Due to ongoing changes and a decline in biodiversity, science today should rely on long-term species-based ecological studies. We have conducted a long-term ecological dynamics study on the water beetle family Scirtidae, which, although it is very abundant in benthic communities, is still poorly studied. The main objective of this study was to investigate the population aspects (composition, diversity, sex ratio) and ecological aspects (emergence patterns, seasonal dynamics and preferences for environmental factors) of the family Scirtidae over 15 years in Plitvice Lakes NP, Croatia. The study was conducted at three sites and in five different substrate types. A total of three taxa with different distributions were recorded in the study area: Hydrocyphon novaki and H. deflexicollis on the tufa barriers and the Elodes sp. in the spring area. The sex ratio was in favour of males in spring and early summer, while it shifted in favour of females towards the end of autumn. The abundance and emergence of the family were primarily determined by the environmental parameters which showed the greatest fluctuations over a period of 15 years: water temperature, water discharge and oxygen saturation. Our results clearly show that Scirtidae can be used as indicators of stream zonation and habitat quality. Based on the methodology and the results of this study, we conclude that Scirtidae should be used in future monitoring and protection measures in karst freshwater habitats in southeastern Europe.

Here we focus on designing, for the first time, microsatellite markers for evolutionary and ecological research on aquatic beetles from the genus Ochthebius (Coleoptera, Hydraenidae). Some of these non-model species, with high cryptic diversity, exclusively inhabit supratidal rockpools, extreme and highly dynamic habitats with important anthropogenic threats. We analysed 15 individuals of four species (O. lejolisii, O. subinteger, O. celatus, and O. quadricollis) across 10 localities from the Mediterranean coasts of Spain and Malta. Using next-generation sequencing technology, two libraries were constructed to interpret the species of the two subgenera present consistently (Ochthebius s. str., O. quadricollis; and Cobalius, the rest of the species). Finally, 20 markers (10 for each subgenus) were obtained and successfully tested by cross-validation in the four species under study. As a by-catch, we could retrieve the complete mitochondrial genomes of O. lejolisii, O. quadricollis, and O. subinteger. Interestingly, the mitochondrial genome of O. quadricollis exhibited high genetic variability compared to already published data. The novel SSR panels and mitochondrial genomes for Ochthebius will be valuable in future research on species identification, diversity, genetic structure, and population connectivity in highly dynamic and threatened habitats such as supratidal coastal rockpools.

The use of wild animals in customary rituals and as a sustenance resource is a longstanding tradition within sub-Saharan Africa. The emergence of commercial trade, has, however, created unattainable demands and has led to the overexploitation of animals. These demands are threatening the conservation of animal species exploited in this trade. Comparatively little research effort has been dedicated to invertebrate species, and, specifically, their non-commercial uses. We explored the uses of water beetles in traditional rituals. We investigate the extent to which each of the non-commercial uses of water beetles exhibits consumptive and non-consumptive use features. The concepts are contested as their application for describing human-animal interactions has been challenged because of insufficient physiological and conservation data on the implications for animals of such interactions. The inadequacy of the available data pertaining to the use of animal resources was particularly pronounced. Most research efforts are skewed towards vertebrates at the expense of invertebrates. Regardless, the study shows that most non-commercial exploitation and uses of water beetles were mainly non-destructive and, if consumptive, the uses could be described as mainly non-lethal consumptive or sub-lethal consumptive. Rituals that could be described as lethal-consumptive comprised a smaller fraction of the uses of water beetles.

Detailed information about the known species groups of Exocelina Broun, 1886 from New Guinea is presented, including species numbers, distribution, and references of species-group diagnoses, keys to the species, and species descriptions. An identification key to all species groups is provided. Phylogeny and morphological character evolution are discussed.

The essential key to routine molecular species identification (DNA barcoding/metabarcoding) is the existence of an error-free DNA barcode reference library providing full coverage of all species. Published studies generally state the need to produce more barcodes, and control their quality, but unfortunately, the number of barcoded species is still low. However, to initiate real progress, we need to know where the gaps lie, how big they are and why they persist. Our aims were to draw and understand the current state of knowledge regarding species diversity, distribution, and barcode coverage, and offer solutions for improvement. In this study, we used two groups of aquatic insects, beetles and true bugs. We have compiled and critically evaluated an essentially complete and up-to-date European list, containing 1527 species. The list served as a basis for the barcode gap analyses in the Barcode-of-Life-Data-System (BOLD) conducted in three subsequent years (2020-2022). The overall barcode coverage of the pan-European fauna was around 50 % in both groups. The lowest coverage was in the Mediterranean, the Balkans and South-eastern Europe. The coverage in each country depended significantly on the local diversity, the number of rare, endemic species and the similarity of its fauna to that of the most active barcoding European countries. Gap analyses showed a very small increase in species coverage (<1 % in European aquatic beetles) despite an ~25 % increase in the number of barcodes. Hence, it is clear that future barcoding campaigns must prioritise quality over quantity. To visibly improve reference libraries, we need to increase the involvement of taxonomic experts and focus on targeted studies and underexplored but biodiversity-rich areas.

Patch size is one of the most important factors affecting the distribution and abundance of species, and recent research has shown that patch size is an important niche dimension affecting community structure in aquatic insects. Building on this result, we examined the impact of patch size in conjunction with presence of larval anurans on colonization by aquatic insects. Hyla chrysoscelis (Cope\'s gray treefrog) larvae are abundant and early colonists in fishless lentic habitats, and these larvae can fill multiple ecological roles. By establishing larvae in mesocosms prior to colonization, we were able to assess whether H. chrysoscelis larvae have priority effects on aquatic insect assemblages. We conducted a series of three experiments in naturally colonized experimental landscapes to test whether (1) H. chrysoscelis larval density affects insect colonization, (2) variation in patch size affects insect colonization, and (3) the presence and larval density of H. chrysoscelis shift colonization of insects between patches of different size. Larval density independently had almost no effect on colonization, while patch size had species-specific effects consistent with prior work. When larvae and patch size were tested in conjunction, patch size had numerous, often strong, species-specific effects on colonization; larval density had effects largely limited to the assemblages of colonizing beetles and water bugs, with few effects on individual species. Higher larval densities in large mesocosms shifted some insect colonization to smaller patches, resulting in higher beta diversity among small patches in proximity to high density large mesocosms. This indicates establishing H. chrysoscelis larvae prior to insect colonization can likely create priority effects that slightly shape insect communities. Our results support the importance of patch size in studying species abundances and distributions and also indicate that colonization order plays an important role in determining the communities found within habitat patches.

The water scavenger beetle genus Tobochares Short & García, 2007 currently contains ten species, including one known but formally undescribed taxon. Although Tobochares was revised in 2017, ongoing fieldwork as well as an expanded concept of the genus has led to the recognition of numerous additional species. Here a combination of morphological and molecular data is presented to review this newly found Tobochares diversity. Fifteen new species are described from South America, bringing the total number of known species to 25: Tobochares akoerio sp. nov. (Suriname), T. arawak sp. nov. (Guyana), T. anthonyae sp. nov. (Venezuela: Bolívar), T. atures sp. nov., (Venezuela: Amazonas), T. benettii sp. nov. (Brazil: Amazonas), T. canaima sp. nov. (Venezuela: Bolívar), T. communis sp. nov. (Brazil: Amapá and Roraima, Guyana, Suriname, Venezuela: Bolívar), T. fusus sp. nov. (Brazil: Amapá, French Guiana), T. goias sp. nov. (Brazil: Goiás), T. kappel sp. nov. (Suriname), T. kolokoe sp. nov. (Suriname), T. luteomargo sp. nov. (Venezuela: Bolívar), T. microps sp. nov. (Suriname), T. pemon sp. nov. (Venezuela: Bolívar), and T. romanoae sp. nov. (Brazil: Roraima). Both morphological and molecular analyses support four clades within the genus, which are here diagnosed and described as species groups. New distributional records are provided for T. kusad Kohlenberg & Short, 2017 and T. sipaliwini Short & Kadosoe, 2011, both of which are recorded from Brazil for the first time. Previously restricted to the Guiana Shield region of South America, the distributional range of the genus is now broadly expanded to include localities as far south as the central Brazilian state of Goiás. Consistent with the biology of the previously described species, almost all the new species described here are associated with seepage and wet rock habitats. Remarkably, one species, T. fusus sp. nov., was collected in both seepage habitats as well as in the rotting fruits of Clusia Linnaeus (Clusiaceae), making it one of the few known acidocerines with terrestrial habits outside of the genus Quadriops Hansen, 1999. High-resolution images of most species are included, as well as a key to species groups, species, and habitat photographs.
ResumenEl género de escarabajos acuáticos detritívoros Tobochares Short & García, 2007 actualmente contiene 10 especies, incluyendo un taxón conocido, pero no descrito. Aunque el género fue revisado en 2017, trabajo de campo en curso, así como un concepto ampliado del género han llevado al reconocimiento de numerosas especies adicionales. Aquí presentamos una combinación de datos morfológicos y moleculares para revisar esta diversidad de Tobochares recientemente encontrada. Quince especies nuevas son descritas de Suramérica, elevando el número total de especies conocidas a 25: Tobochares akoerio sp. nov. (Surinam), T. arawak sp. nov. (Guyana), T. anthonyae sp. nov. (Venezuela: Bolívar), T. atures sp. nov., (Venezuela: Amazonas), T. benettii sp. nov. (Brasil: Amazonas), T. canaima sp. nov. (Venezuela: Bolívar), T. communis sp. nov. (Brasil: Amapá y Roraima, Guyana, Surinam, Venezuela: Bolívar), T. fusus sp. nov. (Brasil: Amapá, Guyana Francesa), T. goias sp. nov. (Brasil: Goiás), T. kappel sp. nov. (Surinam), T. kolokoe sp. nov. (Surinam), T. luteomargo sp. nov. (Venezuela: Bolívar), T. microps sp. nov. (Surinam), T. pemon sp. nov. (Venezuela: Bolívar), y T. romanoae sp. nov. (Brasil: Roraima). También encontramos soporte morfológico y molecular para cuatro clados dentro del género, los cuales son aquí diagnosticados y descritos como grupos de especies. Nuevos registros de distribución son provistos para T. kusad Kohlenberg & Short, 2017 y T. sipaliwini Short & Kadosoe, 2011, ambos registrados para Brasil por primera vez. Previamente restringido a la región del Escudo Guyanés de Suramérica, el rango de distribución del género es ahora ampliamente expandido para incluir localidades tan al sur como el estado de Goiás en el centro de Brasil. Consistentes con la biología de las especies previamente conocidas, casi todas las especies descritas aquí están asociadas con hábitats higropétricos o áreas de drenaje sobre rocas. Notablemente, una especie, T. fusus sp. nov., fue colectada tanto en hábitats higropétricos como en frutos en descomposición de Clusia Linneo (Clusiaceae), constituyéndose en uno de los pocos acidocerinos conocidos con hábitos terrestres fuera del género Quadriops Hansen, 1999. Se incluyen imágenes de alta resolución de la mayoría de las especies incluidas, una clave para los grupos de especies y las especies, así como fotografías de los hábitats.

Abiotic conditions are important considerations in the species sorting process, which ultimately determines the distribution and abundance of species. Freshwater ecosystems will be impacted by ongoing temperature rise and other anthropogenically induced changes, such as nutrient enrichment and eutrophication. Changing characteristics of freshwater habitats will likely impact organisms in numerous ways, including through effects on colonization dynamics. Species are expected to colonize habitat patches where fitness will be the highest for themselves and their offspring, and how habitat selection interacts with changing environments remains an important question. We conducted a warming experiment to test the habitat selection preferences of aquatic beetles and hemipterans between habitat patches (mesocosms) of varying temperatures (via heaters), nutrient addition, and their interaction. Overall, insect abundance and richness were higher in unheated patches, with taxon-specific variation in response to heating. Although nutrients had limited effects on environmental conditions in mesocosms, their addition had no significant effects on insects. Insect assemblages had unique structures across heating treatments, with lower beta diversity and higher effective numbers of species in the warmest mesocosms. Our data support the importance of spatial variation in abiotic factors during the habitat selection process, and in determining species distributions and abundances as shallow lentic ecosystems are impacted by rising global temperatures.

Artificial ponds are increasingly created for the services they provide to humans. While they have the potential to offer habitats for freshwater biodiversity, their contribution to regional diversity has hardly been quantified. In this study, we assess the relative contribution of five types of artificial ponds to regional biodiversity of five different regions, studying amphibians, water beetles and freshwater snails. This biodiversity is also compared with that observed in natural ponds from three of the investigated regions. Our results indicate that artificial ponds host, on average, about 50% of the regional pool of lentic species. When compared to natural ponds, the artificial ponds always supported a substantially lower alpha richness (54% of the natural pond richness). The invertebrate communities presented high values of beta diversity and were represented by a restricted set of widely distributed species, and by numerous rare species. There were discrepancies among the taxonomic groups: overall, amphibians benefited most from the presence of artificial ponds, since 65% of the regional lentic species pools for this group was found in artificial ponds, whereas 43% and 42% was observed in the case of beetles and snails, respectively. However, each invertebrate group was promptly the most benefited animal group in a single pond type. Therefore, artificial pond types were complementary among them in terms of contribution to regional diversity of the three animal groups. Based on these results, we forecast that future human-dominated landscapes in which most ponds are artificial will be particularly impoverished in terms of freshwater biodiversity, underlining the need to conserve existing natural ponds and to create new \"near-natural\" ponds. However, if properly designed and managed, artificial ponds could make a substantial contribution to support freshwater biodiversity at a regional scale. Furthermore, the number and diversity of artificial ponds must be high in each considered landscape.

Specialization to extreme environments is often considered an evolutionary dead-end, leading to irreversible adaptations and reduced evolvability. There is, however, mixed evidence for this macroevolutionary pattern, and limited data from speciose lineages. Here, we tested the effect of habitat specialization to hypersaline waters in the diversification rates of aquatic beetles of the genus Ochthebius (Coleoptera, Hydraenidae), using a molecular phylogeny with more than 50% of the 546 recognized species, including representatives of all but one of the nine recognized subgenera and 17 species groups. Phylogenies were built combining mitochondrial and nuclear genes, with the addition of 42 mitochondrial genomes. Using Bayesian methods of character reconstruction, we show that hypersaline tolerance is an irreversible ecological specialization that arose multiple times. Two lineages of Ochthebius experienced a significant increase in diversification rates, one of them inhabiting hypersaline waters, but there was no overall correlation with habitat or any significant decrease in diversification rates despite the irreversibility of hypersaline tolerance. Our study tested for the first time the impact of hypersaline habitat specialization on diversification rates, finding no support for it to be an evolutionary dead-end. On the contrary, multiple and ancient lineages fully adapted to these extreme osmotic conditions have persisted and diversified over a long evolutionary timescale.