Viktor Baranov

Orthoclads from Eocene Amber from Sakhalin (Diptera: Chironomidae, Orthocladiinae)

Four Middle Eocene orthoclad species, Heterotrissocladius naibuchisp. n., Paraphaenocladius nadezhdaesp. n., Pseudosmittia kodrulaesp. n. and Smittia sukachevaesp. n.. are described and figured. Based on the combination of the diptera fauna composition and paleobotanical data, suggestions on the climate and habitats of the Sakhalin amber forest are given.

Effects of bioirrigation of non-biting midges (Diptera: Chironomidae) on lake sediment respiration

Bioirrigation or the transport of fluids into the sediment matrix due to the activities of organisms such as bloodworms (larvae of Diptera, Chironomidae), has substantial impacts on sediment respiration in lakes. However, previous quantifications of bioirrigation impacts of Chironomidae have been limited by technical challenges such as the difficulty to separate faunal and bacterial respiration. This paper describes a novel method based on the bioreactive tracer resazurin for measuring respiration in-situ in non-sealed systems with constant oxygen supply. Applying this new method in microcosm experiments revealed that bioirrigation enhanced sediment respiration by up to 2.5 times. The new method is yielding lower oxygen consumption than previously reported, as it is only sensitive to aerobic heterotrophous respiration and not to other processes causing oxygen decrease. Hence it decouples the quantification of respiration of animals and inorganic oxygen consumption from microbe respiration in sediment.

Bioturbation enhances the aerobic respiration of lake sediments in warming lakes.

While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m2 was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming.

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 chironomids from Eocene Sakhalinian amber (Diptera; Chironomidae; Orthocladiinae)

Non-biting midges (Diptera: Chironomidae) are recorded in the Sakhalinian amber (Russia) for the first time. Pseudorthocladius zherikhini sp. n. is described in an extant genus of Orthocladiinae also known from the Baltic amber. Antillocladus sp. (Orthocladiinae) is the first representative of this genus recorded from fossil resins.

Two new species of fossil Corethrella Coquillett from Late Eocene Rovno amber, with a species‐level phylogeny for the family based on morphological traits (Diptera: Corethrellidae)

Species in the genus Corethrella Coquillett, the only genus in the family Corethrellidae, feed on the blood of frogs and toads and are unique among Diptera in locating their hosts by sound. Their fossil record goes back to the Cretaceous and comprises seven previously described species from various amber deposits. Herein, we present the first records of Corethrella from Late Eocene Rovno amber (35 Ma), with the description of two new species: Corethrella sontagae sp.n. based on a single male, and Corethrella rovnoensis sp.n. based on a single female. A revised key to fossil species of Corethrella is given. Phylogenetic relationships within Corethrella are investigated based on Bayesian and parsimony analysis, including the new data. All species groups recognized by Borkent (2008) are recovered as monophyletic, with the exception of the drakensbergensis group, which is found to be a paraphyletic grade. Both of the newly described species can be accommodated within modern species groups: C. sontagae shows affinities with the quadrivittata group and C. rovnoensis with the rotunda group.

DNA metabarcoding reveals the complex and hidden responses of chironomids to multiple stressors

BackgroundChironomids, or non-biting midges, often dominate stream invertebrate communities in terms of biomass, abundance, and species richness and play an important role in riverine food webs. Despite these clear facts, the insect family Chironomidae is often treated as a single family in ecological studies or bioassessments given the difficulty to determine specimens further. We investigated stressor responses of single chironomid operational taxonomic units (OTUs) to three globally important stressors (increased salinity, fine sediment and reduced water flow velocity) in a highly replicated mesocosm experiment using a full-factorial design (eight treatment combinations with eight replicates each).ResultsIn total, 183 chironomid OTUs (97% similarity) were obtained by applying a quantitative DNA metabarcoding approach. Whereas on the typically applied family level, chironomids responded positively to added fine sediment and reduced water velocity in the streambed and negatively to reduced velocity in the leaf litter, an OTU-level analysis revealed a total of 15 different response patterns among the 35 most common OTUs only. The response patterns ranged from (a) insensitivity to any experimental manipulation over (b) highly specific sensitivities to only one stressor to (c) additive multiple-stressor effects and even (d) complex interactions.ConclusionEven though most OTUs (> 85%) could not be assigned to a formally described species due to a lack of accurate reference data bases at present, the results indicate increased explanatory power with higher taxonomic resolution. Thus, our results highlight the potential of DNA-based approaches when studying environmental impacts, especially for this ecologically important taxon and in the context of multiple stressors.

Seasonal variation in abundance and diversity of eavesdropping frog-biting midges (Diptera, Corethrellidae) in a neotropical rainforest

1. In the tropics, precipitation patterns result in seasonal fluctuations in the abundance and distribution of plant and animal species. Tropical predators and parasites are therefore faced with seasonal changes in prey and host availability.

The first fossil record of Nandeva Wiedenbrug, Reiss & Fittkau (Diptera: Chironomidae) in early Eocene Fushun amber from China

Giłka, W., Zakrzewska, M., Baranov, V., Wang, B. & Stebner, F., May 2016. The first fossil record of Nandeva Wiedenbrug, Reiss & Fittkau (Diptera: Chironomidae) in early Eocene Fushun amber from China. Alcheringa 40, xxx–xxx. ISSN 0311-5518 The first fossil representative of the extant chironomid genus Nandeva Wiedenbrug, Reiss & Fittkau, 1998 is described based on a specimen found in early Eocene (50–53 Ma) Fushun amber from China. The adult male of Nandeva pudens sp. nov. has the long RM vein as a continuation of M and R4+5, the bare squama, the strongly reduced anal area of the wing and hypopygial characters typical of extant species of the genus. Following the systematic concept based on adult male morphology and characters examinable in fossil specimens, we present N. pudens as a possible member of the Tanytarsini, arguing that Nandeva is part of this tribe or a possible sister group to the tribe. This is the first record of Nandeva from the Palaearctic region. Wojciech Giłka [wojciech.gilka@biol.ug.edu.pl] University of Gdańsk, Department of Invertebrate Zoology and Parasitology, Wita Stwosza 59, 80-308 Gdańsk, Poland; Marta Zakrzewska [marta.zakrzewska@biol.ug.edu.pl] University of Gdańsk, Department of Invertebrate Zoology and Parasitology, Wita Stwosza 59, 80-308 Gdańsk, Poland; Viktor Baranov* [baranov@igb-berlin.de] Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany; Bo Wang† [bowang@nigpas.ac.cn] Chinese Academy of Sciences, Nanjing Institute of Geology and Palaeontology, State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing 210008, PR China; Frauke Stebner [frauke.stebner@uni-bonn.de] University of Bonn, Steinmann-Institute, Section Palaeontology, Nussallee 8, 53115, Bonn, Germany. *Also affiliated with Humboldt University of Berlin, Faculty of Mathematics and Natural Sciences, Geography Department, Rudower Chaussee 16, 12489 Berlin, Germany. †Also affiliated with Chinese Academy of Sciences, Institute of Zoology, Key Laboratory of Zoological Systematics and Evolution, Beijing 100101, PR China.

Adult female of Chaetocladius insolitus Caspers, 1987 (Diptera: Chironomidae) with notes on species distribution

The adult female of Chaetocladius insolitus Caspers, 1987 (Diptera, Chironomidae) is described and discussed in the context of the generic diagnosis of adult females of the genus Chaetocladius Kieffer, 1911. In addition, distributional notes on this rare chironomid species are included.