External thoracic scent efferent system of Scutelleridae (Hemiptera: Heteroptera)

The metathoracic scent glands in the Heteroptera produce defence secretions which are spread outside the body through and by using the thoracic external scent efferent system. That complex system was studied in 18 species from 11 genera of four subfamilies, Elvisurinae, Eurygastrinae, Hoteinae and Scutellerinae of the family Scutelleridae (Pentatomoidea). The results have been compared with published data. The pattern of that system is more consistent at the level of genus, mostly very similar in the congeneric species, but mostly variable within higher taxonomic levels, tribes and subfamilies. Five types of the external scent efferent system are recognized within the family Scutelleridae, basic two of them in studied species: (i) peritreme well developed, covering large part of metapleuron, evaporatorium small, developed only on metapleuron, (ii) evaporatorium large, more conspicuous than moderate-sized to small peritreme, extending to mesopleuron as large structure. The results do not support a hypothesis that the system of structures associated externally with metathoracic scent glands is in correlation with type of a habitat. However, these structures are well usable as diagnostic characters for scutellerid genera (e.g. Cantao, Hyperonchus, Scutellera and Solenosthedium).     

Bird-habitat associations predict population trends in central European forest and farmland birds

Recent studies show differences in population trends between groups of species occupying different habitats. In Czech birds, as well as in many other European countries, populations of forest species have increased, whereas populations of farmland species have declined. The aim of our study was to test whether population trends of particular species were related to finer bird-habitat associations within farmland and forest birds. We assessed bird-habitat associations using canonical correspondence analysis based on data from a 400 km long transect across the Czech Republic. We calculated population trends of 62 bird species using log-linear models based on data from a large-scale annual monitoring scheme, which covers the time series from 1982 to 2005. Within forest birds, species with a closer association with lowland broad-leaved forest have had more positive population trends, whereas species with a closer association with montane and coniferous forest revealed more negative population trends. We attribute these opposite trends to the gradual replacement of coniferous forests by deciduous ones, which took place in the Czech Republic during recent decades. Our analyses revealed a hump-shaped relationship within farmland birds, species most closely associated with farmland habitat revealing the most negative trends, whereas species with intermediate association to farmland habitat showed the most positive population trends. Such a pattern can be explained by the abandonment of previously cultivated areas followed by the spread of unmanaged meadows and scrubland. Changes in quantity or quality of preferred habitats may thus represent major drivers of observed bird population changes.     

A qualitative investigation of major urinary proteins in relation to the onset of aggressive behavior and dispersive motivation in male wild house mice (<Emphasis Type="Italic">Mus musculus domesticus</Emphasis>)

The physiological basis for population differentiation of dispersal timing during individual development in male wild house mice is still unknown. As major urinary proteins (MUPs) are known to convey information about competitive ability in male mice, we examined individual MUP profiles defined by isoelectric-focusing (IEF) patterns in relation to developmental timing of dispersive motivation. As an experimental paradigm marking the development of the dispersal propensity, we used agonistic onset between litter mate brothers when kept in pairs under laboratory conditions. Agonistic onset is known to reflect the initiation of dispersive motivation. Hence, we compared individual MUP IEF patterns between fraternal pairs that did or did not develop agonistic relationships before the age of 2 months. Urine was collected on the day of weaning and at the beginning of adulthood. We investigated whether there was a significant co-occurrence of particular MUP IEF patterns with the agonistic onset in male mice. We assumed that, based on this co-occurrence, particular MUP IEF patterns and/or a particular dynamic of MUP IEF expression from weaning to adulthood may be considered a physiological predictor of a specific behavioral strategy in male mice (i.e. submissive-philopatric or agonistic-dispersive strategy). We found that agonistic males expressed more MUP IEF bands than amicable ones at weaning, but these differences disappeared later on. The presence of two particular IEF bands at weaning was significantly associated with early agonistic onset. Our study suggests that MUPs could have a predictive value for the onset of aggressive behavior and dispersal tendency in male wild house mice.     

Phylogenetic distribution of protease inhibitors of the Kazal-family within the Arthropoda

In mammalian pancreatic cells, the pancreatic secretory trypsin inhibitor (PSTI) belonging to the Kazal-family prevents the premature activation of digestive enzymes and thus plays an important role in a protective mechanism against tissue destruction by autophagy. Although a similar protective mechanism exists in Arthropoda, the distribution of these inhibitors in this phylum remains obscure. A comprehensive in silico search of nucleotide databases, revealed the presence of members of the Kazal-family in the four major subphyla of the Arthropoda. Especially in the Hexapoda and the Crustacea these inhibitors are widespread, while in the Chelicerata and Myriapoda only a few Kazal-like protease inhibitors were found. A sequence alignment of inhibitors retrieved in the digestive system of insects revealed a conservation of the PSTI characteristics and strong resemblance to vertebrate PSTI. A phylogenetic analysis of these inhibitors showed that they generally cluster according to their order. The results of this data mining study provide new evidence for the existence of an ancient protective mechanism in metazoan digestive systems. Kazal-like inhibitors, which play an important protective role in the pancreas of vertebrates, also seem to be present in Arthropoda.     

Grids versus regional species lists: are broad-scale patterns of species richness robust to the violation of constant grain size?

Where distribution maps do not exist ecologists often use regional species lists to examine geographic patterns of species richness, despite the fact that inconsistent grain sizes across areas may complicate interpretation of the results. We compare patterns of species richness of European butterflies and dragonflies using regional species lists (varying grain size) and regular grids (constant grain size). We asked if species lists give results comparable to the gridded data when used in simple macroecological analysis of environmental correlates of species richness. We generated two equal-area grids (220 × 220 km and 440 × 440 km) to map the richness gradients and model species richness as a function of actual evapotranspiration (AET) and range in elevation. Then we used species checklists of 33 administrative regions of unequal sizes to construct the same environmental models while accounting for differences in area. Analysis of butterfly checklist data produced comparable results to the analysis of gridded data. In contrast, dragonfly checklist data had a distorted spatial pattern and much weaker associations with environmental variables than the gridded data. The robustness of checklist data appears to be variable, even within a single geographical region, and may not generate patterns congruent with those found using equal-area grids.     

Detecting Trait-Dependent Diversification Under Diversification Slowdowns

Testing whether a certain biological trait significantly affects clade diversification is central to macroevolutionary research. To this end, many scientists use constant-rate estimators (CR estimators) of diversification. However, it has never been examined whether these estimators report meaningful relationships between traits and diversification even when the diversification itself decelerates over time. In this study, I simulate trait-driven diversification concurrently with diversification slowdowns. Then, I test whether CR estimators manage to uncover the simulated relationships. Results suggest that CR estimators are robust against violation of rate constancy and successfully detect trait-dependent diversification in spite of diversification declines. Interestingly, correct results were recovered whether clade age correlated with clade diversity or not. Further comparison of CR estimators with QuaSSE suggested that QuaSSE performs better under constant diversification, but tends to report spuriously significant outcomes when diversification decelerates (=elevated Type I error). Given that diversification slowdowns have been recently reported for a wide range of taxa, these findings may be of particular relevance for future diversification studies.     

Two South American endemic species of Daphnia from high Andean lakes

Populations of Daphnia peruviana from several high mountain ponds in southern Peru were compared with Harding's type material from the vicinity of Titicaca Lake and the species re-described. Differential diagnosis for three more morphologically similar species from the region is given. New species Daphnia inca found in a mountain pond near the Peru–Chile border is described and compared with other South American species of the subgenus Ctenodaphnia.     

PpSP32-like protein as a marker of human exposure to Phlebotomus argentipes in Leishmania donovani foci in Bangladesh

Phlebotomus argentipes is a predominant vector of Leishmania donovani, the protozoan parasite causing visceral leishmaniasis in the Indian subcontinent. In hosts bitten by P. argentipes, sand fly saliva elicits the production of specific anti-salivary protein antibodies. Here, we have utilised these antibodies as markers of human exposure to P. argentipes in a visceral leishmaniasis endemic area in Pabna district, Bangladesh. The use of whole salivary gland homogenate as an antigen to detect these antibodies has several limitations, therefore it is being superseded by the use of specific recombinant salivary proteins. We have identified three major P. argentipes salivary antigenic proteins recognised by sera of bitten humans, expressed them in a recombinant form (rPagSP04, rPagSP05 and rPagSP06) and tested their applicability in ELISA and immunoblot. One of them, PpSP32-like protein rPagSP06, was identified as the most promising antigen, showing highest resemblance and correlation with the IgG response to P. argentipes salivary gland homogenate. Furthermore, we have validated the applicability of rPagSP06 in a large cohort of 585 individuals and obtained a high correlation coefficient for anti-rPagSP06 and anti-P. argentipes saliva IgG responses. The anti-rPagSP06 and anti-P. argentipes salivary gland homogenate IgG responses followed a similar right-skewed distribution. This is the first report of screening human sera for anti-P. argentipes saliva antibodies using recombinant salivary protein. The rPagSP06 was proven to be a valid antigen for screening human sera for exposure to P. argentipes bites in a visceral leishmaniasis endemic area.