Hojun Song

Abstract: One of the main challenges in analyzing multi-locus phylogenomic data is to find an optimal data partitioning strategy to account for variable evolutionary histories of different loci for any given dataset. Although a number of studies have addressed the issue of data partitioning in a Bayesian phylogenetic framework, such studies in a maximum likelihood framework are comparatively lacking. Furthermore, a rigorous statistical exploration of possible data partitioning schemes has not been applied to mitochondrial genome (mtgenome) data, which provide a complex, but manageable platform for addressing various challenges in analyzing phylogenomic data. In this study, we investigate the issue of data partitioning in the maximum likelihood framework in the context of the mitochondrial phylogenomics of an orthopteran superfamily Acridoidea (Orthoptera: Caelifera). The present study analyzes 34 terminals representing all 8 superfamilies within Caelifera, which includes newly sequenced partial or complete mtgenomes for 11 families. Using a new partition-selection method implemented in the software PartitionFinder, we compare a large number of data partitioning schemes in an attempt to identify the most effective method of analyzing the mtgenome data. We find that the best-fit partitioning scheme selected by PartitionFinder is superior to any a priori schemes commonly utilized in mitochondrial phylogenomics. We also show that over-partitioning is often detrimental to phylogenetic reconstruction. A comparative analysis of mtgenome structures finds that the tRNA gene rearrangement between cytochrome c oxidase subunit II and ATP synthase protein 8 does not occur in the most basal caeliferan lineage Tridactyloidea, suggesting that this gene rearrangement must have evolved at least in the common ancestor of Tetrigoidea and Acridomorpha. We find that mtgenome data contain sufficient phylogenetic information to broadly resolve the relationships across Acridomorpha and Acridoidea.

Abstract: 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 Stal (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.

Abstract: The desert locust (Schistocerca gregaria) has been feared agricultural pest since early civilization, with plagues documented in ancient texts. Population genetic studies of the desert locust are needed to determine genetic variation and movement pattern for efficient control of the pest. In this study, we complemented the limited available microsatellite collection for the desert locust with 34 new polymorphic and multiplexed microsatellite loci. To this aim, we screened an expressed sequence tags library and constructed a partial genomic library enriched for dinucleotide repeats to develop high-throughput and high-quality genotyping assays. We then paid particular attention to quality control and carefully validated 26 of these novel microsatellites and six previously described loci for the absence of null alleles in Western African field populations. This large panel of high-quality microsatellite markers provides new opportunity to infer dispersal rates between populations of the desert locust and help prioritize early monitoring and control. Furthermore, high potential for cross-taxa utility of markers was observed within Schistocerca genus, which includes other locust pest species, with reliable amplification achieved for at least ten of loci per species. Microsatellite markers developed from transcriptome resources were largely devoid of null alleles and were conserved across species compared with those derived from traditional genomic libraries. Accordingly, the number of highly reliable microsatellite markers was greatly improved compared with that of previous studies on Orthopteran species, and this strategy might be broadly applied in other insect species prone to null alleles.

Abstract: Enkephalins play a major role in reproductive physiology in crustaceans; however their role in reproductive development in insects is largely unknown. We investigated the effect of exposure to exogenous leucine-enkephalin (Leu-Enk), methionine-enkephalin (Met-Enk), and the opioid antagonist naloxone on gonad development in the Eastern lubber grasshopper, Romalea microptera. Injection of either Leu-Enk or naloxone alone significantly increased the testicular index and testicular follicular diameter in males, and the ovarian index, oocyte length, and oocyte diameter in females. In contrast, injection of Met-Enk inhibited all measures of reproductive development in both sexes. Surprisingly, co-injection of naloxone with either enkephalin enhanced the effect associated with administration of the enkephalin alone. This study clearly demonstrates the ability of enkephalins to disrupt insect sexual development and also suggests the existence of conserved enkephaline-dependent regulatory mechanisms in insects and crustaceans.

Abstract: Although the specific mechanisms of locust phase transformation are wellunderstood for model locust species such as the desert locust Schistocerca gregaria and the migratory locust Locusta migratoria, the expressions of density-dependent phase polyphenism in other nonmodel locust species are not wellknown. The present paper is an attempt to review and synthesize what we know about these nonmodel locusts. Based on all available data, I find that locust phase polyphenism is expressed in many different ways in different locust species and identify a pattern that locust species often belong to large taxonomic groups which contain mostly nonswarming grasshopper species. Although locust phase polyphenism has evolved multiple times within Acrididae, I argue that its evolution should be studied from a phylogenetic perspective because I find similar density-dependent phenotypic plasticity among closely related species. Finally, I emphasize the importance of comparative analyses in understanding the evolution of locust phase and propose a phylogeny-based research framework.

Abstract: DNA barcoding is a diagnostic method of species identification based on sequencing a short mitochondrial DNA fragment of cytochrome oxidase I (COI), but its ability to correctly diagnose species is limited by the presence of nuclear mitochondrial pseudogenes (numts). Numts can be coamplified with the mitochondrial orthologue when using universal primers, which can lead to incorrect species identification and an overestimation of the number of species. Some researchers have proposed that using more specific primers may help eliminate numt coamplification, but the efficacy of this method has not been thoroughly tested. In this study, we investigate the taxonomic distribution of numts in 11 lineages within the insect order Orthoptera, by analysing cloned COI sequences and further test the effects of primer specificity on eliminating numt coamplification in four lineages. We find that numts are coamplified in all 11 taxa using universal (barcoding) primers, which suggests that numts may be widespread in other taxonomic groups as well. Increased primer specificity is only effective at reducing numt coamplification in some species tested, and only eliminates it in one species tested. Furthermore, we find that a number of numts do not have stop codons or indels, making it difficult to distinguish them from mitochondrial orthologues, thus putting the efficacy of barcoding quality control measures under question. Our findings suggest that numt coamplification is a serious problem for DNA barcoding and more quality control measures should be implemented to identify and eliminate numts prior to using mitochondrial barcodes for species diagnoses.

Abstract: It is generally accepted that male genitalia evolve more rapidly and divergently relative to non-genital traits due to sexual selection, but there is little quantitative comparison of the pattern of evolution between these character sets. Moreover, despite the fact that genitalia are still among the most widely used characters in insect systematics, there is an idea that the rate of evolution is too rapid for genital characters to be useful in forming clades. Based on standard measures of fit used in cladistic analyses, we compare levels of homoplasy and synapomorphy between genital and non-genital characters of published data sets and demonstrate that phylogenetic signal between these two character sets is statistically similar. This pattern is found consistently across different insect orders at different taxonomic hierarchical levels. We argue that the fact that male genitalia are under sexual selection and thus diverge rapidly does not necessarily equate with the lack of phylogenetic signal, because characters that evolve by descent with modification make appropriate characters for a phylogenetic analysis, regardless of the rate of evolution. We conclude that male genitalia are a composite character consisting of different components diverging separately, which make them ideal characters for phylogenetic analyses, providing information for resolving varying levels of hierarchy.

Abstract: The ability to generate large molecular datasets for phylogenetic studies benefits biologists, but such data expansion introduces numerous analytical problems. A typical molecular phylogenetic study implicitly assumes that sequences evolve under stationary, reversible and homogeneous conditions, but this assumption is often violated in real datasets. When an analysis of large molecular datasets results in unexpected relationships, it often reflects violation of phylogenetic assumptions, rather than a correct phylogeny. Molecular evolutionary phenomena such as base compositional heterogeneity and among-site rate variation are known to affect phylogenetic inference, resulting in incorrect phylogenetic relationships. The ability of methods to overcome such bias has not been measured on real and complex datasets. We investigated how base compositional heterogeneity and among-site rate variation affect phylogenetic inference in the context of a mitochondrial genome phylogeny of the insect order Coleoptera. We show statistically that our dataset is affected by base compositional heterogeneity regardless of how the data are partitioned or recoded. Among-site rate variation is shown by comparing topologies generated using models of evolution with and without a rate variation parameter in a Bayesian framework. When compared for their effectiveness in dealing with systematic bias, standard phylogenetic methods tend to perform poorly, and parsimony without any data transformation performs worst. Two methods designed specifically to overcome systematic bias, LogDet and a Bayesian method implementing variable composition vectors, can overcome some level of base compositional heterogeneity, but are still affected by among-site rate variation. A large degree of variation in both noise and phylogenetic signal among all three codon positions is observed. We caution and argue that more data exploration is imperative, especially when many genes are included in an analysis.

Abstract: We present complete mitochondrial genomes (mitogenomes) for three orthopterans (Xyleus modestus, Physemacris variolosa, and Ellipes minuta) and describe MOSAS(manipulation, organization, storage, and analysis of sequences), software we developed to facilitate annotation and analysis.We analyze the base composition, start and stop codons, non-coding regions, and gene order among these and 18 other orthopteran mitogenomes from GenBank and reconstruct a phylogeny of Orthoptera.We propose a tetranucleotide start codon for cox1, and hypothesize that the tRNAAsp–tRNALys rearrangement is a synapomorphy for Acridomorpha, but not Caelifera. We further describe MOSAS, user-friendly software we used for this analysis. MOSAS streamlines sequence data storage, organization, annotation, and alignment, and provides convenient search tools for dataset construction and a robust annotation engine particularly suited to annotating mitogenomes (available at http://mosas.byu.edu).

Abstract: Although Ensifera is a major insect model group, its phylogenetic relationships have been understudied so far. Few phylogenetic hypotheses have been proposed, either with morphological or molecular data. The largest dataset ever used for phylogeny reconstruction on this group is molecular (16S rRNA, 18S rRNA and 28S rRNA sequences for 51 ensiferan species), which has been used twice with different resultant topologies. However, only one of these hypotheses has been adopted commonly as a reference classification. Here we re-analyse this molecular dataset with different methods and parameters to test the robustness and the stability of the adopted phylogeny. Our study reveals the instability of phylogenetic relationships derived from this dataset, especially for the deepest nodes of the group, and suggests some guidelines for future studies. The comparison between the different classifications proposed in the past 70 years for Ensifera and our results allows the identification of potential monophyletic clades (katydids, mole crickets, scaly crickets + Malgasia, true crickets, leaf roller crickets, cave crickets) and the remaining unresolved clades (wetas, Jerusalem crickets and most of the highest rank clades) in Ensifera phylogeny.

Abstract: For the past 250 y, tremendous advances have been made in the field of grasshopper systematics. There have been several breakthroughs that have pushed the field forward, and behind these breakthroughs were numerous visionary taxonomists. This article is a celebration of those taxonomists and their achievements. In this review, I provide a general overview of the field and describe major advances that have shaped our understanding of grasshopper systematics. Specifically, I review the pattern of species description in Acridomorpha (Orthoptera: Caelifera) since Linnaeus, and highlight the achievements of important taxonomists. Finally, I end with some of the problems that we grasshopper taxonomists are facing today and challenge the field as a whole to move forward.

Abstract: Many published phylogenies are based on methods that assume equal nucleotide composition among taxa. Studies have shown, however, that this assumption is often not accurate, particularly in divergent lineages. Nonstationary sequence evolution, when taxa in different lineages evolve in different ways, can lead to unequal nucleotide composition. This can cause inference methods to fail and phylogenies to be inaccurate. Recent advancements in phylogenetic theory have proposed new models of nonstationary sequence evolution; these models often outperform equivalent stationary models. A variety of new phylogenetic software implementing such models has been developed, but the studies employing the new methodology are still few. We discovered convergence of nucleotide composition within mitochondrial genomes of the insect order Coleoptera (beetles). We found variation in base content both among species and among genes in the genome. To this data set, we have applied a broad range of phylogenetic methods, including some traditional stationary models of evolution and all the more recent nonstationary models. We compare 8 inference methods applied to the same data set. Although the more commonly used methods universally fail to recover established clades, we find that some of the newer software packages are more appropriate for data of this nature. The software packages p4, PHASE, and nhPhyML were able to overcome the systematic bias in our data set, but parsimony, MrBayes, NJ, LogDet, and PhyloBayes were not.

Abstract: The mantis genus Tenodera is composed of several species distributed across Africa, Asia and Australasia, along with recent human introductions to North America. Species of the genus are morphologically similar and utilise equivalent habitats across their distribution. Relationships among these species and the morphological characters used to diagnose them have never been formally tested, leaving authors to disagree as to the species composition of Tenodera. With DNA sequence data from five molecular loci and morphological characters from male genitalia, we reconstructed the phylogeny of Tenodera using multiple optimality criteria. All included species were found to be monophyletic in analyses of the combined data. Tenodera sinensis and T. bokiana were both supported as distinct species recovered in separate clades, resolving confusion as to their placement and classification. Our analysis identified a previously undescribed species of Tenodera collected in India, recovered as sister to T. aridifolia and T. sinensis, and exhibiting distinct male genital morphology. In light of the phylogeny, we characterise for the first time, and investigate the evolution of, the male genitalia, which allowed us to discover several transitions in structural forms. We also consider the connection of these transitions to sexual cannibalism and how this behaviour may have led to rapid evolution of the male genitalia.

Abstract: While species-specificity of male genitalia is a well-documented pattern among insects which can be explained by sexual selection, there are a number of species that appear to lack species-specific male genitalia despite the presence of stimulation of female genitalia by male genitalia and remating by females which are the conditions for the sexual selection by cryptic female choice. Such contradiction to the general pattern is found in the species belonging to the grasshopper genus Schistocerca whose male genitalia are known to be very similar across species and not useful taxonomically. In this study shapes and sizes of two functionally different genital structures of four Schistocerca species were examined using geometric morphometic analyses. Both shape and size fail as a species-specific character when examined individually because there were extensive overlaps of both variables among species. However, when both variables were examined simultaneously, distinct species-specific clusters were recovered in each genital structure as well as two structures combined. This finding suggests that the male genitalia of Schistocerca should be considered species-specific because the combination of shape and size of both genital structures is unique for each species even if the individual feature might be similar between species. The idea of species specificity in insect systematics when applied to male genitalia, therefore, needs to be re-examined and should be applied to the shape and size and the composite nature of the structure.

Abstract: We present a mitochondrial (mt) genome phylogeny inferring relationships within Neuropterida (lacewings, alderflies and camel flies) and between Neuropterida and other holometabolous insect orders. Whole mt genomes were sequenced for Sialis hamata (Megaloptera: Sialidae), Ditaxis latistyla (Neuroptera: Mantispidae), Mongoloraphidia harmandi (Raphidioptera: Raphidiidae), Macrogyrus oblongus (Coleoptera: Gyrinidae), Rhopaea magnicornis (Coleoptera: Scarabaeidae), and Mordella atrata (Coleoptera: Mordellidae) and compared against representatives of other holometabolous orders in phylogenetic analyses. Additionally, we test the sensitivity of phylogenetic inferences to four analytical approaches: inclusion vs. exclusion of RNA genes, manual vs. algorithmic alignments, arbitrary vs. algorithmic approaches to excluding variable gene regions and how each approach interacts with phylogenetic inference methods (parsimony vs. Bayesian inference). Of these factors, phylogenetic inference method had the most influence on interordinal relationships. Bayesian analyses inferred topologies largely congruent with morphologically-based hypotheses of neuropterid relationships, a monophyletic Neuropterida whose sister group is Coleoptera. In contrast, parsimony analyses failed to support a monophyletic Neuropterida as Raphidioptera was the sister group of the entire Holometabola excluding Hymenoptera, and Neuroptera + Megaloptera is the sister group of Diptera, a relationship which has not previously been proposed based on either molecular or morphological data sets. These differences between analytical methods are due to the high among site rate heterogeneity found in insect mt genomes which is properly modelled by Bayesian methods but results in artifactual relationships under parsimony. Properly analysed, the mt genomic data set presented here is among the first molecular data to support traditional, morphology-based interpretations of relationships between the three neuropterid orders and their grouping with Coleoptera.

Abstract: Sexual selection theory predicts that genital structures in isolated populations are likely to diverge, but male genitalia are often species-specific, which led to the idea that male genitalia are relatively invariable within species. Previous allometric studies collectively suggested that male genitalia are intraspecifically invariable in size compared with external body parts. We investigated whether male genitalia are invariable in shape in three populations of a grasshopper Schistocerca lineata Scudder, 1899, using two independent methods of geometric morphometric analyses. Specifically, we focused on the idea that male genitalia are complex structures consisting of many functionally different components, and studied how these individual parts diverge among three populations. Individual components of male genitalia show different population-level divergence, resulting in the mosaic pattern of genital divergence. Individual components diverge independently from each other. Body size is positively correlated with genitalia size, but is significantly correlated with the shape of only one of the three genital structures we measured. Thus, different components of male genitalia may be influenced by different evolutionary processes. This study is the first to show that components of complex genitalia evolve separately within a species.

Abstract: The phylogenetic utility of mitochondrial genomes (mtgenomes) is examined using the framework of a preliminary phylogeny of Orthoptera. This study presents five newly sequenced genomes from four orthopteran families. While all ensiferan and polyneopteran taxa retain the ancestral gene order, all caeliferan lineages including the newly sequenced caeliferan species contain a tRNA rearrangement from the insect ground plan tRNA(Lys)(K)-tRNA(Asp)(D) swapping to tRNA(Asp) (D)-tRNA(Lys) (K) confirming that this rearrangement is a possible molecular synapomorphy for this suborder. The phylogenetic signal in mtgenomes is rigorously examined under the analytical regimens of parsimony, maximum likelihood and Bayesian inference, along with how gene inclusion/exclusion, data recoding, gap coding, and different partitioning schemes influence the phylogenetic reconstruction. When all available data are analyzed simultaneously, the monophyly of Orthoptera and its two suborders, Caelifera and Ensifera, are consistently recovered in the context of our taxon sampling, regardless of the optimality criteria. When protein-coding genes are analyzed as a single partition, nearly identical topology to the combined analyses is recovered, suggesting that much of the signals of the mtgenome come from the protein-coding genes. Transfer and ribosomal RNAs perform poorly when analyzed individually, but contribute signal when analyzed in combination with the protein-coding genes. Inclusion of third codon position of the protein-coding genes does not negatively affect the phylogenetic reconstruction when all genes are analyzed together, whereas recoding of the protein-coding genes into amino acid sequences introduces artificial resolution. Over-partitioning in a Bayesian framework appears to have a negative effect in achieving convergence. Our findings suggest that the best phylogenetic inferences are made when all available nucleotide data from the mtgenome are analyzed simultaneously, and that the mtgenome data can resolve over a wide time scale from the Permian (approximately 260 MYA) to the Tertiary (approximately 50 MYA).

Abstract: Locust phase polyphenism is an extreme form of density-dependent phenotypic plasticity in which solitary and cryptic grasshoppers can transform into gregarious and conspicuous locusts in response to an increase in local population density. We investigated the evolution of this complex phenotypic plasticity in a phylogenetic framework using a morphological phylogeny of Cyrtacanthacridinae, which contains some of the most important locust species, and a comprehensive literature review on the biology and ecology of all known members of the subfamily. A phylogenetic analysis based on 71 morphological characters yielded a well-resolved tree and found that locust phase polyphenism evolved multiple times within the subfamily. The literature review demonstrated that many cyrtacanthacridine species, both locust and sedentary, are capable of expressing density-dependent color plasticity. When this color plasticity was divided into two smaller components, background coloration and development of black pigmentation, and when these plastic traits were optimized on to the phylogeny, we found that the physiological mechanisms underlying this plasticity were plesiomorphic for the subfamily. We also found that different locust species in Cyrtacanthacridinae express both similarities and differences in their locust phase polyphenism. Because locust phase polyphenism is a complex syndrome consisting of numerous plastic traits, we treat it as a composite character and dissected it into smaller components. The similarities among locust species could be attributed to shared ancestry and the differences could be attributed to the certain components of locust phase polyphenism evolving at different rates.

Abstract: Nuclear mitochondrial pseudogenes (numts) are nonfunctional copies of mtDNA in the nucleus that have been found in major clades of eukaryotic organisms. They can be easily coamplified with orthologous mtDNA by using conserved universal primers; however, this is especially problematic for DNA barcoding, which attempts to characterize all living organisms by using a short fragment of the mitochondrial cytochrome c oxidase I (COI) gene. Here, we study the effect of numts on DNA barcoding based on phylogenetic and barcoding analyses of numt and mtDNA sequences in two divergent lineages of arthropods: grasshoppers and crayfish. Single individuals from both organisms have numts of the COI gene, many of which are highly divergent from orthologous mtDNA sequences, and DNA barcoding analysis incorrectly overestimates the number of unique species based on the standard metric of 3% sequence divergence. Removal of numts based on a careful examination of sequence characteristics, including indels, in-frame stop codons, and nucleotide composition, drastically reduces the incorrect inferences of the number of unique species, but even such rigorous quality control measures fail to identify certain numts. We also show that the distribution of numts is lineage-specific and the presence of numts cannot be known a priori. Whereas DNA barcoding strives for rapid and inexpensive generation of molecular species tags, we demonstrate that the presence of COI numts makes this goal difficult to achieve when numts are prevalent and can introduce serious ambiguity into DNA barcoding.

Abstract: Coleoptera is the most diverse group of insects with over 360,000 described species divided into four suborders: Adephaga, Archostemata, Myxophaga, and Polyphaga. In this study, we present six new complete mitochondrial genome (mtgenome) descriptions, including a representative of each suborder, and analyze the evolution of mtgenomes from a comparative framework using all available coleopteran mtgenomes. We propose a modification of atypical cox1 start codons based on sequence alignment to better reflect the conservation observed across species as well as findings of TTG start codons in other genes. We also analyze tRNA-Ser(AGN) anticodons, usually GCU in arthropods, and report a conserved UCU anticodon as a possible synapomorphy across Polyphaga. We further analyze the secondary structure of tRNA-Ser(AGN) and present a consensus structure and an updated covariance model that allows tRNAscan-SE (via the COVE software package) to locate and fold these atypical tRNAs with much greater consistency. We also report secondary structure predictions for both rRNA genes based on conserved stems. All six species of beetle have the same gene order as the ancestral insect. We report noncoding DNA regions, including a small gap region of about 20 bp between tRNA-Ser(UCN) and nad1 that is present in all six genomes, and present results of a base composition analysis.

Abstract: Schistocerca cohni n. sp. is described from central Mexico and a Socorro Island endemic species, S. socorro, is redescribed with status change and justified emendation. Male external and internal genitalia are described and illustrated. Biology of the endemic species briefly described.

Abstract:

Abstract: Locust phase polyphenism is a spectacular example of density-dependent phenotypic plasticity. It is generally interpreted as an adaptation to heterogeneous environmental conditions brought on by high population density. However, several nonlocust species are known to express phase-like traits, which is difficult to explain from an adaptive perspective alone. Here I attempt to explain this phenomenon by 1) taking a reaction norm perspective in understanding the mechanisms underlying locust phase and 2) taking a phylogenetic perspective to study how individual reaction norms of locust phase might have evolved. I argue that locust phase polyphenism is a complex syndrome resulting from interactions among different density-dependent plastic reaction norms, each of which can follow a separate evolutionary trajectory, which in turn can be reflected in a phylogeny. Using a phylogeny of Cyrtacanthacridinae (Orthoptera: Acrididae), I explore the evolution of plasticity in density-dependent color change. I demonstrate that locusts and closely related nonlocusts, express similar phenotypic plasticity due to phylogenetic conservatism. Finally, I argue that it is crucial to study the evolution of locust phase polyphenism from both adaptive and phylogenetic perspectives.

Abstract: The locust genus Schistocerca (Stål) has a transatlantic disjunction, which has been controversial for more than a century. Among 50 species within the genus, only one species, the desert locust (S. gregaria Forskål), occurs in the Old World, and the rest occur in the New World. Earlier taxonomists suggested that the desert locust is a migrant from America, but this view was strongly challenged when a large swarm of the desert locust successfully crossed the Atlantic Ocean from West Africa to the West Indies in 1988. The currently accepted view, supported by this incident, is that the New World species are descendants of a gregaria-like ancestor, and the desert locust would be ancestral to the rest of the genus. However, there is surprisingly little evidence to support this view other than the 1988 swarm. I present the most comprehensive phylogenetic study that suggests that the desert locust originated from the New World, contrary to the accepted view. I also present a hypothesis about how the ancestral Schistocerca might have colonized the New World in the first place in light of phylogenetic relationships with other cyrtacanthacridine genera.

Abstract: The North American Alutacea Group of the genus Schistocerca is revised based on phylogenetic analysis and morphological comparison. Phylogenetic analysis suggests that Schistocerca alutacea sensu Dirsh is paraphyletic because S. alutacea albolineata sensu Dirsh is sister to S. obscura. Here, I recognize the monophyletic Alutacea Group consisting of six species: S. alutacea, S. rubiginosa, S. lineata, S. shoshone, S. albolineata, and S. obscura. Previous taxonomic confusion on these species is discussed, and their taxonomic ranks are accordingly raised from subspecies to species level. Neotypes of S. alutacea and S. rubiginosa are designated, and S. insignis is synonymized under S. albolineata syn. nov. Also, I argue for the validity of the name S. lineata and discuss the previous misapplication of nomenclature. Discussion of color variation and an identification key for all North American Schistocerca species are presented.

Abstract: The male genitalia and female ovipositor in Schistocerca americana (Drury) (Orthoptera: Acrididae: Cyrtacanthacridinae) continue to develop after adult emergence. The internal skeleton comprising the phallic complex is affected by cuticle deposition, resulting in qualitative shape changes during sexual maturation. Lateral apodemes of the ovipositor also grow in length and width during sexual maturation. Similar developmental patterns are found in the male genitalia of S. gregaria (Forskål) and Locusta migratoria (Linnaeus), suggesting the possibility that post-adult emergence genitalic development may be widespread within Acridoidea. Newly emerged individuals may be functionally incapable of copulation because the necessary structures have not been fully matured. Taxonomic use of the genitalic structures is discussed in light of the present finding.

Abstract: Carabid beetle communities were compared for adjacent marsh and bog biotopes at the McLean Bogs Preserve, Tompkins Co., New York by means of pitfall-trap sampling. Though the sampled marsh and bog habitats were only 200 m distant, with the umbrotrophic bog isolated from the marsh/fen complex by a Wisconsin-aged glacial esker of only 7 m elevation, the resident wetland carabid species assemblages differed significantly between the sites during the spring and summer seasons. Of 62 species observed in the wetlands, 36 were found exclusively in the marsh biotope, 17 were exclusive to the bog site, and only 9 were found at both sites. This level of wetland habitat fidelity was maintained in spite of potential colonization of the two sites each spring by adult beetles dispersing from overwintering sites in surrounding forest edge habitats. Pitfall sampling found 59 native carabid species, of which 52 were found during a survey conducted from 1916–1925, suggesting that the McLean Bogs Preserve supports locally resident populations for the vast majority of carabid species found during this study. The McLean Bogs Preserve supports geographically southern, peripheral populations of the bog-specialist Platynus mannerheimii Dejean, as well as four marsh/fen-inhabiting species—Trechus crassiscapus Lindroth, Bembidion muscicola Hayward, B. praticola Lindroth, and Bradycellus semipubescens Lindroth—emphasizing the role this preserve plays in maintaining the distributional ranges of both bog- and marsh-resident taxa. The distinct faunas observed in these two proximate biotopes clearly illustrate that comprehensive conservation of the carabid beetle fauna of northeastern North America should involve preservation of a variety of wetland types.