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  1. Abstract

    The phytophagous insect superfamily Coreoidea (Heteroptera) is a diverse group of ~3100 species in five extant families, with many of agricultural importance and model organisms in behavioural studies. Most species (~2800 species) are classified in the family Coreidae (four subfamilies, 37 tribes). While previous phylogenetic studies have primarily focused on the larger and more diverse subfamilies and tribes of Coreidae, several smaller tribes remain poorly studied in a phylogenetic context. Here, we investigated the phylogenetic positions of three less diverse tribes using ultraconserved elements: Agriopocorini, Amorbini, and Manocoreini. Our study is the first to test phylogenetic hypotheses for the Agriopocorini and Amorbini in a cladistic analysis. All three tribes were recovered within the subfamily Coreinae with robust support. The monophyletic Agriopocorini were supported as the sister-group of Colpurini, the monophyletic Amorbini as sister to Mictini, and the monogeneric Manocoreini as sister to Dasynini + Homoeocerini. We briefly discuss the evolution of wing development in Coreidae, putative synapomorphies for clades of interest, and taxonomic considerations. Our study emphasizes the importance of including smaller, less diverse groups in phylogenetic analyses. By doing so, we gain valuable insights into evolutionary relationships, identify future investigations of trait evolution, and resolve systematic controversies.

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  2. Abstract

    Sexually selected weapons, such as the antlers of deer, claws of crabs, and tusks of beaked whales, are strikingly diverse across taxa and even within groups of closely related species. Phylogenetic comparative studies have typically taken a simplified approach to investigate the evolution of weapon diversity, examining the gains and losses of entire weapons, major shifts in size or type, or changes in location. Less understood is how individual weapon components evolve and assemble into a complete weapon. We addressed this question by examining weapon evolution in the diverse, multi-component hind-leg and body weapons of leaf-footed bugs, superfamily Coreoidea (Hemiptera: Heteroptera). Male leaf-footed bugs use their morphological weapons to fight for access to mating territories. We used a large multilocus dataset comprised of ultraconserved element loci for 248 species and inferred evolutionary transitions among component states using ancestral state estimation. Our results suggest that weapons added components over time with some evidence of a cyclical evolutionary pattern—gains of components followed by losses and then gains again. Furthermore, our best estimate indicated that certain trait combinations evolved repeatedly across the phylogeny, suggesting that they function together in battle or that they are genetically correlated. This work reveals the remarkable and dynamic evolution of weapon form in the leaf-footed bugs and provides insights into weapon assembly and disassembly over evolutionary time.

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  3. One of the most fundamental goals of modern biology is to achieve a deep understanding of the origin and maintenance of biodiversity. It has been observed that in some mixed-species animal societies, there appears to be a drive towards some degree of phenotypic trait matching, such as similar coloration or patterning. Here we build on these observations and hypothesize that selection in mixed-species animal societies, such as mixed-species bird flocks, may drive diversification, potentially leading to speciation. We review evidence for possible convergent evolution and even outright mimicry in flocks from southwestern China, where we have observed several cases in which species and subspecies differ from their closest relatives in traits that match particular flock types. However, understanding whether this is phenotypic matching driven by convergence, and whether this divergence has promoted biodiversity, requires testing multiple facets of this hypothesis. We propose a series of steps that can be used to tease apart alternative hypotheses to build our understanding of the potential role of convergence in diversification in participants of mixed-species societies. Even if our social convergence/divergence hypothesis is not supported, the testing at each step should help highlight alternative processes that may affect mixed-species flocks, trait evolution and possible convergence. This article is part of the theme issue ‘Mixed-species groups and aggregations: shaping ecological and behavioural patterns and processes’. 
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    Free, publicly-accessible full text available June 5, 2024
  4. Intra- and interspecific communication is crucial to fitness via its role in facilitating mating, territoriality and defence. Yet, the evolution of animal communication systems is puzzling—how do they originate and change over time? Studying stridulatory morphology provides a tractable opportunity to deduce the origin and diversification of a communication mechanism. Stridulation occurs when two sclerotized structures rub together to produce vibratory and acoustic (vibroacoustic) signals, such as a cricket ‘chirp’. We investigated the evolution of stridulatory mechanisms in the superfamily Coreoidea (Hemiptera: Heteroptera), a group of insects known for elaborate male fighting behaviours and enlarged hindlegs. We surveyed a large sampling of taxa and used a phylogenomic dataset to investigate the evolution of stridulatory mechanisms. We identified four mechanisms, with at least five evolutionary gains. One mechanism, occurring only in male Harmostini (Rhopalidae), is described for the first time. Some stridulatory mechanisms appear to be non-homoplastic apomorphies within Rhopalidae, while others are homoplastic or potentially homoplastic within Coreidae and Alydidae, respectively. We detected no losses of these mechanisms once evolved, suggesting they are adaptive. Our work sets the stage for further behavioural, evolutionary and ecological studies to better understand the context in which these traits evolve and change. 
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    Free, publicly-accessible full text available April 1, 2024
  5. Springer, Mark (Ed.)
    Abstract Despite the increasing feasibility of sequencing whole genomes from diverse taxa, a persistent problem in phylogenomics is the selection of appropriate genetic markers or loci for a given taxonomic group or research question. In this review, we aim to streamline the decision-making process when selecting specific markers to use in phylogenomic studies by introducing commonly used types of genomic markers, their evolutionary characteristics, and their associated uses in phylogenomics. Specifically, we review the utilities of ultraconserved elements (including flanking regions), anchored hybrid enrichment loci, conserved nonexonic elements, untranslated regions, introns, exons, mitochondrial DNA, single nucleotide polymorphisms, and anonymous regions (nonspecific regions that are evenly or randomly distributed across the genome). These various genomic elements and regions differ in their substitution rates, likelihood of neutrality or of being strongly linked to loci under selection, and mode of inheritance, each of which are important considerations in phylogenomic reconstruction. These features may give each type of marker important advantages and disadvantages depending on the biological question, number of taxa sampled, evolutionary timescale, cost effectiveness, and analytical methods used. We provide a concise outline as a resource to efficiently consider key aspects of each type of genetic marker. There are many factors to consider when designing phylogenomic studies, and this review may serve as a primer when weighing options between multiple potential phylogenomic markers. 
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  6. Ruane, Sara (Ed.)
    Abstract Some phylogenetic problems remain unresolved even when large amounts of sequence data are analyzed and methods that accommodate processes such as incomplete lineage sorting are employed. In addition to investigating biological sources of phylogenetic incongruence, it is also important to reduce noise in the phylogenomic dataset by using appropriate filtering approach that addresses gene tree estimation errors. We present the results of a case study in manakins, focusing on the very difficult clade comprising the genera Antilophia and Chiroxiphia. Previous studies suggest that Antilophia is nested within Chiroxiphia, though relationships among Antilophia+Chiroxiphia species have been highly unstable. We extracted more than 11,000 loci (ultra-conserved elements and introns) from whole genomes and conducted analyses using concatenation and multispecies coalescent methods. Topologies resulting from analyses using all loci differed depending on the data type and analytical method, with 2 clades (Antilophia+Chiroxiphia and Manacus+Pipra+Machaeopterus) in the manakin tree showing incongruent results. We hypothesized that gene trees that conflicted with a long coalescent branch (e.g., the branch uniting Antilophia+Chiroxiphia) might be enriched for cases of gene tree estimation error, so we conducted analyses that either constrained those gene trees to include monophyly of Antilophia+Chiroxiphia or excluded these loci. While constraining trees reduced some incongruence, excluding the trees led to completely congruent species trees, regardless of the data type or model of sequence evolution used. We found that a suite of gene metrics (most importantly the number of informative sites and likelihood of intralocus recombination) collectively explained the loci that resulted in non-monophyly of Antilophia+Chiroxiphia. We also found evidence for introgression that may have contributed to the discordant topologies we observe in Antilophia+Chiroxiphia and led to deviations from expectations given the multispecies coalescent model. Our study highlights the importance of identifying factors that can obscure phylogenetic signal when dealing with recalcitrant phylogenetic problems, such as gene tree estimation error, incomplete lineage sorting, and reticulation events. [Birds; c-gene; data type; gene estimation error; model fit; multispecies coalescent; phylogenomics; reticulation] 
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  7. Abstract Biodiversity research has advanced by testing expectations of ecological and evolutionary hypotheses through the linking of large-scale genetic, distributional, and trait datasets. The rise of molecular systematics over the past 30 years has resulted in a wealth of DNA sequences from around the globe. Yet, advances in molecular systematics also have created taxonomic instability, as new estimates of evolutionary relationships and interpretations of species limits have required widespread scientific name changes. Taxonomic instability, colloquially “splits, lumps, and shuffles,” presents logistical challenges to large-scale biodiversity research because (1) the same species or sets of populations may be listed under different names in different data sources, or (2) the same name may apply to different sets of populations representing different taxonomic concepts. Consequently, distributional and trait data are often difficult to link directly to primary DNA sequence data without extensive and time-consuming curation. Here, we present RANT: Reconciliation of Avian NCBI Taxonomy. RANT applies taxonomic reconciliation to standardize avian taxon names in use in NCBI GenBank, a primary source of genetic data, to a widely used and regularly updated avian taxonomy: eBird/Clements. Of 14,341 avian species/subspecies names in GenBank, 11,031 directly matched an eBird/Clements; these link to more than 6 million nucleotide sequences. For the remaining unmatched avian names in GenBank, we used Avibase’s system of taxonomic concepts, taxonomic descriptions in Cornell’s Birds of the World, and DNA sequence metadata to identify corresponding eBird/Clements names. Reconciled names linked to more than 600,000 nucleotide sequences, ~9% of all avian sequences on GenBank. Nearly 10% of eBird/Clements names had nucleotide sequences listed under 2 or more GenBank names. Our taxonomic reconciliation is a first step towards rigorous and open-source curation of avian GenBank sequences and is available at GitHub, where it can be updated to correspond to future annual eBird/Clements taxonomic updates. 
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  8. Avian sex chromosomes evolved after the divergence of birds and crocodilians from their common ancestor, so they are younger than the better-studied chromosomes of mammals. It has long been recognized that there may have been several stages to the evolution of avian sex chromosomes. For example, the CHD1 undergoes recombination in paleognaths but not neognaths. Genome assemblies have suggested that there may be variation in the timing of barriers to recombination among Neognathae, but there remains little understanding of the extent of this variability. Here, we look at partial sequences of ATP5F1A, which is on the avian Z and W chromosomes. It is known that recombination of this gene has independently ceased in Galliformes, Anseriformes, and at least five neoavian orders, but whether there are other independent cessations of recombination among Neoaves is not understood. We analyzed a combination of data extracted from published chromosomal-level genomes with data collected using PCR and cloning to identify Z and W copies in 22 orders. Our results suggest that there may be at least 19 independent cessations of recombination within Neognathae, and 3 clades that may still be undergoing recombination (or have only recently ceased recombination). Analyses of ATP5F1A protein sequences revealed an increased amino acid substitution rate for W chromosome gametologs, suggesting relaxed purifying selection on the W chromosome. Supporting this hypothesis, we found that the increased substitution rate was particularly pronounced for buried residues, which are expected to be more strongly constrained by purifying selection. This highlights the dynamic nature of avian sex chromosomes, and that this level of variation among clades means they should be a good system to understand sex chromosome evolution. 
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