Isolation and characterization of short tandem repeats in an invasive swimbladder nematode,parasitic in Atlantic freshwater eels,Anguillicola crassus

We describe the isolation and characterization of seven polymorphic short tandem repeats (STR) for the eel parasite Anguillicola crassus. This invasive swimbladder nematode endemic in East Asia was recently introduced into Europe. The number of alleles for each STR ranged from 13 to 39 per locus with observed heterozygosities between 0.49 and 0.98. The Taiwanese population displayed higher genetic diversity compared to the Irish sample, an observation consistent with the Asian biogeographical origin of the nematode. Availability of the reported STR will facilitate the investigation of the population genetic structure with regard to multiple invasions.     

Foot Surveys of Large Mammals in Woodlands of Western Tanzania

Abstract: Reliable assessments of large mammal population sizes are crucial for the management of protected areas. We tested feasibility of foot surveys for population assessments of large mammals in western Tanzanian woodland, comparing estimates of herbivore densities from line-transect data from a National Park with those from an adjacent Game Reserve (GR). We used a Geographic Information System (GIS) and Global Positioning System—supported field design, consisting of systematically distributed closed-circuit transects, and recorded sighting distances and angles. Total survey effort was 1,032 km, conducted within the dry season. We fitted detection functions to distance data with the help of DISTANCE 4.1, using the 3 habitat categories woodland, grassland, and swamp as covariates for detection probability. We found estimates of density and abundance to be reliable for 19 out of 20 larger mammalian herbivores and found significant differences in density between the Park and the GR for 5 species, of which 4 had a higher density in the Park and one had a higher density in the GR. Our results show that, using GIS support and modern navigation methods, foot-transect surveys can be effective in providing accurate data on woodland herbivore populations even in large study areas. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):603–610; 2008)     

Carbon dioxide,methane, and nitrous oxide exchanges in an age‐sequence of temperate pine forests

We investigated soil carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) exchanges in an age‐sequence (4, 17, 32, 67 years old) of eastern white pine (Pinus strobus L.) forests in southern Ontario, Canada, for the period of mid‐April to mid‐December in 2006 and 2007. For both CH₄ and N₂O, we observed uptake and emission ranging from ?160 to 245 μg CH₄ m^?2 h^?1 and ?52 to 21 μg N₂O m^?2 h^?1, respectively (negative values indicate uptake). Mean fluxes from mid‐April to mid‐December across the 4, 17, 32, 67 years old stands were similar for CO₂ fluxes (259, 246, 220, and 250 mg CO₂ m^?2 h^?1, respectively), without pattern for N₂O fluxes (?3.7, 1.5, ?2.2, and ?7.6 μg N₂O m^?2 h^?1, respectively), whereas the uptake rates of CH₄ increased with stand age (6.4, ?7.9, ?10.8, and ?23.3 μg CH₄ m^?2 h^?1, respectively). For the same period, the combined contribution of CH₄ and N₂O exchanges to the global warming potential (GWP) calculated from net ecosystem exchange of CO₂ and aggregated soil exchanges of CH₄ and N₂O was on average 4%, <1%, <1%, and 2% for the 4, 17, 32, 67 years old stand, respectively. Soil CO₂ fluxes correlated positively with soil temperature but had no relationship with soil moisture. We found no control of soil temperature or soil moisture on CH₄ and N₂O fluxes, but CH₄ emission was observed following summer rainfall events. LFH layer removal reduced CO₂ emissions by 43%, increased CH₄ uptake during dry and warm soil conditions by more than twofold, but did not affect N₂O flux. We suggest that significant alternating sink and source potentials for both CH₄ and N₂O may occur in N‐ and soil water‐limited forest ecosystems, which constitute a large portion of forest cover in temperate areas.     

Haplotype diversity of the nematode Pristionchus pacificus on Réunion in the Indian Ocean suggests multiple independent invasions

Pristionchus pacificus has been established as a nematode model system in evolutionary developmental biology and evolutionary ecology. Field studies in North and South America, Asia, Africa and Europe indicated that nematodes of the genus Pristionchus live in association with scarab beetles. Here, we describe the first account of soil‐ and beetle‐associated nematodes on an island setting by investigating the island of Réunion in the Indian Ocean. Réunion has high numbers of endemic insects and is one among several attractive islands for biodiversity studies. Being of volcanic origin, Réunion is 2–3 million years old, making it the youngest of the Mascareigne islands. We show that beetle‐ and soil‐derived nematodes on Réunion are nearly exclusively hermaphroditic, suggesting that selfing is favoured over gonochorism (outcrossing) during island colonization. Among members of four nematode genera observed on Réunion, Pristionchus pacificus was the most prevalent species. A total of 76 isolates, in association with five different scarab beetles, has been obtained for this cosmopolitan nematode. A detailed mitochondrial haplotype analysis indicates that the Réunion isolates of P. pacificus cover all four worldwide clades of the species. This extraordinary haplotype diversity suggests multiple independent invasions, most likely in association with different scarab beetles. Together, we establish Réunion as a case study for nematode island biogeography, in which the analysis of nematode population genetics and population dynamics can provide insight into evolutionary and ecological processes. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 170–179.     

Jasmonic acid does not mediate root growth responses to wounding in Arabidopsis thaliana

Jasmonic acid (JA) is a crucial plant defence signalling substance that has recently been shown to mediate herbivory-induced root growth reduction in the ecological model species Nicotiana attenuata . To clarify whether JA-induced reduction of root growth might be a general response increasing plant fitness under biotic stress, a suite of experiments was performed with the model plant Arabidopsis thaliana . JA bursts were elicited in leaves of A. thaliana in different ways. Root growth reduction was neither induced by foliar application of herbivore oral secretions nor by direct application of methyl jasmonate to leaves. Root growth reduction was observed when leaves were infected with the pathogen Pseudomonas syringae pv. tomato, which persistently induces the JA signalling pathway. Yet, high resolution growth analyses of this effect in wild type and JA biosynthesis knock-out mutants showed that it was elicited by the bacterial toxin coronatine that suggests ethylene- but not JA-induced root growth reduction in A. thaliana . Overall, the results demonstrate that the reaction of root growth to herbivore-induced JA signalling differs among species, which is discussed in the context of different ecological defence strategies among species.     

Genetic patterns in the Lathyrus pannonicus complex (Fabaceae) reflect ecological differentiation rather than biogeography and traditional subspecific division

The endangered European relict species complex Lathyrus pannonicus shows distinct morphological variation, reflected by the number of subspecies recognized, and complicated patterns of genetic variation. The traditionally recognized subspecies appear to possess different ecological preferences and disjunct distributions, particularly in the western range of the species. In this study, L. pannonicus was investigated by the correlation of distance matrices based on phytosociological, ecological, molecular and morphological data. Ecological characteristics of selected stands of L. pannonicus throughout Europe were assessed using ‘Ellenberg values’ of all the constituent taxa in phytosociological relevés. Genetic distances were calculated using recently developed methods to analyse high degrees of intra‐individual nuclear‐encoded internal transcribed spacer variability. We found that the remarkable genetic (and morphological) diversity in L. pannonicus could not be explained solely by the fragmentation of the distributional range. Instead, patterns of morphological and genetic differentiation were a reflection of the moisture regime in the sampled stands. Two major lineages could be identified: (1) a lineage adapted to dry conditions (Ellenberg indicator F‐value ≤ 3.5) and (2) a lineage preferring moist conditions (F‐value ≥ 4.5). Although both lineages occurred in close proximity in the Pannonian area, they appeared to be reproductively isolated in general. Further data are needed to determine whether these genetically and ecologically defined lineages, or ecospecies, within the L. pannonicus species complex can be formalized as (Linnaean) species or subspecies. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 165 , 402–421.     

Interaction of xylem and phloem during exudation and wound occlusion in Cucurbita maxima

Collection of cucurbit exudates from cut petioles has been a powerful tool for gaining knowledge on phloem sap composition without full notion of the complex exudation mechanism. Only few publications explicitly mentioned that exudates were collected from the basal side of the cut, which exudes more copiously than the apical side. This is surprising since only exudation from the apical side is supposedly driven by phloem pressure gradients. Composition of carbohydrates and pH values at both wounding sides are equal, whereas protein concentration is higher at the basal side. Apparently, exudation is far more complex than just the delivery of phloem sap. Xylem involvement is indicated by lower protein concentrations after elimination of root pressure. Moreover, dye was sucked into xylem vessels owing to relaxation of negative pressure after cutting. The lateral water efflux from the vessels increases turgor of surrounding cells including sieve elements. Simultaneously, detached parietal proteins (PP1/PP2) induce occlusion of sieve plates and cover wound surface. If root pressure is strong enough, pure xylem sap can be collected after removal of the occlusion plug at the wound surface. The present findings provide a mechanism of sap exudation in Cucurbita maxima, in which the contribution of xylem water is integrated.     

Lifetime prevalence and age-of-onset distributions of mental disorders in the World Health Organization's World Mental Health Survey Initiative

Data are presented on the lifetime prevalence, projected lifetime risk, and age-of-onset distributions of mental disorders in the World Health Organization (WHO)''s World Mental Health (WMH) Surveys. Face-to-face community surveys were conducted in seventeen countries in Africa, Asia, the Americas, Europe, and the Middle East. The combined numbers of respondents were 85,052. Lifetime prevalence, projected lifetime risk, and age of onset of DSM-IV disorders were assessed with the WHO Composite International Diagnostic Interview (CIDI), a fully-structured lay administered diagnostic interview. Survival analysis was used to estimate lifetime risk. Median and inter-quartile range (IQR) of age of onset is very early for some anxiety disorders (7-14, IQR: 8-11) and impulse control disorders (7-15, IQR: 11-12). The age-of-onset distribution is later for mood disorders (29-43, IQR: 35-40), other anxiety disorders (24-50, IQR: 31-41), and substance use disorders (18-29, IQR: 21-26). Median and IQR lifetime prevalence estimates are: anxiety disorders 4.8-31.0% (IQR: 9.9-16.7%), mood disorders 3.3-21.4% (IQR: 9.8-15.8%), impulse control disorders 0.3-25.0% (IQR: 3.1-5.7%), substance use disorders 1.3-15.0% (IQR: 4.8-9.6%), and any disorder 12.0-47.4% (IQR: 18.1-36.1%). Projected lifetime risk is proportionally between 17% and 69% higher than estimated lifetime prevalence (IQR: 28-44%), with the highest ratios in countries exposed to sectarian violence (Israel, Nigeria, and South Africa), and a general tendency for projected risk to be highest in recent cohorts in all countries. These results document clearly that mental disorders are commonly occurring. As many mental disorders begin in childhood or adolescents, interventions aimed at early detection and treatment might help reduce the persistence or severity of primary disorders and prevent the subsequent onset of secondary disorders.     

Lineage specific evolution of an alternative social strategy in Tetramorium ants (Hymenoptera: Formicidae)

The western Palearctic ant, Tetramorium moravicum , is the only species of the large genus known to display two alternative social strategies: macrogyny-monoygyny (characterized by one large queen per colony) and microgyny-polygyny (multiple small queens per colony). The microgyne colonies of this ant are confined to the westernmost part of its distribution area and occasionally co-occur with macrogyne colonies. We investigated phylogenetic and geographical patterns in relation to social strategy by analysing 1031 bp of the mitochondrial cytochrome c oxidase subunit I gene of T. moravicum from the entire known species range. Phylogenetic analyses revealed two clear-cut lineages coinciding with the eastern and western populations, which probably were separated after the late Quaternary glacial periods. Geographical distance analysis suggested allopatric fragmentation of the two lineages. We hypothesize that the two lineages colonized Central Europe postglacially from two directions. The current distribution gap of 500 km between the tip of the eastern lineage, in the Czech Republic, Austria and Hungary, and the western lineage, in Germany, was confirmed by hierarchical population analysis. Macrogyny-monogyny probably was the original condition in T. moravicum ; the alternative strategy of microgyny-polygyny may have evolved at the tip of the western lineage, as recently as the early Holocene.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 247–255.