The predatory behavior of adult females of Thermocyclops decipiens in relation to two cladoceran prey, Ceriodaphnia cornutaand Diaphanosoma spinulosum, was analyzed by laboratory observations. The number of attacks, captures, and ingestionswere quantified. Probabilities of capture after attack (C/A) and ingestion after capture (I/C) were calculated as indicators of preypost-encounter vulnerability. T. decipiens attacked, captured and ingested both cladoceran species, but vulnerabilities of preywere relatively low. C/A was higher in C. cornuta than in D. spinulosum. Larger individuals of D. spinulosum showed higherC/A and I/C than smaller individuals but no effects of size were observed in C. cornuta. The ability of escape as well as thestrength and shape of carapace, seem to partially explain differences in vulnerability among these species. Our results suggestthat intensity of mechanical perturbations and other size-dependent factors, but not body size alone, could be important in determiningpost-encounter prey vulnerability among individuals of a same species.

Many adverse environmental factors influencing the Shatt-al Arab River, southern Iraq, during the past century and especially in recent years, combined with the ever-increasing demand for freshwater in the region, indicate the need to obtain information about its salinity regime. The aim of our study was both to find out what historical data there are and then to compare these with the results of a survey of the salinity and water quality of a stretch of the present river over the year October 2009–September 2010. The evidence suggests that there has been a marked upstream shift in the influence of sea water. Salinity values of 2 and 8‰ were found at two sites where elevated salinity had never been reported previously. Water quality variables indicated increased concentrations over the previous four decades and were beyond the national and international standards. As such changes in a major water resource have serious implications for the inhabitants of Basrah, the biological diversity in the river and the whole Gulf ecosystem, it is suggested that there should be a much more detailed study to provide the evidence needed to convince upstream water users of the need to conserve water and manage the whole catchment properly.

Récapitulation des Gastrotriches d'eau douce déjà signalés de la Faune française. Apport d'une liste d'espèces (dont quelques formes inédites) rencontrées dans les départements des Landes, de la Gironde, de la Charente-Maritime et de la Somme. Description des animaux rencontrés.

Des substrats artificiels, remplacés tous les 20 jours entre juin et novembre, ont été utilisés pour étudier la production et la structure des communautés de microphytes benthiques dans un secteur de rivière long de 50 km et soumis à une importante pollution. Le périphyton de ce milieu, largement dominé par les bactéries filamenteuses (Sphaerotilus natans), se caractérise par un très faible développement des algues (rapport Chl. a/M.O. < 0,25 ‰) et par une croissance élevée (0,5 à 3 g M.O. . m-2.j-1). L'évolution spatio-temporelle du taux de croissance des communautés photoprophes (P) et hétérotrophes (H), du rapport des biomasses (P/H) qui en résulte et de la composition spécifique des biocénoses traduit les variations de la charge polluante. Les possibilités d'utilisation de tels indices pour caractériser les niveaux de pollution organique sont discutées.

Un deuxième inventaire des Chironomidés du Maroc est donné. 87 taxa, la plupart identifiés à l'espèce, sont ajoutésà la première liste portant à 223 le total des espèces actuellement connues du Maroc.La majorité a une large répartition paléarctique ; 7 espèces ont une distribution afrotropicale intéressante ; 10 espècespeuvent être considérées comme des endémiques de la région Sud-Ouest paléarctique.

Two consecutive earthquakes temporary changed a zooplankton community in a high-mountain Lake Krn (altitude 1383 m a.s.l.). It was dominated by the eurytherm copepod, Cyclops vicinus, until 1998, when the first earthquake hit the lake (EMS=5.6). After the earthquake, the population of C. vicinus collapsed and the thermophilic cladoceran, Ceriodaphnia quadrangula, took over. After the second earthquake in 2004 (EMS=4.0), C. vicinus became untraceable. In 2008, few copepods reappeared and by 2010 they became the sole dominant again. Only Secchi-disc depth showed a statistically significant increase over time, while Ntot, Ptot and temperature showed an increasing trend, yet the relationship was insignificant. To compare multi-parameter properties of the water column, the studied period was divided into Period 1 (before the first earthquake), Period 2 (between earthquakes) and Period 3 (after the second earthquake). A Hotteling T2 test confirmed a statistically significant difference between Periods 1 and 2 & 3 (P<0.01), but not between Periods 2 and 3 (P>0.1). During simple laboratory experiment, specimens of C. vicinus were covered with a thin layer of sediment, to mimic the earthquake's effect on their survival. A hypothesis was that the timing of both earthquakes had been crucial for decimation of C. vicinus population as they re-suspended sediment with hibernating copepodites. As these became subsequently buried they were deprived of a re-activation signal and exposed prolonged anoxic conditions there. C. quadrangula temporary filled the void left by the copepod, which needed 6 years to regain its dominance.

Le peuplement zooplanctonique du lac d'Ayamé comprend 45 espèces ou sous-espèces : 26 Rotifères, 15 Cladocères, 4 Copépodes. 20 d'entre elles sont nouvelles pour la Côte d'Ivoire. Quelques espèces peu communes : Dicranophorus claviger cf. venezueliensis, Bosmina tubicen, Thermodiaptomus yabensis caractérisent ce peuplement.

Invertebrate aquatic assemblages in ponds from Mediterranean wetlands are composed of organisms belonging to different taxonomic groups, which present a wide range of sizes (from small rotifers to large crustaceans or insects). Although they are often sampled and analyzed separately, the ecological links among these organisms should be considered, especially in very shallow waters. In our study, invertebrate assemblages (including micro-, macrozooplankton and macroinvertebrates) were characterized in eight shallow lakes from Mediterranean wetlands in Southeastern Spain. A great spatial and temporal variability in the assemblages and in some environmental features was observed. The community was dominated in abundance and species richness by rotifers in most of the water bodies. Fish greatly contributed to the differences in community composition, as fishless ponds presented abundant and diverse cladoceran populations. Nutrient and chlorophyll-a concentration, conductivity and macrophyte cover had also a great influence on these assemblages, especially in micro- and macrozooplankton. The temporal changes observed in some of these variables affect the proportion of invertebrate biomass of the different groups along the study period. All this environmental heterogeneity produces similar responses in the invertebrate groups, in general well adapted to salinity changes or high trophic conditions. Although the heterogeneity and human disturbances can increase regional diversity, they can cause the disappearance of valuable habitats, and finally, the homogeneity in invertebrate assemblages.

La forme de la courbe métabolisme/température (courbe M/T) de la larve de M. testacea varie sous l'influence de facteurs écologiques tels que le courant ou le substrat.

— A toutes les températures entre 5 et 20°C la larve de M. testacea consomme plus d'oxygène quand elle est soumise à une agitation de l'eau.

— On constate une insensibilité à une variation de température de 5°C, quand la larve se trouve dans les conditions expérimentales proches des conditions naturelles : 10 à 15°C et en présence d'un courant.

— L'absence d'un substrat lui permettant de se déplacer ou de s'accrocher (ici un grillage), entraîne également une augmentation de la consommation d'oxygène.

— A 25°C, température sublétale pour ces larves, le niveau du métabolisme respiratoire est le même quelles que soient les conditions expérimentales.

La notion de métabolisme de base chez les poïkilothermes aquatiques est discutée dans le cadre des expériences écologiques.

This study focuses on the host-parasite relationships between species of non-biting midges (Diptera: Chironomidae) and watermites (Acari: Hydrachnidia) in seven springs in Luxembourg. Emergence traps were operated through the season, and identificationof the catches enabled an overview of species composition, abundance and host-parasite associations in the spring communities.Our results show that the Luxembourg springs have similar chironomid diversity to other springs in Europe, and thatparticular species are more often found in certain spring habitats. Furthermore, we show that prevalence of water mite parasitismis highly variable among the sampled chironomid hosts, and that there are several species which were not parasitized despitebeing numerous in our samples. The reasons for the latter observation are discussed, and most of the cases can be explainedby general unavailability of host or parasite, or life cycle incompatibility.

Ce travail traite d'Agriotypus armatus, un Ichneumonide parasite de nymphes de Trichoptères Goeridae et Odontoceridae. Les cycles du parasite et de son hôte ont été étudiés par des prélèvements réguliers effectués sur le terrain et par des techniques particulières au laboratoire.

1. - La famille des Agriotypidae comporte un seul genre avec deux espèces, l'une européenne A. armatus, l'autre japonaise A. gracilis. L'espèce européenne est polymorphe. Selon l'hôte, deux "formes" sont reconnaissables : une forme "armatus", parasite de Goeridae (Silo) et une forme "major", parasite d'Odontoceridae (Odontocerum). Les résultats obtenus ne permettent pas d'affirmer qu'il s'agit de deux espèces, de deux sous-espèces ou simplement de polymorphisme.

2. - L'hôte étudié est Silo piceus (Goeridae). Cette espèce est univoltine. Son développement larvaire comprend 5 stades; il s'effectue dans 11 types de fourreaux. Les larvules éclosent en juillet-août. L'hivernage a lieu au stade 5. L'entrée en prénymphose se produit en mars-avril. C'est à ce moment que les Agriotypes femelles commencent à pondre.

3. - Le développement larvaire d'Agriotypus armatus comprend 5 stades externes. La larve de stade I est agriotypiforme. Les larves des stades II, III et IV, de type vermoïde, se distinguent essentiellement par la taille. Au stade I la larve se place sous les fourreaux alaires de la jeune nymphe et commence à la sucer. Elle demeure là jusqu'au stade IV. Ensuite elle passe à l'arrière de sa victime et achève rapidement de la consommer. La larve de dernier stade occupe tout l'étui du Trichoptère à l'intérieur duquel elle tisse un cocon en soie, prolongé à l'extérieur par un appendice rubané. En même temps, elle remplit ce cocon de gaz.

4. - De l'oeuf au stade larvaire IV, le développement dure 5 semaines environ. Le stade V se prolonge durant près de deux mois. La nymphose et la mue imaginale ont lieu en septembre-octobre. L'imago subit ensuite une longue diapause hivernale qui lui permet d'attendre le printemps.

5. - Pendant ce long séjour sous l'eau, c'est le ruban qui, grâce à sa structure vacuolaire, assure les échanges gazeux entre l'air du cocon et l'eau environnante.

6. - L'émergence des adultes peut être provoquée, dans certaines conditions, par une élévation de la température.

7. - La ponte oblige la femelle à demeurer plusieurs heures sous l'eau. La recherche de l'hôte semble se faire pour une part au hasard. La femelle serait capable de reconnaître certains types d'étuis, mais les caractéristiques de l'hôte lui-même semblent peu influencer le comportement de ponte du parasite. De nombreux oeufs peuvent être pondus sur un même hôte, mais il y a toujours un seul Agriotype qui parvient à complet développement. Agriotypus est un parasite externe solitaire.

La carte altitudinale et l'enregistrement des moyennes thermiques trimestrielles pendant 3 ans dans 35 stations de la région lyonnaise fournissent la même image de la distribution des Planaires : les espèces rhéophiles C. alpina, P. felina et D. gonocephala occupent trois zones successives avec des recouvrements de seulement 0,3 à 0,5 °C dans leurs températures annuelles moyennes. La zone des espèces limnophiles P. tenuis et P. nigra double, en eau calme, les deux zones de P. felina et D. gonocephala. Enfin D. tigrina semble s'étendre davantage vers les températures élevées.

Sans qu'il y ait concordance des valeurs absolues, cette succession reproduit celle qui apparaît dans la physiologie des mêmes espèces, laissant à penser que les mécanismes de la zonation sont d'ordre compétitif. Le remplacement de D. gonocephala par la souche de P. felina introduite dans une station située au niveau du secteur de recouvrement de leurs deux zones thermiques, confirme cette hypothèse.

A new species of the genus Allocyclops Kiefer, 1932 (Cyclopidae, Cyclopinae) is described from the subterranean waters of Barrow Island, Western Australia. It belongs to the subgenus Psammocyclops Kiefer, 1955, but has not any close relatives among the recent known species. With the addition of the new representative the genus Allocyclops now includes thirteen species on all continents, except Asia and Antarctica. A key to aid in their identification is provided.

The habitat preferences, temporal dynamics in density and the life history of two species of mayflies, Metamonius anceps andMeridialaris chiloeensis, were investigated in a Patagonian mountain stream over a period of one year. Benthic samples weretaken in a low order Nothofagus forested stream. M. anceps was univoltine with small nymphs predominating in winter andemergence occurring in summer. M. chiloeensis showed a bivoltine life cycle with a winter and summer generation, andemergence period in spring and summer. Both species were significantly more abundant in the low water period than in the highdischarge season. Gravels supported significantly more individuals of M. chiloeensis than sand in pools and leaf packs. Temporaloverlap of abundance between species was low. The existence of different life history strategies and the temporal shift of maingenerations and density peaks were critical to allow species coexistence.

Using data from nine lakes, sampled between 2002 and 2010, as well as literature we have analysed blooms of Gonyostomum semen (Ehr.) Diesing in a new spreading area (Polesie region, Central–Eastern Poland). We tried to determine habitat suitability for high biomass of the species, including both physicochemical and morphometric features. High biomass of Gonyostomum (>1.4 mg.L−1) was found in three groups of coloured water bodies: (a) very small (<0.002 km2) peat pits with low pH values and mineral content; (b) larger ponds with neutral pH values and intermediate conductivity; (c) natural lakes with intermediate parameters in terms of area, pH and mineral content. There were no statistical differences regarding the values of the species biomass among the groups of lakes. Gonyostomum biomass was closely positively correlated with water colour, whereas it was weakly negatively correlated with lake area and depth. The results show that G. semen in a new spreading area bloomed in a broad spectrum of freshwater habitats.

This study employs histological procedure to elucidate the natural cycles of gonadal development in a population of E. radiata in the Cross River, Nigeria. The cycles of condition indices and shell-free dry mass follow a general pattern in which they increased with the sexual maturity of the species till a peak is reached in June when spawning begins. Then there is a gradual decline, as the spawning event progresses, till a minimum is obtained in October when the animal is spent. Thus, the species spawns once in a year during the peak of the rainy season (June to October). The timing of spawning is such that the young larvae stand to profit from the high plankton biomass during the ensuing dry season months.

The wetlands found in the Brazilian Cerrado are poorly studied environments regarding ecological aspects. Assessing the diversity of aquatic invertebrates in wetlands is a challenging task, since there are no standard sampling methods that minimize the spatial effects caused by macrophytes. The aim of this study was to evaluate the efficiency of a new sampling method for assessing Cladocera richness in macrophyte-rich wetlands of Brazilian Cerrado. In six wetlands, one transect was established which corresponded to a gradient of depth or change in aquatic vegetation. Samples containing cladocerans were collected using plankton net dragged among aquatic vegetation in the dry and rainy seasons. The species accumulation curves using non-parametric estimators and the overestimation of richness were used to determine the sampling efficiency. The species accumulation curves showed different asymptotic trends regarding the season and wetland studied. Especially in the rainy season, an asymptotic trend was not observed in two of the wetlands studied, which may reflect the influence of seasonality on Cladocera assemblage. Nevertheless, the overestimation of species richness showed that the method of sampling was able to find more than 60% of the estimated species richness, regardless of season or wetland studied. These results indicate that the method employed for sampling Cladocera in the Cerrado wetlands can be considered adequate.

Une liste de «46» espèces de Chironomidés récoltées pour la première fois en France continentale est présentée. La moitié (22) proviennent des zones potamiques des fleuves Loire et Rhône. Des corrections et des compléments de répartition sont apportés au premier bilan faunistique (Serra-Tosio & Laville 1991). Huit genres Hayesomyia, Dratnalia, Euryhapsis, Gillotia, Kloosia, Lipiniella, Robackia, Saetheria et un sous-genre Demieryptochironomus (Irmakia) sont signalés en France pour la première fois. Ces nouvelles récoltes (+ Parachironomus mauricii et Pseudomittia gracilis), portent à 646 les espèces de Chironomidés actuellement recensées sur le territoire français. Cela correspond à la moitié de la faune chironomidienne paléarctique connue.

We characterized phytoplankton community succession at different depths of a shallow hypertrophic reservoir in relation to physical and chemical environmental variables. The phytoplankton community was sampled biweekly at three different water depths (surface, middle and bottom) in the reservoir from November 2002 to February 2004. A range of 18 environmental variables including temperature, electrical conductivity (EC), total phosphorus (TP) and total nitrogen (TN) were measured to assess their influence on phytoplankton community succession. As well, combined multivariate analyses with a cluster analysis and a nonmetric multidimensional scale (NMDS) were conducted. Microcystis aeruginosa was the dominant species in all seasons except spring. Thus, Cyanophyceae was a dominant taxonomic group. In spring, Bacillariophyceae dominated, followed by Cryptophyceae and Chlorophyceae. The succession was relatively delayed at the middle and bottom layers compared with at the surface layer. Abundance and species richness of phytoplankton were also higher in the surface layer than in the bottom layer. Cluster analysis classified the phytoplankton community into four clusters at each depth, and the changes were also well reflected in the NMDS ordination. Each cluster showed seasonal patterns characterized by indicator species, as well as environmental variables such as temperature, conductivity, and nutrients including N and P. Seasonal dynamics of the phytoplankton community was the strongest at the surface layer and weakest at the bottom layer. These depth-variable environmental variables are likely to be the key factors driving changes in the phytoplankton community composition.

The generic diagnosis of Euryhapsis Oliver and the description of E. cilium Oliver are augmented. E. fuscipropessp.n. is described as male imago and shown to be close to E. cilium. The systematic position of the genera related toBrillia Kieffer and Eurycnemus van der Wulp is discussed. A review and a key to male and female imagines of generaof the Brillia group with single gonostyli are given. The generic diagnoses of the genera Irisobrillia Oliver, TokyobrilliaKobayashi & Sasa, and Pseudobrillia Niitsuma are augmented or emended. The description of the female imago of T. longicosta Oliver is augmented. T. anderseni sp. n. from Tanzania is described as male and female imago, the description of the male imago of I. Tamamegaseta augmented and the female described. The description of the male imago of P. komorii Niitsuma is augmented.