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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

    Theory predicts that traits with heightened condition dependence, such as sexually selected traits, should be affected by inbreeding to a greater degree than other traits. The presence of environmental stress may compound the negative consequences of inbreeding depression. In this study, we examined inbreeding depression across multiple traits and whether it increased with a known form of environmental stress. We conducted our experiment using both sexes of the sexually dimorphic leaf-footed cactus bug, Narnia femorata (Hemiptera: Coreidae). Adult male cactus bugs have enlarged hind legs used as weapons in male–male contests; these traits, and their homologue in females, have been previously found to exhibit high condition dependence. In this study, we employed a small developmental group size as an environmental stress challenge. Nymph N. femorata aggregate throughout their juvenile stages, and previous work has shown the negative effects of small group size on survivorship and body size. We found evidence of inbreeding depression for survival and seven of the eight morphological traits measured in both sexes. Inbreeding depression was higher for the size of the male weapon and the female homolog. Additionally, small developmental group size negatively affected survival to adulthood. However, small group size did not magnify the effects of inbreeding on morphological traits. These findings support the hypothesis that traits with heightened condition dependence exhibit higher levels of inbreeding depression.

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  3. 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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  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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  5. Abstract

    A longstanding goal of evolutionary biology is to understand among-individual variation in resource allocation decisions and the timing of these decisions. Recent studies have shown that investment in elaborate and costly weapons can result in trade-offs with investment in testes. In this study, we ask the following questions: At what point plasticity in resource allocation to these different structures ceases during development, if at all? Furthermore, can individuals tailor their reproductive behavior to accompany structural changes? We experimentally addressed these questions in the insect Narnia femorata, quantifying resource reallocation across development for the first time, using a phenotypic engineering approach. To investigate whether allocation plasticity diminishes throughout ontogeny, we induced weapon loss at a range of different developmental stages and examined subsequent testes mass and reproductive behavior. We found that relative testes mass increased as weapon investment decreased, implying a direct trade-off between testes and weapon investment. However, autotomy postadulthood ceased to induce larger testes mass. Intriguingly, losing a weapon while young was associated with extended adult mating duration, potentially enabling compensation for reduced fighting ability. Our results highlight the importance of examining the ontogeny of trade-offs between reproductive traits and the flexibility of the relationship between reproductive morphology and behavior.

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  6. Abstract

    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.

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  7. Abstract

    Antipredatory displays that incorporate hidden contrasting coloration are found in a variety of different animals. These displays are seen in organisms that have drab coloration at rest, but when disturbed reveal conspicuous coloration. Examples include the bright abdomens of mountain katydids and the colorful underwings of hawk moths. Such hidden displays can function as secondary defenses, enabling evasion of a pursuant predator. To begin to understand why some species have these displays while others do not, we conducted phylogenetic comparative analyses to investigate factors associated with the evolution of hidden contrasting coloration in leaf‐footed bugs. First, we investigated whether hidden contrasting coloration was associated with body size because these displays are considered to be more effective in larger organisms. We then investigated whether hidden contrasting coloration was associated with an alternative antipredatory defense, in this case rapid autotomy. We found that leaf‐footed bugs with hidden contrasting coloration tended to autotomize more slowly, but this result was not statistically significant. We also found that the presence of a body size association was dependent upon the form of the hidden color display. Leaf‐footed bugs that reveal red/orange coloration were the same size, on average, as species without a hidden color display. However, species that reveal white patches on a black background were significantly larger than species without a hidden color display. These results highlight the diversity of forms that hidden contrasting color signal can take, upon which selection may act differently.

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  8. Abstract

    Next‐generation sequencing technologies (NGS) allow systematists to amass a wealth of genomic data from non‐model species for phylogenetic resolution at various temporal scales. However, phylogenetic inference for many lineages dominated by non‐model species has not yet benefited from NGS, which can complement Sanger sequencing studies. One such lineage, whose phylogenetic relationships remain uncertain, is the diverse, agriculturally important and charismatic Coreoidea (Hemiptera: Heteroptera). Given the lack of consensus on higher‐level relationships and the importance of a robust phylogeny for evolutionary hypothesis testing, we use a large data set comprised of hundreds of ultraconserved element (UCE) loci to infer the phylogeny of Coreoidea (excluding Stenocephalidae and Hyocephalidae), with emphasis on the families Coreidae and Alydidae. We generated three data sets by including alignments that contained loci sampled for at least 50%, 60%, or 70% of the total taxa, and inferred phylogeny using maximum likelihood and summary coalescent methods. Twenty‐six external morphological features used in relatively comprehensive phylogenetic analyses of coreoids were also re‐evaluated within our molecular phylogenetic framework. We recovered 439–970 loci per species (16%–36% of loci targeted) and combined this with previously generated UCE data for 12 taxa. All data sets, regardless of analytical approach, yielded topologically similar and strongly supported trees, with the exception of outgroup relationships and the position of Hydarinae. We recovered a monophyletic Coreoidea, with Rhopalidae highly supported as the sister group to Alydidae + Coreidae. Neither Alydidae nor Coreidae were monophyletic; the coreid subfamilies Hydarinae and Pseudophloeinae were recovered as more closely related to Alydidae than to other coreid subfamilies. Coreinae were paraphyletic with respect to Meropachyinae. Most morphological traits were homoplastic with several clades defined by few, if any, synapomorphies. Our results demonstrate the utility of phylogenomic approaches in generating robust hypotheses for taxa with long‐standing phylogenetic problems and highlight that novel insights may come from such approaches.

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  9. Abstract

    Ample sperm production is essential for successful male reproduction in many species. The amount of sperm a male can produce is typically constrained by the size of his testes, which can be energetically expensive to grow and maintain. Although the economics of ejaculate allocation has been the focus of much theoretical and empirical literature, relatively little attention has been paid to individual adult variation and plasticity at the source of sperm production, the testes themselves. We experimentally address this issue using the insectNarnia femorataStål (Hemiptera: Coreidae). We established the metabolic cost of testicular tissue and then quantified variation in individual testes mass in response to multiple mate quality and quantity treatments.We uncovered extreme variation across individuals and considerable short‐term effects of mating activity on testes dry mass. Importantly, the observed variation in testes mass was associated with notable fitness consequences; females paired with males with larger testes had greater hatching success. Overall, pairing with a female resulted in a 11% reduction indrytestes mass. Despite this apparent considerable mating investment, we found no evidence of strategic allocation to higher quality females or longer‐term changes in testes mass. The dynamic nature of testes mass and its metabolic cost is vital to consider in the context of re‐mating rates, polyandry benefits and general mating system dynamics both in this species and more broadly.

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