Boreoheptagyia ortladamellica sp. nov. (Diptera, Chironomidae) from Italian Alps

A new species from Italian Alps, Boreoheptagyia ortladamellica (Diptera, Chironomidae), is here described. The species is presently known only as adult male, it is similar to B. tibetica, because of the female-like antenna in adult male, but it can be separated by the following characters: much larger size, darker colour, medially pointed aedeagal lobe, knob-like and heavy sclerotized inferior volsella, gonostylus enlarged at basis with short spiniform setae at apex

Pseudosmittia fabioi sp. n., a new species from Sardinia (Diptera: Chironomidae, Orthocladiinae)

A new species of Pseudosmittia Edwards 1932, P. fabioi, from Sardinia (Palearctic region), is described and figured as male and female. The generic diagnosis is emended based on characters found in the new species. The species is characterized by a triangular anal point with microtrichia at apex (not projecting beyond tergite IX), an inferior volsella characterized by a rounded lobe with a setose accessory lobe adpressed to the gonocoxite, a well developed tooth-like projection on the outer margin of the gonostylus, the lack of acrostichals and an antenna with 6 flagellomeres in female

Biomonitoring of lake sediments using benthic macroinvertebrates

The Water Framework Directive (2000/60/EC) is an innovative piece of legislation aimed at protecting the quality of all continental and coastal waters in Europe through an ecological evaluation of the ecosystems. Since it is widely acknowledged that the greater the ecological realism the greater the difficulty of its definition, we describe the different uses of benthic organisms as a tool for assessing the quality of sediment in lakes. We review the responses from single species to the community. We focus on studies in the laboratory and in the field, and we also critically consider the use of predictive models for these evaluations. Our discussion of the information collected underlines the importance of the relation between sensitivity of single species and contaminants. Moreover, the recent approach in developing mechanistic models to predict the response of natural communities seems to be particularly powerful for community ecology, and we strongly recommend more effort along these lines

A key to larvae of Diamesa Meigen, 1835 (Diptera, Chironomidae), well known as adult males and pupae from Alps (Europe)

A key to species belonging to the genus Diamesa Meigen, 1835 (Diptera, Chironomidae) well known as adult males and pupal exuviae from European Alps, is presented; the characters useful in species identification are pictured. The key considers both qualitative and quantitative characters. Thirteen morpho-species are distinguished, probably more species have a very similar larva and can be separated only in the adult or pupal stage. The most discriminant quantitative characters are the length and thickness of anal setae, among qualitative characters the most discriminant ones are the head capsule colour and the split of setae anteriores of labrum. The shape of mental and mandibular teeth are good taxonomic characters, but can be rarely used because teeth are often worn out in samples collected in the field. Quantitative characters show variability within each species, differing according to the sampled site and season, and must be used with caution. The following species groups can be easily separated in the larval stage: i) dampfi, including D. dampfi and D. permacra; ii) latitarsis including D. modesta and D. latitarsis; iii) zernyi including D. zernyi and D. vaillanti. D. starmachi, D. steinboecki, D. goetghebueri, D. bertrami, D. aberrata, D. incallida, D. cinerella, D. tonsa and D. insignipes can be separated from all the other known species in larval stage, but some of them, D. cinerella and D. insignipes for example, have a very similar larva, so are better separated on the basis of their distribution and collection of adults and pupae are strongly recommended to support identifications. A new character bound to head capsule colour is proposed to separate D. insignipes, D. cinerella, D. tonsa and D. zernyi

Revision of type and non-type material assigned to the genus Orthocladius by Goetghebuer (1940–1950), deposited in the Royal Belgian Institute of Natural Sciences (Diptera: Chironomidae)

Selected type and non-type material belonging to the genus Orthocladius van der Wulp, 1874 (Diptera: Chironomidae) sensu G OETGHEBUER (1940\u20131950), deposited in the Royal Belgian Institute of Natural Sciences (RBINS), originally comprising specimens dry pinned or stored in isinglass, were mounted on microscope slides and re-examined. Other chironomids present in the RBINS collection belonging to other genera were also examined. Fifty slides were prepared and identified to species, or to generic level when the condition of the specimens did not allow species identification. The following types, representing taxa formerly considered as nomina dubia, were examined and the concerned species are stated here as valid: Georthocladius collarti (Goetghebuer, 1941) comb. nov., Georthocladius scaturiginis (Goetghebuer, 1940) comb. nov., Lapposmittia succinea (Goetghebuer, 1942) comb. nov., Orthocladius (Euorthocladius) tolleti Goetghebuer, 1944 (new subgenus placement), Orthocladius (Orthocladius) timoni Goetghebuer & Timon-David, 1939, Pseudorthocladius hockaiensis (Goetghebuer, 1933). Orthocladius (Orthocladius) mitisi Goetghebuer, 1938, previously stated as junior synonym of Orthocladius (Orthocladius) glabripennis (Goetghebuer, 1921), is reinstated as valid species. The following new synonyms are proposed: Georthocladius (Georthocladius) collarti = Parachaetocladius retezati Albu, 1972: 19, syn. nov.; Cricotopus (Paratrichocladius) rufiventris (Meigen, 1830) = Orthocladius franzi Goetghebuer, 1949, syn. nov.; Cricotopus (Paratricho-cladius) skirwithensis Edwards, 1929 = Orthocladius nigritus Goetghebuer, 1938, syn. nov. = Paratrichocladius spiesi Ashe & O\u2019Connor, 2012; Hydrobaenus distylus (Potthast, 1914) = Orthocladius antennalis Goetghebuer, 1944, syn. nov. Lecto-types of Orthocladius collarti Goetghebuer, 1941, Orthocladius antennalis Goetghebuer, 1944, Orthocladius timoni Goetghebuer & Timon-David, 1939, and Orthocladius hockaiensis Goetghebuer, 1933 are designated. Non-type material assigned to Orthocladius was also mounted on slides and identified. Although a list of the non-Orthocladius taxa is also provided, no taxonomic changes are proposed for the latter

The effects of tricyclazole treatment on aquatic macroinvertebrates in the field and in laboratory

The effects of tricyclazole treatments on benthic macroinvertebrates in the field and in laboratory were studied. In field conditions, low density of benthic populations was observed, both in treated and untreated plots, which was attributed to the short period of submersion of the rice field and high water temperature, fungicide treatments had no significant effect. Both laboratory acute toxicity test and a test using a mesocosm suggested a low toxicity of tricyclazole on invertebrates. A reduction of the macroinvertebrate density was observed only when tricyclazole concentration was applied at concentrations 100 times the ones tested in the field, acute toxicity test gave an LC50 after 48 h of 26 mg*L\u20131, in agreement with data obtained for other species

Response of chironomid species (Diptera, Chironomidae) to water temperature: effects on species distribution in specific habitats

The response of 443 chironomid species to water temperature was analyzed, with the aim of defining their thermal optimum, tolerance limits and thermal habitat. The database included 4442 samples mainly from Italian river catchments collected from the 1950s up to date. Thermal preferences were calculated separately for larval and pupal specimens and for different habitats: high altitude and lowland lakes in the Alpine ecoregion; lowland lakes in the Mediterranean ecoregion; heavily modified water bodies; kryal, krenal, rhithral and potamal in running waters. Optimum response was calculated as mean water temperature, weighted by species abundances; tolerance as weighted standard deviation; skewness and kurtosis as 3rd and 4th moment statistics. The responses were fitted to normal uni- or plurimodal Gaussian models. Cold stenothermal species showed: i) unimodal response, ii) tolerance for a narrow temperature range, iii) optima closed to their minimum temperature values, iv) leptokurtic response. Thermophilous species showed: i) optima at different temperature values, ii) wider tolerance, iii) optima near their maximum temperature values, iv) platikurtic response, often fitting a plurimodal model. As expected, lower optima values and narrower tolerance were obtained for kryal and krenal, than for rhithral, potamal and lakes. Thermal response curves were produced for each species and were discussed according to species distribution (i.e. altitudinal range in running water and water depth in lakes), voltinism and phylogeny. Thermal optimum and tolerance limits and the definition of the thermal habitat of species can help predicting the impact of global warming on freshwater ecosystems

Revision of the genus Chaetocladius Kieffer (Diptera, Chironomidae), 1st note : description of four new species from Italy

Four new species belonging to the genus Chaetocladius, known to occur in Italy, are here described as adult males: C. aedeagovirgatus sp. nov., C. subalpinus sp. nov., C. ticinoi sp. nov., and C. valdostanus sp. nov. C. aedeagolobatus is characterized by a robust aedeagal lobe, C. subalpinus and C. valdostanus by a characteristic inferior volsella, C. ticinoi by a tubercle on the basis of gonostylus. Geographical distribution of the other species known to occur in Italy is given. A key to adult males is presented

Collective behaviour without collective order in wild swarms of midges

Collective behaviour is a widespread phenomenon in biology, cutting through a huge span of scales, from cell colonies up to bird flocks and fish schools. The most prominent trait of collective behaviour is the emergence of global order: individuals synchronize their states, giving the stunning impression that the group behaves as one. In many biological systems, though, it is unclear whether global order is present. A paradigmatic case is that of insect swarms, whose erratic movements seem to suggest that group formation is a mere epiphenomenon of the independent interaction of each individual with an external landmark. In these cases, whether or not the group behaves truly collectively is debated. Here, we experimentally study swarms of midges in the field and measure how much the change of direction of one midge affects that of other individuals. We discover that, despite the lack of collective order, swarms display very strong correlations, totally incompatible with models of noninteracting particles. We find that correlation increases sharply with the swarm's density, indicating that the interaction between midges is based on a metric perception mechanism. By means of numerical simulations we demonstrate that such growing correlation is typical of a system close to an ordering transition. Our findings suggest that correlation, rather than order, is the true hallmark of collective behaviour in biological systems.Comment: The original version has been split into two parts. This first part focuses on order vs. correlation. The second part, about finite-size scaling, will be included in a separate paper. 15 pages, 6 figures, 1 table, 5 video