Fruit flies (Diptera: Tephritidae) possess high diversity and globally wide distribution, including a range of important agricultural pests. However, the origin, phylogeny and divergence history remain poorly understood. We undertook the first comprehensive mitogenomic study covering phylogenetic reconstruction, divergence time estimation and historical biogeography analyses by analyzing 147 mitochondrial genomes representing three subfamilies, seven tribes, 11 genera and 82 species. The results recovered all the three subfamilies, seven tribes and 11 genera as monophyletic group. Within Dacini subfamily, our phylogeny strongly supported the sister group relationship of (Zeugodacus + Dacus) + Bactrocera, which further supported to raise Zeugodacus as generic level of Dacini. On the other hand, our molecular phylogenetic analyses did not align well with the currently recognized subgeneric designations within Ceratitis, Dacus and Zeugodacus. Some subgenera were recovered as polyphyletic or paraphyletic, implying the incongruence between morphological characters and mitogenomic data. Neither the taxa within the Ceratitis FARQ complex nor those within the Bactrocera dorsalis complex could be clearly distinguished as distinct species corresponding to the morphospecies by mitochondrial phylogenetic tree. Divergence time estimation and historical biogeography analyses indicated that the earliest common ancestor of the Tephritidae, originated in the Palearctic realm at 138.92-71.44 Ma, with the subsequent divergence into Dacinae + Trypetinae and Tephritinae at 115.19-67.45 Ma equally in the Palearctic realm. Dacini might have originated in Laurasia rather than Gondwana and diverged into Bactrocera and Dacus + Zeugodacus at 48.43-28.70 Ma after India plate docked with Laurasia.

The Tephritidae is one of the largest families of Diptera with high diversity and globally wide distribution, including a range of important agricultural pests. However, the origin, phylogeny and evolution history of Tephritidae remain poorly understood. We undertook the first comprehensive mitogenomic study covering phylogenetic reconstruction, divergence time estimation and historical biogeography analyses by analyzing 147 mitochondrial genomes representing three subfamilies, seven tribes, 11 genera and 82 species. The results recovered all the three subfamilies, seven tribes and 11 genera as monophyletic group. Within Dacini subfamily, our phylogeny strongly supported the sister group relationship of (Zeugodacus + Dacus) + Bactrocera, which further supported to raise Zeugodacus as generic level of Dacini. On the other hand, our molecular phylogenetic analyses did not align well with the currently recognized subgeneric designations within Ceratitis, Dacus and Zeugodacus. Some subgenera were recovered as polyphyletic or paraphyletic, implying the incongruence between morphological characters and mitogenomic data. Neither the taxa within the Ceratitis FARQ complex nor those within the Bactrocera dorsalis complex could be clearly distinguished as distinct species corresponding to the morphospecies by mitochondrial phylogenetic tree. Divergence time estimation and historical biogeography analyses indicated that the earliest common ancestor of the Tephritidae, originated in the Palearctic realm at 138.92-71.44 Ma, with the subsequent divergence into Dacinae + Trypetinae and Tephritinae at 115.19-67.45 Ma equally in the Palearctic realm. Dacini might have originated in Laurasia rather than Gondwana and diverged into Bactrocera and Dacus + Zeugodacus at 48.43-28.70 Ma after India plate docked with Laurasia.

While it has been suggested that histone modification can facilitate animal responses to rapidly changing environments, few studies have profiled whole-genome histone modification patterns in introduced species, leaving its role in invasiveness unclear. Here, we screen genome-wide patterns of two important histone modifications, trimethylated Histone H3 Lysine 4 (H3K4me3) and trimethylated Histone H3 Lysine 27 (H3K27me3), in adult thorax muscles of a notorious invasive pest, the Oriental fruit fly Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), using Chromatin Immunoprecipitation with high-throughput sequencing (ChIP-seq). We identified active, repressed and poised promoters, featured by the occupancy of H3K4me3, H3K27me3 and bivalent histone modifications that were respectively annotated with unique genes key to muscle development and structure maintenance. In addition, we found H3K27me3 occupied the entire body of genes, with the average enrichment was almost constant. When comparing to the closely related indigenous Drosophila species, while we found highly conserved histone modifications patterns of distribution and function between the two species, we identified more genes and putative motifs modified by histone modifications that may regulate insect flight capacity and invasiveness compared to D. melanogaster. These findings provide the first evidence of histone modification signature in an invasive species, and will be useful for future studies of epigenetic regulation of invasiveness under global climate change.

Humans have translocated thousands of species, either intentionally or not, from their native ranges to non-native ones, with many established (naturalized) and some now invasive. We report here a global database on the distributions of naturalized alien insects. Currently, 7,741 naturalized alien insect species have been reported from 222 regions, of which 47 species were reported over all six continents, 103 species over five continents, and 208 species over four continents. Naturalized alien insects are taxonomically diverse in all six continents, predominantly occurring in agroecosystems, as well as forests and grasslands. North America has accumulated the greatest number of naturalized alien insect species, while South America has the lowest number. Asia donated the greatest number of its native insect species to other continents, especially to North America and Europe. The global patterns of naturalized alien insects are correlated with transcontinental trade and the number of local scientists who study insect invasions. Most naturalized alien insects have been introduced to multiple continents, further facilitating the expansion of introduced populations through bridgehead effects. Understanding the global exchange and accumulation of alien insects helps the development of an early warning and monitoring system for insect invasions.