With more than 886 species in similar to 137 genera, Ectrichodiinae (Hemiptera: Reduviidae) are the largest animal clade of millipede predators. Recent phylogenetic studies have created a framework for our understanding of ectrichodiine evolutionary history, but no fossil species have been described. Ectrichodiella Fracker and Bruner, 1924, belongs to the earliest diverging lineage of Ectrichodiinae, and a better understanding of the morphology and biodiversity of this genus may provide insights into the early evolution of the subfamily. The genus is com-posed of two described species, Ectrichodiella minima (Valdes, 1910) and Ectrichodiella rafaeli (Gil-Santana and Coletto-Silva, 2005) from Cuba and Brazil, respectively. Here, four new spe-cies of Ectrichodiella are described, with three representing extant taxa known only from French Guiana (E. caballina, n. sp., E. nouraguensis, n. sp., and E. obscura,n. sp.), while the fourth is based on a Miocene Dominican amber fossil (Ectrichodiella electrina, n. sp.). Diagnoses, descriptions, habitus and detailed morphological images, an identification key, and a distribution map are provided. A cladistic analysis based on 45 morphological characters that includes the fossil species corroborates the monophyly of Ectrichodiella, but the relationship of the fossil species to the five extant species remains ambiguous. Nevertheless, this phylogenetic placement makes Ectrichodiella electrina, a valuable fossil calibration for future divergence dating analyses, despite its relatively young age.
Supplemental material for 'Systematics of Ectrichodiella Fracker and Bruner, 1924 : with description of the first fossil millipede assassin bug species (Insecta, Hemiptera, Reduviidae, Ectrichodiinae) (American Museum novitates, no. 4025)' - https://hdl.handle.net/2246/7378
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.
The phytophagous insect superfamily Coreoidea (Heteroptera) is a diverse group of similar to 3100 species in five extant families, with many of agricultural importance and model organisms in behavioural studies. Most species (similar to 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.
Target capture is widely used in phylogenomic, ecological and functional genomic studies. Bait sets that allow capture from a diversity of species can be advantageous, but high-sequence divergence from baits can limit yields. Currently, only four experimental comparisons of a critical target capture parameter, hybridization temperature, have been published. These have been in vertebrates, where bait divergences are typically low, and none include invertebrates where bait-target divergences may be higher. Most invertebrate capture studies use a fixed, high hybridization temperature to maximize the proportion of on-target data, but many report low locus recovery. Using leaf-footed bugs (Hemiptera: Coreoidea), we investigate the effect of hybridization temperature on capture success of ultraconserved elements targeted by (i) baits developed from divergent hemipteran genomes and (ii) baits developed from less divergent coreoid transcriptomes. Lower temperatures generally resulted in more contigs and improved recovery of targets despite a lower proportion of on-target reads, lower read depth and more putative paralogues. Hybridization temperatures had less of an effect when using transcriptome-derived baits, which is probably due to lower bait-target divergences and greater bait tiling density. Thus, accommodating low hybridization temperatures during target capture can provide a cost-effective, widely applicable solution to improve invertebrate locus recovery.
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.
Sequence capture studies result in rich data sets comprising hundreds to thousands of targeted genomic regions that are superseding Sanger‐based data sets comprised of a few well‐known loci with historical uses in phylogenetics (‘legacy loci’). However, integrating sequence capture and Sanger‐based data sets is of interest as legacy loci can include different types of loci (e.g. mitochondrial and nuclear) across a potentially larger sample of species from past studies. Sequence capture data sets include nontargeted sequences, and there has been recent interest in extracting legacy loci from invertebrate data sets. Here, we use published legacy data from leaf‐footed bugs (Hemiptera: Coreoidea) to recover 15 mitochondrial and seven nuclear legacy loci from off‐target sequences in a sequence capture data set, explore approaches to improve legacy locus recovery, and combine these loci with sequence capture data for phylogenetic analysis. Two nuclear loci were determined to already be targeted by sequence capture baits. Most of the remaining loci were successfully recovered from off‐target sequences, but this recovery varied greatly. Additionally, complementing complete mitogenomes with additional reference mitochondrial sequences from a genetic depository did not offer improvement for most of our taxa; however, supplementing these reference sequences with extracted legacy loci offered ≥6% improvement across taxa for a given mitochondrial locus (negligible improvement for nuclear loci). Phylogenetic analysis of legacy and sequence capture data produced a topology generally congruent with recent studies, but support was lower. Thus, future studies may employ the approaches used in this study to integrate legacy data with newly generated sequence capture data sets without added expenses.
Target capture approaches are widely used in phylogenomic studies, yet only four experimental comparisons of a critical parameter, hybridization temperature, have been published. These studies provide conflicting conclusions regarding the benefits of lower temperatures during target capture, and none include invertebrates where bait-target divergences may be higher than seen in vertebrate capture studies. Most capture studies use a fixed hybridization temperature of 65°C to maximize the proportion of on-target data, but many invertebrate capture studies report low locus recovery. Lower hybridization temperatures, which might improve locus recovery, are not commonly employed in invertebrate capture studies. We used leaf-footed bugs and relatives (Hemiptera: Coreoidea) to investigate the effect of hybridization temperature on capture success of ultraconserved elements (UCE) targeted by previously published baits derived from divergent hemipteran genomes and other loci targeted by newly designed baits derived from less divergent coreoid transcriptomes. We found touchdown capture approaches with lower hybridization temperatures generally resulted in lower proportions of on-target reads and lower read depth but were associated with more contigs and improved recovery of UCE loci. Low temperatures were also associated with increased numbers of putative paralogs of UCE loci. Hybridization temperatures did not generally affect recovery of newly targeted loci, which we attributed to their lower bait-target divergences (compared to higher divergences between UCE baits and targets) and greater bait tiling density. Thus, optimizing in vitro target capture conditions to accommodate low hybridization temperatures can provide a cost-effective, widely applicable solution to improve recovery of protein-coding loci in invertebrates.### Competing Interest StatementThe authors have declared no competing interest.
Target capture approaches are widely used in phylogenomic studies, yet few experimental comparisons of critical parameters, e.g. hybridization temperature, have been published. Even fewer studies have focused on invertebrates where bait-target divergences may be high. Most capture studies use a fixed hybridization temperature of 65°C to maximize the proportion of on-target data, but lower temperatures, which might improve locus recovery, are not commonly employed. We used fresh and degraded specimens of leaf-footed bugs and relatives (Hemiptera: Coreoidea) to investigate the effect of hybridization temperature on capture success of previously published ultraconserved elements (UCE) targeted by baits derived from divergent hemipteran genomes and other loci targeted by newly designed baits derived from less divergent coreoid transcriptomes. We found touchdown capture approaches with lower hybridization temperatures generally resulted in lower proportions of on-target reads and lower coverage but were associated with more assembled contigs and improved recovery of targeted UCE loci. Low hybridization temperatures were also associated with increased numbers of putative paralogs of targeted UCE loci and recovery of well-known loci (from off-target reads) with historical uses in Sanger-based molecular phylogenetic studies. Hybridization temperatures did not generally affect recovery of newly targeted loci, which we attributed to lower bait-target divergences (compared to higher divergences between UCE baits and targets) and greater bait tiling density. Thus, optimizing in vitro target capture conditions to accommodate low hybridization temperatures can provide a cost-effective, widely applicable solution to improve recovery of protein-coding loci in invertebrates, while retrieving other potentially useful data for downstream comparative analyses.
Assessing effects of gene tree error in coalescent analyses have widely ignored coalescent branch lengths (CBLs) despite their potential utility in estimating ancestral population demographics and detecting species tree anomaly zones. However, the ability of coalescent methods to obtain accurate estimates remains largely unexplored. Errors in gene trees should lead to underestimates of the true CBL, and for a given set of comparisons, longer CBLs should be more accurate. Here, we furthered our empirical understanding of how error in gene tree quality (i.e., locus informativeness and gene tree resolution) affect CBLs using four datasets comprised of ultraconserved elements (UCE) or exons for clades that exhibit wide ranges of branch lengths. For each dataset, we compared the impact of locus informativeness (assessed using number of parsimony‐informative sites) and gene tree resolution on CBL estimates. Our results, in general, showed that CBLs were drastically shorter when estimates included low informative loci. Gene tree resolution also had an impact on UCE datasets, with polytomous gene trees producing longer branches than randomly resolved gene trees. However, resolution did not appear to affect CBL estimates from the more informative exon datasets. Thus, as expected, gene tree quality affects CBL estimates, though this can generally be minimized by using moderate filtering to select more informative loci and/or by allowing polytomies in gene trees. These approaches, as well as additional contributions to improve CBL estimation, should lead to CBLs that are useful for addressing evolutionary and biological questions.