification of all eight isolates to species level. Single isolate from the Ryazan region was Neoascochyta graminicola. Three other from three different districts of the Amur region were Remotididymella capsici. Two isolates from the Primorskiy territory and Amur region were Stagonosporopsis heliopsidis. Another two from two districts of the Amur region were S. stuijvenbergii. Pathogenicity tests have resulted in conclusion, that all studied isolates were not pathogenic for soybean leaves. Probably, these Phoma-like species are associate with soybean as saprophytes or endophytes. For all these Phoma-like species Glycine max was detected as substrate for the first time. Neoascochyta graminicola is widespread in Europe in association with Poaceae plants. There are only two findings of Remotididymella capsici in the world, both from leaves of Capsicum annuum. First finding was made in the former USSR in 1977 and was identified based on only morphological features. Second findings was collected in the Fiji and verified with multilocus phylogenetic analysis. Stagonosporopsis heliopsidis isolates were revealed in the USA, Canada, Netherlands and Russia and this fungus was believed to be specific for Asteraceae plants. Isolates of Stagonosporopsis stuijvenbergii are known only from soil in the Netherlands. Thus, such species as Neoascochyta graminicola and Stagonosporopsis stuijvenbergii were revealed in the Russia for the first time. Studied Remotididymella capsici isolates were first confirmed findings of this fungus in Russia. Additionally to detailed phylogenetic data, the manuscript is supplement with a detailed description of the cultural and micromorphological features of all species.

An integrative approach to the delineation of locally endemic species: A case study of Vitis baihuashanensis (Vitaceae) and its implication for conservation management

Species definition and classification have long been the subject of controversy, and name changes can often be a source of frustration for both conservationists and the public. Vitis baihuashanensis is a critically endangered grapevine endemic to Beijing with only two remaining wild individuals. Although formerly treated as a synonym of V. amurensis, it was later listed in the List of National Key Protected Wild Plants (LNKPWP) in 2021. Here, we evaluated the taxonomic identity of V. baihuashanensis based on phylogenomic inference and population genetic analysis, and tested the species boundaries under various major species concepts (biological, morphological, ecological, phylogenetic, and integrative species concepts). Phylogenetic inference revealed that the amurensis-baihuashanensis clade was monophyletic, samples of V. baihuashanensis nested within the V. amurensis node. Population genetic analysis demonstrated that V. baihuashanensis samples clustered with V. amurensis. Our findings from field observations, morphological comparisons, pollination experiments, and genetic analyses indicate that V. baihuashanensis and V. amurensis are the same species under the integrative species concept, and support the synonymy of V. baihuashanensis under V. amurensis. Given that V. baihuashanensis was listed in the LNKPWP, we suggest that it be removed in the next update of the list because of limited financial resources. Nevertheless, the two wild individuals deserve conservation attention because of their distinct leaf characteristics and potential of cold tolerance, which could have important applications in the horticulture and grape industries. Our study provides multiple lines of evidence for clarifying the identity of a taxonomically questionable species, as well as valuable suggestion with conservation and management implications.

Revising the Keystone Species Concept for Conservation: Value Neutrality and Non-Nativeness

ABSTRACT The keystone species concept is often used in conservation. However, scientists and conservationists use the concept in many different ways. I suggest that a problem with the concept in conservation is not the lack of a shared definition. Instead, the problem is how the concept is applied to only certain species despite potentially covering a broader suite of species. This highlights unstated values in using the concept in conservation. I use novel examples, such as non-native Burmese pythons in Florida, to motivate this. I argue that the concept should include these species and be used value-neutral.

One Genome, Multiple Phenotypes: Would Rhodnius milesi Carcavallo, Rocha, Galvão & Jurberg, 2001 (Hemiptera, Triatominae) Be a Valid Species or a Phenotypic Polymorphism of R. neglectus Lent, 1954?

Species of the Rhodnius genus have a complex taxonomy because the events of phenotypic plasticity and cryptic speciation make it difficult to correctly classify these vectors. During the taxonomic history of the genus, five synonymization events occurred. Additionally, some authors suggest that R. milesi possibly represent only phenotypic polymorphisms of R. neglectus. Thus, we analyzed the specific status of R. milesi in relation to R. neglectus using phylogenetic studies with the mitochondrial gene cytochrome B and the study of reproductive barriers. The phylogenetic reconstruction grouped R. milesi together with R. neglectus from different localities, demonstrating that these taxa represent the same species based on the phylogenetic species concept. Experimental crosses demonstrate the absence of pre- and postzygotic barriers under laboratory conditions. Additionally, when the hatch rates of crosses are compared to intraspecific crosses, it can be noted that they are high and very similar. Finally, the mortality rate of the hybrids does not indicate hybrid inviability, the absence of chromosome pairing errors does not indicate hybrid sterility, and the proportion between male and female hybrids demonstrates that Haldane’s rule was not acting. Therefore, we perform the formal synonymization of R. milesi with R. neglectus.

Detecting the distribution of and public attitudes to charismatic alien species based on media coverage

Charismatic species are often reported by the media, providing information for detecting population status and public perception. To identify the number and distribution of free-living Black Swan (Cygnus atratus), a charismatic alien species in Chinese mainland and to detect the public and the media attitudes to the species, we analyzed the reports and emotional tendency from media coverage in 2000–2022 using manual reading, crawler extraction and latent Dirichlet allocation. A total of 6654 Black Swans were reported at 711 sites, including 147 individuals at 30 nature reserves. Successful breeding was reported at one-fourth of the total sites, including five nature reserves. The proportion of positive emotional tendency to Black Swans was overwhelming in the reports and was higher than that to alien species in general, suggesting that the public and the media are unaware of the risk of biological invasion. Effective management of invasive species requires the media clarifies the invasion risk of charismatic alien species. Promoting the unity between the harmfulness of abstract concept of alien species and the charisma of a specific alien species among the public help effective management.

Phylogenetic and morphological re-evaluation of Camptophora.

The genetic variety and habitats of Camptophora species, generally known as black yeast, have not been clarified. In this study, we re-evaluated Camptophora based on morphological observations and phylogenetic analyses. Because prior investigations on Camptophora only included a few strains/specimens, 24 Camptophora-related strains were newly obtained from 13 leaf samples of various plant species to redefine the genetic and species concepts of Camptophora. Their molecular phylogenetic relationships were examined using small subunit nuclear ribosomal DNA (nSSU, 18S rDNA), the internal transcribed spacer (ITS) rDNA operon, the large subunit nuclear ribosomal DNA (LSU, 28S rDNA), β-tubulin, the second largest subunit of RNA polymerase II (rpb2), and mitochondrial small subunit DNA (mtSSU). Single- and multi-locus analyses using nSSU-ITS-LSU-rpb2-mtSSU revealed a robust phylogenetic relationship among Camptophora species within Chaetothyriaceae. Camptophora species could be distinguished from other chaetothyriaceous genera by their snake-shaped conidia with microcyclic conidiation and loosely interwoven mycelial masses. Based on the results of phylogenetic analyses, two undescribed lineages were recognized, and Ca. schimae was excluded from the genus. ITS sequence comparison with environmental DNA sequences revealed that the distribution of the genus is restricted to the Asia-Pacific region. Camptophora has been isolated or detected from abrupt sources, and this was attributed to its microcycle. The mechanisms driving genetic diversity within species are discussed with respect to their phyllosphere habitats.

Resolution of the Aleiodesseriatus (Herrich-Schäffer, 1838)-aggregate in the western Palaearctic (Hymenoptera, Braconidae, Rogadinae), with description of a new species.

Two European species are recognised and characterised within the traditional Aleiodesseriatus species concept, based initially on DNA barcoding but with supporting, although slight and sometimes unreliable, morphological differences. Aleiodespseudoseriatus sp. nov. is described and a neotype is designated for Rogasseriatus Herrich-Schäffer, 1838. Specimens from the Russian Far East were also DNA barcoded and were found to belong to a new species distinct from the two European taxa. The two European species were found to use different lithosiine hosts.

Further revisions to the Palaearctic Andrena fauna (Hymenoptera: Andrenidae)

Andrena is the second largest genus of bees, with around 1,700 species known globally following recent revisions (e.g. Wood & Monfared 2022; Pisanty et al. 2022a; Wood 2023a; b; c; d). The genus is relatively young at approximately 25 million years old, and is known for its explosive radiation as one of if not the most rapidly speciating bee lineages (Bossert et al. 2022; Pisanty et al. 2022b). This rapid rate of speciation combined with a preference for Mediterranean and xeric environments means that a large number of Andrena species remain undetected and undescribed, most clearly in difficult-to-access parts of the Middle East and Central Asia. The genus has a long history of study, particularly in the West Palaearctic (Gusenleitner & Schwarz 2002), and there are consequently a large number of original works describing taxa from across the Old World (e.g. Christ 1791; Panzer 1799; Erichson 1835; Smith 1853; Dours 1873; Morawitz 1876; Schmiedeknecht 1882–1884; Radoszkowski 1891; Nurse 1904; Cameron 1908; Friese 1914; Perkins 1914; Cockerell 1917; Strand 1921; Stöckhert 1935; Noskiewicz 1939; Warncke 1965; Osytshnjuk 1995; Xu et al. 2000; Grünwaldt et al. 2005; Tadauchi et al. 2005). Though workers often corresponded, the huge diversity of species and the often subtle characters separating them means that many taxa are synonymous or present other nomenclatural challenges, but this still remains to be established for many taxa despite historical and contemporary revisionary works (e.g. Warncke 1967; Tadauchi & Xu 1999; 2003; Gusenleitner & Schwarz 2002; Xu et al. 2000; Xu & Tadauchi 2002; 2005; 2009; 2012; Gusenleitner et al. 2005; Pisanty et al. 2018; Astafurova et al. 2022a; 2023; Praz et al. 2022; Wood & Monfared 2022; Wood 2023a; b; c). Against this context, revisionary works on Old World Andrena must balance i) the long history of species description and subsequent use, often with unclear or inconsistent species concepts; ii) the rapid speciation rate of Andrena combined with their often sporadic appearance and highly local distributions leading to enormous species diversity, and iii) the ongoing and incomplete treatment of older names, some of which have not been revised due to inability to locate types or inability to visit specific collections. The present work represents an additional contribution to this ongoing work through resolving existing nomenclatural problems and describing or elevating distinct Old World Andrena species.

Species and Speciation in the Termite-Cultivated Fungus Termitomyces

Termitomyces is a genus of basidiomycete fungi cultivated by termites of the subfamily Macrotermitinae. This symbiosis originated in central Africa, and subsequently, the fungus-growing termites have colonized almost the entire African continent including Madagascar as well as significant parts of Asia. Around 40 species of Termitomyces have been described based on morphology of the sexual fruit bodies, which are associated with some 330 species of fungus-growing termites distributed over 11 genera. However, the total number of fungal species may be higher as not all species regularly produce mushrooms, and morphological variation does not seem to be a reliable criterion for species delimitation in this group. In this study we estimated the total number of species based on ITS-barcode criteria and assessed host specificity and geographic differentiation to infer patterns of speciation. We estimated the total number of phylogenetic species using two methods of DNA sequence-based species delimitation; Automatic Barcode Gap Discovery (ABGD) and the Generalized Mixed Yule Coalescent (GMYC) model on a large dataset of over 1,500 ITS sequences from laboratory cultures, fungarium specimens and the public database NCBI Genbank. This resulted in an estimated 87 species hypotheses using ABGD and 94 species hypotheses using the GMYC model. A phylogenetic reconstruction was performed on representative sequences of the 87 species hypotheses identified by ABGD (the most conservative estimate) constrained by a well-supported phylogeny based on whole-genome data to address host specificity and geographical differentiation. Five main clades were recovered which generally were associated with species of one or two host genera, except for samples collected from the genera Microtermes and Ancistrotermes, which formed two separate non-sister clades. We did not find any evidence for long-term host fidelity as would be expected for species with strict uniparental vertical symbiont transmission. We found strict geographic separation between African and Asian species of Termitomyces and infer a minimum of seven inter-continental migrations. We show that epigeous fruiting of the T. microcarpus group has a single evolutionary origin in Africa and that fruiting in species of this group likely is induced by the fungus rather than by the host-termite species. In contrast, fruiting in the symbionts of some species of Microtermes and Macrotermes may be suppressed by the host-termite species, since mushrooms of certain fungal species are found when those species are associated with some termite-host genera, but never when associated with other host genera. We discuss some examples of incongruence between morphological and phylogenetic species concepts and give suggestions to improve the taxonomy of the genus Termitomyces.