A combined study of morphology, stem anatomy and isozyme patterns was used to reveal the identity of sterile plants from two rivers on the Germany/France border. A detailed morphological examination proved that the putative hybrid is clearly intermediate between Potamogeton natans and P. nodosus. The stem anatomy had characteristics of both species. The most compelling evidence came from the isozyme analysis. The additive “hybrid” banding patterns of the six enzyme systems studied indicate inheritance from P. natans and P. nodosus. In contrast, other morphologically similar hybrids were excluded: P. ×gessnacensis (= P. natans × P. polygonifolius) by all the enzyme systems, P. ×fluitans (= P. lucens × P. natans) by AAT, EST and 6PGDH, and P. ×sparganiifolius (= P. gramineus × P. natans) by AAT and EST. All samples of P. ×schreberi are of a single multi-enzyme phenotype, suggesting that they resulted from a single hybridization event and that the present-day distribution of P. ×schreberi along the Saarland/Moselle border was achieved by means of vegetative propagation and long-distance dispersal. Neither of its parental species occur with P. ×schreberi or are present upstream, which suggests that this hybrid has persisted vegetatively for a long time in the absence of its parents. The total distribution of this hybrid is reviewed and a detailed account of the records from Germany is given. P. ×schreberi appears to be a rare hybrid. The risk of incorrect determination resulting from the identification of insufficiently developed or inadequately preserved plant material is discussed.
Continent-wide loss of traditionally managed humid meadows is raising concern for associated butterfly specialists across Europe. However, not all species associated with this biotope are threatened, and the Lesser Marbled Fritillary (Brenthis ino) has even spread locally. We employed mark-recapture and transect walks to study its population structure and patterns of landscape occupancy in a hilly region of western Bohemia, Central Europe, to determine which life history or demography traits might be responsible for its success. A population studied by mark-recapture harboured more than 1000 individuals and was interconnected with other populations. This was further supported by a fit of the inverse power function to dispersal data. Observations of adult behaviour revealed a broad host plant range: at least three species of plants were used by the single population. On a landscape scale, the butterfly exhibited an aggregated distribution matching its host plants. It was associated with the distribution of characteristic plants and butterflies of semi-natural humid meadows, but its frequency exceeded those of other humid grasslands specialists. The relatively broad host range coupled with varying biotope requirements of individual host plant species results in a wide biotope range for the butterfly, explaining its persistence in fragmented Central European landscapes.
An invasive sawfly Aproceros leucopoda Takeuchi, 1939, which originates from East Asia, has colonized elms (Ulmus spp.) in Austria, Hungary, Poland, Romania, Slovakia and the Ukraine, at least since 2003. In Europe, the larvae can completely defoliate native and non-native elm trees and may cause at least partial dieback. Field observations indicate that elms are infested independent of their age and site characteristics. The life cycle of A. leucopoda is described based on material reared in Hokkaido, Japan. Parthenogenetic reproduction, short life cycle of summer generations and the ability to produce four generations per year result in the production of numerous progeny. The evolution of a seasonal dimorphism in head morphology, a simple cocoon that is attached directly to the host plant and a short period spent in the cocoon stage during summer, are putative apomorphies shared by Aproceros Takeuchi, 1939 and Aprosthema Konow, 1899. These traits reduce developmental costs and contribute to the proliferation of A. leucopoda. No specialized parasitoid, that can effectively reduce outbreaks of this species, is known. It is likely that this pest will spread into central and south-western Europe. Further monitoring of A. leucopoda is required to assess future range extensions in Europe, its exacerbating effect on Dutch elm disease and to find a suitable biocontrol agent. Concise keys to imaginal and larval stages are presented that will facilitate the identification of A. leucopoda.
I review the effects of habitat fragmentation on carabid beetles (Coleoptera, Carabidae) and examine whether the taxon could be used as an indicator of fragmentation. Related to this, I study the conservation needs of carabids. The reviewed studies showed that habitat fragmentation affects carabid assemblages. Many species that require habitat types found in interiors of fragments are threatened by fragmentation. On the other hand, the species composition of small fragments of habitat (up to a few hectares) is often altered by species invading from the surroundings. Recommendations for mitigating these adverse effects include maintenance of large habitat patches and connections between them. Furthermore, landscape homogenisation should be avoided by maintaining heterogeneity of habitat types. It appears that at least in the Northern Hemisphere there is enough data about carabids for them to be fruitfully used to signal changes in land use practices. Many carabid species have been classified as threatened. Maintenance of the red-listed carabids in the landscape requires species-specific or assemblage-specific measures.
The Japanese beetle, Popillia japonica Newman, is an introduced pest on Terceira, one of nine islands in the Azorean Archipelago. Research conducted on Terceira indicates that entomopathogenic nematodes in the families Steinernematidae and Heterorhabditidae provide good to excellent control of Japanese beetle larvae, but the species that have been evaluated are not native to the Azores. An efficacious species that is native to the archipelago might provide increased capabilities for persisting and recycling in Azorean soil and weather conditions. Surveys on the islands of Terceira and Santa Maria resulted in the isolation of two Heterorhabditis strains (São Mateus and Praia Formosa) with good larvicidal activity for P. japonica. Initial bioassays conducted with Steinernema glaseri (Steiner) originally from North Carolina against P. japonica third instar larvae and pupae produced LC50 values of 3.2 × 105 infective juveniles (IJs)/m2 and 0.9 × 105 IJs/m2, respectively. Comparative bioassays of the native isolates and S. glaseri against P. japonica revealed similar larvicidal activity. The LC50s of the São Mateus and Praia Formosa isolates against third instar larvae were 3.64 × 105 and 4.44 x 105 IJs/m2, respectively. The LC50 of S. glaseri ranged from 3.2 to 5.5 × 105 IJs/m2. The higher larvicidal activity of the Azorean Heterorhabditis isolates for P. japonica indicates that native nematodes are as effective as S. glaseri. Heterorhabditid species also have demonstrated ability for persistence and apparent recycling under conditions where sustainable control of this introduced pest is needed. Studies comparing the dispersal behavior of the Heterorhabditis bacteriophora Poinar São Mateus isolate with that of S. glaseri and native and exotic strains of Steinernema carpocapsae (Weiser) revealed that the H. bacteriophora isolate demonstrated a greater propensity to disperse than other strains in the presence or absence of P. japonica larvae. In the presence of a host, a greater proportion of H. bacteriophora and S. glaseri dispersed than either of the two S. carpocapsae strains.
The pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae), is a well-studied species in terms of its colour polymorphism, where it occurs as two distinct colour morphs, red and green. It is proposed that the occurrence and maintenance of this polymorphism is an adaptive response to environmental factors, in particular natural enemies and host plant quality. We hypothesized that these adaptations are directly mirrored in the energy reserves accumulated by the different colour morphs during their pre-adult stages and reflect their specialization for particular ecological roles. We quantitatively measured the different energy reserves of red and green pea aphids and found that the total energy reserves of these morphs did not differ. Interestingly, these reserves were made up of different components in the red and green colour morphs. There was a higher percentage content of water-soluble carbohydrates and lipids in the red clones and higher percentage content of protein in green clones. These finding are in accordance with green clones being more fecund than red ones and needing more protein for reproduction than red clones, which produce more winged offspring when crowded or in response to the presence of natural enemies and so, need more lipids and carbohydrates to fuel their walking and flight. Apparently, different colour morphs are physiologically specialized to adjust their energy reserves in relation to their specific ecological adaptations and maximize their fitness in terms of dispersal, reproduction, defense and survival., Seyed Mohammad Ahsaei ... []., and Obsahuje seznam literatury
Analysis of the mitochondrial DNA (mtDNA) control region (CR) was used to examine the dispersal of females of a geometrid moth, Epirrita autumnata, in Fennoscandia. A 542-bp-portion of the CR of 200 individuals from four northern and four southern localities was sequenced. The mtDNA CR of E. autumnata contains a substantial amount of variation as a total of 108 mtDNA haplotypes were observed. Between the northern and the southern localities (~1100 km), there was a moderate level of genetic differentiation (FST = 0.128). The amount of variation in the mtDNA CR of E. autumnata was lower in the north than in the south. The reduction in genetic variability may result from a combination of historical bottlenecks that date back to the post-glacial recolonization of Fennoscandia and, present-day bottlenecks due to the northern E. autumnata populations experiencing repeated outbreaks followed by collapse in population size. On a small spatial scale (0.6-19 km), within the northern and southern areas, no genetic differentiation was detected suggesting ongoing gene flow due to the dispersal of E. autumnata females among the localities. This finding was contrary to our earlier expectation of poor flying ability of E. autumnata females.
Dryocosmus kuriphilus (Hymenoptera: Cynipidae), also known as the Asian chestnut gall wasp, is a non-native invasive species that has recently appeared in many regions of Europe, including the Iberian Peninsula. This species is an important pest of chestnut trees in several regions and is of concern for foresters in these areas. The results of this research revealed 14 different hotspots of infestation of D. kuriphilus and resulted in the development of models that predict the distribution of D. kuriphilus in Spain over the next 37 years (2019-2055). These results indicate a rapid spread in all Spanish chestnut forests and identify areas that are theoretically highly suitable and susceptible to colonization by this cynipid based on predictions of three different niche models. Although D. kuriphilus is able to induce galls on all chestnut trees, the models indicate that there are differences in the suitability of the different regions for this species. This differential suitability results in some areas having better environmental conditions than others for D. kuriphilus, which is a factor that should be taken into account in its management and biological control. This study of the current distribution, patterns of dispersal using GIS and potentially suitable areas for D. kuriphilus, using niche models will assist in the management and control of this pest in Spain., Diego Gil-Tapetado, José F. Gómez, Francisco J. Cabrero-Sañudo, José L. Nieves-Aldrey., and Obsahuje bibliografii
Thee species of the genus Gobio occur in the hydrographical network of the Czech Republic, belonging to the basins of three seas (the North, black, and Baltic seas). G. Gobio is distributed over streams belonging to all three sea basins. It is most common in their middle reaches, which are inhabited by fish communities of the Barbus-Chondrostoma type. Compared to that past, the population numbers of this species have not undergone any marked changes. G. kesslerii occurs only in the Bečva River (a tributary to the Morava River) and in the Morava River upstream of the mouth of the Bečva River (danube basin, Black Sea). G. albipinnatus is distributed over the Morava and Dyje rivers and their tributaries (Danube basin, Black Sea). Compared to a century ago, the extent of distribution of G. albipinnatus has dropped to about 50%, which is due chiefly to stream canalisation and water pollution. At present, G. albipinnatus has been ascertained in the lower part of the River Labe, yet there are some doubts as to the originality of this occurrence. The localities of G. albipinnatus and/or G. kesslerii are shared with G. Gobio, with which they hybridise. No evidence is available of the occurrence of G. uranoscopus (Agassiz, 1828) in the Czech Republic, although it does occur in neighbouring Slovakia and Austria. The most important devastation factors, which limited the distribution of the gudgeon in the past, include the construction and operation of dams and weirs, stream canalisation and water pollution. National laws project G. kesslerii as critically endangered and G. albipinnatus as endangered. Both species are listed in European conservation laws (Council Directive no. 92/43/EEC) and, therefore, special areas of conservation have been delimited for them within the NATURA 2000 system.
The chotts in Algeria are temporary salt lakes recognized as important wintering sites of water birds but neglected in terms of the diversity of the insects living on their banks. Around a chott in the wetland complex in the high plains near Constantine (eastern Algeria), more than half of the species of plants are annuals that dry out in summer, a situation that prompted us to sample the vegetation in spring over a period of two years. Three zones were identified based on an analysis of the vegetation and measurements of the salt content of the soils. Surveys carried out at monthly intervals over the course of a year revealed temporal and spatial variations in biodiversity and abundance of grasshoppers. The inner zone is colonized by halophilic plants and only one grasshopper species (Dericorys millierei) occurs there throughout the year. Two polyphagous species of Calliptamus, which can feed on halophilic plants migrate from adjacent areas into the inner zone in August to feed on the plants growing there. The other species of grasshoppers remain in outer zones as they are unable to feed on halophilic plants. The greatest abundance of grasshoppers from August to winter was recorded in the inner zone and in spring and early summer in the outer zones. The dependence of D. millierei on bushes of Amaranthaceae and its moderate flight ability, features of the family Dericorytidae, limit this species ability to colonize neighbouring chotts., Sarah Mahloul, Abboud Harrat, Daniel Petit., and Obsahuje bibliografii