Search

The reduviid subfamily Triatominae, also called kissing bugs, are vectors of Chagas disease, which is one of the most seriously neglected tropical parasitic diseases. Only three complete mitochondrial genomes of kissing bugs from the genus Triatoma have been sequenced to date. To better understand the diversity of mitochondrial genomes and the evolution of kissing bugs, mitochondrial genomes of three kissing bugs, Triatoma migrans, Panstrongylus rufotuberculatus, and Rhodnius pictipes, were sequenced using next-generation sequencing and a comparative mitochondrial genomic analysis of three genera and two tribes in Triatominae was conducted. Kissing bug mitochondrial genomes shared a similar pattern of nucleotide composition, gene order, and structure of control region. The comparison among orthologous protein-coding genes indicated that different genes had different rates of molecular evolution and six genes (ND1, ND2, ND4L, ND5, ND6, and ATP8) had higher evolutionary rates than other protein-coding genes. Phylogenetic analyses inferred from mitochondrial genome sequences supported a sister relationship between Triatominae and Stenopodainae, and the genus Triatoma was paraphyletic. The present study revealed the high conservation of the mitochondrial genome organization of kissing bugs and highlighted the utility of mitochondrial genomes in the phylogenetic study of Triatominae.

Two new species of the insect order Zoraptera, Zorotypus robustus sp. nov. and Zorotypus oligophleps sp. nov., are described and figured based on two well-preserved specimens in mid-Cretaceous amber from the Hukawng Valley of northern Myanmar. Compared to known extinct angel insects, the two new species are readily distinguished by characters of the antennae, wings, terminal abdominal segments, and the spination of the metafemur and metatibia. Furthermore, the wing venation of Zorotypus oligophleps sp. nov. is uniquely specialized, with the absence of the first abscissa of Rs and CuA in the forewing, as well as the absence of M1+2 in the hindwing. These two new taxa provide novel morphological diversity of angel insects.

Mitochondrial phylogenomics is often controversial, in particular for inferring deep relationships. The recent rapid increase of mitochondrial genome data provides opportunities for better phylogenetic estimates and assessment of potential biases resulting from heterogeneity in nucleotide composition and mutation rates. Here, we gathered 76 mitochondrial genome sequences for Heteroptera representing all seven infraorders, including 17 newly sequenced mitochondrial genomes. We found strong heterogeneity in base composition and contrasting evolutionary rates among heteropteran mitochondrial genomes, which affected analyses with various datasets and partitioning schemes under site-homogeneous models and produced false groupings of unrelated taxa exhibiting similar base composition and accelerated evolutionary rates. Bayesian analyses using a site-heterogeneous mixture CAT+GTR model showed high congruence of topologies with the currently accepted phylogeny of Heteroptera. The results confirm the monophyly of the six infraorders within Heteroptera, except for Cimicomorpha which was recovered as two paraphyletic clades. The monophyly of Terheteroptera (Cimicomorpha and Pentatomomorpha) and Panheteroptera (Nepomorpha, Leptopodomorpha and Terheteroptera) was recovered demonstrating a significant improvement over previous studies using mitochondrial genome data. Our study shows the power of the site-heterogeneous mixture models for resolving phylogenetic relationships with Heteroptera and provides one more case showing that model adequacy is critical for accurate tree reconstruction in mitochondrial phylogenomics.

Summary Blood-feeding insects, as vectors of disease for humans and livestock alike, have garnered significant interest [1, 2], but our understanding of their early evolution is hindered by the scarcity of available material and the difficulty in distinguishing early hematophages from non-blood-feeding relatives. Here, we report a new family of true bugs including two new genera and species from the Early Cretaceous Yixian Formation in Northeastern China. By utilizing geochemical methods for determining their diets and combining morphological and taphonomic data, we demonstrate that these new species represent the earliest evidence of blood feeding among true bugs, extending the geological record of such lineages by approximately 30 million years. Remarkably, one of the bugs appears to have perished immediately following a blood meal, which may have been from coexisting mammals, birds, or avian-related dinosaurs. These records expand the phylogenetic and ecological diversity of blood-feeding insects in the Early Cretaceous, enriching our knowledge of paleoecological associations in these ancient environments.

Insect parasitism was known in China for a long time in the form of parasitic tachinid flies of silkworms (Bombyx mori L.). These tachinid flies were first mentioned in the Chinese literature around 300 AD. The developmental cycle of this tachinid (possibly a species of the genus Exorista) were clearly described by Lu Dian in 1096. This antedates the first descriptions of insect parasitoids from Europe by 600 years. Another parasitic fly, a flesh fly (possibly Blaesoxipha lapidosa Pape) was noted as the main parasitoid of Locusta migratoria manilensis Meyen in 1196. The first Chinese record with a correct description of the life cycle of a hymenopteran parasitoid dates from 1704.