Filling knowledge gaps in insect conservation by leveraging genetic data from public archives

Insect decline has become a growing concern in recent years, with studies showing alarming declines in populations of several taxa. Our knowledge about genetic spatial patterns and evolutionary history of insects still exhibits significant gaps hindering our ability to effectively conserve and manage insect populations and species. Genetic data may provide valuable insights into the diversity and the evolutionary relationships of insects' species and populations. Public repositories, such as GenBank and BOLD, containing vast archives of genetic data with associated metadata, offer an irreplaceable resource for researchers contributing to our understanding of species diversity, population structure and evolutionary relationships. However, there are some issues in using these data, as they are often scattered and may lack accuracy due to inconsistent sampling protocols and incomplete information. In this paper we describe a curated georeferenced database of genetic data collected in GenBank and BOLD, for insects listed in the International Union for Conservation of Nature (IUCN) Italian Red Lists (dragonflies, bees, saproxylic beetles and butterflies). After querying these repositories, we performed quality control and data standardization steps. We created a dataset containing approximately 33 000 mitochondrial sequences and associated metadata about taxonomy, collection localities, geographic coordinates and IUCN Red List status for 1466 species across the four insect lists. We describe the current state of geographical metadata in queried repositories for species listed under different conservation status in the Italian Red Lists to quantify data gaps posing barriers to prioritization of conservation actions. Our curated dataset is available for data repurposing and analysis, enabling researchers to conduct comparative studies. We emphasize the importance of filling knowledge gaps in insect diversity and distribution and highlight the potential of this dataset for promoting other research fields like phylogeography, macrogenetics and conservation strategies. Our database can be downloaded through the Zenodo repository in SQL format.Database URL: https://zenodo.org/records/837518

Diet and foraging ecology of the Hoopoe Upupa epops in a Mediterranean area of Central Italy

During the breeding season, the Hoopoe Upupa epops inhabits traditional and diversified rural habi- tats with high availability of bare ground and short grass areas where it forages. Only a few studies addressed the breeding diet of this species. Most of them were conducted in the intensively cultivated plains of southern Switzerland, where Gryllotalpa gryllotalpa represents the most common prey. In contrast, limited information is available for Mediterranean habitats. To fill this knowledge gap, we investigated the foraging behaviour of the species in a Mediterranean heterogeneous agricultural area in Central Italy during the 2020-2021 breeding seasons. 1123 prey items brought to the nest by adults were identified using camera traps positioned near four natural nests. Insect larvae constitute 84% of the diet, of which 61% are represented by Cicada orni nymphs. The importance of cicadas in the Hoopoe diet has been never described in the literature before. C. orni seems to substitute G. gryllotalpa in the more arid and hard soil of Mediterranean areas. The observed provisioning rate to clutches showed a maximum daily mean of over 14 prey per hour. To investigate Hoopoe foraging micro- habitat selection, six different microhabitat variables were measured at 64 1 m2 plots located at an equal num- ber of foraging and random control points, by using a grid of 100 squares (10x10 cm each). Habitat selection analysis indicates that short herbaceous sward and low herbaceous cover are the fundamental factors driving foraging microhabitat selection. Our study contributed to enhancing the limited knowledge of the Hoopoe diet and foraging ecology in Mediterranean habitats and demonstrates, for the first time, the importance of Cicada orni nymphs in the diet of the species in this biogeographical region

Genetic and morphological studies of Trichosirocalus species introduced to North America, Australia and New Zealand for the biological control of thistles

Trichosirocalus horridus sensu lato has been used as a biological control agent of several invasive thistles (Carduus spp., Cirsium spp. and Onopordum spp.) since 1974. It has been recognized as a single species until 2002, when it was split into three species based on morphological characters: T. horridus, Trichosirocalus briesei and Trichosirocalus mortadelo, each purported to have different host plants. Because of this taxonomic change, uncertainty exists as to which species were released in various countries; furthermore, there appears to be some exceptions to the purported host plants of some of these species. To resolve these questions, we conducted an integrative taxonomic study of the T. horridus species complex using molecular genetic and morphological analyses of specimens from three continents. Both mitochondrial cytochrome c oxidase subunit I and nuclear elongation factor 1α markers clearly indicate that there are only two distinct species, T. horridus and T. briesei. Molecular evidence, morphological analysis and host plant associations support the synonymy of T. horridus (Panzer, 1801) and T. mortadelo Alonso-Zarazaga & Sánchez-Ruiz, 2002. We determine that T. horridus has been established in Canada, USA, New Zealand and Australia and that T. briesei is established in Australia. The former species was collected from Carduus, Cirsium and Onopordum spp. in the field, whereas the latter appears to be specific to Onopordum

Systematic study of the genus Rossimyiops Mesnil (Diptera: Tachinidae)

The systematic position and generic limits of Rossimyiops Mesnil, 1953 (type species: R. whiteheadi Mesnil, 1953) are critically redefined. Examination of the male terminalia allowed us to demonstrate the unjustified placement of Rossimyiops within the subfamily Dexiinae, tribe Dufouriini and its probable affiliation with the subfamily Tachininae, tribe Minthoini. The following generic names are synonymised with Rossimyiops Mesnil, 1953: Mesnilomyia Kugler, 1972 (type species: M. magnifica Kugler, 1972) syn. nov., and Persedea Richter, 2001 (type species: P. exquisita Richter, 2001) syn. nov. The following new combinations are proposed: Rossimyiops achilleae (Kugler, 1972) comb. nov., R. exquisitus (Richter, 2001) comb. nov., R. longicornis (Kugler, 1972) comb. nov., R. magnificus (Kugler, 1972) comb. nov., and R. subapertus (Herting, 1983) comb. nov. Mesnilomyia rufipes Zeegers, 2007 is established as a synonym of Persedea exquisita Richter, 2001, syn. nov. Rossimyiops austrinus Cerretti sp. nov. from Namibia and Rossimyiops djerbaensis Cerretti sp. nov. from Tunisia are described, illustrated and compared with the other known species of the genus. Male terminalia and female external morphology of R. subapertus and R. whiteheadi are described for the first time. Finally, Mesnilomyia calyptrata Zeegers, 2007 is removed from this genus and placed as Tachinidae incertae sedis

Paternity analyses for the planning of SIT projects against the red palm weevil

The red palm weevil Rhynchophorus ferrugineus is an invasive pest from southeastern Asia and Melanesia that has spread widely across the Middle East and the Mediterranean Basin over the last 30 years. Its endophagous larvae cause huge amounts of damage to several palm tree species from the Arecaceae family. Many of these palms are economically important for agricultural and ornamental purposes. Therefore, a lot of attention has recently been focused on studying this species with the aim of identifying sustainable and effective eradication strategies. Sterile insect techniques are biological control strategies that are currently being investigated for their potential to eradicate this pest in selected invasion areas. Mating system features (e.g., polyandry and related features) can affect the success and suitability of these approaches. The main goal of this research was to assess the performance of a previously developed microsatellite panel in terms of the paternity assignment of progeny from laboratory mating experiments. Using a simulation approach, we evaluated the reliability of the microsatellite markers in the paternity tests both in complex laboratory experiment scenarios and on the progeny of wild-caught gravid females to help future studies on the RPW mating system. As a case study of the simulation results, we performed two double-mating experiments, genotyped the progeny and estimated the P2 values to compare to the expected progeny genotypes according to the crossing scheme of each experiment. The results of our simulations on laboratory experiments showed that it was possible to carry out paternity assignments for all progeny with reliable statistical confidence using our 13 microsatellites set. On the contrary the low genetic variability measured in red palm weevil populations in invaded areas made the resolution power of our loci too low to carry out paternity analyses on natural populations. Results of laboratory crossing were completely congruent with the expectations from the Mendelian laws

Curation of a reference database of COI sequences for insect identification through DNA metabarcoding: COins

DNA metabarcoding is a widespread approach for the molecular identification of organisms. While the associated wet-lab and data processing procedures are well established and highly efficient, the reference databases for taxonomic assignment can be implemented to improve the accuracy of identifications. Insects are among the organisms for which DNA-based identification is most commonly used; yet, a DNA-metabarcoding reference database specifically curated for their species identification using software requiring local databases is lacking. Here, we present COins, a database of 5' region cytochrome c oxidase subunit I sequences (COI-5P) of insects that includes over 532 000 representative sequences of >106 000 species specifically formatted for the QIIME2 software platform. Through a combination of automated and manually curated steps, we developed this database starting from all COI sequences available in the Barcode of Life Data System for insects, focusing on sequences that comply with several standards, including a species-level identification. COins was validated on previously published DNA-metabarcoding sequences data (bulk samples from Malaise traps) and its efficiency compared with other publicly available reference databases (not specific for insects). COins can allow an increase of up to 30% of species-level identifications and thus can represent a valuable resource for the taxonomic assignment of insects' DNA-metabarcoding data, especially when species-level identification is needed https://doi.org/10.6084/m9.figshare.19130465.v1

Molecular biogeography of Mediterranean and southern African disjunctions as exemplified by pollen beetles of the Meligethes planiusculus species-group and related taxa (Coleoptera: Nitidulidae; Meligethinae)

We investigated the apparent disjunction expressed in two related assemblages of species of the genus Meligethes, i.e. M. fruticola and its allies in the Cape region of South Africa and the M. planiusculus group in the Mediterranean region. We also inferred possible dynamics in the radiation of the Meligethes planiusculus complex within Macaronesia utilizing morphological, molecular and bionomical data, exploring potential historical and palaeoecological scenarios regulated by a molecular clock dating system. We reconstructed phylogenetic relationships of the M. planiusculus complex and of related Mediterranean (M. tristis), tropical (M. scotti) and southern African (M. chevrolati, M. conformis, and M. fruticola) species, using COI mitochondrial gene sequences. Phylogenetic reconstructions support an unambiguous distinction of two major clades grouping European-Mediterranean M. canariensis, M. isoplexidis andM. planiusculus specimens in one clade and the South-African specimens related to M. fruticola in another. Molecular markers suggested that the European-Mediterranean taxon M. tristis is unambiguously more distantly related to the partly sympatric M. canariensis, M. isoplexidis and M. planiusculus, than to the geographically isolated Southern African taxon, M. fruticola. However, morphological data revealed that M. tristis is more closely related to M. planiusculus and its allies while occupying a position internal to the M. planiusculus species group, but external to the M. planiusculus complex. Results of divergence estimation analyses suggest a splitting between ancestors of the European-Mediterranean species of the M. planiusculus complex and that of the African species M. fruticola at ~21-23 MYA. Molecular results also demonstrated that the remaining Afrotropical species are more related to the M. planiusculus and M. fruticola complexes than to M. tristis. This evidence clearly indicates that the Holarctic M. planiusculus group represents a paraphyletic assemblage with heterochronic Afrotropical origin. The estimated times of divergence supports evidence from other researchers of an ‘Arid Corridor’, or of a ‘Central or Eastern High Africa Corridor’, which connected several times in the last twenty MY the European-Mediterranean and eastern/southern African areas, and facilitated species migration northwards and southwards. The dynamics of the Meligethes planiusculus complex radiation in Macaronesia apparently followed a contradictory biogeographical scenario than the sequence of events recently hypothesized for their host-plants (Echium, Boraginaceae)

UPDATING THE TAXONOMY AND DISTRIBUTION OF THE EUROPEAN OSMODERMA, AND STRATEGIES FOR THEIR CONSERVATION (COLEOPTERA, SCARABAEIDAE, CETONIINAE)

Results of a molecular analysis on the European hermit beetles (the Osmoderma eremita species-complex), recently published in a companion paper, are shortly dis- cussed and commented. These results indicate a clear-cut distinction between two clades. The first one includes the W-European O. eremita Scopoli, 1763, and the two Italian endemic taxa O. italicum Sparacio, 2000 and O. cristinae Sparacio, 1994, from southern peninsular Italy and Sicily, respectively. The second one includes the widespread E-European O. barnabita Motschulsky, 1845 (nom. resurr.), and the southern Balcanic O. lassallei Baraud & Tauzin, 1991 from Greece and European Turkey. Within the two clades, molecular data well support a specific rank for O. lassallei and O. barn­abita on one side, and of O. eremita and O. cristinae on the other side, while the taxonomic position of O. italicum, more closely related with O. eremita, is still uncertain, waiting for analysis of additional specimens of this very rare taxon. Current geographical distribution, interspecific genetic diversification, and relatively low levels of intraspecific genetic divergence in O. eremita sensu stricto, are hypothesized to be the result of multiple speciation events (mainly occurred in refugial forest areas of the Italian and Balkan peninsulas and Sicily before and during the Pleistocene glacial peaks), followed by fast post-glacial northward and westward expansion of some species. The need of further genetic data on the rare and threatened hermit beetle species and the importance of more detailed information on their distribution ranges are emphasized and discussed, in order to plan conservation strategies in the near future. An updated worldwide checklist of the species of the genus Osmoderma is finally presented

UPDATING THE TAXONOMY AND DISTRIBUTION OF THE EUROPEAN OSMODERMA, AND STRATEGIES FOR THEIR CONSERVATION (Coleoptera, Scarabaeidae, Cetoniinae)

Results of a molecular analysis on the European hermit beetles (the Osmoderma eremita species-complex), recently published in a companion paper, are shortly dis- cussed and commented. These results indicate a clear-cut distinction between two clades. The first one includes the W-European O. eremita Scopoli, 1763, and the two Italian endemic taxa O. italicum Sparacio, 2000 and O. cristinae Sparacio, 1994, from southern peninsular Italy and Sicily, respectively. The second one includes the widespread E-European O. barnabita Motschulsky, 1845 (nom. resurr.), and the southern Balcanic O. lassallei Baraud & Tauzin, 1991 from Greece and European Turkey. Within the two clades, molecular data well support a specific rank for O. lassallei and O. barn­abita on one side, and of O. eremita and O. cristinae on the other side, while the taxonomic position of O. italicum, more closely related with O. eremita, is still uncertain, waiting for analysis of additional specimens of this very rare taxon. Current geographical distribution, interspecific genetic diversification, and relatively low levels of intraspecific genetic divergence in O. eremita sensu stricto, are hypothesized to be the result of multiple speciation events (mainly occurred in refugial forest areas of the Italian and Balkan peninsulas and Sicily before and during the Pleistocene glacial peaks), followed by fast post-glacial northward and westward expansion of some species. The need of further genetic data on the rare and threatened hermit beetle species and the importance of more detailed information on their distribution ranges are emphasized and discussed, in order to plan conservation strategies in the near future. An updated worldwide checklist of the species of the genus Osmoderma is finally presented