Bechstein’s bat, Myotis bechsteinii is a European tree-dwelling vespertilionid bat species, which has to be considered as index species for old growth broadleaved woodland. However factors affecting density and habitat selection are still poorly understood. Therefore 22 representative woodland areas in Luxembourg that are located in the central geographic range of the Bechstein`s bat, were analysed. During 76 nights, forest dwelling bats were registered by intensive mist netting, 47 Bechstein bats were radio-tracked to identify tree-roosts and 24 individuals were radio-tracked on 3-5 consecutive nights to determine their foraging areas. In total 14 reproduction areas and 12 nursery colonies were localized, with the number of females ranging between 20–70 individuals (mean 34 ± 18.1 ind.). The distribution of Bechstein’s bat revealed to be uneven and to be significantly positively correlated to mean temperature and the presence of Melico-Fagetum forest with a marked amount of old oak trees. Nevertheless the height, the mean precipitation and the occurrence of Luzulo-Fagetum forest is negatively correlated to the occurrence of M. bechsteinii. Altogether, 78 tree-roosts from nursery colonies were identified. Colonies use a day-roost complex and show a significant preference for woodpecker holes. Female Bechstein’s bats foraged on a mean area of 46 ha (MCP) with small core feeding areas (mean: 2.1 ha) which show no, or only a small overlap with each other. Roosting and feeding sites are characterised by canopy and understorey structures similar to native woodlands. The results of this study leads to a scientific data base for conservation and long time monitoring for this bat species.
Flight activity in a pentatomid bug, Graphosoma lineatum, was measured under different photoperiodic conditions. Insects started flying 3 days after adult ecdysis and the percentage of flying adults became highest about 1 week after the ecdysis, regardless of the photoperiod. Under long day (18L : 6D), high flight activity was continued, whereas under short day (12L : 12D), most adults stopped flying when diapause was induced. In both photoperiods, a small number of adults showed flight of a long duration, longer than 30 minutes. Thus, no evidence was found relating the long flight to diapause. It is suggested that diapause adults of G. lineatum do not overwinter far from their breeding sites and thus there is no migration to hibernation sites. Also, the long flight is probably only a foraging flight, enabling the bugs to find their dispersed host plants.
Food habits of blue sheep, Pseudois nayaur in the Helan Mountains of China were studied from November 2003 to October 2004 to better understand diet composition, seasonal variation, and feeding habitat preference. Blue sheep consumed 41 plant species that contributed >0.01% to the diets. During autumn, winter, and spring, primary species consumed were Stipa spp., Ulmus pumila, and Poa spp. Blue sheep also showed the different preference for these plant species. Graminoids were the largest proportion of the diet (36.7–58.8%) throughout the year, followed by the tree and shrub categories. Sedges were the smallest proportion of the diet (0.7–7.1%). Among the four habitat types, blue sheep showed pronounced preference for montane woodland steppe. Differences in the diets of Helan Mountains blue sheep from those of blue sheep elsewhere may reflect adaptations for geographical range, vegetation, and other factors.
In a Geoffroy’s bat Myotis emarginatus colony in central Iberia, we investigated the foraging behaviour of six lactating females by means of radio-tracking and the diet of 23 individuals by faecal analysis. The bats preferred to forage mainly in pine plantations, riparian woodland, and scrubland, whereas native dehesa (a loose semi-natural oak Quercus rotundifolia and Q. suber woodland) was not exploited as expected. By far the most important prey type for this bat in the Mediterranean were spiders. We conclude that Geoffroy’s bat prefers to forage in multistratified dense habitats, even if these include nonnative plantations. The vertical structuring and especially high cover, along with the combination of both parameters are important for this highly manoeuvrable, clutter-tolerant bat. This is valid even when the vertical component is much reduced as occurs in scrubland, in the first succession steps to woodland creation, and in degraded conditions. Under such circumstances, aerial weaving spiders might be detected and captured when lying in their webs. It is likely that dehesa is too loosely wooded to offer suitable characteristics for orb-weaving aerial spiders to build webs, and thus it may not be as attractive for M. emarginatus as more dense habitats.
Animals, including human beings, tend to respond more strongly to stimuli that are associated with the highest relative rewards. This applies not only to food rewards but also to reproductive success. In the present review article this issue is discussed for insects in connection with intersexual communication and flower-visiting behaviour. Implications of the preference for supernormal visual releasing stimuli are examined from a sensory and evolutionary perspective, including a consideration of the choice of potential mates and recognition of the most rewarding flowers., Karl Kral., and Obsahuje bibliografii
A recent study (H e t h et al. 2002) challenged the idea of “blind” foraging in herbivorous underground dwellers by showing that subterranean rodents of several species use olfaction to discriminate between soils in which plants had or had not been growing. Here we address additional questions about odour-based foraging underground. We tested responses of Zambian mole-rats (Cryptomys anselli and C. kafuensis) to putative carrot kairomones using tunnel T-mazes. Mole-rats distinguished peat moistened with hydroponic as well as filtered hydroponic “carrot water” from peat moistened with distilled water. Furthermore, mole-rats detected carrot kairomones that percolated over the course of a week through the soil to a distance of 30 cm. These results demonstrate that 1) Attractiveness of soil is given by contents of primary root kairomones not caused by microbial activity in planted soil. 2) Carrot-kairomones are water-soluble molecules of less than 0.6 μm diameter. 3) Carrot-kairomones diffuse around the plant, making plants detectable from a distance.
Daubenton’s bat Myotis daubentonii is one of the most common bat species of Europe, hunting its prey in the surroundings of water bodies, with different microhabitats. To explore the local adaptability to different environmental conditions, we compared the diet of Daubenton’s bats at four different sites in a lake landscape in northern Germany with a main focus on prey diversity. Bats were caught (n = 85) in mist nets for collecting individual faecal pellets (n = 276). Pellets were dissected and the occurrence of identifiable pieces of each prey group was evaluated and grouped in five different frequency groups. We found 17 different groups of arthropods
among the prey, with a clear dominance of Chironomidae and Trichoptera. There were significant differences among the sampling sites in prey diversity but not in prey richness.The changes in prey diversity were associated with sample sites. We conclude that on a local scale there is low variability in diet of Daubenton’s bat caused by hunting in various habitat structures in the surroundings of water bodies. Our results highlight the ecological flexibility of M. daubentonii, which could be an explanation for the commonness of M. daubentonii across Europe in comparison to the rather rare pond bat (Myotis dasycneme), which has similar habitats and main prey group preferences.
The transition between foraging and farming represents one of the most discussed topics in human history. This study deals with demographic aspects of farming spread in Central Europe (6th millenium BC). On the theoretical and empirical level and on the basis of demographic modelling, we argue that both south-eastern farmers and local foragers participated on the establishment of farming communities in Central Europe., Patrik Galeta, Jaroslav Brůžek., and Obsahuje bibliografii
Analysis of the stomach contents of otters recovered from South West England between 1999 and 2003 revealed that prey items taken were principally species of fish and amphibians, with mammals and birds occasionally taken. The fork length of fish recorded was 30 to 720 mm. Eel Anguilla anguilla was the dominant prey item, with up to five present per stomach. Estimated lengths ranged from 100 to 450 mm. Other common prey items were bullhead Cottus gobio and brown trout Salmo trutta. In addition to these freshwater species, there were recordings of sea bass Dicentrarchus labrax and thick lipped mullet Chelon labosus, indicating foraging in both freshwater and marine habitats. A seasonal peak was observed in the relative frequency of amphibians in diet, as otters took advantage of spawning aggregations. However, there were no seasonal trends in the relative frequency of other species in otter diet, with eel, bullhead and cyprinid species taken regularly in all months.
In searching both for food to produce eggs and for suitable oviposition sites, females of aphidophagous ladybirds must be adapted to exploit prey that vary greatly in their occurrence and abundance over both space and time. A simple model of ladybird searching and oviposition behaviour emerged in the 1950s: adult ladybirds are highly mobile in traversing the landscape, but become less active and produce more eggs as their rate of aphid consumption increases. The net result is that most eggs tend to be laid at sites of high aphid density. Laboratory and field experiments and observations over the past several decades have generally supported this basic model, although the linkage between ladybird dispersal activity and local aphid density often appears to be relatively weak. Not all ladybird eggs are laid in patches of high aphid density. Females use resources from limited prey consumption to produce eggs in modest numbers. They may thus be prepared to lay some eggs quickly when they succeed in finding aphids in high numbers, but otherwise they may have little choice but to lay these eggs in suboptimal sites. Upon locating patches of high prey density, females are faced with the decision of how long to remain. The basic model raises the possibility that these females become passively trapped at such patches until local aphid density collapses. Recent studies, however, suggest that detection of oviposition-deterring pheromones may promote earlier departure from prey patches. Females may also have an innate tendency to disperse throughout their lives regardless of local conditions, as a bet-hedging strategy to spread their eggs widely over space. Additional studies are needed to evaluate further the degree to which females actively determine and vary the rhythms of dispersal and reproduction in response to the unpredictable and short-lived nature of populations of their aphid prey