Identification and morphology of two polycentropodid caddisfly larvae from the Cevennes and the French and Italian Alps: Plectrocnemia cevennensis Coppa 2011 and Plectrocnemia praestans McLachlan 1884

The collection of adults, mature male pupae, and the absence of confusing species at the sampling sites located in the Cevennes and French Alps enabled descriptions of the hitherto unknown larvae of Plectrocnemia cevennensis Coppa 2011 and P. praestans McLachlan 1884 (Trichoptera, Polycentropodidae). We present information on the morphology of the larvae and illustrate the most important diagnostic features. In the context of the larval key to European Plectrocnemia species by Waringer & Graf (2020), P. cevennensis keys together with P. scruposa McLachlan 1880, whereas P. praestans keys with P. conspersa (Curtis 1834). These two species pairs are morphologically very close; P. cevennensis and P. scruposa can be separated by the numbers of secondary setae on the last abdominal sternum, but the separation of P. praestans and P. conspersa is not always possible.

On the Biological Regulators of Bloodsucking Blackflies(Diptera:Simuliidae) of Mixed Forests of Belorussian and Ukrainian Woodlands

This article considers the natural regulators of blood-sucking Simuliidae subzone of mixed forests on the territory of Belarus and Ukraine. In the mixed forests, the major regulators of preimaginal phases of bloodsucking blackflies are microsporidia (Polidyspirenia simulii, Polidyspirenia sp., Thelohania fibrata, Amblyospora bracteata, A. varians), fungi and mermithides (Gastromermis boophthorae). Caddisfly larvae (Hydropsyche angustipennis, Neureclipsis bimaculata, Polycentropus flavomaculatus, Cyrnus flavidus, Oligostomis reticulata, Brachycentrus subnubilus and Rhyacophila nubila) and fishes (Scardinius erythrophthalmus, Rutilus rutilus, Carassius carassius, Gobio gobio) significantly reduce the number of blackflies larvae and pupae. Adult blackflies are eaten by spiders (Araneus diadematus) dragonflies, robberflies, wasps, frogs (Rana temporaria and Rana terrestris), and insectivorous birds (Delichon urbicum, Hirundo rustica, Apus apus). Bactolarvicid and BLP-2477 are among the most effective biological products.

Dynamic microhabitat shifts in space and time of caddisfly larvae (Insecta: Trichoptera) in a first‐order calcareous mountain stream

By studying substrate (choriotope) preferences of 25 caddisfly taxa in the Schreierbach stream, a calcareous, first order tributary of the Ybbs river (Lower Austria), we aimed on (1) detecting microhabitat preferences in space and time, (2) to relate this information with ontogenetic choriotope shifts, and (3) to explore relationships between feeding guilds and choriotopes chosen. For this, we took six sets of bi-monthly multi-habitat samples of larvae at three stream sections (360 samples). Densities were highest in Drusinae juveniles (53.60 %), Micrasema morosum (15.14 %), Drusus discolor (13.31 %) and D. monticola (4.46 %), and were significantly higher in the upper stream section (1900 ± 1039 larvae m− 2) than in the central (205 ± 23) and lower (141 ± 22). Ivlev electivity indices revealed preferences for Macrolithal in Rhyacophila spp. and Tinodes dives, for Microlithal in Drusinae juveniles, for Megalithal and Phytal in filtering Drusinae and Micrasema, and for Xylal and Akal in Limnephilinae. A cluster analysis of choriotope electivity yielded five clusters, corresponding with functional feeding types. At the instar level, the chosen grain size increased with increasing instar in some species. Observed habitat shifts in space and time reflected the interaction of instar-specific choriotope choice and longitudinal translocations.

Caddisflies (Trichoptera, Insecta)as Bioindicator of Water Quality Assessment in a Small Stream in Northern Thailand

The influence of environmental variables and the potential as bioindicators of larval stages of the species of Trichoptera were evaluated in a small stream in northern Thailand from January to November 2017. A total of 1,191 individual caddisfly larvae belonging to 7 families and 13 genus were found. The larvae of the family Glossosomatidae were the most abundant, followed by Hydropsychidae and Calamoceratidae. The genus Glossosoma, Hydromanicusand Hydropsyche were the most abundant genus in this study. Results of the CCA ordination showed that total dissolved solids, electrical conductivity, and water temperature were the most important factors affecting the abundance and diversity of caddisfly larvae. Changes in the caddisfly larvae may indicate changes in physicochemical factors owing to urbanization or other anthropogenic. The results showed that the order Trichoptera, identified to the species or genus level, can potentially be used to assess environmental water quality status in freshwater ecosystems. This study suggested that species richness of aquatic insects may indicate the conservation value of the habitats because of their significant responses to environmental factors.

Radiocesium-bearing microparticles cause a large variation in 137Cs concentration in the aquatic insect, Stenopsyche marmorata, in the Ota River, Fukushima, Japan

<p>Radiocesium-bearing microparticles (CsMPs), which are insoluble, Cs-bearing, silicate glass particles, have been found in terrestrial and freshwater environments after the TEPCO's Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in Japan. Few studies have investigated the distribution of CsMPs in freshwater ecosystems and their uptake by aquatic organisms. In this study, we determined the uptake of CsMPs by aquatic insects in the Ota River in Fukushima. Although aquatic insects are usually measured for radioactivity in bulk samples of several tens of insects, we investigated the variability of <sup>137</sup>Cs concentration in individual aquatic insects, and the influence of CsMPs on them. Measurement of <sup>137</sup>Cs concentrations in detritivorous caddisfly (Stenopsyche marmorata) larvae and carnivorous dragonfly larvae showed that 3 of 47 caddisfly larvae had considerably higher radioactivity, whereas no such outliers were observed in dragonfly larvae. These caddisfly larvae were confirmed to contain the CsMPs emitted from Unit 2 of the FDNPP, using a scanning electron microscope and radioactivity measurements after isolation of the CsMPs. CsMPs were also found in potential food sources of caddisfly larvae, such as periphyton and drifting particulate organic matter, indicating that larvae may ingest CsMPs along with food particles of similar size. Our study demonstrated that CsMPs could be taken up by aquatic insects and possibly by the fish consuming them. The existence of CsMPs can result in sporadic, extremely high <sup>137</sup>Cs concentrations, and large variations in samples, and consequently obscure the actual transfer and temporal trends of <sup>137</sup>Cs in freshwater ecosystems.</p>

Tools for instar determination of European caddisfly larvae (Insecta: Trichoptera)

The paper explores the adult-forewing-length to larval-head-width relationship as a basis for instar determination of final instar caddisfly larvae on a family level. In addition, reference data from published sources were used to extract series of percentage-head-width increments and factors-of-increase for penultimate to first instars. This material provides estimates for head widths of earlier instars on the family level.

Contribution to the knowledge of the caddisfly fauna of Algeria: An updated checklist of Algerian Trichoptera with new records from the Aures region

The caddisfly fauna of Algeria is poorly known and the few sporadic studies available were carried out decades ago. In this study, caddisfly larvae, pupae, and adults were collected in 11 stream localities from the Aures region, northeastern Algeria. Caddisflies were regularly sampled between April 2018 and February 2020. Two genera are new records to Algeria: Plectrocnemia and Setodes. In addition, four Trichoptera species are new to the Algerian fauna: Tinodes dives, Hydropsyche modesta, Plectrocnemia conspersa and Setodes acutus. Future caddisfly surveys in the region will doubtlessly contribute significantly to the incompletely known Trichoptera fauna of Algeria.