Diacyclops cohabitatus Monchenko 1980 known only from the groundwater of the Carpathian mountains in Ukraine is redescribedfrom specimens collected in the Danube alluvial plain, the Lobau, at Vienna. In this area two stygobiont species belongingto the D. languidoides - group co-occur as well. D. cohabitatus can be differentiated from these latter Diacyclops specieson the basis of several morphological traits of antennae, P4 and caudal rami. Its relationship with other members of the D. languidoides- group (e.g. D. languidoides goticus) is discussed.

Treize espèces de Plécoptères ont été récoltées dans deux rivières et leurs affluents, sur le versant occidental du Mont Liban entre Saïda et Beyrouth. Les auteurs décrivent des formes nouvelles ou mal connues : Brachyptera galeata Koponen, Protonemura libanica Aubert (larve), Pr. pectinata sp. nov., Leuctra fusca latior ssp. nov., L. kopetdaghi Zhiltzova (larve), Capnia turkestanica brevicula ssp. nov. Une larve hélicomère de B. galeata et un adulte gynandromorphe de Pr. libanica sont figurés.

Afrobaetodes lenae n. sp. is described at the larval stage. It represents the first report of Afrobaetodes in Madagascar and outsidecontinental Africa. The species presents all the very peculiar apomorphies of Afrobaetodes. It is distinguished from theAfrican species by the absence of tracheation on the abdominal gills and the absence of compact tufts of stout setae on the pronotum.Affinities and ecology are discussed.

Description illustrée de la larve au dernier stade de Baetis cyrneus n.sp. Cette espèce, rencontrée en Corse, appartient au groupe alpinus : elle est comparée à cette dernière espèce et à B. punicus Thomas, Boumaiza et Soldán.

Plusieurs specimens de Camptocercus du Rio Uracoa (nord-est du Vénézuéla) ont été identifiés à Camptocercus australis var. dadayi décrit de Colombie par Stingelin (1913).Sur la base de l'étude morphologique des individus vénézuéliens et des données de la littérature, le statut de ce taxon, d'abord rattaché à la forme australienne (australis), puis à la forme paléarctique (lilljeborgi) de Camptocercus, est discuté.L'ensemble des caractères propres aux populations sud-américaines permet de les séparer des formes australienne et paléarctique, et de leur attribuer un rang spécifique.

The present study focus on some aspects of zooplankton structure in the Alcantara River (Sicily, Italy), in relation to environmental factors. Zooplankton samplings were performed in spring in four sites, located from up- to downstream along the river course. Four low-flow velocity station points were chosen along a transversal river section in each site. Samples were taken from all station points in the four sites by two different mesh sizes (55 and 100 μm) rectangular nets. Rotifer abundances were an order of magnitude higher in 55 μm mesh size samples than in 100 μm mesh size ones. The two communities also resulted significantly different (ANOSIM test, ρ=0.212; P=0.1%). Generally, low abundances (from 3470±5133 to 422±474 ind.m−3) were explained by low chlorophyll a concentration and the high-flow regime of this river. Rotifer dominated the zooplankton community. Cladocerans, copepods and nauplii occurred with considerably lower abundances than rotifers. However, the relative contributions of these taxa to total abundances depended on the mesh sizes used. Euchlanis and Adineta genera exhibited the highest abundances in the rotifer assemblage. Conductivity alone or in association with temperature and dissolved oxygen was the most important environmental factor affecting rotifer community distribution. Cephalodella sp., Lepadella sp. and Trichotria pocillum showed a high positive relation to pico-plankton, showing this fraction as a possible rotifer food item. This paper demonstrated a higher efficiency of the finest net to characterize riverine zooplankton community that increases from up to downstream in terms of abundances and diversity.

L'auteur donne une liste de 29 espèces de Chironomides capturés en vol ou obtenus à partir d'élevages de larves prélevées dans les eaux douces et les eaux saumâtres de Camargue. On remarque parmi elles la présence de 3 espèces d'origine africaine.

Pour la première fois, une liste faunistique de 81 taxa de Chironomidés - 63 identifiés à l'espèce - récoltés par dérive dans 23 oueds du Nord, 2 oueds et 5 oasis du Sud de la Tunisie est présentée.La faune est à dominante paléarctique (55 espèces : 87,3 %). Les 12,7 % restants (8 espèces) sont des éléments de la faune méditerranéenne (3), nord-africaine (2), afrotropicale-ouest paléarctique (2), panpaléotropicale (1).De nouvelles récoltes d'imagos et nymphes [math] matures sont nécessaires pour confirmer l'apparente nouveauté spécifique de 5 types d'exuvies nymphales appartenant aux genres Larsia, Parakiefferiella, Paratanytarsus, Tanytarsus, Virgatanytarsus. 170 espèces de Chironomidés sont à présent recensées d'Afrique du Nord.

The present study evaluated the relative growth and allometry of Massartella brieni Lestage and Thraulodes sp. (Leptophlebiidae: Ephemeroptera). The morphometric analysis was based on 23 measurements and was conducted using a multivariate approach. Throughout postembryonic ontogeny, all of the head measurements, including those of the mouthparts, exhibited negative allometric growth. The mesothorax and wing pad exhibited positive allometric growth. The hind legs lengths in M. brieni and the fore and hind legs lengths in Thraulodes sp. exhibited positive allometry. The abdominal length in these two species exhibited positive allometric growth. Positive allometry was also observed along the abdomen width for M. brieni, and isometry was observed for Thraulodes sp. The relative strengthening of the thorax (in preparation for the winged stage) and the relative increase in the abdomen (which may be related to the development of the reproductive structures) during growth indicate that many of the structures that exhibit positive allometric growth are related to the transition from the aquatic to the adult stage of development.

Six substrats artificiels immergés au dégel dans la zone rocheuse (—1 —4 m) du lac de Port-Bielh (2 285 m), relevés à cinq périodes de l'année, sont colonisés par les Chironomides (90 %) et notamment par les formes libres et mobiles (Tanypodinae, Corynoneura) qui prédominent dans la biocénose littorale.

Ils permettent d'obtenir de précieux renseignements d'ordre qualitatif sur la composition des biocénoses, la microdistribution, les migrations au cours du développement (Psectrocladius sordidellus). Ils s'avèrent convenir plus particulièrement pour l'évaluation quantitative des populations inféodées aux substrats rocheux, permanentes (Limnea) ou temporaires (Paratanytarsus austriacus, Cyrnus cintranus).

Un autre type de substrat doit être envisagé pour les Chironomides constructeurs de fourreaux (Microtendipes, Micropsectra) de même pour les Oligochètes et les Pisidiums, vivant sur ou dans les zones de sédiments accumulés entre les blocs rocheux.

Dans ce travail, les auteurs dressent un premier inventaire faunistique des Chironomidés du Liban où 142 taxa ont été identifiés dans les deux rivière Oronte et Litani de la plaine de la Bekaa et dans la rivière côtière Beyrouth.81 espèces se révèlent nouvelles pour la région de la Méditerranée orientale : 131 sont nouvelles pour le Moyen-Orient dont les seules données antérieures concernaient la faune lacustre d'Israël.La distribution géographique des Chironomidés du Liban permet de situer cette région au carrefour des influences paléarctique, éthiopienne et orientale.

The new genus Metapelopia is established for species of Pentaneurini from the southeast Brazil. Generic diagnoses for larva, pupa and adult male are provided together with descriptions of all life stages of the new species Metapelopia corbii. The pupa and larva of an additional species in Metapelopia is described, but not formally named. In addition, keys to the males, pupae and larvae of genera in the Thienemannimyia group are provided.

Historically, the Kissimmee River meandered over an extensive floodplain wetland. In response to catastrophic flooding and settlement pressures in Central Florida, the Kissimmee was channelized, converting the complex, braided channel into a straightened canal. The result has been a sharp decrease in fringing wetland habitat and associated biota. Soon after channelization was completed, environmental concerns prompted the State of Florida to start examining options for restoration to reestablish the river's natural hydrology and restore lost wetland habitat. The grass shrimp, Palaemonetes paludosus has been identified as a keystone invertebrate species in this system. This study was designed to examine its distribution, diel movement, and growth within the two dominant macrophyte communities of the Kissimmee River riparian marsh: Nuphar and Polygonum. Results indicated that grass shrimp were more abundant in Polygonum beds. This species also showed no well-defined diel migration, although we found a significant vertical pattern in some instances. Palaemonetes paludosus growth was highest on periphyton and Polygonum leaves. Grass shrimp distribution may be explained by their decreased susceptibility to predation because of the higher habitat complexity inherent in Polygonum beds.

L'incapacité des poissons à se maintenir dans un courant d'eau modéré est considérée comme la manifestation biologique de la présence de poison. La toxicité est mesurée par le temps écoulé jusqu'à la manifestation. De jeunes carpes (espèce d'eau stagnante) sont utilisées. L'appareil permet d'obtenir alternativement un courant vertical (0,5 cm/s) ou horizontal (6-15 cm/s). L'eau peut circuler en circuit fermé (tests statiques) ou en circuit ouvert (tests dynamiques). Les comportements provoqués par l'effet du poison sur les carpes sont enregistrés au moyen de cellules photoélectriques.

In karst sink-holes within the environs of Czajków, and in an old fishpond within the Skorocice gypsum valley, 24 taxa of euglenophytes, comprising Euglena (10), Phacus (9), Lepocinclis (2), and Trachelomonas (3) were found. Four of them, Phacus elegans Pochmann, Ph. arnoldii Swirenko var. ovatus Popova, Ph. plicatus Conrad, and Ph. curvicauda Swir. var. robusta Allorge & Lefèvre, are new for the Polish flora, and rarely reported worldwide.

Cyanobacterial blooms cause extensive ecological damages in aquatic environments. Heterotrophic nanoflagellates (HNF) play an important role in controlling the populations of cyanobacteria in natural water bodies. In this study, we report a HNF, NF-WJ05, which grazes efficiently on the toxic cyanobacterium Microcystis aeruginosa strain PCC 7806. The morphological characteristics of the nanoflagellate observed by optical microscope and confocal microscope showed that NF-WJ05 could be a Paraphysomonas. The sequences of the internal transcribed spacer (ITS) regions of rDNA including the 5.8S rDNA region was determined and compared with sequences available in databases. The 5.8S rDNA sequence showed a high degree of similarity to those belonging to species of Chromophyta. However, sequences similar to that of its ITS were not found in the databases. Several environmental factors affecting the grazing efficiency of NF-WJ05 on cyanobacteria were evaluated. The more suitable conditions for grazing were 30°C and pH 5.0 with stirring. Ammonia inhibited the grazing, whereas low concentrations of phenol increased the grazing rate with an optimal concentration at 50 µg.L-1.

Reservoirs cause hydrological changes (i.e., water level stabilization) that favor the colonization of aquatic macrophytes. Knowing the ecological factors that determine the occurrence of these plants is critical for water management (e.g., plant control) and biodiversity conservation. In this sense, the present study investigated colonization patterns of Ludwigia sedoides in Lajeado reservoir (Tocantins River, Amazon Basin), in order to identify variables that influence colonization at habitat scale. We investigated the relationship between colonization (coverage area and occurrence) and morphometric (fetch, slope, depth and distance from shoreline) and biotic variables (local diversity of macrophytes and co-occurrence patterns). Stepwise regression selected fetch, depth and slope as the best variables to explain the variation in L. sedoides coverage, which together explained 46% of data variability. Fetch and slope were negatively correlated with coverage, whereas depth showed a positive correlation. No biotic variable was included in the model (P>0.05). However, the investigation of the geometric shape of bivariate correlations (null models) showed positive relationships with local species richness and richness of life forms (i.e., submerged, emergent, floating and epiphytic). In addition, an analysis of species co-occurrence (C-score) revealed that L. sedoides is negatively associated with some macrophyte species. We believe, however, that these results may be associated with species preferences for particular environmental conditions. In conclusion, the present study indicated that morphometric variables are potential predictors of the colonization of L. sedoides in Lajeado reservoir. Sheltered sites with low slope and moderate depths represent favorable environment for colonization and growth.

The chironomid populations of a 6th order section (400 m) of the middle Garonne river were studied monthly from September 1996 to October 1997. For the first time the main channel of the river was investigated including two floodplain waters : a side arm and an oxbow. Two sampling techniques were used for drift and benthic collections. A total of 21 766 specimens (pupae and pupal exuviae) were sorted and 137 species were identified. Among these, 12 species are new for the fauna of France : their ecology and biogeography are given. The chironomid population of the backwaters is especially diverse and distinctive since the waterbody is disconnected from the main channel. The studied section appears to be transitional corresponding with the epipotamal-metapotamal zones. The embankment of the watercourse since 1958, which has isolated floodplain waters and increased the current velocity in the main channel, mainly explains the dual typologic status observed. The main channel is colonised by rheophilous Orthocladiinae whereas the backwaters shelter a mixed population of limnophilous Chironominae and potamobiont Orthocladiinae. This study demonstrates the urgency for preserving floodplain waters because of their species richness, their uniqueness and their faunal interaction with the main channel. The strong faunal contribution of floodplain waters highlights the topicality and the value in investigating the less disturbed potamal zones of large rivers to increase our knowledge on biodiversity, ecology and biogeography of chironomid populations.