Genetic legacies of mega-landslides: Cycles of isolation and contact across flank collapses in an oceanic island.

Catastrophic flank collapses are recognized as important drivers of insular biodiversity dynamics, through the disruption of species ranges and subsequent allopatric divergence. However, little empirical data supports this conjecture, with their evolutionary consequences remaining poorly understood. Using genome-wide data within a population genomics and phylogenomics framework, we evaluate how mega-landslides have impacted evolutionary and demographic history within a species complex of weevils (Curculionidae) within the Canary Island of Tenerife. We reveal a complex genomic landscape, within which individuals of single ancestry were sampled in areas characterized by long-term geological stability, relative to the timing of flank collapses. In contrast, individuals of admixed ancestry were almost exclusively sampled within the boundaries of flank collapses. Estimated divergence times among ancestral populations aligned with the timings of mega-landslide events. Our results provide first evidence for a cyclical dynamic of range fragmentation and secondary contact across flank collapse landscapes, with support for a model where this dynamic is mediated by Quaternary climate oscillations. The context within which we reveal climate and topography to interact cyclically through time to shape the geographic structure of genetic variation, together with related recent work, highlights the importance of topoclimatic phenomena as an agent of diversification within insular invertebrates.

A new species of Toxorhinus Lacordaire (Coleoptera: Curculionidae: Dryophthorinae; Rhynchophorini) from Ecuador.

Toxorhinus amarillo Anderson, new species (Coleoptera: Curculionidae: Dryophthorinae; Rhynchophorini), is here described from Ecuador (Cotopaxi, Biochoa Otonga). The species is compared to the other two species in the genus.

Two new species of Optatus Pascoe and Macroptatus Heller (Coleoptera, Curculionidae, Baridinae), with a reappraisal of generic characters.

Macroptatus deppens Prena new species is described from México and El Salvador. Optatus stockwelli Prena new species is described from Panamá. Optatus Pascoe, 1889 and Macroptatus Heller, 1906 are maintained as distinct genera based on the development of the prosternal process separating the procoxae. Other previously used characters on the rostrum, tarsus, and metaventrite grade together across species or are deemed species-specific. Species of these genera appear to be associated with Annona fruits.

Two new species of Metamasius Horn, 1873 (Coleoptera: Curculionidae: Dryophthorinae) from Ecuador and Colombia.

Two new species of South American Metamasius Horn (Coleoptera: Curculionidae: Dryophthorinae) are described: Metamasius onorei new species from Cotopaxi, Ecuador and Metamasius pilirostris new species from west of Río Yurumangui, Colombia. Diagnostic characters and images are provided for both new species to facilitate identification.

Saotomia tuberculata, a new genus and species of Peritelini (Coleoptera; Curculionidae; Entiminae) from São Tomé, West Africa.

Saotomia tuberculata, a new genus and species of Peritelini (Curculionidae; Entiminae) from São Tomé, West Africa is described. The new genus is most similar to the other African genera Dysommatus Marshal, 1933 and Fernandius Marshall, 1954. Important taxonomic characters are illustrated.

Acythopeus glyptorhis, a new gall-inducing weevil (Coleoptera, Curculionidae, Baridinae) damaging gac vines in Southeast Asia.

Acythopeus glyptorhis Prena, sp. n. is described from northern Vietnam, Taiwan and Hainan Island (China). Existing host records of other cucurbit-associated Baridinae are reviewed. They are native to the Old World and may include as many as 80 species.

Description of two new species of Rhamphus related to R. oxyacanthae (Curculionidae, Curculioninae, Rhamphini) from Italy based on a morphological study supported by molecular data.

Two new species of the weevil genus Rhamphus from Italy are herein described: R. bavierai n. sp. (Sicily) and R. hampsicora n. sp. (Sardinia). Both are morphologically and from a molecular perspective close to R. oxyacanthae (Marsham, 1802) and R. monzinii Pesarini Diotti, 2012. Aside from a diagnostic description and a synoptic key, distribution data and notes on the host plants of the four species are reported. Whereas R. monzinii can be distinguished by several morphological characters, the other three species are morphologically very similar to each other and separable only by the combination of a few subtle characters. On the contrary, a preliminary molecular study revealed substantial divergences of mtCOI from 6.2 to 14.9% between the species, confirming the importance of an integrative taxonomy.

Two new species of Metapocyrtus (Metapocyrtus) Heller 1912 from Mindanao, Philippines (Curculionidae, Entiminae, Pachyrhynchini).

Two new species of Curculionidae, Pachyrhynchini, Metapocyrtus waoensis sp. nov., and M. lanaoensis sp. nov., both from western Mindanao are described. Images of habitus and fully everted endophallus and illustrations of male genitalia are provided for each species.

First records of Xylosandrus compactus (Coleoptera: Curculionidae, Scolytinae) in the Iberian Peninsula: an expanding alien species?

Xylosandrus compactus (Eichhoff) (Col.: Curculionidae, Scolytinae) is an ambrosia beetle species native to subtropical Eastern Asia, with great concern due to its high invasive ability. This species has invaded 54 countries worldwide, including 4 European countries (Italy, France, Greece, and Spain); it was detected in Mallorca (Balearic Islands, Spain) in October 2019. In the present work, X. compactus is recorded for the first time in the Iberian Peninsula (Girona province, NE Spain); specimens were collected in Banyoles (August 2020, attacking twigs of Laurus nobilis and Liquidambar styraciflua) and Platja d'Aro (October 2020, attacking twigs of L. nobilis). Up-to-date information is presented about its geographical distribution, host plants, biology, symptoms, associate damages, and the possible origin of this species in Europe.

Revision of Dendrochilus (Coleoptera, Scolytinae)-with description of two new species from Tanzania.

The genus Dendrochilus Schedl, 1963 is revised. Two new species are described from the Udzungwa Mountains in Tanzania. Dendrochilus tener sp. nov., and D. udzungwae sp. nov. are closely related with few morphological differences but are clearly separated by molecular data from four gene fragments. Together with the type species D. strombosiopsis Schedl, 1957 from Congo, the genus now includes three species. An identification key to species is provided.

Late Miocene eastwards transatlantic dispersal of flightless anchonine weevils (Coleoptera: Curculionidae: Molytinae).

The weevil genera Aethiopacorep Voisin and Titilayo Cristóvão Lyal are the only native African members of the nearly pantropical and poorly known tribe Anchonini. All Anchonini are flightless, a trait likely limiting dispersal, yet these weevils are found on both sides of the Atlantic Ocean. A phylogenetic analysis of 79 terminals and 3248 aligned positions from one mitochondrial and two nuclear ribosomal fragments supports a clade of West African Anchonini nested within American Anchonini. As suggested by previous authors, the Asian genera Himalanchonus Zherikhin and Otibazo Morimoto do not form a clade with the tribe's core, and along with Cycloterinus Kolbe, Euthycodes Pascoe, Leptanchonus Morimoto, Nepalanchonus Zherikhin, and Tanyomus Champion, are here removed from Anchonini and placed as Molytinae incertae sedis. So defined, the monophyletic tribe Anchonini contains 36 genus-group names, all but two denoting American taxa. Using molecular clock analysis, we estimate the separation of the West African Anchonini from its American sister at 9.5-5.2 million years ago (Ma). This date greatly postdates the Cretaceous opening of the Atlantic Ocean (about 100 Ma) and, therefore, evokes a single transatlantic dispersal to West Africa, likely by over-water rafting, leading to subsequent diversification. We postulate this to be the first documented eastwards crossing of the Atlantic Ocean by terrestrial non-volant arthropods based on morphological and molecular data.

Patterns of host tree use within a lineage of saproxlic snout-less weevils (Coleoptera: Curculionidae: Scolytinae: Scolytini).

The influence of plants in the diversification of herbivorous insects, specifically those that utilize moribund and dead hosts, is little explored. Host shifts are expected because the effectiveness of toxic secondary chemicals is lessened by decay of dead plants. Feeding on dead plants also releases herbivorous insect lineages from diversifying within a particular plant lineage. Thus, phylogenetic constraints on the herbivorous insect lineage imposed by the host plants are diminished and repeated patterns of species diversification in an association with unrelated host trees is hypothesized (i.e., taxon cycle). Scolytini, a diverse weevil tribe, specialize on many different dead and moribund plant taxa as a source of food. These species and their hosts offer an opportunity to examine the association between dead host plants and the extent of phylogenetic constraints. A phylogeny of the Scolytini was reconstructed with likelihood and Bayesian analyses of DNA sequence data from nuclear (28S, CAD, ArgK) and mitochondrial (COI) genes. Ancestral host usage and geography was reconstructed using likelihood criteria and conservation of host use was tested. Results supported a monophyletic Scolytini, Ceratolepis, Loganius, and a paraphyletic Scolytus, Camptocerus and Cnemonyx. Diversification of the Scolytini generally occurred well after their host taxa diversified and suggests a sequential evolution of host use. In this scenario the beetle imposes little selection pressure on the tree but the tree provides a platform for beetle evolution. Major changes in host tree use occurred during periods of global cooling associated with changes in beetle biogeography. Diversification of beetles occurred on common and widespread hosts and there was likely a single origination of conifer-feeding from angiosperm-feeding species during the early Pliocene and a radiation of beetle species from the Palearctic to the Nearctic. Overall, the observed patterns of Scolytini host use are conserved and are similar to those expected in a taxon pulse diversification. That is, after a host switch to an unrelated tree, the beetles diversify within the host plant lineage. The need to locate an ephemeral food resource, i.e., a dying tree, likely maintains host specificity once a host shift occurs. These findings suggest that characteristics of dead and moribund host plants (e.g. secondary chemicals) influence the diversification of these saproxlic weevils despite the reduction of selection pressures.

Semiochemical-based Reproductive Isolation Among Sympatric Species of Trypodendron (Coleoptera: Curculionidae: Scolytinae).

Trypodendron retusum (LeConte) (Coleoptera: Curculionidae: Scolytinae) females excised from newly attacked trembling aspen, Populus tremuloides Michaux (Salicaceae), were shown for the first time to produce the aggregation pheromone (+)-lineatin. Coupled gas chromatographic-electroantennographic detection analysis (GC-EAD) disclosed that the antennae of T. retusum, as well as the antennae of three sympatric species, native T. lineatum (Olivier) and T. rufitarsus (Kirby) and exotic T. domesticum (L.), respond to synthetic (+)-lineatin, but not the (-) enantiomer. In contrast, the antennae of T. betulae Swaine responded to SR- and RR-linalool oxide pyranoid and did not detect lineatin. GC-EAD analysis of volatiles from host and nonhost tree species revealed that conifer-produced α-pinene and angiosperm-produced conophthorin and salicylaldehyde were perceived by the antennae of all three native lineatin-perceiving species, suggesting behavioral activity. Field trapping experiments showed that salicylaldehyde synergized the response of coastal, but not interior, T. retusum to lineatin and inhibited the response of T. lineatum and T. rufitarsus. In the absence of salicylaldehyde, α-pinene appeared to inhibit the response of interior T. retusum to lineatin, while for T. lineatum and T. rufitarsus it had an apparent positive additive or synergistic effect. No behavioral response occurred to conophthorin. The results provide evidence for semiochemical-based reproductive isolation between T. retusum and T. betulae, and between these two angiosperm-infesting species and the two conifer-infesting species. They do not explain how isolation could be maintained between T. lineatum and T. rufitarsus.

Contrasting Relationship of True Weevils (Curculionidae) and Woody Plants Diversity in Semi-arid Landscape Units.

In general, insect herbivore diversity is positively correlated to plant diversity since plant assemblages structure different microhabitats and provide food resources for such insects. Although poorly studied, insect herbivores in tropical dry forests are positively affected by tree species richness and the structural architecture of vegetation. In this study, we analyzed whether true weevil and woody plants present similar patterns of diversity across different landscape units in a Neotropical tropical dry forests located in Brazil, and if there is a correlation among their assemblages. We used Hill numbers according to species richness and the inverse of Simpson to compare the taxonomic diversity of true weevils and plants in nine landscape units located at the São Francisco river basin in the states of Sergipe and Alagoas, north-eastern Brazil. All trees and shrubs with diameter at breast height (1.3 m) ≥ 5 cm were sampled, and true weevils were collected using a modified Malaise trap. We used co-correspondence analysis to test if plants and true weevil species tend to co-occur. A total of 538 true weevils from 60 species was collected, and a total of 1419 plants belonging to 49 species was recorded. There is no general pattern of co-occurrence and diversity among true weevils and plants, indicating that the plant community is not structuring true weevil assemblage in the Caatinga. However, there was positive relationship between Sibinia sp4 and Fabaceae-Mimosoideae. These results suggest true weevil-plant relationships in the Caatinga differ from that of more mesic ecosystems. Therefore, we observed that the mechanisms that regulate herbivore-plant diversity relationships do not always follow a positive relationship, as observed in previous studies.

Semiochemicals for intraspecific communication of the fig weevil Aclees sp. cf. foveatus (Coleoptera: Curculionidae): a first survey.

The fig tree weevil Aclees sp. cf. foveatus (Coleoptera: Curculionidae), introduced in Italy in 2005, is currently causing significant economic and environmental losses to fig tree nurseries and orchards in Central Italy. Fig damages are due to the adults feeding on leaves and fruits, and to the galleries dug by the xylophagous larvae in the trunk, which lead the plants to death. To date, no chemical or biological control methods resulted to be effective against this invasive pest. In order to gain information about possible semiochemicals involved in mate recognition and choice, both the volatile organic compounds (VOCs) and the epicuticular lipids of male and female specimens were analysed. VOCs emissions of specimens were characterized essentially by monoterpenes, while epicuticular lipids contained long chained 2-ketones, alkanes, alkenes, including some methyl alkenes, and several fatty acid propyl esters. The attractiveness of reconstituted VOCs blends of the two sexes was tested in electrophysiological and behavioural assays in laboratory conditions. Both the male and the female reconstituted VOCs drove a significant response towards individuals of the opposite sex, thus demonstrating features of sexual attractants. Our results suggest a possible application of VOCs blends as pheromonic attractants in field monitoring and mass trapping of Aclees sp. cf. foveatus.

Rapid Molecular Identification of Scolytinae (Coleoptera: Curculionidae).

Routine identification of bark and ambrosia beetles is done using morphology. For people lacking the necessary taxonomic knowledge, proper identification of a novel specimen can be challenging and time consuming. This study compares the usefulness of four genetic markers (28S, EF-1a, ITS2, and COI) and five primer pairs (D2F1/D3R2, eflafor1/eflarev1, ets149/efa754, ITS2F/ITS2R, and LCO1490/HCO2198) to identify Scolytinae beetles, and outlines a molecular identification strategy, with results possible in two days. Markers COI and EF-1a were selected based on the ability of the respective primers to amplify DNA from multiple genera (Coptoborus, Xyleborus, Hypothenemus, Theoborus, and Araptus) and the ability of the resulting sequences to provide accurate and unambiguous matches in GenBank. BLASTn analysis of EF-1a sequences (both primer pairs) correctly identified four out of the five genera and COI sequences identified at least one sample of every genus tested and was the only primer pair to correctly identify Araptus specimens. Further, 28S sequences successfully identified Coptoborus, Xyleborus, and Theoborus but not Hypothenemus or Araptus. The low number of EF-1a (1), 28S (7), and ITS2 (0) sequences from Araptus individuals present in GenBank compared with COI (137) is likely the reason that only the latter marker was capable of identifying members of this genus. ITS2 sequences were insufficient to identify any of the samples tested. This study also determined the minimum quantity of DNA that could be used for molecular identification. Primers D2F1 and D3R2, which had the highest rate of amplification in all genera tested, could yield an informative sequence with as little as 0.00048 ng of DNA, however, at least 0.0024 ng was needed for reliable amplification.

Occurrence and Distribution of Rhinoncus sibiricus (Coleoptera: Curculionoidea) and Its Preference for Two Buckwheat Species in China.

Rhinoncus sibiricus Faust, a major pest of buckwheat, has invaded the buckwheat cultivation areas of China for years. This pest was first found in Russia in 1940, causing great damage during the entire buckwheat-growing season. In China, there are few records on R. sibiricus, and studies regarding pest damage on buckwheat are unknown. The occurrence and distribution of this species in China is still not clear. We therefore conducted field surveys for 6 yr to identify the distribution range and the degree of pest damage caused by R. sibiricus in the buckwheat-planting areas of China and tested its preference for two Fagopyrum species in common garden experiments. The results showed that R. sibiricus had a larger distribution range in the Northern rather than the Southern part of China, and that pest damage was more serious in northern China. The pest preferred F. tataricum (Tartary buckwheat, Polygonales: Polygonaceae) over F. esculentum (Common buckwheat, Polygonales: Polygonaceae), but caused damage to both, indicating its potential for distribution in southern China. This study clarified the occurrence, distribution, and damage traits of R. sibiricus in the buckwheat cultivation areas of China, which will help explain the pest attack traits and inform strategies for pest control and prediction.

Population Structure of Two Flightless Weevils of Genus Scepticus Roelofs (Coleoptera, Curculionidae) with Seashore Habitat in Japan.

To elucidate the genetic population structure of two coastal weevils, Scepticus griseus and S. tigrinus, we conducted molecular phylogenetic analyses of the mitochondrial DNA cytochrome c oxidase subunit I (COI) region (1308 bp) and cytochrome c oxidase subunit II (COII) region (584 bp). A total of 650 individuals (S. griseus, 444 individuals; S. tigrinus, 206 individuals) were obtained from 64 sites. The haplotype networks of both species showed three major lineages with roughly regional distribution. However, the two species show quite different genetic structures; S. griseus has a complicated structure while that of S. tigrinus is simple. We hypothesize that the genetic structure of each of these two weevil species reflects climatic oscillations during the Pleistocene, and the differences in genetic structure between S. griseus and S. tigrinus may represent a unique evolutionary history scenario in each species.

An Assessment of Old and New Characters Using Traditional and Geometric Morphometrics for the Identification of Dendroctonus approximatus and Dendroctonus parallelocollis (Curculionidae: Scolytinae).

There have been numerous changes in the nomenclature of species of Dendroctonus. The case of Dendroctonus parallelocollis Chapuis and Dendroctonus approximatus Dietz has been particularly noteworthy. These bark beetles colonize pine trees but are not aggressive species. The high morphological similarity, their overlapping geographical distribution, and the limited knowledge of these species have resulted in taxonomic confusion. The aim of the present study was to assess morphological characters reported in the literature and to scrutinize new characters that might be useful for the separation of these species. We evaluated 26 morphological attributes and performed geometric morphometrics analysis of the antenna, pronotum, spermatheca, and seminal rod to test if the variations in the shape of these structures allow the recognition of additional discrete characters to differentiate them. Our results show that five double-state characters of external morphology are useful to identify these species, and the shape of antenna, spermatheca, and seminal rod.

Game of clones: Is Wolbachia inducing speciation in a weevil with a mixed reproductive mode?

Parthenogenesis is widely distributed in Metazoa but it is especially frequent in weevils (Coleoptera, Curculionidae) with one fifth of all known cases. Previous studies have shown that in the tribe Naupactini parthenogenetic reproduction most likely originated with an infection of the endoparasitic bacterium Wolbachia pipientis. In particular, Pantomorus postfasciatus possess a mixed reproductive mode: some populations have males while in others they are absent, and females produce clones by thelytoky. To better understand this scenario, we studied the population structure and infection status in 64 individuals of P. postfasciatus from Argentina and Brazil. We sequenced two mitochondrial (COI and COII) and one nuclear (ITS-1) fragments and obtained two very divergent haplogroups, one corresponding to the sexual populations uninfected with Wolbachia, and another conforming a monophyletic parthenogenetic (or presumptively parthenogenetic) and infected clade. Each of these haplogroups was identified as an independently evolutionary unit by all species delimitation analyses accomplished: multilocus *BEAST and BP&P, and single locus GMYC and K/θ rule. Additionally, present evidence suggests that Wolbachia infection occurred at least twice in all-female populations of P. postfasciatus with two different bacterial strains. Speciation mediated by Wolbachia is a recently described phenomenon and the case of P. postfasciatus is the first known case in a diplo-diploid insect. A model that describes how thelytoky-inducing phenotypes of Wolbachia could generate new lineages is discussed.