Macroinvertebrate assemblages in an artificial habitat—a settling basin of a hydroelectric power plant: comparison with a natural riffle habitat

The macroinvertebrate assemblages in an artificial habitat, the settling basin of a hydroelectric power plant, were investigated and compared with those in a natural habitat, riffles in a nearby river. This study showed that macroinvertebrate density was much higher in the settling basin than in the riffles. Macroinvertebrate assemblage composition differed between the settling basin and the riffles. The difference was probably due to the widespread bryophyte beds in the settling basin. Cincticostella, Brachycentrus, Ephmerella, and chironomid midges, which are usually abundant in bryophyte beds, were present at much higher densities in the settling basin. Cheumatopsyche and Taeniopterygidae were also present at higher densities in the settling basin than in the natural riffles. In contrast, Epeorus was present at lower density in the settling basin than in the natural riffles. This study suggests that the settling basin increases β-diversity in riverine ecosystems.     

Rapid recovery of an insect–plant interaction following habitat loss and experimental wetland restoration

This study examined the impact of wetland habitat loss and isolation on an insect–plant interaction, and the subsequent rate of recovery of the interaction following experimental habitat restoration. We compared herbivore colonisation rates and herbivory damage by ‘Batrachedra’ sp. (Lepidoptera: Coleophoridae) on experimentally placed potted Sporadanthus ferrugineus (Restionaceae) plants at increasing distances (up to 800 m) from an intact habitat (the source population). These tests showed that even a moderate degree of isolation (i.e. greater than 400 m) from the intact wetland habitat caused an almost complete collapse of the insect–plant interaction, at least in the short term. The number of eggs and larvae of colonising ‘Batrachedra’ sp., as well as average larval size and the proportion of S. ferrugineus stems damaged, all decreased logarithmically with increasing distance from the intact habitat, presumably due to dispersal limitation of the herbivore. Subsequently, to test whether the interaction can recover following habitat restoration, we surveyed herbivore colonisation rates and herbivory damage on naturally regenerated S. ferrugineus plants on experimentally restored ‘islands’ at increasing distances (up to 800 m) from an intact habitat. The rate of recovery of the interaction was surprisingly rapid (i.e. between 196 and 308 weeks). The degree of difference in the density of eggs and larvae, and in the proportion of stems damaged with increasing isolation from the intact wetland, gradually diminished over 196 weeks. After 308 weeks there was no significant difference in the insect–plant interaction between the intact wetland sites and any of the experimentally restored sites up to 800 m away. These results suggest that some insect–plant interactions can recover rapidly from habitat loss with restoration management.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

The emergence of an ‘ethnic economy’? The spatial relationships of migrant workers in London's health and hospitality sectors

This paper examines how the globalized nature of London's service sector redefines spatial relationships for recent migrants working in the health and hospitality industries. Findings from the qualitative data demonstrate that recent temporary migrants to the UK employ broader strategies to secure employment than accounted for by current theories. The migrants in our case studies overwhelmingly utilized global and local recruitment and employment agencies, as well as sought employment in industries already established as ‘ethnic economies’. We suggest that this might be attributed to a lack of interaction with established co-ethnic immigrant communities; temporary migration trajectories; and living arrangements with co-migrants. We conclude by emphasizing the need to broaden our understanding of ethnic economies and social networks in light of these changing spatial relationships that have emerged through the globalization of the service sector in the UK.     

The influence of landscape structure on ants and dung beetles diversity in a Mediterranean savanna—Forest ecosystem

Ants and dung beetles are focal indicators of change in several ecological processes and successional vegetation stages in Mediterranean landscapes. Despite relatively good knowledge of local species distributions, there are few data on their distributions at different scales. In the present study, the influence of multiscale landscape structure was examined using both ants and dung beetles to identify species that can serve as indicators and detectors of changes in vegetation structure. Multiscale analysis is necessary to explore the different roles of indicator and detector species for use as tools in studies focused on monitoring ecological changes. The study area was the Cabañeros National Park, in the center of the Iberian Peninsula. This site was selected because it is a good setting to evaluate the effects of typical vegetation mosaics on Mediterranean species at different scales. In this study, dung beetles and ants were trapped for one year. A multiscale analysis was designed using three different vegetation habitats (forest, scrubland and grassland) and landscape matrices (woodland, scrubland and grassland). Among dung beetles, 23 indicator species (IndVal values higher than 70%) were found at different scales of analysis. In addition, 20 dung beetle species were characterized as detector species (IndVal values between 45 and 70%) for the three different levels analyzed. Similar to the dung beetles, the ants had different species assemblages at various habitats and landscape levels; however, no indicator ant species were found in this study. All species with significant IndVal values (n = 8) were identified as detector species. Thus, ant and dung beetle assemblages were influenced in different ways by vegetation structure. Both groups showed strong individual species responses to different Mediterranean landscape conditions and vegetation types. Further, both insect groups showed a great number of detector species, which can be useful in ecosystem management because they have varying degrees of preference and sensitivity for different ecological states (such as successional vegetation stages). The diverse indicator and detector species identified in this work could be useful tools for the detection of landscape structure changes at both levels habitat patches and landscape matrix. However, a generalisation of the results at landscape scale should be taken with precaution, but they encourage to study more regions and similar landscapes. The use of more than one indicator group in the analysis confirms the importance of selecting groups with different sensitivities at varying spatial scales as well as different ecosystem functions. This strategy allows the establishment of a clear baseline with which to analyze future direct and indirect impacts of management in Mediterranean protected areas.     

The history of comparative anatomy in Jena — an overview

Summary Comparative anatomy and zoology both have long academic traditions in Jena. At first, the two subjects developed in parallel and had many similarites in research topics. This development is covered in the first part of the paper. The close relationship between the two subjects started to break apart when Carl Gegenbaur and Ernst Haeckel were active at Jena University. In 1865 Haeckel became the first full professor of zoology in Jena, and zoology became more independent from comparative anatomy. In the second part of our paper, we follow the developments in comparative anatomy in Jena from Gegenbaur’s immediate students up until the end of Hans B?ker’s tenure in Jena in the mid-1930s. Certain subjects are in focus throughout this period, for example vertebrate head morphology and development, (the “head problem”), the relationship between anatomy and biology, and evolutionary questions. Some of these subjects have remained important research topics in zoology and comparative anatomy in Jena until the present day.     

Are changes in breeding habitat responsible for recent population changes of long-distance migrant birds?

Capsule: The direction and magnitude of changes in structure of UK woodlands since the 1980s, are inconsistent with them playing a causative role in the declines of four migrant bird species in upland oak woods.

Aims: To investigate whether changes in woodland structure were a possible cause of population changes of four Afro-Palearctic migrants (Wood Warbler Phylloscopus sibilatrix, Tree Pipit Anthus trivialis, Pied Flycatcher Ficedula hypoleuca and Common Redstart Phoenicurus phoenicurus) in the upland oakwoods of western and northern Britain.

Methods: Bird population estimates and measures of woodland structure were recorded in two time periods 1982–85 and 2003–04 across six regions of the UK. We modelled the effect of habitat change and initial habitat state on population changes between the two time periods. The predicted effects of habitat change on populations were then compared with observed population changes across the different regions.

Results: All four species underwent population declines; there were also significant increases in ground cover and understorey cover. The number of birds in 2003–04 was influenced by habitat structure at this time in addition to showing regional differences. Change in bird numbers varied between regions and was affected by both the initial habitat state and change in habitat structure, with regional variation in the effect of habitat change. There was however no relationship between the predicted effect of change in habitat structure on population size and observed regional population changes.

Conclusions: Changes in woodland structure are unlikely to be the main driver of population change in these four migrant bird species, and large-scale factors affecting demographics in other parts of their breeding range or in their wintering areas are likely reasons for local population declines.     

Antagonistic effects of floral scent in an insect–plant interaction

In southwestern USA, the jimsonweed Datura wrightii and the nocturnal moth Manduca sexta form a pollinator–plant and herbivore–plant association. Because the floral scent is probably important in mediating this interaction, we investigated the floral volatiles that might attract M. sexta for feeding and oviposition. We found that flower volatiles increase oviposition and include small amounts of both enantiomers of linalool, a common component of the scent of hawkmoth-pollinated flowers. Because (+)-linalool is processed in a female-specific glomerulus in the primary olfactory centre of M. sexta, we hypothesized that the enantiomers of linalool differentially modulate feeding and oviposition. Using a synthetic mixture that mimics the D. wrightii floral scent, we found that the presence of linalool was not necessary to evoke feeding and that mixtures containing (+)- and/or (−)-linalool were equally effective in mediating this behaviour. By contrast, females oviposited more on plants emitting (+)-linalool (alone or in mixtures) over control plants, while plants emitting (−)-linalool (alone or in mixtures) were less preferred than control plants. Together with our previous investigations, these results show that linalool has differential effects in feeding and oviposition through two neural pathways: one that is sexually isomorphic and non-enantioselective, and another that is female-specific and enantioselective.     

What is an edge species? The implications of sensitivity to habitat edges

For decades, researchers have categorized species as “edge‐loving” or “edge‐avoiding”, but recent studies that show inconsistencies in responses have called these labels into question and led to a sense that edge effects are idiosyncratic and difficult to understand. We suggest that species would be better categorized according to their sensitivity to edges, not the direction of observed responses because no species should be expected to show the same response to all edge types. Measures of edge sensitivity will apply widely across taxa and landscapes and allow metrics that are broadly comparable, making generalities easier to discern. Finally, while the direction of observed edge responses remains a critical (but largely understood) dynamic, most reported edge responses are neutral, so discovering when species are least likely to respond to edges will increase our understanding of edge ecology and associated fragmentation effects. We offer a case study that measures edge sensitivity of 15 butterfly species at 12 edge types. We found that sensitivity is weakly related to vulnerability to predation, but more importantly we show how our results generate new predictions about edge sensitivity that can be explored in future studies.     

Lack of fidelity revealed in an insect–fungal mutualism after invasion

Symbiont fidelity is an important mechanism in the evolution and stability of mutualisms. Strict fidelity has been assumed for the obligate mutualism between Sirex woodwasps and their mutualistic Amylostereum fungi. This assumption has been challenged in North America where the European woodwasp, Sirex noctilio, and its fungal mutualist, Amylostereum areolatum, have recently been introduced. We investigate the specificity of the mutualism between Sirex and Amylostereum species in Canada, where S. noctilio co-infests Pinus with native Sirex nigricornis and its mutualist, Amylostereum chailletii. Using phylogenetic and culture methods, we show that extensive, reciprocal exchange of fungal species and strains is occurring, with 75.3 per cent of S. nigricornis carrying A. areolatum and 3.5 per cent of S. noctilio carrying A. chailletii. These findings show that the apparent specificity of the mutualism between Sirex spp. and their associated Amylostereum spp. is not the result of specific biological mechanisms that maintain symbiont fidelity. Rather, partner switching may be common when shifting geographical distributions driven by ecological or anthropogenic forces bring host and mutualist pairs into sympatry. Such novel associations have potentially profound consequences for fitness and virulence. Symbiont sharing, if it occurs commonly, may represent an important but overlooked mechanism of community change linked to biological invasions.     

Differential effects of flower feeding in an insect host–parasitoid system

In many insect host–parasitoid systems, both the host and its parasitoids forage on shared floral resources. As a result of insect behaviour, morphology and physiology, flower species may act selectively at different levels of such systems, e.g., between the trophic levels of hosts and parasitoids, between species within a guild, between sexes or individuals within a species or between life history traits within an individual. We asked if effects of selectivity are consistent across levels in the horse chestnut leafminer, Cameraria ohridella, and its parasitoid complex. Insects were exposed singly in no-choice feeding trials to twelve common flower species and their survival and reproduction were recorded. Only one of twelve flower species (Ranunculus acris) tended to selectively favour the longevity of leafminers, but not of parasitoids. No flower species were found to favour parasitoids only. Both trophic levels profited from feeding on Anthriscus sylvestris, however, parasitoids benefited up to eight times more than their hosts. No differences were found among the species of the parasitoid guild, but females lived significantly longer than males, and single individuals within species were able to exploit generally unfavourable flower species. Out of the seven flower species that increased the longevity of leafminer females, only Chaerophyllum hirsutum significantly enhanced the number of eggs laid. Fecundity was generally positively correlated with longevity of leafminer females, but two flower species (C. hirsutum, Taraxacum officinale) had an additional positive effect on fecundity. In conclusion, we demonstrated that flowers act differently on life history traits in a host–parasitoid system at a multitude of biological levels and that these effects are not always consistent across levels. Selective plant-derived resources can therefore modify herbivore–natural enemy interactions in ways that are more complex than currently appreciated.     

Does lack of available suitable habitat explain the patchy distributions of rare calcicole fern species?

In Canada, as in many countries, a relatively large number of fern species occur in specialized habitats and have low numbers of known populations containing few individuals. It has been suggested that the distribution of ferns is mostly determined by factors of climate and habitat due to relatively low limitations in ferns for dispersal and establishment. Here, we attempt to explain whether the local patchy distribution of three calcicole fern species rare in Canada ( Asplenium ruta-muraria , Pellaea atropurpurea and Woodsia obtusa ) is due to a lack of available habitat. Analyses based on micro-scale differences between sites occupied by the ferns and nearby, unoccupied sites did not reveal any significant differences, thereby indicating that the rarity of these species is not entirely driven by the rarity of their microhabitat at a local scale. Our results suggest that the widely accepted premise that ferns are not limited by dispersal or establishment should be reconsidered, as such limitations are the only likely explanation for empty available and suitable habitat.     

The effects of mechanically-induced stress in plants — a review

Mechanically-induced stress (MIS) occurs naturally in plants as the aerial parts are moved, usually by wind, but also by such agents as rain and animals. It can be induced indoors by various actions such as rubbing or bending the stem or shaking or brushing the entire shoot. The most noticeable effect of MIS is a reduction in stem, leaf or petiole length invariably resulting in plants which are smaller and more compact than unstressed controls. However, the response of other variables can often differ between species and there may be either increases or decreases in stem or petiole diameter, root: shoot weight ratio, chlorophyll content or drought resistance. Why species should differ in this way, and what is the endogenous control mechanism for MIS responses, are inanswered questions. Ethylene, which increases as a result of MIS in several species may cause some MIS responses such as increased stem diameter, epinasty or a change in sex expression. However, evidence suggests that MIS retardation of extension growth may equally be due to lower or supraoptimal auxin levels or lower gibberellin levels.The uses in the field of the growth promoter gibberellin or the growth retardant chlormequat chloride (CCC) appear to be examples of respectively reversing or stimulating MIS growth response. MIS may be applied indoors if short compact plants are needed, either for aesthetic purposes as with floral crops, or if hardier and more manageable plants are needed, such as seedlings for transplanting in the field. Much more research is needed to estimate the importance of MIS in the field and to assess how such knowledge may be used to improve crop yield.     

How high is your hummock? The importance of Triodia height as a habitat predictor for an endangered marsupial in a fire‐prone environment

Fire and seral vegetation succession are known to influence the distribution and abundance of a wide range of arid and semi‐arid mammal species. In Triodia hummock grasslands, the gradual increase in Triodia cover after fire is a significant factor influencing mammal distribution and abundance. However, the height of fire‐adapted hummock grass species is often ignored during habitat preference studies despite the fact that taller hummocks are likely to have improved insulation properties and greater protection from predators. We tested the relative importance of a range of Triodia habitat characteristics in determining the distribution and abundance of a fire‐adapted mammal inhabiting Triodia mallee dune fields in semi‐arid Australia. We sampled 77 sites and collected information on habitat attributes including Triodia cover, height and time since fire. The 90th percentile Triodia height (>400 mm) was the most reliable predictor of sandhill dunnart abundance, and breeding, inferred through the presence of subadults. The presence of adult sandhill dunnarts was best explained by Triodia cover, increasing when cover exceeded 25%. We suggest that while Triodia cover may be an important variable for predicting the presence of adult sandhill dunnarts, the height of Triodia is important for breeding, when tall Triodia are possibly sought for nesting sites. These Triodia height and cover requirements were not recorded at sites until at least 10 years post fire but the relationship between fire and Triodia cover and height was inconsistent; after 20 years Triodia cover declined with increasing fire age while the 90th percentile Triodia height remained relatively constant. This incongruence may explain why the presence of sandhill dunnarts appears more constrained by a minimum rather than maximum time since fire and could help explain patterns of post‐fire distribution in other arid zone mammals. Importantly, the 90th percentile Triodia height highlighted the possible significance of scattered, tall Triodia hummocks for arid zone fossorial mammals.     

Do competitive intraguild interactions affect space and habitat use by small carnivores in a forested landscape?

Complex interactions such as interference competition and predation, including intraguild predation, are now recognized as important components in animal community structure. At the lower end of a guild, weasels may be highly affected by other guild members due to small body size in relation to other predators. In 2000 and 2001, we radio-collared 24 ermines Mustela erminea and 25 long-tailed weasels M. frenata in 2 areas that differed in abundance of guild members. We tested the hypothesis that when faced with an increased density of other guild members, weasels would modify space and habitat use to reduce the risk of predation associated with encounters involving guild members. We predicted that weasels would increase use of specific habitats (such as refuges) to reduce encounter rates in the presence of a greater number of guild members. Because M. erminea is smaller than M. frenata and thus better able to take advantage of small rodent burrows as refuges from predators and as feeding grounds, we also predicted that M. frenata would show a stronger response to a higher abundance of guild members than M. erminea . Results were consistent with our predictions. Faced with an increased abundance of guild members, M. frenata showed increased habitat selectivity and reduced activity levels, which resulted in increased daily travel distances and increased home ranges. Mustela erminea responded to an increased abundance of guild members through reduced use of preferred habitat which M. frenata already occupied. The contrasting pattern of habitat selection observed between the 2 mustelid species suggested cascading effects, whereby large-predator pressure on M. frenata relaxed pressure of M. frenata on M. erminea . Our results draw attention to the likelihood that competitive intraguild interactions play a facilitating role in M. erminea – M. frenata coexistence.     

The Rate of Human Germline Mutations—Variable Factor of Evolution and Diseases

Russian Journal of Genetics - The emergence of genetic diseases and evolutionary processes are associated with the flow of genetic information from one generation to another, in which genetic...     

The induction of autophagy in isolated insect fat body by β-ecdysone

The fat body in Calpodes undergoes sequential organelle specific autophagy as a first step in the cell remodeling process necessary for metamorphosis to the pupa. This autophagy begins at about 36 hr before pupation and coincides with a critical period after which an isolated abdomen will pupate without further influence from the prothoracic glands. This suggested that autophagy might be induced by ecdysone. Fat body taken before the critical period and cultured in a medium containing β-ecdysone undergoes autophagy. Fat body from the same animal maintained in hormone-free medium retains the pre-critical period morphology with no autophagy. Autophagy is therefore directly induced by β-ecdysone. Fat body taken soon after the critical period continues with the autophagic sequence in hormone-free medium. Therefore the entire autophagic sequence is induced and does not require the continuing presence of hormone. Protein storage granule formation and cell dissociation, which occur in fat body at metamorphosis, are also induced by β-ecdysone.     

Coca—The mainstay of an arduous native life in the Andes

For centuries the alkaloids of coca leaves have sustained the natives of the Andes in their onerous existence, but only recently have the effects of this drug been clinically studied.     

The role of calcium in chloroplasts—an intriguing and unresolved puzzle

More than 70?years of studies have indicated that chloroplasts contain a significant amount of calcium, are a potential storage compartment for this ion, and might themselves be prone to calcium regulation. Many of these studies have been performed on the photosynthetic light reaction as well as CO(2) fixation via the Calvin-Benson-Bassham cycle, and they showed that calcium is required in several steps of these processes. Further studies have indicated that calcium is involved in other chloroplast functions that are not directly related to photosynthesis and that there is a calcium-dependent regulation similar to cytoplasmic calcium signal transduction. Nevertheless, the precise role that calcium has as a functional and regulatory component of chloroplast processes remains enigmatic. Calcium concentrations in different chloroplast subcompartments have been measured, but the extent and direction of intra-plastidal calcium fluxes or calcium transport into and from the cytosol are not yet very well understood. In this review we want to give an overview over the current knowledge on the relationship between chloroplasts and calcium and discuss questions that need to be addressed in future research.     

The insect abdomen--a heartbeat manager in insects?

Different possibilities of coordination between circulation, respiration and abdominal movements were found in pupae of Pieris brassicae, Tenebrio molitor, Galleria mellonella and Leptinotarsa decemlineata. Coordination principles depend on metabolic rate: the need to support circulation with abdominal movements appears only at higher metabolic rates. Integration between different abdominal movements and circulation depends on species, on physiological state and, supposedly, on internal morphology. At low metabolic rates, there is no need for a very intensive hemolymph flow, and the dorsal vessel is capable of initiating and/or maintaining necessary hemolymph flow. Starting from a certain metabolic level, it is possible that the abdomen is used to accelerate hemolymph flow in the case of a large amount of hemolymph. When the necessary flow speed has been reached, relatively weak pulsation of the dorsal vessel with accessory pulsatile organs and diaphragms can easily maintain the necessary flow intensity. Heart activity may sometimes be initiated by abdominal movements via cardiac reflex or mechanical excitation. Sometimes, when heart function is weakened by histolysis, the abdomen may temporarily take over the main circulatory function or occasionally contribute to acceleration of low-speed hemolymph flow. In this case the functions are simultaneous and may be triggered by some mediator(s). In active adult insects the whole body is moving, and hence hemolymph circulates and the tracheal system is effectively ventilated by a whole body ensemble consisting of the dorsal vessel, moving organs, body appendages and accessory pulsatile organs. The mechanism of autocirculation (analogous to autoventilation in gas exchange) is a probable mechanism in circulation in adult insects.