Limb ablation and regeneration in Harmonia axyridis: costs for regenerators,but benefits for their progeny

Previous work revealed that Harmonia axyridisPallas (Coleoptera: Coccinellidae) in Beijing, China, were capable of regenerating a forelimb amputated in the fourth instar; 75% of surviving individuals fully regenerated the limb during pupation. In this study, we tested a population of H. axyridis invasive in North America and found that virtually 100% of beetles surviving the operation successfully regenerated the limb. Ablated/regenerated beetles spent longer in pupation, and emerging females were smaller than controls. However, reproductive success was unaffected in all pairwise crosses of control/regenerated adults; there were no differences in pre‐oviposition period, the time required to produce 10 clutches, 10‐day fecundity, or the fertility of eggs, whereas ablated/regenerated parents paid a developmental cost, their progeny obtained benefits. Offspring of crosses that included a regenerated parent tended to have faster larval development than the control cross, although not all were significantly different from controls. However, when either or both parents were ablated and regenerated, their daughters were heavier than controls at emergence. Limb regeneration during pupation appears to activate a physiological cascade which increases the magnitude of beneficial parental effects normally conferred to progeny, possibly via pleiotropic effects. The invasive North American H. axyridis population appears to have higher regeneration capacity than the Chinese population tested previously, although how regeneration capacity might be associated with invasiveness remains unclear. Limb regeneration ability may be a side effect of selection on other traits that confer high fitness under either natural or sexual selection, as it seems unlikely to confer fitness benefits directly in this species.     

First evidence of Ediacaran–Fortunian elliptical body fossils in the Brioverian series of Brittany,NW France

Body fossils are described for the first time from the Upper Brioverian (Ediacaran–Fortunian) deposits of Central Brittany (NW France). The material consists of a dozen of specimens preserved on two slates, recently collected in a quarry in Saint‐Gonlay. The fossils, centimetric in size, have an elliptical and acuminated outline, with a peripheral bulge but without conspicuous concentric or radial lines. These body fossils are preserved in slates that are locally rich in grazing traces, sometimes associated with microbial mats. The sedimentological characteristics of these deposits correspond to a shallow marine shelf environment, with a low to moderate hydrodynamism. Such findings, in concomitance with previous ichnological discoveries, unravel the potential of the Brioverian strata from Brittany as a new locality to provide answers on Ediacaran and early Cambrian biocenoses.     

A 3D Individual-Based Model to Study Effects of Chemotaxis,Competition and Diffusion on the Motile-Phytoplankton Aggregation

In this paper, we develop a 3D-individual-based model (IBM) to understand effect of various small-scale mechanisms in phytoplankton cells, on the cellular aggregation process. These mechanisms are: spatial interactions between cells due to their chemosensory abilities (chemotaxis), a molecular diffusion and a demographical process. The latter is considered as a branching process with a density-dependent death rate to take into account the local competition on resources. We implement the IBM and simulate various scenarios under real parameter values for phytoplankton cells. To quantify the effects of the different processes quoted above on the spatial and temporal distribution of phytoplankton, we used two spatial statistics: the Clark–Evans index and the group belonging percentage. Our simulation study highlights the role of the branching process with a weak-to-medium competition in reinforcing the aggregating structure that forms from attraction mechanisms (under suitable conditions for diffusion and attraction forces), and shows by contrast that aggregations cannot form when competition is high.     

Black-headed gulls (<Emphasis Type="Italic">Chroicocephalus ridibundus</Emphasis>) - a natural reservoir of potentially pathogenic microfungi?

Mycological studies of selected populations of black-headed gulls were carried out in response to the increasing interest in wild birds as reservoirs of potentially pathogenic fungi and links in the epidemiological chain of mycoses hazardous to human and animals. The biological material comprised swabs from the beaks and cloacae of adult and young birds subjected to standard mycological diagnostics. 79.5% of samples were positive, comprising 22 fungal species belonging to 10 genera, mainly Candida, Rhodotorula, Aspergillus, Fusarium, Cryptococcus, and Trichosporon. The most frequently isolated species were Candida albicans and Rhodotorula rubra, found in the beaks of females and young birds and in the cloacae of young birds with comparable frequency. Cryptococcus laurentii, Cr. neoformans, Aspergillus niger, A. flavus, and Rh. muscilaginosa were isolated relatively frequently from all birds. The results highlight the ecological importance of wild birds in the circulation of potentially pathogenic fungi in the biosphere.     

Predation by polyphagous carabid beetles on eggs of a pest slug: Potential implications of climate change

Harpalus rufipes and Poecilus cupreus are two widespread polyphagous carabids which are known to destroy eggs of the pest slug Deroceras reticulatum in the laboratory. To examine the effect of temperature on the predation of the eggs of D. reticulatum by H. rufipes and P. cupreus, a laboratory experiment with different temperatures and a semi‐field experiment including simulated warming were performed. In both experiments, H. rufipes killed more eggs than P. cupreus, and the predatory activity of the former increased significantly with increasing temperature. To our knowledge, this is the first study on predatory activity of polyphagous carabids on the eggs of a pest slug performed under a climate warming scenario. Results suggest that biological pest control performed by polyphagous carabids such as H. rufipes upon pest slugs may be enhanced under predicted climate warming conditions.     

Comparative analysis of airborne bacteria and fungi in two salt mines in Poland

The aim of this work was to determine the genera or species composition and the number of colony forming units of airborne bacteria and fungi, respectively, in two salt mines in Poland “Wieliczka” (Lesser Poland) and “Polkowice–Sieroszowice” (Lower Silesia). Both of them are working environments characterized by extreme conditions, and additionally “Wieliczka,” officially placed on the UNESCO World Heritage Sites’ list, plays a role of tourist attraction. There are also some curative chambers located in this mine. Air samples were taken once in December 2015, between 6:00 a.m. and 9:00 a.m. There were nine measurement points located about 200 m underground in “Wieliczka” and six measurement points located in the working shafts about 400 m underground in “Polkowice–Sieroszowice.” The total volume of each air sample was 150 L. Air samples, collected in individual measurement points of both salt mines, were inoculated on two microbiological media: potato dextrose agar and tryptic soy agar using the impact method. We identified 10 and 3 fungal genera in the “Wieliczka” Salt Mine and in “Polkowice–Sieroszowice,” respectively. The most common were fungi of the Penicillium genus. In both mines, the Gram-positive bacteria of genus Micrococcus were detected most frequently. Among identified microorganisms, there were neither pathogenic fungi nor bacteria. The most prevalent microorganisms detected in indoor air were Gram-positive cocci, which constituted up to 80% of airborne microflora. Our results showed that microorganisms recorded in the air samples are not a threat to workers, tourists or patients. Neither pathogens nor potentially pathogenic microorganisms, listed as BSL-2, BSL-3 or BSL-4, were detected. The microbes identified during our analysis commonly occur in such environments as the soil, water and air. Some of the detected bacteria are component of natural microflora of human skin and mucous membranes, and they can cause only opportunistic infections in individuals depending on their health condition.