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The Mesozoic is a key era for the rise of the modern insect fauna. Among the most important evolutionary events in Mesozoic insects are the radiation of holometabolous insects, the origin of eusocial and parasitoid insects, diversification of pollinating insects, and development of advanced mimicry and camouflage. These events are closely associated with the diversification of insect ecological behaviors and colonization of new ecospaces. At the same time, insects had evolved more complex and closer ecological associations with various plants and animals. Mesozoic insects played a key and underappreciated ecological role in reconstructing and maintaining terrestrial ecosystems. A greater understanding of the history of insects may help to mitigate future changes in insect diversity and abundance.

Resource pulses, occasional events of ephemeral resource superabundance, represent a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. They are widespread in extant ecosystems; however, little is known about their deep-time record. We report the earliest-known mayfly swarm from the Early Jurassic Xiwan biota of southern China. Our taphonomic and sedimentological analyses show that these mayflies were buried on the bottom of a calm lake after post-mating death. Our suite of analyses suggests that the complex mating-swarm behavior was already well established in mayflies by the Early Jurassic. More importantly, our find represents the earliest-known resource pulse of insects, a mechanism that can play a substantial role in nutrient transport from aquatic ecosystems to surrounding terrestrial ecosystems. Such an aquatic-terrestrial ecosystem linkage may be a key novelty in Mesozoic lacustrine ecosystems. Our results high-light the underappreciated ecological significance of insects in deep-time terrestrial ecology.

Orthoptera constitutes an important ecological component of the global fauna. Its Early Jurassic record is limited in China and its evolution is poorly understood after the end-Triassic mass extinction. Several orthopterans are described herein from the Lower Jurassic Badaowan and Sangonghe formations of the southern Junggar Basin, Xinjiang, NW China. From the Badaowan Formation, a new species, Parahagla cheni sp. nov., is established and assigned to Chifengiinae (Hagloidea: Prophalangopsidae), which represents the oldest record of this subfamily. From the Sangonghe Formation, a forewing fragment is attributed to Sinagryllus xinjiangensis Wang et al., 2019 (Grylloidea: Baissogryllidae), another forewing fragment and a metathoracic leg without attribution. Discovery of these fossils increases the biodiversity of Orthoptera in the Early Jurassic, and further indicates that orthopterans likely flourished in the Junggar area during the Early Jurassic. An analysis of orthopteran biodiversity at generic and species levels reveals an extinction in Orthoptera in the Late Triassic, especially for the superfamilies Hagloidea and Oedischioidea, which suffered a substantial extinction. This extinction happened in the Late Triassic, earlier than the mass extinction of marine animals at the end of the Triassic.

The avoidance of detection by predators and parasites is critical to survival. Two complex mechanisms for such avoidance are mimicry and camouflage, with fossils providing valuable insight into the evolution of these strategies. Such fossil evidence is, however, rare, and the frequent partial and lopsided occurrence. Here, we report a diverse insect assemblage exhibiting these adaptations from mid-Cretaceous Kachin amber (99 million years ago), including plant mimesis in Tridactylidae (pygmy mole crickets) and debris-carrying camouflage in Gelastocoridae (toad bugs) and Psocodea (bark lice). Critically, Mesozoic plant mimesis in Tridactylidae is supported by our Siamese Network analysis, a Deep Learning model and potentially powerful tool for investigating ancient mimicry. Together with previously known records, our fossils demonstrate that most extant debris-carrying insects (eight groups with direct camouflage) had evolved exogenous camouflage by the mid-Cretaceous. Our results suggest that a complex biological response was already widespread among insects in mid-Cretaceous ecosystems during the rise of angiosperms, probably in response to similar selective pressures as experienced by their extant counterparts.

Acoustic communication has played a key role in the evolution of a wide variety of vertebrates and insects. However, the reconstruction of ancient acoustic signals is challenging due to the extreme rarity of fossilized organs. Here, we report the earliest tympanal ears and sound-producing system (stridulatory apparatus) found in exceptionally preserved Mesozoic katydids. We present a database of the stridulatory apparatus and wing morphology of Mesozoic katydids and further calculate their probable singing frequencies and analyze the evolution of their acoustic communication. Our suite of analyses demonstrates that katydids evolved complex acoustic communication including mating signals, intermale communication, and directional hearing, at least by the Middle Jurassic. Additionally, katydids evolved a high diversity of singing frequencies including high-frequency musical calls, accompanied by acoustic niche partitioning at least by the Late Triassic, suggesting that acoustic communication might have been an important driver in the early radiation of these insects. The Early—Middle Jurassic katydid transition from Haglidae- to Prophalangopsidae-dominated faunas coincided with the diversification of derived mammalian clades and improvement of hearing in early mammals, supporting the hypothesis of the acoustic coevolution of mammals and katydids. Our findings not only highlight the ecological significance of insects in the Mesozoic soundscape but also contribute to our understanding of how acoustic communication has influenced animal evolution.

A new genus and species of the extinct beetle-like dictyopteran family †Umenocoleidae, †Laticephalana liuyani gen. et sp. nov., is described based on a well-preserved adult female from mid-Cretaceous Kachin (Myanmar/Burmese) amber. The new genus is characterized by two conspicuous autapomorphies, a triangular posterior extension of the head capsule and four large protuberances of the pronotum. Both structures can be interpreted as mechanic protective devices, but alternative/additional interpretations are possible. The large female subgenital plate is an autapomorphy of Dictyoptera. The transverse pronotal furrow suggests a placement in a clade with †Alienopteridae and Mantodea. A close relationship between †Laticephalana and †Enervipraela is tentatively supported by a very narrow pronotum and relatively short antennae. The very broad head of †Laticephalana with widely separated large compound eyes indicates predaceous habits, and the slender body and well-developed hindwings good flying abilities. The specializations of the distal legs, very similar to the conditions found in †Alienopteridae, suggest a preference for the foliage of trees and shrubs.

As an important combination of behaviour and pattern in animals to resemble benign objects, biolog ical mimesis can effectively avoid the detection of their prey and predators. It at least dates ba...

The Early Miocene (16–23 Mya) amber of Ethiopia constitutes a new source of fossil ants for Africa, where they are otherwise poorly documented. Here we report a diversified assemblage of six subfamilies and at least 19 genera that are still predominantly alive in the Afrotropics today. In this first account, a particular reference is made to the subfamily Dolichoderinae, with the description of two new species: Technomyrmex svojtkai Perrichot & Engel sp. nov. and Ravavy goldmani Boudinot & Perrichot sp. nov. The first is illustrated and described based on synchrotron-radiation microcomputed tomography, and the second represents the first fossil record for the tribe Bothriomyrmecini and Ravavy, a Malagasy and Afrotropical genus that was hitherto monotypic. The ant composition in Ethiopian amber is congruent with the global pattern emerging across ants and showing a Neogene diversification almost exclusively within extant genera.

International audience; Chrysopidae (green lacewings) is one of the species-rich families of Neuroptera. The Cretaceous fossils of green lacewing currently comprise 11 genera and 26 species. Here we describe a new green lacewing species, Mesypochrysa coadnata sp. nov., from mid-Cretaceous Burmese amber. The new species belongs to the extinct subfamily Limaiinae and is characterized by the RP with seven zigzagged branches, the forewing CuA with four pectinate branches, and the hind wing CuA with three pectinate branches. The exquisite preservation of the new fossils facilitates the understanding of the genital morphology of the Mesozoic green lacewings.

New fossil species of the genus Diapus (Coleoptera: Curculionidae: Platypodinae) are described in Miocene amber from Ethiopia and Zhangpu, China, based on male and female specimens. We report 24 male and 6 female specimens in Zhangpu amber and one male from Ethiopian amber. However, the number of specimens in Ethiopian amber will probably increase when more material is available for study. The large amount of Diapus specimens supports the paleoenvironmental reconstruction of the Zhangpu amber forest as a megathermal seasonal rainforest. The new species highlight that Platypodinae diversification likely associated with angiosperms may have started in the Cretaceous with an increase of diversity in the Miocene. The specimens described here are the first record of Diapus preserved in amber.

Xu, C.P., Fang, Y., Heads, S., Zhang, Q., Jarzembowski, E.A. & Wang, B. 2 December. 2019. The first Orthoptera (Insecta) from the Triassic of China. Alcheringa 44, 93–98. ISSN 0311-5518.The extinct...

Grylloidea is a large superfamily of orthopteran insects, comprising over 4,000 species in four extant families (Gryllidae, Mogoplistidae, Gryllotalpidae and Myrmecophilidae) and two extinct families (Baissogryllidae and Protogryllidae) to date (Resh & Cardé, 2009; Cigliano et al., 2018; Wang et al., 2019). Grylloids, commonly known as true crickets, are a group of adaptable insects occurring in all the temperate parts of the world except the highest mountain peaks. And interestingly, there are several apterous grylloid genera (e.g., Caconemobius) living in mangrove swamps, where they use the stems to submerge themselves in saltwater and are able to “skate” on water surfaces (Resh & Cardé, 2009; Kim & Kim, 2010).

The trichopteran family Odontoceridae is reported in mid-Cretaceous Burmese amber by two genera: the extant Psilotreta, with one described extinct species, P. fossilis sp. nov.; and the extinct Palaeopsilotreta, with five species, two of which are newly found and described here, P. kachini sp. nov., P. succini sp. nov. The two genera are closely related and show great similarities in the venation of the forewings and hindwings, but their males differ markedly in the shape of the antennae. In Palaeopsilotreta the males have bipectinate antennae and in Psilotreta the antennae are simple and filiform.

The Zhangpu biota provides a new insight into biodiversity redistribution during the Mid-Miocene Climatic Optimum., During the Mid-Miocene Climatic Optimum [MMCO, ~14 to 17 million years (Ma) ago], global temperatures were similar to predicted temperatures for the coming century. Limited megathermal paleoclimatic and fossil data are known from this period, despite its potential as an analog for future climate conditions. Here, we report a rich middle Miocene rainforest biome, the Zhangpu biota (~14.7 Ma ago), based on material preserved in amber and associated sedimentary rocks from southeastern China. The record shows that the mid-Miocene rainforest reached at least 24.2°N and was more widespread than previously estimated. Our results not only highlight the role of tropical rainforests acting as evolutionary museums for biodiversity at the generic level but also suggest that the MMCO probably strongly shaped the East Asian biota via the northern expansion of the megathermal rainforest biome. The Zhangpu biota provides an ideal snapshot for biodiversity redistribution during global warming.

International audience; Phorid flies are an abundant and diverse dipteran family in modern faunas, yet poorly represented in the fossil record. Here, we describe the first fossil species of the millipede parasitizing genus Myriophora, M. asiatica n. sp., and three new fossil species of the ant parasitizing genus Apocephalus, A. miocenus n. sp., A. dominicanus n. sp., and A. chiapanecus n. sp. discovered in Miocene amber deposits from China, Dominican Republic, and Mexico. Moreover, we add details on the previously described species Apocephalus succineus Brown, previously described in Dominican amber, with the description of a new specimen. We also include a dichotomous key for all Apocephalus species described in the fossil record..

A new species of Cascogryllus and a new genus of Tridactylidae (pygmy mole crickets) are established based on two specimens from mid-Cretaceous Kachin amber. Amberotridactylus cheni gen. et sp. nov. is mainly characterized by nine-segmented antennae, absence of swimming plates (tibial lamellae) on serrated metatibia, metatarsus slightly longer than apical spurs, and absence of subapical denticular process on metatarsus. Amberotridactylus cheni gen. et sp. nov. is the first representative of the subfamily Tridactylinae from the Mesozoic and the oldest fossil record of this subfamily. Cascogryllus setosus sp. nov. is mainly identified by ten-segmented antennae, prosternum with a prosternal tubercle, curved ScA nearly ending on mid-length of ScP, R present, and almost identical length of paraproctal lobes and cerci. Our findings enrich the biodiversity of pygmy mole crickets in the Cretaceous.

Billoperla starki gen. et sp. nov., a new extinct stonefly genus and species is described based on a well-preserved male adult in mid-Cretaceous Burmese amber and assigned to the subfamily Acroneuriinae of Perlidae. Its sternum 9 with a triangular hammer, and its epiproct is large, well-developed and upcurved, being distinctive for both the extant and extinct Perlidae. The new fossil genus is diagnostic mainly by the RA vein almost reaching wing apex, tergum 10 unmodified, paraprocts reduced, hammer present, and by the large and apically modified epiproct.

GABAergic neurons in the rostromedial tegmental nucleus (RMTg) receive major input from the lateral habenula (LHb), which conveys negative reward and motivation related information, and project intensively to midbrain dopamine neurons, including those in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). The RMTg-VTA circuit has been shown to be linked to the affective behavior, but the role of the RMTg-SNc circuit in aversion and depression has not been well understood. This study demonstrated that exciting or inhibiting VgatRMTg-SNc neurons was sufficient to increase or decrease immobility time in the forced swim test (FST), respectively. Furthermore, exciting the VgatRMTg-SNc pathway caused aversive behavior. Ninety percent of the SNc putative dopamine neurons were inhibited in extracellular recordings. Furthermore, inhibiting the VgatRMTg-SNc pathway reversed behavioral despair in chronic restraint stress (CRS) depression model mice. Manipulations of the pathway did not affect the hedonic value of the reward in the sucrose-preference test (SPT) or general motor function. In conclusion, these results indicate that the VgatRMTg-SNc pathway regulates aversive and despair behavior, which suggests that the RMTg may mediate the role of LHb in negative behaviors through regulating the activity of SNc neurons.

A new genus and species of the enigmatic beetle-like family Umenocoleidae, Enervipraeala nigra gen. et sp. nov., is described based on a well-preserved specimen from mid-Cretaceous Kachin (Myanmar) amber. The new genus mainly differs from the other genera in the ratio of the width of the head and pronotum, the square-shaped pronotum, the subrectangular dark pattern of the forewing, and few branches of radial veins on the hindwing. The internal taxonomy of Umenocoleidae is briefly discussed. Vitisma Vrsanský, 1999 and Permoponopterix Nel, Prokop et Kirejtshuk, 2014 are excluded from Umenocoleoidea, and Antophiloblatta Sendi, 2020, Jantaropterix Vrsanský et Grimaldi, 2003, Lepidopterix Sendi, 2020 and Perspicuus Koubova, 2020 are transferred from Umenocoleidae to Cratovitismidae. Alienopterix Mlynský, Vrsanský et Wang, 2018 and Vzrkadlenie Vrsanský, 2020 are transferred from Alienopteridae to Cratovitismidae.

A new genus and species, Birmaninemobius hirsutus gen. et sp. nov., is described on the basis of a well-preserved orthopteran specimen in mid-Cretaceous Burmese amber and attributed to the subfamily Nemobiinae (ground crickets) of the family Trigonidiidae (Grylloidea). As the first record of Nemobiinae from mid-Cretaceous Burmese amber, this new taxon not only provides novel morphological diversity in ground crickets but also indicates that the ground crickets lived in Burma (Tethyan islands) as early as the mid-Cretaceous.

A new genus and species, Liutiaogoucuna arachnoidea gen. et sp. nov., is established based on a stick insect with almost complete four wings preserved in the Lower Cretaceous Yixian Formation of Inner Mongolia, northeastern China, and assigned to the subfamily Susumaniinae of Susumaniidae (Phasmatodea). The discovery of the new taxon provides novel morphological diversity of Susumaniinae, both in forewing and hindwing venation. The high diversity of stick insects with four wings developed in the Early Cretaceous Jehol Biota indicates that even lack of advanced camouflage, this kind of Phasmatodea had good adaptability in the Early Cretaceous Jehol ecosystem.

A new fossil stonefly, Borisoperla kondratieffi gen. et sp. nov., is described and illustrated based on a well-preserved male insect from mid-Cretaceous Burmese amber. The new taxon exhibits typical external characters of Peltoperlidae. Zwickoperla Chen and Wang, 2020 comb. nov. is transferred from Perlidae to Peltoperlidae. A new fossil subfamily of Peltoperlidae, Borisoperlinae subfam. nov. is established for Borisoperla gen. nov. and Zwickoperla. This study represents the first fossil record of Peltoperlidae.

A new species of stick insect, Cretophasmomima traceyae sp. nov., is proposed based on a forewing preserved in the Lower Cretaceous Weald Clay Formation (Wealden Group) of Surrey, southern England, and attributed to the genus Cretophasmomima Kuzmina, 1985 of the subfamily Susumaniinae (order Phasmatodea: superfamily Susumanioidea). As the first record of the Susumaniioidea from the English Wealden, this new species establishes the presence of Susumaniioidea in northwest Europe during the Early Cretaceous and extends the global distribution of susumanioids (stem-group stick insects) to the Cretaceous of Europe.

A new mole cricket, Tresdigitus rectanguli gen. et sp. nov., is described based on a well-preserved specimen from mid-Cretaceous Burmese amber. It can be definitely attributed to the family Gryllotalpidae (mole cricket), but cannot be incorporated into any existing subfamily of Gryllotalpidae because of the unusual combination of its characteristics. This new find is not only the second record of Gryllotalpidae from mid-Cretaceous Burmese amber, but also provides novel morphological diversity in Gryllotalpidae, showing original characteristics of body structures especially protibial dactyls.

The first mud cricket, Archaicaripipteryx rotunda gen. et sp. nov., is described based on a well-preserved specimen from mid-Cretaceous Burmese amber. It can be definitely assigned to Ripipterygidae based on its uninflated mesotibiae, unsegmented cerci and each ventral valve with a powerful side tooth. However, the morphology of this new mud cricket shows distinguishing characteristics including interocular distance at least the width of the compound eyes, metatarsus at least twice the length of the metatibial spurs, and distinctive subapical denticular process on the metatarsus, providing novel morphological diversity of the Ripipterygidae. Archaicaripipteryx rotunda gen. et sp. nov. is not only the first record of the Ripipterygidae from mid-Cretaceous Burmese amber, but also the oldest fossil record of Ripipterygidae, extending the geological range of this family by approximately 80 million years.

A new genus and species, Magnidactylus robustus gen. et sp. nov., is described on the basis of a well-preserved orthopteran insect from mid-Cretaceous Burmese amber and attributed to the subfamily Dentridactylinae of the family Tridactylidae (Orthoptera: Tridactyloidea). This new taxon not only provides novel morphological diversity in Tridactylidae (pygmy mole crickets), but also represents the largest one of all the tridactylids reported from mid-Cretaceous Burmese amber. The pygmy mole crickets of mid-Cretaceous Burmese amber had no swimming plates, suggesting that their habitat was less related to freshwater than the extant ones.

A new fossil long-horned grasshopper together with a simple leg of Orthoptera were collected from the third member of the Sinuiju Formation from Paekto-dong, Sinuiju City, North Pyongan Province, Democratic People's Republic of Korea (DPRK). A new genus and species, Sinuijuboilus baektoensis gen. et sp. nov., is assigned to the family Prophalangopsidae. The new find not only broadens the distribution of the family Prophalangopsidae but also increases its diversity. This is the first fossil Orthoptera to be formally described from the Mesozoic of DPRK.

The habenula is a nuclear complex composed of the lateral habenula (LHb) and medial habenula (MHb), two distinct structures. Much progress has been made to emphasize the role of the LHb in the pathogenesis of depression. In contrast, relatively less research has focused on the MHb. However, in recent years, the role of the MHb has begun to gain increasing attention. The MHb connects to the interpeduncular nucleus (IPN) both morphologically and functionally. The MHb-IPN pathway plays an important role in regulating higher brain functions, including cognition, reward, and decision making. It indicates a role of the MHb in the pathogenesis of depression. Thus, we investigated the role of the MHb-IPN pathway in depression. MHb metabolic activity was increased in the chronic unpredictable mild stress (CUMS)-exposed rat model of depression. MHb lesions in the CUMS-exposed rats reversed anhedonia-like behavior, as observed in the sucrose preference test, and significantly downregulated the elevated metabolic activity of the IPN. Substance P (SP)-containing neurons of the MHb were found to innervate the IPN and to be the main source of SP in the IPN. SP content of IPN tissue of the CUMS-exposed rats was increased and MHb lesions reversed this change. In the in vitro experiment, firing rate recordings showed that SP perfusion increased the activity of IPN neurons. Our results suggest that hyperactivity of the MHb-IPN circuit is involved in the anhedonia-like behavior of depression, and that SP mediates the effect of the MHb on IPN neurons.