Generalization of Mimics Imperfect in Colour Patterns: The Point of View of Wild Avian Predators

Current research of imperfect mimicry brings ambiguous results. Experiments simulating more natural conditions rather than laboratory experiments show lower willingness of avian predators to attack less perfect mimics. We decided to simulate a natural situation by testing responses of wild‐caught adult avian predators (Great tit – Parus major) to variously perfect mimics of the red firebug (Pyrrhocoris apterus), which were in previous studies shown to elicit avoidance in Great tits. Presented mimics were perfect in all traits (firebug with its own colour pattern), imperfect in colour pattern (firebug with modified colour pattern), perfect in colour pattern, but imperfect in other visual traits (cockroach with firebug colour pattern), and imperfect in colour pattern as well as in other visual traits (cockroach with modified colour patterns). Modification of the pattern focused on the rounded spots on firebug's hemielytra, which is a conspicuous trait within the pattern. The pattern modification had no influence on the number of birds attacking the prey; nevertheless, birds spent more time observing the cockroaches that displayed the perfect firebug colour pattern than in the case of any other prey. Moreover, firebugs that displayed the perfect firebug colour pattern were observed for the shortest time (equal to that of the model – unmodified firebug). Cockroaches were attacked more often than firebugs, which suggest that birds were able to use additional visual cues (shape of legs and antennae) in prey recognition. Given these result, we conclude that differences in morphological traits characteristic for used prey taxa (true bugs, cockroaches) seem to be more important in the prey's protection than its colour pattern.     

Sex‐specific differences in Sand Martin Riparia riparia nest attentiveness

Capsule Nest attentiveness during the night is significantly lower in males but varies with the activities of the breeding cycle. Male nest attentiveness shows minima during the burrowing and egg‐laying phases, and also during the brooding of chicks in second or re‐nest broods.     

Long-term changes in numbers and distribution of wintering waterbirds in the Czech Republic, 1966–2008

Capsule?Of 26 species of wintering waterbirds, 18 showed an increase in numbers, five showed a decrease and two showed no change.

Aim?To assess long-term trends in the numbers and distribution of the 26 most abundant wintering waterbird species in the Czech Republic.

Methods?We used International Waterbird Census data from between 48 and 639 wetland sites which had been counted annually in the Czech Republic from 1966 to 2008. From these data long-term changes in numbers and distributions were determined. Log-linear Poisson regression analysis was used to estimate missing data using trim software. The distribution of each species was described as the ratio of the number of sites occupied by that species to the total number of sites investigated.

Results?Increasing trends were found for 18 species, five species were found to be declining, one species was stable and two species were found with uncertain trends. Wintering distributions (the ratio of sites occupied by a given species to the total number of sites counted) increased in 16 species and decreased in two species, broadly correlated with the species changes in numbers.

Conclusion?In most species changes in numbers as well as changes in distribution followed the Western Palearctic population trends. Those species which increased were mainly piscivores and included geese, ducks and gulls. Scarcer species also exhibited an increase in numbers. The changes in numbers (both positive and negative) were more frequent among species associated with running water, whereas species which showed uncertain trends were more frequently recorded on standing water, which is more affected by variable weather conditions.     

Population increase of forest birds in the Czech Republic between 1982 and 2003

Capsule Populations of most forest bird species increased between 1982 and 2003, probably due to increased forest cover and changes in forest age-class composition.

Aims To determine population changes of forest birds in the Czech Republic and to determine their possible causes.

Methods Population data were collected via the Breeding Bird Monitoring Programme, which is based on skilled volunteers counting birds at point transects using a standardized technique. Population trends and indices for the period 1982–2003 were calculated for 47 species using log-linear models. Published data on development of forest cover and forest age composition in the Czech Republic were used to indicate environmental change over the same period.

Results Populations of most forest species increased between 1982 and 2003. There was also an increase in forest cover and an increase in the proportion of older forest age-classes. The increase in forest specialist birds was positively correlated with the average increase in forest coverage.

Conclusions The populations of Czech forest birds have increased in the last two decades. This contrasts with widely reported declines of farmland bird populations throughout Europe. The correlation between populations of specialized forest species and extent of forest habitat suggests that changes in land-use are an important factor. However, increasing cover of mature forests could have a similar effect on the populations of specialist species.     

Surfactin production enhances the level of cardiolipin in the cytoplasmic membrane of Bacillus subtilis

Surfactin is a cyclic lipopeptide antibiotic that disturbs the integrity of the cytoplasmic membrane. In this study, the role of membrane lipids in the adaptation and possible surfactin tolerance of the surfactin producer Bacillus subtilis ATCC 21332 was investigated. During a 1-day cultivation, the phospholipids of the cell membrane were analyzed at the selected time points, which covered both the early and late stationary phases of growth, when surfactin concentration in the medium gradually rose from 2 to 84 μmol·l^− 1. During this time period, the phospholipid composition of the surfactin producer's membrane (Sf⁺) was compared to that of its non-producing mutant (Sf⁻). Substantial modifications of the polar head group region in response to the presence of surfactin were found, while the fatty acid content remained unaffected. Simultaneously with surfactin production, a progressive accumulation up to 22% of the stress phospholipid cardiolipin was determined in the Sf⁺ membrane, whereas the proportion of phosphatidylethanolamine remained constant. At 24 h, cardiolipin was found to be the second major phospholipid of the membrane. In parallel, the Laurdan generalized polarization reported an increasing rigidity of the lipid bilayer. We concluded that an enhanced level of cardiolipin is responsible for the membrane rigidification that hinders the fluidizing effect of surfactin. At the same time cardiolipin, due to its negative charge, may also prevent the surfactin-membrane interaction or surfactin pore formation activity.     

Chromosomal variation in social voles: a Robertsonian fusion in Günther’s vole

The study reports on chromosomes in several populations of social voles from south-eastern Europe and the Middle East. The standard karyotypes of individuals of Microtus hartingi and Microtus guentheri originating from both south-eastern Europe and Asia Minor comprised 54 mostly acrocentric chromosomes. However, variation between populations was found in the amount and distribution of C-heterochromatin in certain autosomes and the sex chromosomes. Furthermore, a specific pattern of argyrophilic nucleolar organizer region distribution was recorded in different geographic populations. In a population from Asia Minor, a heterozygous centric fusion of two autosomes was found. The G-banded karyotypes of M. guentheri and Microtus socialis were compared, and tandem fusions of autosomes were suggested as possible mechanism of the divergence. The karyotypes of the nine currently recognized species of social voles are reviewed, and implications of chromosomal data for systematics are evaluated.     

Two Trichosporon species isolated from Central-European mygalomorph spiders (Araneae: Mygalomorphae)

Trichosporon (Dikarya: Basidiomycota) is a genus of anamorphic yeasts typically associated with soil and water, although many species are causative agents of diseases in animals and man. Here we provide the first compelling evidence that spiders can be occasionally colonized by at least two Trichosporon species. Trichosporon dulcitum (Berkhout) Weijman 1979 was isolated from the exoskeleton of purse-web spider Atypus piceus, while Trichosporon porosum (Stautz) Middelhoven, Scorzetti & Fell 2001 was isolated from the exoskeleton of purse-web spider Atypus affinis. Both of the species were identified based on DNA sequence analysis of the host specimens displaying macroscopic signs of the superficial white mycosis on their exoskeleton. Only two specimens with macroscopic signs of superficial yeast growth were identified among the 125 individuals of A. affinis, A. piceus and Atypus muralis examined that were collected at various sites throughout the Czech Republic. The consistent burrow microclimate, uninterrupted occupancy of the single burrow for several subsequent years, and presence of prey remnants in the burrow below the purse-web may play a role in the course of infection of the mygalomorphs examined. The phylogenetic relationships of Trichosporon species are analyzed, concluding that association with invertebrates clusters predominantly among four groups of closely related species in independent Trichosporon clades.     

The first case of fatal pneumonia caused by Panton–Valentine leukocidin-producing Staphylococcus aureus in an infant in the Czech Republic

Panton–Valentine leukocidin-producing strains of Staphylococcus aureus can cause severe skin and soft tissue infections and necrotizing pneumonia with a high mortality rate. This is a report on the first case of fatal pneumonia with mediastinitis in an infant in the Czech Republic. The causative agent was a methicillin-susceptible S. aureus strain with pronounced production of the PVL toxin and hyperproduction of enterotoxin A.     

At the edge and on the top: molecular identification and ecology of Daphnia dentifera and D. longispina in high-altitude Asian lakes

The occurrence of members of the highly diverse Daphnia longispina complex in Southern and Central Asian high-mountain lakes has been recognized for more than a century. Until now, however, no molecular data have been available for these populations inhabiting the “Roof of the World.” Here, we present the first identification for D. gr. longispina from that region based on a molecular phylogeny. Our findings show that alpine lakes in the Pamir and Himalaya mountains host populations of widespread species of the complex, for which these are the highest known localities. A spineless morph from the Himalaya region, previously labeled as D. longispina var. aspina, was clustering tightly with D. dentifera, while a population from the Pamir mountain range was grouped with D. longispina. In addition, we analyzed ecological data available for lakes in the Khumbu region (Himalaya) to investigate ecological preferences of non-pigmented D. gr. longispina. The identified factors can at least partly be related to avoidance of high UV conditions by this species. We conclude that the widespread species D. dentifera and D. longispina also colonized the Asian high-mountain lakes, and identify the need for further research to trace the possible effect of rapid environmental changes in this region on the diversity and ecology of high-altitude Daphnia populations.