The evolution of sexual and parthenogenetic Warramaba: a window onto Plio–Pleistocene diversification processes in an arid biome

Environmental changes over the Plio‐Pleistocene have been key drivers of speciation patterns and genetic diversification in high‐latitude and mesic environments, yet comparatively little is known about the evolutionary history of species in arid environments. We applied phylogenetic and phylogeographic analyses to understand the evolutionary history of Warramaba grasshoppers from the Australian arid zone, a group including sexual and parthenogenetic lineages. Sequence data (mitochondrial COI) showed that the four major sexual lineages within Warramaba most likely diverged in the Pliocene, around 2–7 million years ago. All sexual lineages exhibited considerable phylogenetic structure. Detailed analyses of the hybrid parthenogenetic species W. virgo and its sexual progenitors showed a pattern of high phylogenetic diversity and phylogeographic structure in northern lineages, and low diversity and evidence for recent expansion in southern lineages. Northern sexual lineages persisted in localized refugia over the Pleistocene, with sustained barriers promoting divergence over this period. Southern parts of the present range became periodically unsuitable during the Pleistocene, and it is into this region that parthenogenetic lineages have expanded. Our results strongly parallel those for sexual and parthenogenetic lineages of the gecko Heteronotia from the same region, indicating a highly general effect of Plio‐Pleistocene environmental change on diversification processes in arid Australia.     

Genetic mosaic in a marine species flock

We used molecular approaches to study the status of speciation in coral reef fishes known as hamlets (Serranidae: Hypoplectrus). Several hamlet morphospecies coexist on Caribbean reefs, and mate assortatively with respect to their strikingly distinct colour patterns. We provide evidence that, genetically, the hamlets display characteristics common in species flocks on land and in freshwaters. Substitutions within two mitochondrial DNA (mtDNA) protein-coding genes place hamlets within a monophyletic group relative to members of two related genera (Serranus and Diplectrum), and establish that the hamlet radiation must have been very recent. mtDNA distances separating hamlet morphospecies were slight (0.6 +/- 0.04%), yielding a coalescent estimate for the age of the hamlet flock of approximately 430 000 years. Morphospecies did not sort into distinct mtDNA haplotype phylogroups, and alleles at five hypervariable microsatellite loci were shared broadly across species boundaries. None the less, molecular variation was not distributed at random. Analyses of mtDNA haplotype frequencies and nested clades in haplotype networks revealed significant genetic differences between geographical regions and among colour morphospecies. We also observed significant microsatellite differentiation between geographical regions and in Puerto Rico, among colour morphospecies; the latter providing evidence for reproductive isolation between colour morphospecies at this locale. In our Panama collection, however, colour morphospecies were mostly genetically indistinguishable. This mosaic pattern of DNA differentiation implies a complex interaction between population history, mating behaviour and geography and suggests that porous boundaries separate species in this flock of brilliantly coloured coral reef fishes.     

Barcoding,molecular taxonomy,and exploration of the diversity of shrews (Soricomorpha: Soricidae) on Mount Nimba (Guinea)

We tested the efficiency of cytochrome oxidase I (COI)‐barcoding as a taxonomic tool to discriminate and identify sympatric shrew species on Mount Nimba (Guinea). We identified 148 specimens at the species level using morphological characters and comparison with type specimens, including several taxa from Mount Nimba. We identified ten morphospecies and tested aspects of genetic diversity and monophyly using genetic data from three mitochondrial (16S, cytochrome b, and COI) and one nuclear marker (the breast cancer gene, BRCA). Nine morphospecies were validated under the phylogenetic and genetic species concepts, including the recently diverged species Crocidura buettikoferi, Crocidura theresae, and Crocidura grandiceps. Under the same concepts, our analyses revealed the presence of two cryptic species amongst animals identified as Crocidura muricauda. We then tested the efficiency of barcoding thanks to commonly used phenetic methods, with the 148 specimens representing 11 potentially valid species based on morphological and molecular data. We show that COI‐barcoding is a powerful tool for shrew identification and can be used for taxonomic surveys. The comparison of genetic divergence values shows the presence of a barcoding gap (i.e. difference between the highest intraspecific and the lowest interspecific genetic divergence values). Given that only a few COI sequences are available for Afrotropical shrews, our work is an important step forward toward their enrichment. We also tested the efficiency of the three other sequenced markers and found that cytochrome b is as efficient as COI for barcoding shrews. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 672–687.     

Collembola as alternative prey sustaining spiders in arable ecosystems: prey detection within predators using molecular markers

Collembola comprise a major source of alternative prey to linyphiid spiders in arable fields, helping to sustain and retain these predators as aphid control agents within the crop. Polymerase chain reaction primers were developed for the amplification, from spider gut samples, of DNA from three of the most abundant species of Collembola in wheat crops in Europe, namely Isotoma anglicana, Lepidocyrtus cyaneus and Entomobrya multifasciata. The primers amplified fragments of the mitochondrial cytochrome oxidase subunit I (COI) gene and were designed following alignment of comparable sequences for a range of predator and prey species. Each of the primer pairs proved to be species-specific to a Collembola species, amplifying DNA fragments from 211 to 276 base pairs in length. Following consumption of a single collembolan, prey DNA was detectable in 100% of spiders after 24 h of digestion. We report the first use of DNA-based techniques to detect predation by arthropods on natural populations of prey in the field. All three species of Collembola were consumed by the spiders. By comparing the ratios of the Collembola species in the field with the numbers of spiders that gave positive results for each of those species, it was possible to demonstrate that the spiders were exercising prey choice. Overall, a single target species of Collembola was eaten by 48% of spiders while a further 16% of spiders contained DNA from two different species of Collembola. Preference was particularly evident for I. anglicana, the species most frequently found in spider guts yet the least numerous of the three target species in the field.     

Adaptive sympatric speciation of polychromatic "roundfin" sailfin silverside fish in Lake Matano (Sulawesi)

The significance of sympatric speciation is one of the most controversial topics in evolutionary biology. Theory suggests that different factors can lead to speciation in full geographical contact, including selection and nonrandom mating. Strict criteria have been established for assessing sympatric speciation, which have been met in only a very few cases. Here, we investigate differentiation among sympatric morphospecies and color morphs of "roundfin" sailfin silversides (Telmatherinidae), small freshwater fish endemic to ancient Lake Matano in Central Sulawesi (Indonesia). Morphospecies are distinct according to body shape (geometric morphometrics), population structure (population-level amplified fragment length polymorphism [AFLP] markers), ecology, and mating behavior (habitat transects, stomach contents). Explorative genome scans based on AFLPs indicate that divergent selection affects only 1.3-4.2% of the analyzed loci, suggesting an early stage of speciation. Transect data demonstrate strong assortative mating and adaptive niche differentiation. However, we find no restrictions in gene flow among the conspicuous male color morphs. In summary, our data are consistent with a sympatric mode of divergence among three morphospecies under conditions effectively ruling out allopatric scenarios. Substantial, but incomplete, reproductive isolation suggests an early stage of speciation, most likely due to ecological selection pressure.     

DNA barcodes and phylogenetic affinities of the terrestrial slugs Arion gilvus and A. ponsi (Gastropoda,?Pulmonata,Arionidae)

The Iberian Peninsula is a region with a high endemicity of species of the terrestrial slug subgenus Mesarion. Many of these species have been described mainly on subtle differences in their proximal genitalia. It therefore remains to be investigated 1) whether these locally diverged taxa also represent different species under a phylogenetic species concept as has been shown for other Mesarion species outside the Iberian Peninsula, and 2) how these taxa are phylogenetically related. Here, we analysed DNA sequence data of two mitochondrial (COI and 16S) genes, and of the nuclear ITS1 region, to explore the phylogenetic affinities of two of these endemic taxa, viz. Arion gilvus Torres Mínguez, 1925 and A. ponsi Quintana Cardona, 2007. We also evaluated the use of these DNA sequence data as DNA barcodes for both species. Our results showed that ITS did not allow to differentiate among most of the Mesarion molecular operational taxonomic units (MOTUs) / morphospecies in Mesarion. Yet, the overall mean p-distance among the Mesarion MOTUs / morphospecies for both mtDNA fragments (16.7% for COI, 13% for 16S) was comparable to that between A. ponsi and its closest relative A. molinae (COI: 14.2%; 16S: 16.2%) and to that between A. gilvus and its closest relative A. urbiae (COI: 14.4%; 16S: 13.4%). Hence, with respect to mtDNA divergence, both A. ponsi and A. gilvus, behave as other Mesarion species or putative species-level MOTUs and thus are confirmed as distinct ‘species’.     

Phylogeny of Neotropical Lepidocyrtus (Collembola: Entomobryidae): first assessment of patterns of speciation in Puerto Rico and phylogenetic relevance of some subgeneric diagnostic characters

A phylogenetic analysis of the Neotropical members of genus Lepidocyrtus was conducted to assess the pattern of speciation in Puerto Rico while testing the phylogenetic information content of two characters used to diagnose subgenera. The analysis included twenty‐two species of Lepidocyrtus from the Neotropical Region for which information on the tergal chaetotaxy of the trunk was available, two species of Holarctic Lepidocyrtus, three species of Pseudosinella, two species of Metasinella used in outgroup analysis and ninety‐two informative characters. The results do not support a monophyletic origin for the Puerto Rican Lepidocyrtus, suggesting the current fauna originated through repeated invasions from abroad. Three instances of endemic speciation can be inferred from the cladograms. The geographical distribution and diversity of colour forms suggest that L. caprilesi and L. paracaprilesi speciated sympatrically, whereas vicariance can explain speciation for L. lepargus and L. maldonadoi. The mode of speciation for L. dispar and L. biphasis remains unclear because the proportion of morphological variation between these species does not fit the proportions expected under the sympatric model suggested by their geographical distribution. The results support an early conclusion regarding appendicular scale distribution as a poor indicator of phylogenetic relationships. Taxa defined using this character are likely to be polyphyletic. The results disagree with a previous study in documenting low levels of homoplasy for the dental tubercle, implying that this character contains phylogenetic information useful in defining subgenera. However, the presence or absence of a dental tubercle is not diagnostic and should be used in combination with other characters. Comparisons of levels of homoplasy in Neotropical and Hawaiian Lepidocyrtus suggest that the relative position of two setae on the second abdominal tergum may be a better subgeneric character than other characters currently in use.     

Recent radiation of endemic Caribbean Drosophila of the dunni subgroup inferred from multilocus DNA sequence variation

Studies of island endemism provide a unique opportunity to elucidate fundamental mechanisms of speciation. Here we examine intra- and interspecific DNA sequence variation at four unlinked genetic loci among populations of the Drosophila dunni subgroup to provide a detailed genealogical portrait of the process of speciation among these island endemic species. Our data indicate two major rounds of diversification that have shaped the D. dunni subgroup. The first occurred 1.6-2.6 million years ago and separated three major lineages, one in Puerto Rico and the Virgin Islands, a second in the northern Lesser Antilles and Barbados, and a third in St. Vincent and Grenada. A second round of diversification occurred in the last 96,000 years in the northern Lesser Antilles and Barbados. The four distinct species that resulted from this recent round of diversification maintain relatively high amounts of genetic variation, similar to that of a closely related mainland species, and share extensive ancestral polymorphism. These data suggest a minimal role for population bottlenecks linked to founder events in the history of the D. dunni subgroup. Further, the recent divergence of these island populations highlights the extremely rapid development of reproductive isolation and distinct patterns of abdominal pigmentation that has occurred in these species.     

Uncovering historical signature of mitochondrial DNA hidden in the nuclear genome: the biogeography of Schistocerca revisited

Inadvertent coamplification of nuclear mitochondrial pseudogenes (numts) is a serious problem in mitochondrial systematics, but numts can also be a valuable source of information because they represent ancient forms of mtDNA. We present a conceptual framework of numt accumulation, which states that in a given species there can be two types of numts, synaponumts and autaponumts, resulting from integration occurring respectively before and after a speciation event. In a given clade, a species that diverged early can only have its own autaponumts as well as synaponumts that were already present in the genome of the last common ancestor. A species that diverged more recently may, however, have many different synaponumts integrated at each different divergence as well as its own autaponumts. Therefore it is possible to decipher the evolutionary history of a species based on the phylogenetic distribution of numts in a simultaneous analysis of numts and extant mtDNA. In this study, we test this idea empirically in the context of addressing a controversial question regarding the biogeography of the grasshopper genus Schistocerca Stål (Orthoptera: Acrididae), based on numts of the cytochrome c oxidase subunit I (COI) gene. We find that our empirical data can be explained adequately by our conceptual framework, and that the phylogenetic distribution of COI numts reveals intricate evolutionary histories about past speciation events that are otherwise difficult to detect using conventional markers. Our study strongly favours the Old World origin of the desert locust, Schistocerca gregaria and the New World Schistocerca species are descendants from an ancestral gregaria‐like species that colonized the New World via westward transatlantic flight. However, the phylogenetic distribution of S. gregaria numts raises a distinct possibility that there might have been multiple founding events from Africa to America to give rise to the present‐day diversity of the genus. This is a case study for a creative use of numts as molecular fossils, and we demonstrate that numts provide an interesting and powerful phylogenetic signal, much more than what extant mtDNA or nuclear gene sequences might be able to provide.     

Molecular evaluation of nominal species in the Ceratitis fasciventris, C. anonae, C. rosa complex (Diptera: Tephritidae)

Ceratitis fasciventris, C. anonae and C. rosa form a complex of economically important fruit fly pests infesting a variety of crops in African countries. Hitherto only adult males of these species can be distinguished easily by morphological characters. Other stages cannot, and for some taxa the taxonomic interpretation and species boundaries remain unclear. In order to clarify phylogenetic relationships and taxonomic status of these species, sequences of mitochondrial (16S, COI, ND6) and nuclear markers (period, ITS1) were analysed in specimens of the three morphospecies throughout the distribution of the complex. Maximum likelihood trees did not recover monophyletic groups corresponding to the morphospecies. Conversely, ND6 and COI divided West African C. fasciventris specimens in two consistent and bootstrap supported clades, involving specimens from Benin and from Mali/Ivory Coast, while the nuclear gene fragments per and ITS1 recovered a well-supported clade corresponding to C. fasciventris from Kenya/Uganda. Hence, the phylogenetic relationships and taxonomic interpretation of the complex appear more intricate than previously hypothesised. The current molecular data do not allow to identify C. fasciventris, C. anonae and C. rosa as distinct phylogenetic species but rather suggest that the morphospecies C. fasciventris is itself a complex of cryptic taxa.     

Molecular phylogenetic relationships of the deep-sea fish genus Coryphaenoides (Gadiformes: Macrouridae) based on mitochondrial DNA

In order to characterize the phylogenetic relationship and deep-sea adaptation process of the deep-sea fish genus Coryphaenoides, the nucleotide sequences of the mitochondrial (mt) 12 S rRNA and COI gene sequences for seven Coryphaenoides species were analyzed. Our molecular phylogenetic tree shows a new arrangement of seven Coryphaenoides species, which form two distinct groups, abyssal and nonabyssal species, and differs from the results of previous taxonomic studies. Using the mutation rate of mitochondrial genes, the divergence time between abyssal and nonabyssal Coryphaenoides was found to be 3.2-7.6 million years ago. Our study suggests that hydraulic pressure plays an important role in the speciation process in the marine environment.     

Evolution, biogeography, and the utility of mitochondrial 16s and COI genes in phylogenetic analysis of the crab genus Austinixa (Decapoda: Pinnotheridae)

This study used molecular data (mitochondrial 16s and COI) for the first time to explore evolutionary relationships among species of the pinnotherid crab genus Austinixa. Low levels of phylogenetic signal were detected for COI. High levels of phylogenetic signal were detected for 16s, indicating it is a more useful marker for inferring species level phylogenies in Austinixa. Phylogeographic patterns among species of Austinixa are consistent with allopatric speciation due to numerous climatic and oceanographic fluctuations during the last 5-6 my. In addition, all but two species have been derived since the closure of the Isthmus of Panama, a pattern consistent with hypotheses that the marine biota of the Caribbean and southeastern North America underwent a pulse of biotic turnover within the last 2-3 my. Austinixa aidae and Austinixa hardyi had identical 16s sequences, and differed by only 2 bp in COI, raising questions about the validity of A. hardyi as a distinct species.     

Geographical patterns of genetic divergence in the widespread Mesoamerican bumble bee Bombus ephippiatus (Hymenoptera: Apidae)

Bumble bees (Bombus Latreille) are an important group of social insects, well recognized throughout northern temperate regions as important pollinators of wild and agricultural plants. Little is known about the biology of this group in southern portions of the Americas, especially in Mesoamerica, a region of geological and ecological complexity from Mexico through Central America. One ubiquitous Mesoamerican species, Bombus ephippiatus, is enigmatic. Like many other Bombus, this species is homogeneous in body structure yet exhibits striking intraspecific color pattern polymorphism across its range, leading to uncertainty about its genealogical boundaries. It has been grouped taxonomically with B. wilmattae, a species narrowly restricted to southern Mexico and northern Guatamala. Furthermore, the relationships between these two taxa and a third species, B. impatiens, found only in America north of Mexico, have been controversial. Our phylogenetic analysis of DNA sequences from mitochondrial COI and nuclear PEPCK and CAD resolves the phylogeny of these three taxa as (B. impatiens, (B. ephippiatus, B. wilmattae)). Additional data from eight nuclear microsatellite markers reveal complex patterns of genetic divergence and isolation among populations of B. ephippiatus across its extensive geographic range, providing evidence for multiple independent evolutionary lineages. These lineages correspond not only to geographic and habitat variation across their range, but also to distinct color pattern groups present in the species. Knowledge of the phylogeny and genetic divergence of the B. ephippiatus group will provide a framework for understanding evolutionary and ecological origins of color pattern polymorphism in bumble bees, as well as providing insight into geographical factors enhancing speciation in Mesoamerica.     

Parallel habitat specialization within the wolf spider genus Hogna from the Galápagos

Within most island archipelagos, such as the Galápagos, similar ecological gradients are found on geographically isolated islands. Species radiations in response to these ecological gradients may follow different scenarios being (i) a single habitat specialization event followed by secondary colonization of each ecotype on the different islands or (ii) repeated and parallel habitat specialization on each island separately. This latter scenario has been considered less likely as gene flow might hamper such ecotypic differentiation. At least for the Galápagos, the extent to which this process is involved in species radiations remains yet poorly understood. Within the wolf spider genus Hogna, seven species are described that can be divided into three different ecotypes based on general morphology and habitat preference i.e. species that inhabit the pampa vegetation in the highlands, species that occur in coastal dry habitats and one generalist species. Comparison of the species phylogeny based on one mitochondrial (COI) and one nuclear (28S) gene fragment convincingly demonstrates that ‘pampa’ and ‘coastal dry’ species evolved in parallel on the islands Santa Cruz and San Cristóbal. Despite the observation that allozymes analysis indicated that each species forms a distinct genetic cluster, phylogenetic divergence within these species complexes was very low and paraphyletic and most likely due to hybridization rather than incomplete lineage sorting, as demonstrated for the Santa Cruz species complex. This suggests that within‐island speciation occurred under low levels of gene flow. Species phylogeny in general did not follow the progression of island emergence as a molecular clock analysis suggested that island endemic species may have diverged after as well as before the emergence of the islands. This represents the first clear example of parallel and within‐island speciation because of habitat specialization on the Galápagos and that such divergence most likely occurred under historic gene flow.     

Global phylogeography of a cryptic copepod species complex and reproductive isolation between genetically proximate "populations"

The copepod Eurytemora affinis has a broad geographic range within the Northern Hemisphere, inhabiting coastal regions of North America, Asia, and Europe. A phylogenetic approach was used to determine levels of genetic differentiation among populations of this species, and interpopulation crosses were performed to determine reproductive compatibility. DNA sequences from two mitochondrial genes, large subunit (16S) rRNA (450 bp) and cytochrome oxidase I (COI, 652 bp), were obtained from 38 populations spanning most of the species range and from two congeneric species, E. americana and E. herdmani. Phylogenetic analysis revealed a polytomy of highly divergent clades with maximum sequence divergences of 10% in 16S rRNA and 19% in COI. A power test (difference of a proportion) revealed that amount of sequence data collected was sufficient for resolving speciation events occurring at intervals greater than 300,000 years, but insufficient for determining whether speciation events were approximately simultaneous. Geographic and genetic distances were not correlated (Mantel's test; r = 0.023, P = 0.25), suggesting that populations had not differentiated through gradual isolation by distance. At finer spatial scales, there was almost no sharing of mtDNA haplotypes among proximate populations, indicating little genetic exchange even between nearby sites. Interpopulation crosses demonstrated reproductive incompatibility among genetically distinct populations, including those that were sympatric. Most notably, two geographically distant (4000 km) but genetically proximate (0.96% 16S, 0.15% COI) populations exhibited asymmetric reproductive isolation at the F2 generation. Large genetic divergences and reproductive isolation indicate that the morphologically conservative E. affinis constitutes a sibling species complex. Reproductive isolation between genetically proximate populations underscores the importance of using multiple measures to examine patterns of speciation.     

Tests of pleistocene speciation in montane grasshoppers (genus Melanoplus) from the sky islands of western North America

There has a been a resurgence of debate on whether the Pleistocene glaciations inhibited speciation. This study tests a model of Pleistocene speciation, estimating the phylogenetic relationships and divergence times of 10 species of montane grasshoppers, genus Melanoplus, using 1300 bp of the mitochondrial gene cytochrome oxidase I (COI). Based on average pairwise distances (corrected for multiple substitutions using Kimura's two-parameter model), all species appear to have originated within the Pleistocene. Sequence divergences between species are less than 4%, corresponding to divergence times less than 1.7 million years ago. Branching patterns among the species suggest that speciation was associated with more than one glacial-interglacial cycle. A likelihood-ratio test rejected a model of simultaneous species origins, the predicted branching pattern if species arose from the fragmentation of a widespread ancestor. These grasshoppers live in an area that was previously glaciated and, as inhabitants of the northern Rocky Mountain sky islands, underwent latitudinal and probably altitudinal shifts in distribution in response to climatic fluctuations. Given the repeated distributional shifts and range overlap of the taxa, there most likely has been ample opportunity for population mixing. However, despite periodic glacial cycles, with more than 10 major glaciations over the past million years and climatic fluctuations over as short a time scale as 10(3) to 10(4) years, the dynamic history of the Pleistocene did not preclude speciation. Although relationships among some taxa remain unresolved, these grasshopper species, even with their recent origins, exhibit genetic coherence and monophyletic or paraphyletic gene trees. The frequency of glacial cycles suggests that the speciation process must have been extremely rapid. These species of grasshoppers are morphologically very similar, differing primarily in the shape of the male genitalia. These characters are posited to be under sexual selection, may play an important role in reproductive isolation, and are known to diverge rapidly. This suggests the rapidity of evolution of reproductive isolation may determine whether species divergences occurred during the Pleistocene glaciations.     

DNA条形码技术在北京百花山地区夜蛾科物种鉴定中的应用

为了探讨DNA条形码技术在夜蛾物种鉴定中的可行性, 本研究利用条形码通用引物扩增了北京百花山地区43种夜蛾75个样本的线粒体细胞色素C氧化酶亚基I （mitochondrial cytochrome c oxidase subunit I, COI）基因序列, 以Kimura双参数模型进行种内种间遗传距离分析、 使用邻接法（neighbor-joining, NJ）和最大简约法（maximum parsimony, MP）分别构建系统发育树, 并利用分子序列差异阈值对样本进行分子可操作分类单元（molecular defined operational taxonomic units, MOTU）划分。结果表明： 所有夜蛾种类通过系统发育树可以成功区分; 种内平均遗传距离(0.03%)远远小于种间平均遗传距离(11.29%); 采用较为保守的1%的序列差异阈值将75个夜蛾样本分为42个MOTU, 正确率为95%, 除了MOTU04包含2个物种外, 剩余41个MOTU与形态种呈现一一对应的关系。结果显示, 基于COI基因的DNA条形码对于本研究中所涉及的夜蛾具有较好的区分, 可以作为一种有效的工具在夜蛾科昆虫物种鉴定中进行应用。     

Variation in "biodiversity value" of peatmoss species in Sphagnum section Acutifolia (Sphagnaceae)

Species are the most common currency by which biodiversity is measured, but species are not equivalent in "biodiversity value" because of differences in phylogenetic history and current population processes. Morphologically defined species in Sphagnum section Acutifolia (Bryophyta) were compared with regard to how phylogenetically distinct each is from its sister species and how much nucleotide variation each encompasses. Comparisons were based on sequence variation at seven nuclear and chloroplast loci. Assignment of collections to morphospecies accounted for about 57-75% of the overall nucleotide variation at the seven loci, but morphospecies differed greatly in how much nucleotide diversity they encompass. In addition, morphospecies varied widely in their genetic distinctiveness, estimated as the length of the stem branch from the most recent common ancestor and numbers of differentially fixed and shared polymorphic nucleotides among taxa. Levels of molecular diversity within morphospecies were not correlated with their degree of isolation. Factors that affected the biodiversity value of species include age, mode of origin, demographic history, and reproductive biology.     

Many ways to make darker flies: Intra‐ and interspecific variation in Drosophila body pigmentation components

Body pigmentation is an evolutionarily diversified and ecologically relevant trait with substantial variation within and between species, and important roles in animal survival and reproduction. Insect pigmentation, in particular, provides some of the most compelling examples of adaptive evolution, including its ecological significance and genetic bases. Pigmentation includes multiple aspects of color and color pattern that may vary more or less independently, and can be under different selective pressures. We decompose Drosophila thorax and abdominal pigmentation, a valuable eco‐evo‐devo model, into distinct measurable traits related to color and color pattern. We investigate intra‐ and interspecific variation for those traits and assess its different sources. For each body part, we measured overall darkness, as well as four other pigmentation properties distinguishing between background color and color of the darker pattern elements that decorate each body part. By focusing on two standard D. melanogaster laboratory populations, we show that pigmentation components vary and covary in distinct manners depending on sex, genetic background, and temperature during development. Studying three natural populations of D. melanogaster along a latitudinal cline and five other Drosophila species, we then show that evolution of lighter or darker bodies can be achieved by changing distinct component traits. Our results paint a much more complex picture of body pigmentation variation than previous studies could uncover, including patterns of sexual dimorphism, thermal plasticity, and interspecific diversity. These findings underscore the value of detailed quantitative phenotyping and analysis of different sources of variation for a better understanding of phenotypic variation and diversification, and the ecological pressures and genetic mechanisms underlying them.     

Molecular phylogeny of Crematogaster subgenus Decacrema ants (Hymenoptera: Formicidae) and the colonization of Macaranga (Euphorbiaceae) trees

To elucidate the evolution of one of the most species-rich ant-plant symbiotic systems, the association between Crematogaster (Myrmicinae) and Macaranga (Euphorbiaceae) in South-East Asia, we conducted a phylogenetic analysis of the ant partners. For the phylogenetic analysis partial mitochondrial cytochrome oxidase I and II were sequenced and Maximum Parsimony analysis was performed. The analyzed Crematogaster of the subgenus Decacrema fell into three distinct clades which are also characterized by specific morphological and ecological traits (queen morphology, host-plants, and colony structure). Our results supported the validity of our currently used morphospecies concept for Peninsula Malaysia. However, on a wider geographic range (including North and North-East Borneo) some morphospecies turned out to be species complexes with genetically quite distinct taxa. Our phylogenetic analysis and host association studies do not indicate strict cocladogenesis between the subgenus Decacrema and their Macaranga host-plants because multiple ant taxa occur on quite distinct host-plants belonging to different clades within in the genus Macaranga. These results support the view that host-shifting or host-expansion is common in the ants colonizing Macaranga. Additionally, the considerable geographic substructuring found in the phylogenetic trees of the ants suggests that allopatric speciation has also played a role in the diversification and the current distribution of the Decacrema ants.