Although the Onga River system is relatively small, it is home to three spined loach species, Cobitis takatsuensis, C . sp. ‘yamato’ complex, and C. striata (the Onga form of the middle race). The aim of the present study is to examine the relationship between the distribution pattern of the species and the physical parameters of the habitat. We mapped the distribution of these three species and measured six environmental factors at 86 points in this river system. Model selection was performed with a generalized linear model (GLM) using the AIC (Akaike’s Information Criterion) to find the best model for the distribution pattern of each species. The dependent variable was the presence/absence of each species, and the independent variables were six environmental factors. The environmental factors that had a positive effect were turbidity for C. takatsuensis, turbidity and river gradient for C. sp. ‘yamato’ complex, and turbidity, river gradient and width of dry riverbed for C. striata. In addition, the coexisting fish species also differ among the three loaches. These results revealed that the three spined loach species select particularly different habitats and can therefore coexist in this small river system.
Overlapping measurements in the length of the genitalia of Leptidea sinapis/reali collected in Slovenia triggered an investigation of a possible natural hybridization between these two well known sibling species of butterflies. Random polymorphic DNA (RAPD) was used to generate species specific markers and sequences of the cytochrome oxidase subunit one gene for determination of the progeny. RAPD's clustering and mitochondrial DNA (mtDNA) phylogeny were congruent with the taxonomic placement of specimens of both species, but slightly incongruent with the results of the analysis of genital morphology. Two specimens with L. reali genitalia measurements, but genetically belonging to L. sinapis, had species specific RAPD markers of both species indicating probable hybrid origin. All the specimens with genitalia of intermediate length were also genetically assigned to L. sinapis indicating a possible one way introgression as predicted from their genitalia morphology. Leptidea sinapis was found predominantly in xerothermic habitats in Slovenia, whereas L. reali was more of a generalist except in the sub-Mediterranean region where it is limited to humid meadows.
The larval and juvenile development was compared between Lefua echigonia and Lefua sp., both endemic and endangered species in Japan. L. echigonia larvae collected in sunny wetlands were planktonic and swam in the middle to upper layers in lentic waters, whereas L. sp. larvae swam with their abdomen facing toward the substrate along the river bottom in well shaded waters of mountain streams. Larvae and juveniles of both species have a distinct dark band on the lateral side of snout. L. echigonia larvae have melanophores on the dorsal body, gut region, and around the lateral midline, whereas melanophores distribute broadly on the body in L. sp. larvae. Eyes are located more dorsally in larvae of L. sp.: in the ventral view of the head, the eyes of L. echigonia larvae could be seen, but those of L. sp. larvae could not be seen. L. echigonia larvae and juveniles have relatively large eyes and eye diameters were larger than the snout lengths. Lefua sp. larvae and juveniles have relatively small eyes and eye diameters were smaller than the snout lengths. These characters of melanophore distribution, eye size, and eye location are concluded to show adaptation for each habitat.
The Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is known to thrive principally in shrubby and arboreal habitats. This study focuses on the occurrence of this exotic species and its seasonal abundance in various field crops. The abundance of adults, larvae and pupae of H. axyridis was evaluated over a three-year period, from 2009 to 2011, in four important agronomical crops (wheat, corn, broad bean and potato) in Belgium. From May to September, 48 1-m² quadrats were visually inspected in each of the fields sampled on several farms every seven days. H. axyridis colonized and reproduced in all of the four crops studied, with the largest numbers recorded in corn and broad bean crops. Larvae and adults of H. axyridis were recorded mainly in corn and to a much less extent in wheat and potato crops. From 2009 to 2011, the mean weekly abundance of H. ayxridis remained constant except in corn crops, where the recorded densities of all the immature stages and adults were higher in 2011 than in 2009. The population dynamics of aphids and H. axyridis are well described by a symmetric logistic function (S-shape) of cumulative population size. H. axyridis was not always recorded where aphids were abundant, e.g. aphids were abundant on wheat where no H. axyridis were recorded. H. axyridis start reproducing after the peak in aphid population, suggesting that H. axyridis is able to complete its development by feeding on alternative prey such as larvae and pupae of the same and other species of ladybird and other aphidophagous species. H. axyridis is often considered to be bivoltine but it only completes one generation per year in field crops. The second generation generally develops late in the season in other habitats., Axel Vandereycken ... [et al.]., and Obsahuje seznam literatury
The thermal relations, diel, and annual activity and microhabitat use of Lacerta agilis were studied in the Pyrenean isolated range of this species. Although, this heliothermic lizard demonstrated thermoregulatory capability, thermal constraints attributable to the mountain climate were observed. The activity pattern was that typical of cold temperate lizards but the beginning of activity was delayed in comparison with lowland populations. The reproductive cycle determined different activity patterns for males and females. The ontogenetic and seasonal changes in microhabitat use detected suggest influence of body size, reproductive condition in adults, and interference with other individuals in juveniles.
With climatic warming there is an expectation that phytophagous insects will increasingly use alien (non native) plants as nectar sources and larval host plants. Alien plant use is investigated in British butterflies. Butterflies are considered to be larval host plant specialists relative to their use of nectar plants. Supporting this view, use of alien plants as nectar sources (50.1%, 27 novel plant families) is almost twice that of their use as larval host plants (21.6%; three novel plant families). Some 80% of the variation in percent alien nectar plant use is accounted against 30% of that for percent alien host plant use. The key variable accounting for alien plant use is butterfly mobility. Other prominent variables that facilitate access to alien nectar plants are southern distributions, longer adult life span, host plants in garden biotopes. A different set of variables additionally account for alien host plant exploitation (% alien host plant use: woody host plants; number of alien host plants: polyphagy; greater abundance of native host plants in gardens). Although threatened butterfly species do not depend on alien plants, this may well reflect on specialisation in resource use accompanying habitat fragmentation and an inability to use novel resources that are becoming increasingly available. Detailed study of alien resources is advocated to assess the importance of alien plant resources for phytophagous insects.
This is a report on a post-lactating female soprano pipistrelle, Pipistrellus pygmaeus, which in autumn exploited habitats from sea level to the transition zone between alpine and sub-alpine areas. It travelled more than 12.3 kilometres from its roost and returned to its roost at sea level on all four nights when it was tracked. In addition to the telemetry bat, several soprano pipistrelles utilized high altitudes during the days of tracking as heard on ultrasound detector.
Soil samples were collected from the whole territory of the Czech Republic, and the presence of entomopathogenic nematodes from the families Steinernematidae and Heterorhabditidae was evaluated by Galleria traps method. Of the 342 samples studied, 53.8% were positive for entomopathogenic nematodes with only one positive for the heterorhabditid, Heterorhabditis megidis Poinar, Jackson ct Klein. 1987. Of steinernematid species, Steinernema kraussei (Steiner, 1923), Steinernema felliae (Filipjev, 1934), Steinernema affine (Bovicn, 1937), Steinernema intermedium (Poinar, 1985), Steinernema bicornutum Tallosi, Peters et F.hlers, 1995, and Steinernema sp. belonging to “glaseri" group were recovered. With several exceptions the nematodes occurred in all the ecosystems, subecosystcms and habitats studied. They were more frequently found in samples from tree than open habitats, from light than heavy soil, and their incidence was ubiquitous, rather than patchy. Dependence of entomopathogenic nematodes on insect incidence seemed to be elementary for both their incidence and abundance. The sampling sites with moderate to severe insect abundance were 66.5 % positive for nematodes while those with slight or no visible insect abundance only 15 %.
Low detectability of small nocturnal carnivores and biases associated to different census methods hamper the interpretation and reliability of the results of censuses and habitat studies of many cryptic and elusive species, especially because of false-negatives and/or lack of negatives. In order to overcome this problem, methodologies based on the use of presence-only data have been used to predict distribution of species. In this paper, we used presence data of two abundant nocturnal carnivores to test for segregation in their habitat. We compared niche overlap between the common genet and the stone marten at two different spatial scales, home range scale and landscape scale, through logistic regression analyses using presence-only data from Biscay, an area in which both species are common and widespread. We found great niche overlap at both spatial scales, but in spite of it logistic regression analyses found statistically significant differences in the predictor values of some variables. Habitat of genets and stone marten was differentiated by areas with dense vegetation that were of importance for genets, and open areas that were characteristic of stone marten habitat. We suggest that competition between the two species causes the observed segregation.
Sparse-elm grassland is the remarkable landscape of Hunshandak Sandland in Inner Mongolia Autonomic Region of China. Maximum quantum efficiency (Fv/Fm) of 99 native plant species (85 grasses, 11 shrubs, and 3 trees) of different plant functional Types (PFTs) distributed in fixed sand dune, lowland, and wetland was investigated. Deep-rooted plant species (tree, shrub, and perennial grass) had higher Fv/Fm values than the shallow-rooted species (annual grasses), suggesting that soil drought is the major environmental stress. Annual C4 grasses had higher Fv/Fm values than annual C3 or CAM ones, indicating that C4 photosynthesis is more ecologically adaptive than CAM and C3 grasses. According to the habitats with annual C3 grass distribution, Fv/Fm values were in the order of fixed dune>lowland>wetland, suggesting that salt and pH value may enhance irradiance or heat stress for those distributed in pickled and watery habitats. Based on such characteristics, Ulmus pumila, Salix gordejevii, Caragana microphylla, Agriophyllum pungens, and Agropyron cristatum are recommended as ideal species for ecological restoration in degraded sand-land ecosystems. and Yong-Geng Li ... [et al.].