Field observation of foraging behavior by a group of adult diving beetles Agabus (Gaurodytes) bipustulatus preying on an adult Lissotriton boscai

Adult dytiscids prey on a variety of items including other invertebrates but also larger prey such as frogs and fish. Observations of anuran larvae predation are common. However, there have been no reports concerning predation on caudata post‐metamorphosis by dytiscids. Here we describe a predation event by a group of adult diving beetles of the species Agabus (Gaurodytes) bipustulatus (Linnaeus, 1767) on an adult Lissotriton boscai (Lataste in Tourneville, 1879). This report represents the first observation of foraging behavior of adult diving beetles preying on and consuming a living post‐metamorphic newt.     

Mitochondrial DNA diversity and taxa delineation in the land snails of the Iberus gualtieranus (Pulmonata,Helicidae) complex

Iberus gualtieranus is a species complex of land snails that is endemic to the Iberian Peninsula. The species taxonomy of the group is based merely on the basis of shell morphology, but validity of the existing taxonomy is uncertain. Using mitochondrial DNA (mtDNA) data (cytochrome oxidase I and 16S rRNA sequences) we were able to validate the observed phylogenetic taxa within the I. gualtieranus s.l. complex by means of the analysis of specimens of the different morphospecies, together with the study of topotypes. Strong incongruences were obtained between morphology and molecular data. The Iberus alonensis morphospecies comprised several genetically divergent but morphologically cryptic lineages. Considering (1) the allopatric distribution of the operational taxonomic units (OTUs), (2) the morphological differentiation, (3) the possible occurrence of hybridization among the different lineages, and (4) the strong differentiation of the mtDNA phylogroups, we suggest the main lineages obtained, for the time being, may be treated as evolutionary species. The robust phylogenetic reconstruction obtained allows us to consider I. alonensis s.s., Iberus campesinus, Iberus carthaginiensis, and Iberus gualtieranus s.s. as valid species. Two additional unnominated taxa of the alonensis shell type have also been identified. Further subdivisions are also considered, including Iberus gualtieranus mariae and Iberus gualtieranus ornatissimus. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 722–737.     

Genetic structure and demographic history of brown trout (Salmo trutta) populations from the southern Balkans

1. The present study was designed to characterize the genetic structure of brown trout ( Salmo trutta ) populations from the southern Balkans and to assess the spread of non-native strains and their introgression into native trout gene pools. We analysed polymorphism at nine microsatellite loci in seven supposedly non-admixed and three stocked brown trout populations.
2. The analyses confirmed the absence of immigration and extraordinarily strong genetic differentiation among the seven non-introgressed populations in parallel with low levels of intrapopulation genetic variability. In contrast, analyses of the stocked populations revealed that the genetic integrity of the local populations had been substantially changed, and the populations must be characterized as hybrid swarms. The pattern of population differentiation observed at microsatellites contrasted to that depicted previously by mtDNA variation. However, the close relationships between populations from the Danube and Axios river systems proposed solely by microsatellites could be explained by palaeogeographic events.
3. Our research showed that most of the populations examined represent unique gene pools, whose existence is critically compromised. Therefore, appropriate management and conservation strategies should be developed urgently in order to protect the subspecific biodiversity and to reverse currently negative trends.     

Structural, physical and chemical characteristics of Microcystis aeruginosa hyperscums from a hypertrophic lake

SUMMARY. 1. This paper examines the structural, physical and chemical characteristics of cyanobacterial hyperscums (floating scums of densely packed eyanobacteria. measuring decimetres in thickness, that are covered by a dry crust of photo-oxidized cells) from hypertrophic Hartbeespoort Dam, South Africa. 2. The hyperscum community was a cyanobacterial-baclcrial association, in which the cyanobacterium Microcystis aeruginosa comprised 98% of the biovolumc, with cell concentrations exceeding 10⁹ ml^?1. 3. The buoyancy mechanism of M. aeruginosa and evaporation at the surface led to increasing compaction of the colonies with declining distance from the surface, and the formation of three distinct, but continuous layers: a 1–2 mm dry surface crust (water content: 14%, chlorophyll a concentration: 3 g l^?1), a 5–10 mm compact layer just below the crust (77% water, 1 g l^?1 chlorophyll a), and a less compact layer (96% water, 200–500 mg l^?1 chlorophyll a) from about 1 cm depth to the bottom, comprising the bulk of the hyperscum. 4. The crust attenuated all the incident light and reduced free gas exchange. Beneath it continuously dark anaerobic, highly reduced conditions prevailed. As the hyperscum aged over 3 months in 1984, at 10 cm depth the pH gradually declined from 6.6 to 5.9, interstitial water ammonia-N concentrations increased from 0.45 to 119 mg l^?1, soluble reactive phosphorus from 2.8 to 83.3 mg l^?1, and dissolved organic carbon reached a maximum of 460 mg l^?1. At any point in time these concentrations declined gradually with increasing depth within the hyperscum, and declined dramatically beneath the hyperscum. Similar patterns were recorded in another hyperscum in 1986. 5. The chemical and temperature depth profiles indicated that free water movement took place around and under the hyperscum, but within it water movement was restricted to diffusion. 6. Gas bubbles composed of 28% methane. 19% CO₂, 53% N₂, and traces of H₂ trapped within the hyperscum, and the presence of volatile fatty acids in the interstitial water were indicative of anaerobic decomposition processes mediated by fermenting and methanogenic bacteria, and N:P ratios below 1.5 in the interstitial water suggested that nitrogen was lost as gas, possibly through denitrification. 7. We hypothesize that the major sites of decay of M. aeruginosa were the crust and the compact layer beneath it, while deeper within the hyperscum this cyanobacterium could survive prolonged periods of dark anaerobic conditions. This hypothesis requires confirmation.