Dynamic micro-geographic and temporal genetic diversity in vertebrates: the case of lake-spawning populations of brown trout (Salmo trutta)

Conservation of species should be based on knowledge of effective population sizes and understanding of how breeding tactics and selection of recruitment habitats lead to genetic structuring. In the stream‐spawning and genetically diverse brown trout, spawning and rearing areas may be restricted source habitats. Spatio–temporal genetic variability patterns were studied in brown trout occupying three lakes characterized by restricted stream habitat but high recruitment levels. This suggested non‐typical lake‐spawning, potentially representing additional spatio–temporal genetic variation in continuous habitats. Three years of sampling documented presence of young‐of‐the‐year cohorts in littoral lake areas with groundwater inflow, confirming lake‐spawning trout in all three lakes. Nine microsatellite markers assayed across 901 young‐of‐the‐year individuals indicated overall substantial genetic differentiation in space and time. Nested gene diversity analyses revealed highly significant (≤P = 0.002) differentiation on all hierarchical levels, represented by regional lakes (F_LT = 0.281), stream vs. lake habitat within regional lakes (F_HL = 0.045), sample site within habitats (F_SH = 0.010), and cohorts within sample sites (F_CS = 0.016). Genetic structuring was, however, different among lakes. It was more pronounced in a natural lake, which exhibited temporally stable structuring both between two lake‐spawning populations and between lake‐ and stream spawners. Hence, it is demonstrated that lake‐spawning brown trout form genetically distinct populations and may significantly contribute to genetic diversity. In another lake, differentiation was substantial between stream‐ and lake‐spawning populations but not within habitat. In the third lake, there was less apparent spatial or temporal genetic structuring. Calculation of effective population sizes suggested small spawning populations in general, both within streams and lakes, and indicates that the presence of lake‐spawning populations tended to reduce genetic drift in the total (meta‐) population of the lake.     

Molecular Characterization of Gregarines from Sand Flies (Diptera: Psychodidae) and Description of Psychodiella n. g. (Apicomplexa: Gregarinida)

ABSTRACT. Sand fly and mosquito gregarines have been lumped for a long time in the single genus Ascogregarina and on the basis of their morphological characters and the lack of merogony been placed into the eugregarine family Lecudinidae. Phylogenetic analyses performed in this study clearly demonstrated paraphyly of the current genus Ascogregarina and revealed disparate phylogenetic positions of gregarines parasitizing mosquitoes and gregarines retrieved from sand flies. Therefore, we reclassified the genus Ascogregarina and created a new genus Psychodiella to accommodate gregarines from sand flies. The genus Psychodiella is distinguished from all other related gregarine genera by the characteristic localization of oocysts in accessory glands of female hosts, distinctive nucleotide sequences of the small subunit rDNA, and host specificity to flies belonging to the subfamily Phlebotominae. The genus comprises three described species: the type species for the new genus— Psychodiella chagasi ( Adler and Mayrink 1961 ) n. comb., Psychodiella mackiei ( Shortt and Swaminath 1927 ) n. comb., and Psychodiella saraviae ( Ostrovska, Warburg, and Montoya-Lerma 1990 ) n. comb. Its creation is additionally supported by sequencing data from other gregarine species originating from the sand fly Phlebotomus sergenti . In the evolutionary context, both genera of gregarines from mosquitoes ( Ascogregarina ) and sand flies ( Psychodiella ) have a close relationship to neogregarines; the genera represent clades distinct from the other previously sequenced gregarines.     

Effects of soil frost on soil respiration and its radiocarbon signature in a Norway spruce forest soil

Apart from a general increase of mean annual air temperature, climate models predict a regional increase of the frequency and intensity of soil frost with possibly strong effects on C cycling of soils. In this study, we induced mild soil frost (up to −5 °C in a depth of 5 cm below surface) in a Norway spruce forest soil by removing the natural snow cover in the winter of 2005/2006. Soil frost lasted from January to April 2006 and was detected down to 15 cm depth. Soil frost effectively reduced soil respiration in the snow removal plots in comparison to undisturbed control plots. On an annual basis 6.2 t C ha⁻¹ a⁻¹ were emitted in the control plots compared with 5.1 t C ha⁻¹ a⁻¹ in the snow removal plots. Only 14% of this difference was attributed to reduced soil respiration during the soil frost period itself, whereas 63% of this difference originated from differences during the summer of 2006. Radiocarbon (Δ¹⁴C) signature of CO₂ revealed a considerable reduction of heterotrophic respiration on the snow removal plots, only partly compensated for by a slight increase of rhizosphere respiration. Similar CO₂ concentrations in the uppermost mineral horizons of both treatments indicate that differences between the treatments originated from the organic horizons. Extremely low water contents between June and October of 2006 may have inhibited the recovery of the heterotrophic organisms from the frost period, thereby enhancing the differences between the control and snow removal plots. We conclude that soil frost triggered a change in the composition of the microbial community, leading to an increased sensitivity of heterotrophic respiration to summer drought. A CO₂ pulse during thawing, such as described for arable soils several times throughout the literature, with the potential to partly compensate for reduced soil respiration during soil frost, appears to be lacking for this soil. Our results from this experiment indicate that soil frost reduces C emission from forest soils, whereas mild winters may enhance C losses from forest soils.     

Systematic revision of the genus Everettia Godwin‐Austen, 1891 (Mollusca: Gastropoda: Dyakiidae) in Sabah,northern Borneo

The species of the snail genus Everettia in the Malaysian state of Sabah are superficially similar and difficult to distinguish by their shells. This paper presents new data on the taxonomy and distribution of Everettia in Sabah that have accumulated since the revision by Godwin‐Austen in 1891. By using morphological and molecular phylogenetic approaches, we reveal at least seventeen species of Everettia in Sabah, of which eleven are new to science, namely: Everettia layanglayang sp. nov. , Everettia lapidini sp. nov. , Everettia paulbasintali sp. nov. , Everettia occidentalis sp. nov. , Everettia jasilini sp. nov. , Everettia safriei sp. nov. , Everettia interior sp. nov. , Everettia jucundior sp. nov. , Everettia planispira sp. nov. , Everettia monticola sp. nov. , and Everettia dominiki sp. nov. , and one new subspecies, namely, Everettia corrugata williamsi ssp. nov. Phylogenetic analysis of mitochondrial COI and 16S, and nuclear ITS‐1 sequences demonstrates the monophyly of most of the morphologically well‐defined species. Our results show that certain aspects of classical morphology‐based taxonomy for Everettia species, especially with regard to the unique combination of shell surface sculptures, animal head colour, and mantle pigmentation, are solid. A dichotomous key to the Sabah species and subspecies of Everettia is provided. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157 , 515–550.     

Three new species of deep‐sea Gromia (Protista,Rhizaria) from the bathyal and abyssal Weddell Sea,Antarctica

We describe three new species of the genus Gromia from bathyal and abyssal depths in the Weddell Sea. The new species are characterized by a combination of morphological and molecular criteria. All three species possess a distinct oral capsule and a layer of ‘honeycomb membranes’, which form the inner part of the organic test wall. Both these features are typical of gromiids. Their identification as gromiids is confirmed by analyses of partial small subunit ribosomal DNA (SSU rDNA) gene sequences. Gromia marmorea sp. nov. is a rounded species with a prominent oral capsule and a characteristically mottled appearance. In Gromia melinus sp. nov. , the test surface exhibits a polygonal pattern of ridges, with a layer of clay particles coating the surface between the ridges. Gromia winnetoui sp. nov. represents an elongate morphotype in which the organic test is enclosed within an agglutinated case, a feature previously unknown in gromiids. Phylogenetic analysis using the maximum‐likelihood method revealed that all three species form distinct clades, reflecting the morphological differences among Weddell Sea species, as well as between deep‐water Southern Ocean Gromia and previously described gromiids. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157 , 451–469.     

Inadvertent gene silencing of argininosuccinate synthase (bcass1) in Botrytis cinerea by the pLOB1 vector system

For several years, researchers working on the plant pathogen Botrytis cinerea and a number of other related fungi have routinely used the pLOB1 vector system, based on hygromycin resistance, under the control of the Aspergillus nidulans oliC promoter and what was reported to be the β‐tubulin (tubA) terminator. Recently, it has been demonstrated that this vector contains a 446‐bp portion of the B. cinerea argininosuccinate synthase gene (bcass1) rather than the tubA terminator. As argininosuccinate synthase is essential for the production of l ‐arginine, inadvertent gene silencing of bcass1 may result in partial l ‐arginine auxotrophy and, indeed, may lead to altered phenotypes in planta. In this article, we report our findings relating to possible problems arising from this incorrect plasmid construction. As an absolute baseline, gene disruption of bcass1 was carried out and generated a strict auxotroph, unable to grow without exogenous arginine supplementation. The knockout displayed an alteration in host range in planta, showing a reduction in pathogenicity on strawberries, French bean leaves and tomatoes, but maintained wild‐type growth on grape, which is in accordance with the reported arginine availability in such tissues. Deliberate gene silencing of bcass1 mirrored these effects, with strongly silenced lines showing reduced virulence. The degree of silencing as seen by partial auxotrophy was correlated with an observed reduction in virulence. We also showed that inadvertent silencing of bcass1 is possible when using the pLOB1 vector or derivatives thereof. Partial arginine auxotrophy and concomitant reductions in virulence were triggered in approximately 6% of transformants obtained when expressing enhanced green fluorescent protein, luciferase, monomeric red fluorescent protein or β‐glucuronidase using the pLOB1‐based expression system, which inadvertently contains 446 bp of the bcass1 coding sequence. We recommend the testing of transformants obtained using this vector system for arginine auxotrophy in order to provide assurance that any observed effects on the development or virulence are a result of the desired genetic alteration rather than accidental bcass1 silencing.     

Cyclic temperatures influence growth efficiency and biochemical body composition of vertically migrating fish

1. Diel vertical migrations (DVM) are frequently observed in pelagic fish and zooplankton populations. In addition to predator avoidance and foraging opportunity, bioenergetics optimisation has been hypothesised to cause the selective advantage of migrating fish. However, experimental confirmation of growth advantages of fish held at naturally observed cyclic temperatures, and food densities are surprisingly rare. 2. We compared growth rates, growth efficiencies and energy budgets of vendace (Coregonus albula, Salmoniformes) fed daily rations of 10% body mass and held at low (4.5 °C), high (8 °C) and cyclic (switch between 4.5 and 8 °C) temperatures over a period of 6 weeks. Biochemical body composition was evaluated by bioimpedance analyses and direct determination of water, lipid and protein content in a subset of fish. 3. Growth rate and food conversion efficiency were similar in fish held at high and cyclic temperatures, but higher than those found at low temperatures. Body condition of fish at cyclic temperatures was maximised, but these fish also had the highest water content. The proportion of lipids and proteins was slightly depleted in fish held at cyclic and low temperatures relative to the high temperature treatment. Accordingly, growth and biochemical composition of fish responded specifically to cyclic temperatures and were not simply intermediate between those found at low and high temperatures. 4. We could not confirm a bioenergetics advantage of fish switching between high and low temperatures. However, there were no substantial extra metabolic costs through exposure to cyclic temperatures, and hence, fish performing DVM may benefit from predation avoidance without compromising their metabolic balance and hence growth rates. These results suggest that the evolution of DVM is a multi‐faceted process with no single ultimate explanation.     

Redefining the damselfly families: a comprehensive molecular phylogeny of Zygoptera (Odonata)

An extensive molecular phylogenetic reconstruction of the suborder Zygoptera of the Odonata is presented, based on mitochondrial (16S, COI) and nuclear (28S) data of 59% of the 310 genera recognized and all (suspected) families except the monotypic Hemiphlebiidae. A partial reclassification is proposed, incorporating morphological characters. Many traditional families are recovered as monophyletic, but reorganization of the superfamily Coenagrionoidea into three families is proposed: Isostictidae, Platycnemididae and Coenagrionidae. Archboldargia Lieftinck, Hylaeargia Lieftinck, Palaiargia Förster, Papuargia Lieftinck and Onychargia Selys are transferred from Coenagrionidae to Platycnemididae, and Leptocnemis Selys, Oreocnemis Pinhey and Thaumatagrion Lieftinck from Platycnemididae to Coenagrionidae. Each geographically well‐defined clade of Platycnemididae is recognized as a subfamily, and thus Disparoneurinae (i.e. Old World ‘Protoneuridae’) is incorporated, Calicnemiinae is restricted, and Allocnemidinae (type genus: Allocnemis Selys) subfam.n ., Idiocnemidinae (type genus: Idiocnemis Selys) subfam.n . and Onychargiinae (type genus: Onychargia Selys) subfam.n . and Coperini trib.n . (type genus: Copera Kirby) are described. Half of Coenagrionidae belongs to a well‐supported clade incorporating Coenagrion Kirby and the potential subfamilies Agriocnemidinae, Ischnurinae and Pseudagrioninae. The remainder is less well defined, but includes the Pseudostigmatidae and New World Protoneuridae that, with Argiinae and Teinobasinae, may prove valid subfamilies with further evidence. Ninety‐two per cent of the genera formerly included in the polyphyletic Amphipterygidae and Megapodagrionidae were studied. Pentaphlebiidae, Rimanellidae and Devadattidae fam.n . (type genus: Devadatta Kirby) are separated from Amphipterygidae, and Argiolestidae, Heteragrionidae, Hypolestidae, Philogeniidae, Philosinidae and Thaumatoneuridae from Megapodagrionidae. Eight further groups formerly placed in the latter are identified, but are retained as incertae sedis; the validity of Lestoideidae, Philogangidae and Pseudolestidae is confirmed. For some families (e.g. Calopterygidae, Chlorocyphidae) a further subdivision is possible; Protostictinae subfam.n . (type genus: Protosticta Selys) is introduced in Platystictidae. Numerous new combinations are proposed in the Supporting Information. Many long‐established families lack strong morphological apomorphies. In particular, venation is incongruent with molecular results, stressing the need to review fossil Odonata taxonomy: once defined by the reduction of the anal vein, Protoneuridae dissolves completely into six clades from five families.     

Potential for passive internal dispersal: eggs of an aquatic leaf beetle survive passage through the digestive system of mallards

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Clonality and genetic variation in Amylostereum areolatum and A. chailletii from northern Europe

Genetic variation within and between vegetative compatibility groups (VCGs) of Amylostereum areolatum (Fr.) Boid. and Amylostereum chailletii (Pers.: Fr.) Boid. isolates was investigated. DNA fingerprints were made using the M13 core sequence as a primer. A total of 53 isolates of A. areolatum and 57 isolates of A. chailletii from Lithuania, Sweden, Denmark and Great Britain were studied. In all cases isolates belonging to the same VCG showed identical DNA banding patterns, suggesting that VCGs correspond to clones. In A. areolatum the vast majority of the isolates (spread by Sirex juvencus L.) were assigned to dispersive clones, that have wide geographical distribution (i.e. the same genotypes were detected in Lithuania, Sweden and Denmark), with low genetic variation between the different clones. By contrast, A. chailletii population structure was consistent with the spread of airborne basidiospores produced by outcrossing. Only a small fraction of A. chailletii isolates studied, could be assigned to dispersal clones with a local distribution, spread by Urocerus gigas L. Overall, M13 fingerprinting detected low genetic differentiation in both species in the samples we studied.