The higher termites (Termitidae) are keystone species and ecosystem engineers. They have exceptional biomass and play important roles in decomposition of dead plant matter, in soil manipulation, and as the primary food for many animals, especially in the tropics. Higher termites are most diverse in rainforests, with estimated origins in the late Eocene (∼54 Ma), postdating the breakup of Pangaea and Gondwana when most continents became separated. Since termites are poor fliers, their origin and spread across the globe requires alternative explanation. Here, we show that higher termites originated 42-54 Ma in Africa and subsequently underwent at least 24 dispersal events between the continents in two main periods. Using phylogenetic analyses of mitochondrial genomes from 415 species, including all higher termite taxonomic and feeding groups, we inferred 10 dispersal events to South America and Asia 35-23 Ma, coinciding with the sharp decrease in global temperature, sea level, and rainforest cover in the Oligocene. After global temperatures increased, 23-5 Ma, there was only one more dispersal to South America but 11 to Asia and Australia, and one dispersal back to Africa. Most of these dispersal events were transoceanic and might have occurred via floating logs. The spread of higher termites across oceans was helped by the novel ecological opportunities brought about by environmental and ecosystem change, and led termites to become one of the few insect groups with specialized mammal predators. This has parallels with modern invasive species that have been able to thrive in human-impacted ecosystems.

A phylogeny of the Torymidae (Chalcidoidea) is estimated using 4734 nucleotides from five genes. Twelve outgroups and 235 ingroup taxa are used, representing about 70% of the recognized genera. Our analyses do not recover Torymidae as monophyletic and we recognize instead two families: Megastigmidae (stat. rev.) and Torymidae s.s. (stat. rev.). Within Torymidae s.s., we recognize six subfamilies and six tribes, including Chalcimerinae, Glyphomerinae and Microdontomerinae (subf. nov.), and two new tribes: Boucekinini and Propalachiini (trib. nov.). Seven unclassified genera (i.e. Cryptopristus, Echthrodape, Exopristoides, Exopristus, part of Glyphomerus, Thaumatorymus, Zaglyptonotus) are assigned to tribes within our new classification. Five genera are restored from synonymy-Ameromicrus and Didactyliocerus from under Torymoides (stat. rev.), Iridophaga and Iridophagoides from under Podagrionella (stat. rev.) and Nannocerus from under Torymus (stat. rev.)-and three genera are synonymized-Allotorymus under Torymus syn. nov., Ditropinotus under Eridontomerus syn. nov. and Pseuderimerus under Erimerus syn. nov. A Palaearctic or Eurasian origin for Torymidae is proposed. The ancestral area of Megastigmidae is indicated as the Australian region. The most probable ancestral life strategy for Torymidae s.s. is ectoparasitism on gall-forming Cynipidae. The life strategy and putative hosts of the common ancestor of Megastigmidae remain uncertain.

The European spruce bark beetle, Ips typographus, is a serious pest of spruce forests in Europe, and its invasion and development inside spruce tissues are facilitated by microorganisms. We investigated the core gut bacterial and fungal microbiomes of I. typographus throughout its life cycle in spring and summer generations. We used cultivation techniques and molecular identification in combination with DNA and RNA metabarcoding. Our results revealed that communities differ in the throughout the life cycle and generations proportion of dominantly associated microbes, rather than changes in species composition. The bacteriome consisted mostly of the phylum Gammaproteobacteria, with the most common orders and genera being Enterobacteriales (Erwinia and Serratia), Pseudomonadales (Pseudomonas) and Xanthomonadales. The fungal microbiome was dominated by yeasts (Saccharomycetes—Wickerhamomyces, Kuraishia and Nakazawaea), followed by Sordariomycetes (Ophiostoma bicolor and Endoconidiophora polonica). We did not observe any structure ensuring long-term persistence of microbiota on any part of gut epithelium, suggesting that microbial cells are more likely to pass through the beetle's gut with chyme. The most abundant taxa in beetle's gut were also identified as dominant in intact spruce phloem. Therefore, we propose that these taxa are acquired from the environment rather than specifically vectored between generations.

The evolutionary success of termites has been driven largely by a complex communication system operated by a rich set of exocrine glands. As many as 20 different exocrine organs are known in termites. While some of these organs are relatively well known, only anecdotal observations exist for others. One of the exocrine organs that has received negligible attention so far is the labral gland. In this study, we examined the structure and ultrastructure of the labrum in soldiers of 28 termite species. We confirm that the labral gland is present in all termite species, and comprises two secretory regions located on the ventral side of the labrum and the dorso-apical part of the hypopharynx. The labrum of Neoisoptera has a hyaline tip, which was secondarily lost in Nasutitermitinae, Microcerotermes and species with snapping soldiers. The epithelium of the gland generally consists of class 1 secretory cells, with an addition of class 3 secretory cells in some species. A common feature of the secretory cells is the abundance of smooth endoplasmic reticulum, an organelle known to produce lipidic and often volatile secretions. Our observations suggest that the labral gland is involved in communication rather than defence as previously suggested. Our study is the first to provide a comprehensive picture of the structure of the labral gland in soldiers across all termite taxa.