Continuous versus discrete quantity discrimination in dune snail (Mollusca: Gastropoda) seeking thermal refuges

The ability of invertebrates to discriminate quantities is poorly studied, and it is unknown whether other phyla possess the same richness and sophistication of quantification mechanisms observed in vertebrates. The dune snail, Theba pisana, occupies a harsh habitat characterised by sparse vegetation and diurnal soil temperatures well above the thermal tolerance of this species. To survive, a snail must locate and climb one of the rare tall herbs each dawn and spend the daytime hours in an elevated refuge position. Based on their ecology, we predicted that dune snails would prefer larger to smaller groups of refuges. We simulated shelter choice under controlled laboratory conditions. Snails’ acuity in discriminating quantity of shelters was comparable to that of mammals and birds, reaching the 4 versus 5 item discrimination, suggesting that natural selection could drive the evolution of advanced cognitive abilities even in small-brained animals if these functions have a high survival value. In a subsequent series of experiments, we investigated whether snails used numerical information or based their decisions upon continuous quantities, such as cumulative surface, density or convex hull, which co-varies with number. Though our results tend to underplay the role of these continuous cues, behavioural data alone are insufficient to determine if dune snails were using numerical information, leaving open the question of whether gastropod molluscans possess elementary abilities for numerical processing.

Regularities of Vertical Propagation Mammals of the Mountain Massive Munku-Sardyk

The Munku-Sardyk mountain range is an important link in the Eastern Sayan mountain system, performing a barrier and refugial role for various mammalian species, in the transition zone between the Central Asian steppe and the Siberian taiga. Thus, the southern steppe slopes are the northern limit in the distribution of the Tuvan and Mongolian voles, Tarbagan marmot, tolai hare, mountain weasel and manul. For the Altai mole, brown bear, sable, Siberian musk deer, reindeer and elk, the southern border of their distribution lies in the forest zone of the Khubsugul region. The paper presents the basic information about the features of the vertical distribution of mammals on the southern and northern slopes of the massif. The complex structure of the vertical zonation of the mountain range and the harsh habitat conditions are of paramount importance in the distribution and number of mammals inhabiting it. The species composition of communities in five high-altitude belts is presented: forest-steppe, mountain- taiga, subalpine, alpine and nival. A comparative analysis of the degree of similarity of mammalian communities, depending on the altitudinal zonality and exposure of the slope, using the Jaccard coefficient, based on the analysis of qualitative data, has been carried out. A high degree of similarity of the lower belt with the higher one was revealed on both slopes of the mountain range. The highest degree of similarity between the mountain-taiga and subalpine belts was noted, and the lowest degree was observed in the forest-steppe and nival belts that were separated from each other. The low species diversity in the nival belt is associated with the harsh habitat conditions associated with the absence of protective feeding stations and mechanisms of adaptation to hypoxia in most mammals living in the lower part. When comparing the community of mammalian faunas between the belts of the southern and northern slopes, a high similarity of mountain-taiga belts and a decrease in the proportion of common species with height were noted. The obtained information eliminates the existing gaps in the territory poorly studied in the zoogeographic plan and makes it possible to form a unified environmental policy in the transboundary region.

Flower-visiting insects observed on the critically endangered alpine plant species Callianthemum kernerianum Freyn ex A. Kerner (Ranunculaceae)

In the present paper we provide the first contribution to the knowledge of the flower-visiting insect assemblages of the alpine plant species Callianthemum kernerianum Freyn ex A. Kerner (Ranunculaceae). This focal plant species was selected since it is a steno-endemic and critically endangered species belonging to the IUCN red-list. Fifteen taxa were recorded, among which very few are true pollinators, whereas all the others can be considered only indirect pollinators. The peculiar phenology of the plant and the harsh habitat conditions in which it grows probably affect the richness and abundance of flower-visiting insects as well as of true pollinators. This could be the reason for this plant to be a self-compatible species.

Resilience of the Natural Phyllosphere Microbiota of the Grapevine to Chemical and Biological Pesticides

ABSTRACTThe phyllosphere is colonized by complex microbial communities, which are adapted to the harsh habitat. Although the role and ecology of nonpathogenic microorganisms of the phyllosphere are only partially understood, leaf microbiota could have a beneficial role in plant growth and health. Pesticides and biocontrol agents are frequently applied to grapevines, but the impact on nontarget microorganisms of the phyllosphere has been marginally considered. In this study, we investigated the effect of a chemical fungicide (penconazole) and a biological control agent (Lysobacter capsiciAZ78) on the leaf microbiota of the grapevine at three locations. Amplicons of the 16S rRNA gene and of the internal transcribed spacer were sequenced for bacterial and fungal identification, respectively. Pyrosequencing analysis revealed that the richness and diversity of bacterial and fungal populations were only minimally affected by the chemical and biological treatments tested, and they mainly differed according to grapevine locations. Indigenous microbial communities of the phyllosphere are adapted to environmental and biotic factors in the areas where the grapevines are grown, and they are resilient to the treatments tested. The biocontrol properties of phyllosphere communities against downy mildew differed among grapevine locations and were not affected by treatments, suggesting that biocontrol communities could be improved with agronomic practices to enrich beneficial populations in vineyards.