New World spittlebugs (Hemiptera: Cercopidae: Ischnorhininae): Dated molecular phylogeny, classification, and evolution of aposematic coloration

Prosapia bicincta (Hemiptera: Cercopidae) abundance, plant associations, and impacts on groundcover in Hawai'i Island rangelands

The twolined spittlebug, Prosapia bicincta (Say), is a major economic pest of forage grass and turfgrass. Prosapia bicincta was first detected in rangelands on Hawai'i Island in 2016 and has since spread to an estimated 72,000 ha in the North and South Kona districts. This study aimed to quantify P. bicincta abundance, plant associations, and impacts on groundcover over time. Monthly surveys of P. bicincta nymphs and adults were conducted from February 2018 to September 2022 along 17 established 100-m transects at 4 ranches located in Kona, Hawai'i Island, spanning an elevation gradient from 519 to 1,874 m above sea level (a.s.l.). Monitoring revealed P. bicincta occurs from 519 to 1,679 m a.s.l., primarily in Kikuyu grass (Cenchrus clandestinus (Hochst. ex Chiov.)) Morrone (Poales: Poaceae) pastures. Peaks in P. bicincta abundance coincided with the wet season, with most activity occurring from April to October and little to no activity between November and March. Mid elevation (1,000-1,300 m) transects had significantly higher mean P. bicincta abundance (126 nymphs/m2) relative to low (500-999 m) (64 nymphs/m2) and high elevations (>1,300 m) (20 nymphs/m2). Sites with the highest abundance of P. bicincta were also associated with the greatest decrease in mean grass cover (30%) and were replaced by forbs, bare ground, and shrubs. Grasses accounted for 72% of the total P. bicincta detections, with the remaining plants comprised of legumes (16%), sedges (6%), and forbs (6%). Twenty new P. bicincta plant associations were found. This information will help improve the effectiveness of management to suppress populations below economic thresholds.

Eocene aposematic patterns persist in modern European Lycidae beetles despite the absence of co-mimics

Ancient aposematic signals might have evolved under different ecological circumstances. Using European Cenozoic amber and phylogenetic reconstruction, we evaluated the evolution of net-winged beetle aposematism. We describe Priabonian Hiekeolycus winkleri sp. nov. from Baltic amber, review known fossil species, and suggest earlier high diversity and morphological conservativeness of European Lycidae since the Eocene. We hypothesize the presence of red and black/red aposematic patterns in Eocene Europe. The analyses suggest the Oligocene to Miocene dispersal of additional species from East Asia and their advergence to autochthonous patterns. Recently dispersed lycids have retained similarities with their East Asian relatives. Net-winged beetles are rare in Europe after the Quaternary climatic oscillations, and we hypothesize a currently relaxed selection for shared aposematic signals. Neophobia, and eventually inborn rejection of brightly colored prey, putatively preserved ancient aposematism under changing conditions. Evidence from paleontology and phylogenetics can provide insight into the long-term persistence of old adaptations under changing conditions.

Evolution of satDNAs on holocentric chromosomes: insights from hemipteran insects of the genus Mahanarva

Satellite DNAs (satDNAs) constitute one of the main components of eukaryote genomes and are involved in chromosomal organization and diversification. Although largely studied, little information was gathered about their evolution on holocentric species, i.e., diffuse centromeres, which, due to differences in repeat organization, could result in different evolutionary patterns. Here, we combined bioinformatics and cytogenetic approaches to evaluate the evolution of the satellitomes in Mahanarva holocentric insects. In two species, de novo identification revealed a high number of satDNAs, 110 and 113, with an extreme monomer length range of 18-4228 bp. The overall abundance of satDNAs was observed to be 6.67% in M. quadripunctata and 1.98% in M. spectabilis, with different abundances for the shared satDNAs. Chromosomal mapping of the most abundant repeats of M. quadripunctata and M. spectabilis on other Mahanarva reinforced the dynamic nature of satDNAs. Variable patterns of chromosomal distribution for the satDNAs were noticed, with the occurrence of clusters on distinct numbers of chromosomes and at different positions and the occurrence of scattered signals or nonclustered satDNAs. Altogether, our data demonstrated the high dynamism of satDNAs in Mahanarva with the involvement of this genomic fraction in chromosome diversification of the genus. The general characteristics and patterns of evolution of satDNAs are similar to those observed on monocentric chromosomes, suggesting that the differential organization of genome compartments observed on holocentric chromosomes compared with monocentric chromosomes does not have a large impact on the evolution of satDNAs. Analysis of the satellitomes of other holocentric species in a comparative manner will shed light on this issue.

More than 80 years without new taxa: analysis of morphological variation among members of Mexican Aeneolamia Fennah (Hemiptera, Cercopidae) support a new species in the genus

The genus Aeneolamia includes eight described species and 32 subspecies widely distributed in America. In Mexico, two species (A.contigua and A.albofasciata) and one subspecies (A.contiguacampecheana) are recognized. In a recent study of Cercopidae in Mexico, a new species of Aeneolamia was noted from Oaxaca, Mexico based on body color and the ornamentation patterns of tegmen, without a formal taxonomic description. To test the hypothesis of an extant new taxon within the genus a comprehensive analysis of intraspecific morphological variation from 46 morphological features was performed, four related to tegmen color patterns in both sexes, six to male genitalia, and 36 continuous characters measured in specimens of both sexes of Mexican Aeneolamia from several geographical localities using traditional univariate, multivariate morphometric, and geometric morphometric methods. This is the first time that this approach has been used in Cercopidae. Aeneolamiadanpecki Castro, Armendáriz & Utrera, sp. nov. from Oaxaca showed pronounced morphological differences in tegmen coloration patterns, the shape of different elements of the male genitalia, and body measurements compared to the other Mexican members of Aeneolamia; therefore, it is described as a new species.

Chromosome-Level Genome Assembly of Callitettix versicolor (Rice Spittlebug)

The spittlebug family Cercopidae (Hemiptera: Auchenorrhyncha: Cicadomorpha: Cercopoidea) is distributed worldwide. Some Cercopidae species are agricultural pests that are responsible for substantial economic damage. However, the genomics of spittlebugs has rarely been studied and their complete genome assembly is yet to be reported. Here, we present the draft reference genome of Callitettix versicolor Fabricius (Hemiptera: Cercopidae) at the chromosome level. The assembled draft genome was 974.99 Mb with a contig N50 of 5.63 Mb, and the longest contig being 24.54 Mb. Hi-C technology was used to obtain an approximately 958.71 Mb chromosome-level genome on 10 pseudochromosomes, which covered 98.33% of the assembly. Repeat sequences accounted for 38.88% of the genomic sequences. A total of 21,937 protein-coding genes were detected in the reference genome, 89.97% of which were annotated in public databases. The high-quality reference genome of C. versicolor reported in this study will provide a valuable genomic resource for future ecological and evolutionary studies of spittlebugs.

Spittlebugs (Hemiptera: Cercopidae): Integrated Pest Management on Gramineous Crops in the Neotropical Ecozone

Spittlebug (Hemiptera: Cercopidae) species cause large economic losses on gramineous crops (Poaceae) in tropical and subtropical America. These insects are key pests of sugarcane and forages, crops that experienced a quick expansion in extensive monocultures in Brazil, Colombia, and Mexico. Mobilization toward sustainable crop and livestock systems to supply the growing demand of meat, milk, and sugar in Latin America and the Caribbean region implies developing sustainable and feasible strategies of integrated pest management to control spittlebugs. This review combines information on Cercopidae taxonomy, geographical distribution, insect biology, and control strategies to contribute to the development of integrated pest management in grasses and sugarcane in the Neotropics.

Male terminalia of Cercopidae (Hemiptera, Cicadomorpha): towards a consensus terminology

The study of male genital appendages is often necessary to identify a species and to characterise the higher systematics ranks for the Cercopidae, a large family of Hemiptera. Therefore, many authors have used them in their work but without any clear consensus on the terms used for each part constituting the male terminalia. A standardised terminology is important for the quality of a taxonomic description but even more essential when we want to compare species and establish a primary homology between states of character and their use in the frame of phylogenetic analysis. The use of a consensus terminology should ensure that we are all observing, speaking and describing the same genital appendage and comparing homologous characters. In order to propose a consensus terminology, we have reviewed all the major works on the anatomy of terminalia for the family since the first description using those characters in 1922. We proposed the use of consensual terms, listed with their definitions. In addition we studied a diversified panel of male specimens, chosen in order to represent as many Cercopidae tribes as possible. We categorised five different groups of Cercopidae according to their male terminalia structures. This opens the reflection on the evolutionary patterns for these structures.

Biology and Life Stages of Pine Spittle Bug Ocoaxo assimilis Walker (Hemiptera: Cercopidae)

The first records of outbreaks of the Pine Spittle bug Ocoaxo assimilis Walker were recently identified from Puebla, Mexico, which promoted more than 2600 ha of forest foliar fall. Beyond the taxonomic and distribution information of this species, the basic traits of its biology remain unknown. This study aims to describe some biological aspects of O. assimilis, in a natural pine forest at Nicolás Bravo, Puebla (NB). Using morphological characteristics and a phylogenetic analysis of a fragment of cytochrome oxidase subunit I mtDNA (COI), immature instars with adults were studied; the instar number was determined by means of a multivariate analysis of 19 morphological characteristics of 121 specimens. The systematic sampling to evaluate the occurrence of nymphal specimens during a year, plus host selection experiments, allowed for determination of the abundance over time, voltism, and host preferences. Phylogenetic analysis of the COI supported that both nymphs and adults collected in NB correspond to O. assimilis. Principal coordinate analysis supported the existence of five nymphal stages. Field sampling and host selection experiments indicated that this species displays a single generation per year, is associated with the rainy season, and that specimens from the three first nymphal stages feed on roots of eight host species (one grass, four herbaceous species, one bush, and two trees). From the fourth instar, the insects feed on pine roots to complete their development, and when they are adults, they migrate to needles of young or mature pine stands of Pinus pseudostrobus to feed and reproduce.

The Insect Circulatory System: Structure, Function, and Evolution

Although the insect circulatory system is involved in a multitude of vital physiological processes, it has gone grossly understudied. This review highlights this critical physiological system by detailing the structure and function of the circulatory organs, including the dorsal heart and the accessory pulsatile organs that supply hemolymph to the appendages. It also emphasizes how the circulatory system develops and ages and how, by means of reflex bleeding and functional integration with the immune system, it supports mechanisms for defense against predators and microbial invaders, respectively. Beyond that, this review details evolutionary trends and novelties associated with this system, as well as the ways in which this system also plays critical roles in thermoregulation and tracheal ventilation in high-performance fliers. Finally, this review highlights how novel discoveries could be harnessed for the control of vector-borne diseases and for translational medicine, and it details principal knowledge gaps that necessitate further investigation.

Comparative analysis of the mitochondrial genomes of oriental spittlebug trible Cosmoscartini: insights into the relationships among closely related taxa

Background

Cosmoscartini (Hemiptera: Cercopoidea: Cercopidae) is a large and brightly colored Old World tropical tribe, currently containing over 310 phytophagous species (including some economically important pests of eucalyptus in China) in approximately 17 genera. However, very limited information of Cosmoscartini is available except for some scattered taxonomic studies. Even less is known about its phylogenetic relationship, especially among closely related genera or species. In this study, the detailed comparative genomic and phylogenetic analyses were performed on nine newly sequenced mitochondrial genomes (mitogenomes) of Cosmoscartini, with the purpose of exploring the taxonomic status of the previously defined genus Okiscarta and some closely related species within the genus Cosmoscarta.

Results

Mitogenomes of Cosmoscartini display similar genomic characters in terms of gene arrangement, nucleotide composition, codon usage and overlapping regions. However, there are also many differences in intergenic spacers, mismatches of tRNAs, and the control region. Additionally, the secondary structures of rRNAs within Cercopidae are inferred for the first time.

Based on comparative genomic (especially for the substitution pattern of tRNA secondary structure) and phylogenetic analyses, the representative species of Okiscarta uchidae possesses similar structures with other Cosmoscarta species and is placed consistently in Cosmoscarta. Although Cosmoscarta bimacula is difficult to be distinguished from Cosmoscarta bispecularis by traditional morphological methods, evidence from mitogenomes highly support the relationships of (C. bimacula + Cosmoscarta rubroscutellata) + (C. bispecularis + Cosmoscarta sp.).

Conclusions

This study presents mitogenomes of nine Cosmoscartini species and represents the first detailed comparative genomic and phylogenetic analyses within Cercopidae. It is indicated that knowledge of mitogenomes can be effectively used to resolve phylogenetic relationships at low taxonomic levels. Sequencing more mitogenomes at various taxonomic levels will also improve our understanding of mitogenomic evolution and phylogeny in Cercopidae.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5365-7) contains supplementary material, which is available to authorized users.

Comparative analysis of seven mitochondrial genomes of Phymatostetha (Hemiptera: Cercopidae) and phylogenetic implications

In this study, we present seven mitochondrial genomes (mitogenomes) of Phymatostetha. Each mitogenome contains the entire set of 37 genes, which arranged in the same order as the putative ancestral pattern of insects. The nucleotide composition of Phymatostetha mitogenomes is biased toward A/T, with rRNAs and PCG12 (i.e. the first and second codon positions of PCGs) exhibit the highest and lowest A + T content, respectively. Relative synonymous codon usage of PCGs also show that degenerate codons are biased to use more A/T than G/C. All tRNAs exhibit typical clover-leaf structure, with the exception of trnS1. Additionally, unpaired nucleotides are detected in trnS1 anticodon stem and trnR acceptor stem. Phylogenetic relationships, based on the dataset of 13 PCGs, 22tRNAs, and two rRNAs, are analyzed using both the Bayesian and maximum likelihood methods. Our results clearly revealed the systematic status of Phymatostetha species and robustly supported the monophyly of this genus, in which Phymatostetha semele is sister to other Phymatostetha species. It was demonstrated that mitogenome was an effective molecular marker to adequately resolve phylogeny at low taxonomic levels.