How consistent are the transcriptome changes associated with cold acclimation in two species of the Drosophila virilis group?

This work was financially support by a Marie Curie Initial Training Network grant, “Understanding the evolutionary origin of biological diversity” (ITN-2008–213780 SPECIATION), grants from the Academy of Finland to A.H. (project 132619) and M.K. (projects 268214 and 272927), a grant from NERC, UK to M.G.R. (grant NE/J020818/1), and NERC, UK PhD studentship to D.J.P. (NE/I528634/1).For many organisms the ability to cold acclimate with the onset of seasonal cold has major implications for their fitness. In insects, where this ability is widespread, the physiological changes associated with increased cold tolerance have been well studied. Despite this, little work has been done to trace changes in gene expression during cold acclimation that lead to an increase in cold tolerance. We used an RNA-Seq approach to investigate this in two species of the Drosophila virilis group. We found that the majority of genes that are differentially expressed during cold acclimation differ between the two species. Despite this, the biological processes associated with the differentially expressed genes were broadly similar in the two species. These included: metabolism, cell membrane composition, and circadian rhythms, which are largely consistent with previous work on cold acclimation/cold tolerance. In addition, we also found evidence of the involvement of the rhodopsin pathway in cold acclimation, a pathway that has been recently linked to thermotaxis. Interestingly, we found no evidence of differential expression of stress genes implying that long-term cold acclimation and short-term stress response may have a different physiological basis.PostprintPeer reviewe

Variation in the Male Pheromones and Mating Success of Wild Caught Drosophila melanogaster

Drosophila melanogaster males express two primary cuticular hydrocarbons (male-predominant hydrocarbons). These act as sex pheromones by influencing female receptivity to mating. The relative quantities of these hydrocarbons vary widely among natural populations and can contribute to variation in mating success. We tested four isofemale lines collected from a wild population to assess the effect of intrapopulation variation in male-predominant hydrocarbons on mating success. The receptivity of laboratory females to males of the four wild-caught lines varied significantly, but not consistently in the direction predicted by variation in male-predominant hydrocarbons. Receptivity of the wild-caught females to laboratory males also varied significantly, but females from lines with male-predominant hydrocarbon profiles closer to a more cosmopolitan one did not show a correspondingly strong mating bias toward a cosmopolitan male. Among wild-caught lines, the male-specific ejaculatory bulb lipid, cis-vaccenyl acetate, varied more than two-fold, but was not associated with variation in male mating success. We observed a strong inverse relationship between the receptivity of wild-caught females and the mating success of males from their own lines, when tested with laboratory flies of the opposite sex

Molecular and Behavioral Differentiation among Brazilian Populations of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae)

Lutzomyia longipalpis is the main vector of visceral leishmaniasis in the Americas. There is strong evidence that L. longipalpis is a species complex, but there is still no consensus regarding the number of species occurring in Brazil. We combined molecular and behavioral analyses of a number of L. longipalpis populations in order to help clarify this question. This approach has allowed us to identify two main groups of populations in Brazil. One group probably represents a single species distributed mainly throughout the coastal regions of North and Northeast Brazil and whose males produce the same type of copulation song and pheromone. The second group is more heterogeneous, probably represented by a number of incipient species with different levels of genetic divergence among the siblings that produce different combinations of copulation songs and pheromones. The high level of complexity observed raises important questions concerning the epidemiological consequences of this incipient speciation process

Zdravstveno obrazovanje i informiranje koje provode službe medicine rada u Finskoj

This article discusses health education and communication in Occupational Health Services (OHS) based on a questionnaire study conducted in Finnish OHS in 2005. The study focused on educational activities carried out by OH professionals and directed at individual employees, work communities and groups, and representatives of client organisations. The questionnaire was sent to 1132 OH professionals - physicians, nurses, physiotherapists and psychologists - working in 130 OHS units, and representing different OHS providers in Finland. 635 respondents (162 physicians, 342 nurses, 96 physiotherapists, 35 psychologists) returned the questionnaire. The overall response rate was 58 %. There were statistically significant differences in educational activities by different professional groups; differences were also related to the length of working experience in OHS. For all OH professionals, individual employees were the primary clients of health education and communication. Education was less often directed at work communities and representatives of client organisations. However, many issues related to health and well-being at work are not within the reach of individual employees. The impact of health education would be more evident if it also reached those organisational stakeholders with discretion in decision-making. Furthermore, OH personnel should pay attention to the social aspect of learning and work more with groups and work communities.U ovome se članku raspravlja o zdravstvenom obrazovanju i informiranju koje provode službe medicine rada, a na temelju istraživanja provedenog među tim službama 2005. U središtu su ispitivanja bile obrazovne aktivnosti medicinara rada usmjerene na radnike kao pojedince, radne zajednice i skupine te predstavnike korisničkih organizacija. Upitnik su dobila 1132 medicinara rada, uključujući liječnike, medicinske sestre, fizioterapeute i psihologe zaposlene u 130 jedinica koje pružaju usluge medicine rada u Finskoj. Ispunjene je upitnike vratilo 635 sudionika (162 liječnika, 342 sestre, 96 fizioterapeuta te 35 psihologa). Ukupni odgovor iznosio je 58 %. Zamijećene su statistički značajne razlike u obrazovnim aktivnostima između pojedinih zanimanja, a one su bile povezane i sa stažem u medicini rada. Svim medicinarima rada pojedinačni radnici primarni su korisnici zdravstvenoga obrazovanja i informiranja. Obrazovanje se rjeđe usmjeravalo na radne zajednice i predstavnike korisničkih organizacija. Međutim, mnoga otvorena pitanja vezana uz zdravlje i dobrobit na radu nisu u nadležnosti pojedinačnih zaposlenika. Utjecaj zdravstvenoga obrazovanja bio bi stoga svrhovitiji kada bi ono obuhvatilo i one strukture koje donose odluke. Osim toga, osoblje medicine rada treba obratiti pozornost na socijalni aspekt učenja te treba više raditi sa skupinama i radnim zajednicama

Quantification of carbon and phosphorus co-limitation in bacterioplankton: new insights on an old topic

Because the nature of the main resource that limits bacterioplankton (e.g. organic carbon [C] or phosphorus [P]) has biogeochemical implications concerning organic C accumulation in freshwater ecosystems, empirical knowledge is needed concerning how bacteria respond to these two resources, available alone or together. We performed field experiments of resource manipulation (2×2 factorial design, with the addition of C, P, or both combined) in two Mediterranean freshwater ecosystems with contrasting trophic states (oligotrophy vs. eutrophy) and trophic natures (autotrophy vs. heterotrophy, measured as gross primary production:respiration ratio). Overall, the two resources synergistically co-limited bacterioplankton, i.e. the magnitude of the response of bacterial production and abundance to the two resources combined was higher than the additive response in both ecosystems. However, bacteria also responded positively to single P and C additions in the eutrophic ecosystem, but not to single C in the oligotrophic one, consistent with the value of the ratio between bacterial C demand and algal C supply. Accordingly, the trophic nature rather than the trophic state of the ecosystems proves to be a key feature determining the expected types of resource co-limitation of bacteria, as summarized in a proposed theoretical framework. The actual types of co-limitation shifted over time and partially deviated (a lesser degree of synergism) from the theoretical expectations, particularly in the eutrophic ecosystem. These deviations may be explained by extrinsic ecological forces to physiological limitations of bacteria, such as predation, whose role in our experiments is supported by the relationship between the dynamics of bacteria and bacterivores tested by SEMs (structural equation models). Our study, in line with the increasingly recognized role of freshwater ecosystems in the global C cycle, suggests that further attention should be focussed on the biotic interactions that modulate resource co-limitation of bacteria.This research was supported by Junta de Andalucía (Excelencia P09-RNM-5376 to JMMS) and the Spanish Ministry Ciencia e Innovación (CGL2011-23681 to PC)

Food webs under changing biodiversity - Top-down control

Report on effects of changing predation pressure on benthic and pelagic specie

The genetic architecture of sexually selected traits in two natural populations of Drosophila montana

The work was supported by the National Environment Research Council (grant NE/E015255/1 to MGR and RKB) and the Academy of Finland (project 132619 to AH).We investigated the genetic architecture of courtship song and cuticular hydrocarbon traits in two phygenetically distinct populations of Drosophila montana. To study natural variation in these two important traits, we analysed within-population crosses among individuals sampled from the wild. Hence, the genetic variation analysed should represent that available for natural and sexual selection to act upon. In contrast to previous between-population crosses in this species, no major quantitative trait loci (QTLs) were detected, perhaps because the between-population QTLs were due to fixed differences between the populations. Partitioning the trait variation to chromosomes suggested a broadly polygenic genetic architecture of within-population variation, although some chromosomes explained more variation in one population compared with the other. Studies of natural variation provide an important contrast to crosses between species or divergent lines, but our analysis highlights recent concerns that segregating variation within populations for important quantitative ecological traits may largely consist of small effect alleles, difficult to detect with studies of moderate power.PostprintPeer reviewe