The Emergence of the Family Scirtidae (Insecta: Coleoptera) in Lotic Karst Habitats: A Case Study over 15 Years.

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.

Long-Term Chironomid Emergence at a Karst Tufa Barrier in Plitvice Lakes National Park, Croatia.

Chironomids are found in all types of freshwater habitats; they are a ubiquitous and highly diverse group of aquatic insects. Plitvice Lakes National Park is the oldest and largest national park in Croatia and consists of numerous and diverse freshwater habitats, making the area an ideal location for long-term research into the chironomid emergence patterns and phenology. The main objectives of this study were to identify the composition of the chironomid community, determine the phenology of the identified species, and assess the main factors influencing their emergence in Plitvice Lakes. During 14 years of research, more than 13,000 chironomids belonging to more than 80 species were recorded. The most abundant species was found to be Parametriocnemus stylatus. The highest abundance of chironomids was recorded in lotic habitats with faster water current over substrates of moss and algae and pebbles. Water temperature and the availability of organic matter were found to be the main factors that drive chironomid emergence at the tufa barrier studied. In the last years of this study, a prolonged flight period was observed. Although this is not statistically significant (at this stage of the study), it could be due to a higher water temperature in winter.

New records for the Western Balkans cranefly fauna (Diptera, Tipuloidea) with the description of a new Baeoura Alexander (Diptera, Limoniidae).

The cranefly (Tipuloidea) fauna of the Western Balkans is still poorly known. In this study, occurrence data of 77 species is reported, of which two species are newly recorded for Albania, eight species for Bosnia and Herzegovina, twelve for Croatia, and seven for Slovenia, respectively. A new species, Baeouraneretvaensis Kolcsár & d'Oliveira, sp. nov. is described from Bosnia and Herzegovina, Montenegro, and Slovenia. Images of the habitus, wing, and male and female terminalia of the new species are provided. Furthermore, images of male terminalia and wings of thirteen additional species are presented.

Defining Patterns and Rates of Natural vs. Drought Driven Aquatic Community Variability Indicates the Ongoing Need for Long Term Ecological Research.

Most ecologists have used climate change, as an omnipresent pressure, to support their findings in researching the vulnerability of specific taxa, communities, or ecosystems. However, there is a widespread lack of long-term biological, biocoenological, or community data of periods longer than several years to ascertain patterns as to how climate change affects communities. Since the 1950s, southern Europe has faced an ongoing trend of drying and loss of precipitation. A 13-year research program in the Dinaric karst ecoregion of Croatia aimed to comprehensively track emergence patterns of freshwater insects (true flies: Diptera) in a pristine aquatic environment. Three sites, spring, upper, and lower tufa barriers (calcium carbonate barriers on a barrage lake system that act as natural damns), were sampled monthly over 154 months. This coincided with a severe drought event in 2011/2012. This was the most significant drought (very low precipitation rates for an extended period of time) in the Croatian Dinaric ecoregion since the start of detailed records in the early 20th century. Significant shifts in dipteran taxa occurrence were determined using indicator species analysis. Patterns of seasonal and yearly dynamics were presented as Euclidian distance metrics of similarity in true fly community composition compared at increasing time intervals, to ascertain the degree of temporal variability of similarity within the community of a specific site and to define patterns of similarity change over time. Analyses detected significant shifts in community structure linked to changes in discharge regimes, especially to the drought period.

Extreme freshwater discharge events exacerbated by climate change influence the structure and functional response of the chironomid community in a biodiversity hotspot.

Global climate change is expected to exacerbate extreme discharge events in freshwater ecosystems as a consequence of changes in precipitation volume and snow cover duration. Chironomid midges were used as a model organism in this study because of their small size and short life cycles, which enable fast colonization of new habitats and great resilience. This resilience is often expressed in easy recolonization after an extreme event. Chironomid samples together with physico-chemical water measurements were collected for 14 years, between 2007 and 2020, in a karst tufa barrier that is part of the Plitvice Lakes National Park in Croatia. More than 13,000 individuals belonging to >90 taxa were collected. Mean annual water temperature increased by 0.1 °C during this period. Multiple change-point analysis revealed three main periods by discharge patterns: the first one from January 2007 to June 2010, the second from July 2010 to March 2013, characterised by extreme low discharge, and the third from April 2013 to December 2020, characterised by an increase in extreme peak discharge values. Based on multilevel pattern analysis, indicator species of the first and the third discharge period were detected. The ecological preferences of these species indicate an environmental change related to the changes in discharge. Along with species composition, functional composition has changed with the abundance of passive filtrators, shredders and predators increasing over time. Species richness and abundance did not change over the period of observation, thus emphasizing the importance of species-level identification in detecting the earliest community response to change that would otherwise be overlooked.

The Century Old Taxonomic Confusion Surrounding Wiedemannia zetterstedti Fallén and Related Species Is Resolved (Diptera: Empididae): Revision of the W. zetterstedti Group.

The Wiedemannia zetterstedti species group is revised after examination of all available type specimens and includes one new species (W. ulrichi Ivkovic & Sinclair sp. nov.) and four redescribed species (W. czernyi (Bezzi), W. longipennis (Mik) stat. rev., W. rufipes (Oldenberg) stat. rev. and W. zetterstedti (Fallén)). The following new synonyms are proposed: W. (Roederella) ouedorum Vaillant, 1952 = W. czernyi (Bezzi, 1905); Paramesia riparia Robert, 1836 = W. zetterstedti (Fallén, 1826). Lectotypes are designated for the following species/subspecies: Atalanta hirtiloba Speiser, Brachystoma escheri Zetterstedt, Clinocera czernyi Bezzi, Clinocera longipennis Mik, Paramesia riparia Robert, and Roederia czernyi rufipes Oldenberg. In addition to morphological evidence, molecular species concepts were investigated using a molecular phylogenetic divergence-based species delimitation (bPTP) and results confirmed the morphological conclusions. A key to species is presented and geographic distributions are mapped.

New synonyms and new species of European aquatic dance flies (Diptera, Empididae).

Knowledge of the European aquatic dance flies (Clinocerinae, Hemerodromiinae) is updated. The following new synonyms are proposed: Chelifera pallida Vaillant, 1981 with Chelifera diversicauda Collin, 1927, syn. nov.; Chelifera giraudae Vaillant, 1981 and Chelifera berdeni Vaillant, 1978 (nomen nudum) with Chelifera subangusta Collin, 1961, syn. nov.; Hemerodromia slovenica Horvat & Wagner, 1989 with Hemerodromia laudatoria Collin, 1927, syn. nov.; Hemerodromia maculata Vaillant, 1968 with Hemerodromia unilineata Zetterstedt, 1842, syn. nov.; Wiedemannia aerea Vaillant, 1967 with Wiedemannia hastata (Mik, 1880), syn. nov.; Wiedemannia brevilamellata Wagner, 1985 with Wiedemannia debilis Collin, 1961, syn. nov.; Wiedemannia bilobata Oldenberg, 1910 with Wiedemannia oxystoma (Bezzi, 1905), syn. nov. Lectotypes are designated for Clinocera (Wiedemannia) oxystoma Bezzi, 1905, Wiedemannia aerea Vaillant, 1967, Wiedemannia bilobata Oldenberg, 1910, Philolutra erminea Mik, 1887, Wiedemannia hastata (Mik, 1880), Wiedemannia mirousei Vaillant, 1956 and Phaeobalia pokornyi Mik, 1886. A neotype is designated for Wiedemannia alpina Vaillant, 1953. Wiedemannia rudolfi Wagner & Ivkovic, sp. nov. and Phaeobalia remschakae Wagner sp. nov. are described and figures of male terminalia are provided.

High endemicity in aquatic dance flies of Corsica, France (Diptera, Empididae, Clinocerinae and Hemerodromiinae), with the description of a new species of Chelipoda.

All known records of aquatic dance flies (Empididae, Clinocerinae: 21 species; Hemerodromiinae: eight species) from the island of Corsica (France) are summarized, including previously unpublished data and data on the newly described species Chelipoda puschae Ivkovic, Perovic & Grootaert, sp. nov. This species was collected during the "La Planète Revisitée Corsica 2019" survey and represents the first description of a new species in the genus Chelipoda from the European-Mediterranean region in more than 180 years. A key to European species of Chelipoda is provided. Including the new species, five species are recorded from Corsica for the first time: Dolichocephala malickyi Wagner, 1995, Dolichocephala oblongoguttata (Dale, 1878), Dolichocephala ocellata (Costa, 1854), Chelifera subangusta Collin, 1961, and Hemerodromia unilineata Zetterstedt, 1842. The new species is described and illustrated, and new records of aquatic dance flies from Corsica are given, with new data on 17 species in eight different genera. At present, 29 species of aquatic dance flies are known from Corsica, with 10 species endemic to the island.

Peeling the Layers of Caddisfly Diversity on a Longitudinal Gradient in Karst Freshwater Habitats Reveals Community Dynamics and Stability.

Freshwater biodiversity is facing a severe crisis due to many human impacts, yet the diversity dynamics of freshwater communities and possibilities of assessing these are vastly unexplored. We aimed at emphasizing different aspects of portraying diversity of a species-rich, aquatic insect group (caddisflies; Trichoptera) across four different habitats in an anthropogenically unimpacted, connected karst barrage lake/riverine system. To define diversity, we used common indices with pre-set sensitivity to species abundance/dominance; i.e., sensitivity parameter (species richness, Shannon, Simpson, Berger-Parker) and diversity profiles based on continuous gradients of this sensitivity parameter: the naïve and non-naïve diversity profiles developed by Leinster and Cobbold. The non-naïve diversity profiles show diversity profiles with regard to the similarity among species in terms of ecological traits and preferences, whereas the naïve diversity profile is called mathematically "naïve" as it assumes absolute dissimilarity between species that is almost never true. The commonly used indices and the naïve diversity profile both ranked the springs as least diverse and tufa barriers as most diverse. The non-naïve diversity profiles based on similarity matrices (using feeding behavior and stream zonation preferences of species), showed even greater differences between these habitats, while ranking stream habitats close together, regardless of their longitudinal position. We constructed the Climate Score index (CSI) in order to assess how diversity and species' vulnerability project the community's resistance and/or resilience to climate change. The CSI ranked the springs as most vulnerable, followed by all habitats longitudinally placed below them. We highlight the importance of integrating ecological information into biodiversity and vulnerability assessment of freshwater communities.

Aquatic dance flies of Czech Republic (Empididae: Clinocerinae and Hemerodromiinae): new records and updated species list.

New records are provided for aquatic dance flies from Czech Republic, with new distribution records for 19 species in six different genera. Four species are newly recorded from Czech Republic: Dolichocephala ocellata (Costa, 1854), Kowarzia tenella (Wahlberg, 1844), Wiedemannia insularis Collin, 1927 and Wiedemannia wachtli (Mik, 1880). There are now 43 species of aquatic dance flies recorded from Czech Republic.

The Empididae (Diptera) of Serbia: faunistic survey and description of a new Empis species.

The Empididae fauna of Serbia is summarised including currently 50 confirmed species belonging to nine genera: Clinocerinae-Kowarzia Mik (1), Phaeobalia Mik (2), Wiedemannia Zetterstedt (4); Empidinae-Empis Linnaeus (16), Hilara Meigen (11), Rhamphomyia Meigen (6); Hemerodromiinae-Chelifera Macquart (7), Hemerodromia Meigen (2), Phyllodromia Zetterstedt (1). A checklist of species is provided. Empis (Empis) serbica sp. nov. is described.

Checklist of aquatic Diptera (Insecta) of Plitvice Lakes National Park, Croatia, a UNESCO world heritage site.

Studies on aquatic Diptera in the Plitvice Lakes National Park (Croatia) conducted in the last 50 years have produced 157 species and 7 taxa of aquatic Diptera placed in 13 families. Samples were collected at 25 sampling sites representing the four main types of karst aquatic habitats: spring, stream, tufa barriers and lakes. All records of all the aquatic families of Diptera in Plitvice Lakes NP are summarized, including previously unpublished data. Twelve species new for Plitvice Lakes NP are recorded for the first time, belonging to the families: Chironomidae - Labrundinia longipalpis (Goetghebuer, 1921), Nilothauma brayi (Goetghebuer, 1921), Potthastia longimanus Kieffer, 1922, Polypedilum (Polypedilum) nubeculosum (Meigen, 1804), Tanytarsus brundini Lindeberg, 1963; Dixidae - Dixella autumnalis (Meigen, 1838); Scathophagidae - Acanthocnema latipennis Becker, 1894 and Stratiomyidae - Oxycera pardalina Meigen, 1822, Oxycera limbata Loew, 1862, Oxycera turcica Ustuner & Hasbenli, 2004, Nemotelus pantherinus (Linnaeus, 1758), Oplodontha viridula (Fabricius, 1775). The most species-rich family was the Chironomidae with 62 species (and an additional seven taxa), followed by the Empididae with 22 species and Limoniidae with 19 species. The highest number of species was recorded in springs. The relatively low number of species in certain families and the complete absence of some aquatic families shows that further research into the aquatic Diptera in Plitvice Lakes NP is needed.

The genus Dixa (Diptera, Dixidae) in Croatian lotic habitats, with a checklist of species and relationships with the fauna of neighbouring countries.

Invertebrate surveys in Croatia conducted between 2005 and 2018 included 39 sampling sites yielding bycatch samples of Dixidae (Diptera). All records of this family from the territory of Croatia are summarized, including previously unpublished data. Collections contained six species of Dixa Meigen - D. dilatata Strobl, D. maculata Meigen, D. nebulosa Meigen, D. nubilipennis Curtis, D. puberula Loew, and D. submaculata Edwards, with Dixa dilatata reported from Croatia for the first time. Information relating to the ecoregions in which species were found and specific species traits are provided. Compared to neighbouring countries, the Croatian species assemblage is most similar to the fauna of Italy and least similar to that of Serbia and Montenegro.

New species and records of the Pericoma trifasciata group from Croatia (Diptera: Psychodidae).

Pericoma miljenkoi sp. nov. is described based on adult males from the Plitvicka jezera National Park, Croatia. Pericoma trifasciata is recorded from Croatia for the first time, and COI DNA barcodes are given from specimens collected in Germany. An emended key to adult Pericoma of the trifasciata group is presented. The Croatian Psychodidae fauna now stands at 35 species.

Dolichopodidae of riverbeds and springs in Croatia with an updated checklist of Croatia (Diptera).

Several invertebrate surveys in Croatia conducted between 2005 and 2014 and including; e.g., Plitvice Lakes, produced 123 bycatch samples of Dolichopodidae (Diptera) from 68 sampling sites collected at 36 localities in seven counties. Seventy-seven were retrieved from emergence traps, six from pan traps and 40 were collected with sweep net and/or aspirator. They contained 420 dolichopodid flies that belonged to 64 species in 22 genera. Four species, Campsicnemus umbripennis, Hercostomus chetifer, Liancalus virens and Syntormon pallipes, accounted for over half of the yields. Contrary to most species that were found in largest numbers in rivers, and their beds in particular, S. pallipes and Hercostomus gracilis were considerably more abundant at springs. Fifty-five species could be added to the national checklist which raises the total number to 94 species. All species records are given, the habitat of each species is described, if possible, and taxonomic notes are provided for some dubious species. Finally, elements are presented to support the assumption that the extant dolichopodid species richness of Croatia is at least three- to fourfold of the current number.

Aquatic dance flies (Diptera, Empididae, Clinocerinae and Hemerodromiinae) of Greece: species richness, distribution and description of five new species.

All records of aquatic dance flies (37 species in subfamily Clinocerinae and 10 species in subfamily Hemerodromiinae) from the territory of Greece are summarized, including previously unpublished data and data on five newly described species (Chelifera horvati Ivkovic & Sinclair, sp. n., Wiedemannia iphigeniae Ivkovic & Sinclair, sp. n., W. ljerkae Ivkovic & Sinclair, sp. n., W. nebulosa Ivkovic & Sinclair, sp. n. and W. pseudoberthelemyi Ivkovic & Sinclair, sp. n.). The new species are described and illustrated, the male terminalia of Clinocera megalatlantica (Vaillant) are illustrated and the distributions of all species within Greece are listed. The aquatic Empididae fauna of Greece consists of 47 species, with the following described species reported for the first time: Chelifera angusta Collin, Hemerodromia melangyna Collin, Clinocera megalatlantica, Kowarzia plectrum (Mik), Phaeobalia dimidiata (Loew), W. (Chamaedipsia) beckeri (Mik), W. (Philolutra) angelieri Vaillant and W. (P.) chvali Joost. A key to species of aquatic Empididae of Greece is provided for the first time. Information related to the European Ecoregions in which species were found is given. Compared to the other studied countries in the Balkans, the Greek species assemblage is most similar to that of the Former Yugoslav Republic of Macedonia.

Blackflies (Diptera: Simuliidae) in Croatia: species richness, distribution and relationship to surrounding countries.

All records of blackflies (Simuliidae) from the territory of Croatia are summarized, including previously unpublished data. The blackfly fauna of Croatia consists of 28 species. Simulium (Nevermannia) angustitarse (Lundström), Simulium (Nevermannia) cryophilum (Rubtsov) complex, Simulium (Nevermannia) lundstromi (Enderlein), Simulium (Nevermannia) vernum Macquart complex, Simulium (Simulium) argyreatum Meigen, Simulium (Simulium) bezzii (Corti) complex, Simulium paraequinum Puri and Simulium pseudequinum Séguy are reported for the first time from Croatia. Information related to the ecoregions, in which species were found and specific species traits are given. Genus Prosimulium Roubaud is represented by one species only. Genus Simulium Latreille is represented by 27 species in six subgenera, with subgenus Simulium Latreille s. str. being most species rich (13 species) and subgenera Boophthora Enderlein and  Trichodagmia Enderlein represented each by only one species. Compared to the neighboring countries, the Croatian species assemblage is most similar to the fauna of Slovenia and least similar to that of Italy. The relatively low number of species, presence of several species complexes and unclear identity of other species show that further research of blackflies in Croatia is needed.

Blind Flight? A New Troglobiotic Orthoclad (Diptera, Chironomidae) from the Lukina Jama - Trojama Cave in Croatia.

The genus Troglocladius Andersen, Baranov et Hagenlund, gen. n. is erected based on T. hajdi Andersen, Baranov et Hagenlund, sp. n. collected at 980 m depth in the Lukina jama-Trojama cave system in Croatia. Morphological features such as pale color, strongly reduced eyes and very long legs make it a typical cave animal. Surprisingly, it has also retained large wings and appears to be capable of flight which would make T. hajdi the first flying troglobiont worldwide, disproving previous beliefs that bats are the only animals capable of flying in complete darkness. Morphologically the new species does not readily fit within any described genus, but shares characteristics with genera both in the tribes "Metriocnemini" and "Orthocladiini". Bayesian molecular phylogenetic analysis using the markers COI, 18S rDNAs, 28S rDNA, CADI, and CADIV groups it with the genera Tvetenia, Cardiocladius and Eukiefferiella in the tribe "Metriocnemini". Troglocladius hajdi may be parthenogenetic, as only females were collected. The discovery confirms the position of the Dinaric arch as a highly important hotspot of subterranean biodiversity.

New records of Limoniidae and Pediciidae (Diptera) from Croatia.

New records are provided for Limoniidae and Pediciidae from Croatia, with new distribution records for species in 12 different genera. Four genera and 18 species are newly recorded for Croatia. Until now, including this data, 87 Limoniidae and eight Pediciidae have been recorded from Croatia. In this paper we confirm presence of Ormosia (Oreophila) bergrothi (Strobl, 1895) and we give the first records of Dicranota (Paradicranota) pavida (Haliday, 1833) and Molophilus (Molophilus) repentinus Starý, 1971 from Balkan Peninsula.

New records of Muscidae (Diptera) from Mediterranean countries.

New records are provided for Muscidae from four different Mediterranean countries, with new distribution records for species in ten different genera. Seven species are newly recorded for Croatia, four species for Montenegro and one species for Bosnia & Herzegovina. In this paper we give the first confirmation of an aquatic larval stage for Lispocephalabrachialis (Rondani, 1877), Lispocephalaspuria (Zetterstedt, 1838) and Lispocephalamikii (Strobl, 1893). A first record of the species Coenosialyneborgi Pont, 1972 since its original description is also provided.