In Bonobos Yawn Contagion Is Higher among Kin and Friends

In humans, the distribution of yawn contagion is shaped by social closeness with strongly bonded pairs showing higher levels of contagion than weakly bonded pairs. This ethological finding led the authors to hypothesize that the phenomenon of yawn contagion may be the result of certain empathic abilities, although in their most basal form. Here, for the first time, we show the capacity of bonobos (Pan paniscus) to respond to yawns of conspecifics. Bonobos spontaneously yawned more frequently during resting/relaxing compared to social tension periods. The results show that yawn contagion was context independent suggesting that the probability of yawning after observing others'' yawns is not affected by the propensity to engage in spontaneous yawns. As it occurs in humans, in bonobos the yawing response mostly occurred within the first minute after the perception of the stimulus. Finally, via a Linear Mixed Model we tested the effect of different variables (e.g., sex, rank, relationship quality) on yawn contagion, which increased when subjects were strongly bonded and when the triggering subject was a female. The importance of social bonding in shaping yawn contagion in bonobos, as it occurs in humans, is consistent with the hypothesis that empathy may play a role in the modulation of this phenomenon in both species. The higher frequency of yawn contagion in presence of a female as a triggering subject supports the hypothesis that adult females not only represent the relational and decisional nucleus of the bonobo society, but also that they play a key role in affecting the emotional states of others.     

Socio-ecological contagion in Veganville

In order to meet the 2015 Paris Agreement for 1.5 °C global warming, per capita emissions need to come down to 2.9 tonnes by 2030. Food systems are known to be a significant source of an individual's carbon footprint and demand attention in sustainability management. The objective of this research is to conceptualise and define an intersection between contagion theory and socio-ecological systems models. This is achieved using a population dynamics model between two groups characterised by a distinct food regime: omnivores and vegans. The greenhouse gas emissions of each food regime is used to estimate the city's changing carbon foodprint as the food regimes shift by social contagion. Social contagion is identified as a catalyst for social tipping points, and emission pathways are explored with a variety of different contagion variables to test sensitivity towards a tipping point. The main finding is that the urban carbon foodprint can be reduced significantly with widespread adoption of veganism, but that the foodprint reaches a minimum at 1.97 tonnes CO₂-equivalent per capita. This demonstrates the need to embed food demand in urban climate governance such as nudging towards plant-based food alternatives. Nudging is discussed as a lever of ecological importance to social contagion. Lastly, socio-ecological contagion is defined as the interactions between social contagion and damage done to ecological systems to measure peer-to-peer spread of environmental stewardship agendas, such as the journey to Veganville.     

Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy

In humans, the susceptibility to yawn contagion has been theoretically and empirically related to our capacity for empathy. Because of its relevance to evolutionary biology, this phenomenon has been the focus of recent investigations in non-human species. In line with the empathic hypothesis, contagious yawning has been shown to correlate with the level of social attachment in several primate species. Domestic dogs (Canis familiaris) have also shown the ability to yawn contagiously. To date, however, the social modulation of dog contagious yawning has received contradictory support and alternative explanations (i.e., yawn as a mild distress response) could explain positive evidence. The present study aims to replicate contagious yawning in dogs and to discriminate between the two possible mediating mechanisms (i.e., empathic vs. distress related response). Twenty-five dogs observed familiar (dog’s owner) and unfamiliar human models (experimenter) acting out a yawn or control mouth movements. Concurrent physiological measures (heart rate) were additionally monitored for twenty-one of the subjects. The occurrence of yawn contagion was significantly higher during the yawning condition than during the control mouth movements. Furthermore, the dogs yawned more frequently when watching the familiar model than the unfamiliar one demonstrating that the contagiousness of yawning in dogs correlated with the level of emotional proximity. Moreover, subjects’ heart rate did not differ among conditions suggesting that the phenomenon of contagious yawning in dogs is unrelated to stressful events. Our findings are consistent with the view that contagious yawning is modulated by affective components of the behavior and may indicate that rudimentary forms of empathy could be present in domesticated dogs.     

Chimpanzees Show a Developmental Increase in Susceptibility to Contagious Yawning: A Test of the Effect of Ontogeny and Emotional Closeness on Yawn Contagion

Contagious yawning has been reported for humans, dogs and several non-human primate species, and associated with empathy in humans and other primates. Still, the function, development and underlying mechanisms of contagious yawning remain unclear. Humans and dogs show a developmental increase in susceptibility to yawn contagion, with children showing an increase around the age of four, when also empathy-related behaviours and accurate identification of others’ emotions begin to clearly evince. Explicit tests of yawn contagion in non-human apes have only involved adult individuals and examined the existence of conspecific yawn contagion. Here we report the first study of heterospecific contagious yawning in primates, and the ontogeny of susceptibility thereto in chimpanzees, Pan troglodytes verus. We examined whether emotional closeness, defined as attachment history with the yawning model, affected the strength of contagion, and compared the contagiousness of yawning to nose-wiping. Thirty-three orphaned chimpanzees observed an unfamiliar and familiar human (their surrogate human mother) yawn, gape and nose-wipe. Yawning, but not nose-wiping, was contagious for juvenile chimpanzees, while infants were immune to contagion. Like humans and dogs, chimpanzees are subject to a developmental trend in susceptibility to contagious yawning, and respond to heterospecific yawn stimuli. Emotional closeness with the model did not affect contagion. The familiarity-biased social modulatory effect on yawn contagion previously found among some adult primates, seem to only emerge later in development, or be limited to interactions with conspecifics. The influence of the ‘chameleon effect’, targeted vs. generalised empathy, perspective-taking and visual attention on contagious yawning is discussed.     

Micronuclei frequency in children exposed to environmental mutagens: a review

Cytogenetic monitoring has been traditionally used for the surveillance of populations exposed to genotoxic agents. In recent years sensitivity problems emerged in surveys of populations exposed to low levels of mutagens, and therefore alternative approaches have been explored. Biomonitoring studies in children are a promising field, since because of evident differences in the uptake, metabolism, distribution and excretion of mutagens this population seems to be more susceptible than adults. Further, the effect of major confounders such as cigarettes smoking, occupation, life-style, and dietary factors plays a minor role. Among cytogenetic assays, the micronucleus assay (MN) has several advantages and is increasingly used. A review was then carried out to synthesize the published data on the occurrence of MN in children and adolescents (age range 0-18 years), and to assess the impact of genotoxic exposure on MN frequency. Overall, 20 papers from international literature and 8 Russian papers were included. An effect of age was found within this age range, while the influence of gender on MN frequency was irrelevant. These results were confirmed by the re-analysis of data for 448 children selected from the HUMN database. An effect of chronic and infectious diseases on MN levels has been reported by various authors. Most studies describing the effect of exposure to genotoxic agents (ionizing radiation, chemicals, drugs, environmental tobacco smoke) found an increase of MN in exposed children. The limited number of published papers indicates that the conduct of properly designed studies on the effect of environmental pollutants in children may be difficult. This review confirmed the usefulness of MN assay in biomonitoring studies conducted in children, revealing that in many circumstances investigating children increases the sensitivity of the study, even with low dose exposures.     

An inbreeding-incompatibility genetic system in Drosophila melanogaster and its frequency in natural populations

Inbreeding effects on egg hatchability and viability of Drosophila melanogaster are analysed in relation with a single genetic system, with alleles Is ^- and Is ⁺, which is postulated to control inbreeding sensitivity of natural populations. The frequency of the Is allelic constitution has been estimated by two different ways in eleven natural populations. This provides the basis for a straightforward test of the single-locus hypothesis of inbreeding sensitivity. A positive, though slight correlation between the two estimates (r=0.39) adds to the evidence in support of the hypothesis. Furthermore, the frequency of the Is allelic constitution ranges from 0.23 to 0.61 in the populations. These high frequency values suggest that the Is system may have a great impact in determining the response of a population to inbreeding and thus the valuc of genetic load. We relate this single-gene phenomenon to mutator effects and the single-gene determinism of self-incompatibility in plants and fungi.     

Effect of the fuel system icing inhibitor diethylene glycol monomethyl ether on the biodegradation of jet fuel in soil

Microbial degradation of jet fuel leads to the accumulation of sludge in fuel distribution systems and storage tanks. To prevent this phenomenon, the biocidal anti-icing inhibitor diethylene glycol monomethyl ether (DiEGME) is routinely added to the fuel. The fate of DiEGME in soil and its consequent effect on the biodegradation of jet fuel by indigenous soil microflora have not been investigated. The aim of this work was to study the kinetics of biodegradation of jet fuel in dark rendzina soil, as affected by the presence of DiEGME. Our data show that the degradability in soil of jet fuel amended with DiEGME was tenfold higher than that of non-amended fuel. Consequently, there was an increase in the jet-fuel-utilizing soil microbial populations during the 100 days of incubation of soil samples amended with jet fuel containing DiEGME. Gas chromatograms of distilled fractions of jet fuel extracted from the soil demonstrated that most of the light fractions' extracts could not be detected at the end of the 100-day incubation. The relative concentration of aromatic compounds in the soil contaminated with DiEGME-amended jet fuel increased during incubation, demonstrating the lower biodegradation rate of these components compared with other fuel components. DiEGME was partially degraded by the general microbial population of the soil. Maximal DiEGME degradation was obtained with specific jet-fuel-utilizing microbial strains – Pseudomonas aeruginosa and Cladosporium resinae – that were added to a carbon-free mineral medium. The degradation rate of DiEGME by specific strains or by soil mixed populations bore an inverse relationship to the DiEGME concentration. The finding that DiEGME can be degraded by indigenous soil microorganisms may have facilitated its utilization also by jet-fuel-degrading microorganisms.     

Changing environmental spectra influence age-structured populations: increasing ENSO frequency could diminish variance and extinction risk in long-lived seabirds

As global climate changes, there is increasing need to understand how changes in the frequencies of environmental variability affect populations. Age-structured populations have recently been shown to filter specific frequencies of environmental variability, favoring generational frequencies, and very low frequencies, a phenomenon known as cohort resonance. However, there has been little exploration of how changes in the spectra of environmental signals will affect the stability and persistence of age-structured populations. To examine this issue, we analyzed a likely example to show how changes in the frequency of an influential climate phenomenon, the El Niño-Southern Oscillation (ENSO), could affect a marine bird population. We used a density-dependent, age-structured population model to calculate the transfer function (i.e., the frequency-dependent sensitivity) of Brandt’s cormorant (Phalacrocorax penicillatus), a representative marine bird species known to be influenced by ENSO. We then assessed how the population would be affected by ENSO forcing that was doubled and halved in frequency. The transfer function indicated this population is most sensitive to variance at low frequencies, but does not exhibit the sensitivity to generational frequencies (cohort resonance) observed in shorter-lived species. Doubling the frequency of ENSO unexpectedly resulted in higher mean adult population abundance, lower variance, and lower probability of extinction, compared to forcing with the historical or reduced ENSO frequency. Our results illustrate how long-lived species with environmentally driven variability in recruitment, including many species of marine birds and fish, may respond in counterintuitive ways to anticipated changes in environmental variability.     

Mycorrhizal fungi improve growth of Juniperus communis but only at sufficiently high soil element concentrations

High nitrogen (N) deposition rates can cause soil eutrophication and acidification causing harmful effects to many plant species. One species that seems to be affected is Juniperus communis, populations of which are declining in Western Europe, due to a lack of regeneration. This is primarily caused by limited seedling recruitment and low viable seed production; factors that have both been attributed to increased levels of N deposition. J. communis sapling performance could be dependant on mycorrhizal fungi (MF) in their roots, but how – and under what conditions – MF contribute to the performance of J. communis has not been studied before. Here we experimentally tested the effect of MF on J. communis cuttings along an acidity gradient in situ. To manipulate the interaction with MF, we used ingrowth cores, effectively allowing for root-MF interactions or strongly reducing these. After six months we measured growth and needle nutrient concentrations of cuttings with a normal or reduced mycelial network. MF had a positive effect on absolute growth of our cuttings. However, this effect was weakened as soil Mg²⁺, Ca²⁺ and Na⁺ concentrations declined. Soil pH itself was not directly associated with the effect of MF on J. communis. MF also decreased needle phosphorous concentrations, most likely because the increased plant growth by MF diluted its concentration in the plants. We conclude that MF stimulate the performance of J. communis, but that leaching of cations, accelerated by N deposition, negatively affects their mutualism and thereby the performance of J. communis saplings. This highlights the potential positive role of MF in effective conservation and restoration efforts of J. communis habitats in Western Europe and the importance of prioritising the reduction of ongoing eutrophication and acidification.     

Niche invasion,competition and coexistence amongst wild and domestic Bolivian populations of Chagas vector Triatoma infestans (Hemiptera,Reduviidae, Triatominae)

The model developed for human parasites by Bottomley et al. (2007) [52] has been adapted to the dynamics of triatomines to better understand the processes of niche invasion, competition among species and coexistence. In Bolivia, both wild and domestic populations of Triatoma infestans exist. Their ecological niches are normally separated and the two populations do not interbreed, behaving as two distinct species. However, it has been suggested that the two populations may compete, highlighting therefore the potential risk of wild populations invading human dwellings. The model revealed the importance of the basic reproduction rates R₀ of triatomine colonies for the risk of invasion. This depends not only on life traits such as survival and fecundity, but also on (1) the density-dependence phenomenon that limits triatomine establishment, (2) on house exposure to infection and (3) on the correlation between house susceptibility to domestic T. infestans and house susceptibility to wild T. infestans. Competition and coexistence amongst the two groups of T. infestans may occur under particular conditions, but are very unlikely.     

Inter-population variation in thermal sensitivity of the tropical toad Duttaphrynus melanostictus,across a small spatial scale in Sri Lanka

Inter-population disparities in a species have been shown to occur as an adaptation to different thermal regimes in the environment. We investigated the thermal sensitivities of the tropical toad Duttaphrynus melanostictus (Asia Common Toad) from two populations at different altitudes: Nuwara-Eliya – 1870 m, and Polonnaruwa – 25 m, above mean sea level. The two locations were separated by what may be considered a short direct distance – 110 km. Thermal sensitivity trials were conducted at six temperatures between 12 and 39 °C. Assessments were made using the performance indicators jump distance, jump force, contact time on the test plate following stimulus to jump, and righting time after being overturned. Optimum performance is taken to be the greatest jump distance and jump force, the least contact time on the test plate, and the least righting time. The populations at the two altitudes had markedly different thermal sensitivities – toads in the cool area (Nuwara-Eliya) performed at an optimal level under low temperatures, whereas the toads in the warm area (Polonnaruwa) performed optimally under high temperatures. The finding that the thermal optima (i.e., the temperatures at which the optimal performance for the four performance indicators was recorded) of the toads in Polonnaruwa were below the mean maximum ambient temperature at this location suggests that these toads would be more susceptible to global warming than those in Nuwara-Eliya whose thermal optima were above the mean maximum ambient temperature in that location. This was consistent with the narrower thermal safety margin (i.e., difference between the mean optimum temperature and mean ambient temperature) of toads in Polonnaruwa, compared to those in Nuwara-Eliya. Importantly, these findings demonstrate that, although thermal sensitivity is considered a conservative trait, differentiation does occur even over a small spatial scale presumably because it offers an adaptive advantage to the population concerned.     

Biogeography and systematics of Aricia butterflies (Lepidoptera,Lycaenidae)

Butterflies of the Aricia species group represent a paradigm of unresolved taxonomy, both at the genus and species levels. We studied phylogenetic relationships, biogeography, and systematics based on genetic – nuclear and mitochondrial – and morphometric – external (wings) and internal (genitalia) – data. We show that Aricia is a monophyletic genus comprising the taxa Pseudoaricia, Ultraaricia and Umpria, which are here considered junior synonyms of Aricia. The taxa allous, inhonora, issekutzi, mandzhuriana, myrmecias and transalaica, which have often been raised to species rank, are shown to probably represent subspecies or synonyms. We show that montensis is likely a good species that is sister to all A. artaxerxes populations across the Palearctic region. The species A. anteros and A. morronensis are shown to display deep intraspecific divergences and they may harbor cryptic species. We also discovered that A. cramera and A. agestis exhibit a pattern of mutual exclusion on islands, and a parapatric distribution in mainland with a narrow contact zone where potential hybrids were detected. The lack of a prezygotic barrier that prevents their coexistence could explain this phenomenon. This study will hopefully contribute to the stability of the systematics of Aricia, a group with potential for the study of the link between speciation and biogeography.     

Adaptation of the repellency response to DEET in Rhodnius prolixus

For many years it has been accepted that DEET interferes with the detection of odours from the host instead of having a repellent effect. However, recent work showed that DEET acts as an odorant molecule and elicits a behavioural response in the absence of other stimuli. Therefore, DEET must promote some phenomenon connected with the stimuli-sensory system interaction, such as a sensory adaptation, where the sensory system regulates its sensitivity to different stimuli intensities during continuous or repetitive exposure. In this work, we studied different aspects of the insect-DEET interaction through behavioural observations. Previous exposure of fifth instar Rhodnius prolixus nymphs to DEET decreased the behavioural response to this repellent. We observed a decrease in repellence after different times of continuous stimulation with DEET in a time-dependent manner. The response to DEET was recovered 10 min after exposure, when insects were continuously stimulated during 5 or 10 min; maximum repellence was recovered 20 min after exposure when insects were stimulated for 20 min. DEET produced a repellent effect when nymphs were exposed only to its vapours. These results suggest that exposure to DEET produces adaptation in R. prolixus nymphs, and that the behavioural response elicited by DEET occurs via olfaction when no other stimuli are present.     

New Insights into the Molecular Epidemiology and Population Genetics of Schistosoma mansoni in Ugandan Pre-school Children and Mothers

Significant numbers of pre-school children are infected with Schistosoma mansoni in sub-Saharan Africa and are likely to play a role in parasite transmission. However, they are currently excluded from control programmes. Molecular phylogenetic studies have provided insights into the evolutionary origins and transmission dynamics of S. mansoni, but there has been no research into schistosome molecular epidemiology in pre-school children. Here, we investigated the genetic diversity and population structure of S. mansoni in pre-school children and mothers living in lakeshore communities in Uganda and monitored for changes over time after praziquantel treatment. Parasites were sampled from children (<6 years) and mothers enrolled in the longitudinal Schistosomiasis Mothers and Infants Study at baseline and at 6-, 12- and 18-month follow-up surveys. 1347 parasites from 35 mothers and 45 children were genotyped by direct sequencing of the cytochrome c oxidase (cox1) gene. The cox1 region was highly diverse with over 230 unique sequences identified. Parasite populations were genetically differentiated between lakes and non-synonymous mutations were more diverse at Lake Victoria than Lake Albert. Surprisingly, parasite populations sampled from children showed a similar genetic diversity to those sampled from mothers, pointing towards a non-linear relationship between duration of exposure and accumulation of parasite diversity. The genetic diversity six months after praziquantel treatment was similar to pre-treatment diversity. Our results confirm the substantial genetic diversity of S. mansoni in East Africa and provide significant insights into transmission dynamics within young children and mothers, important information for schistosomiasis control programmes.     

Daptomycin treatment impacts resistance in off-target populations of vancomycin-resistant Enterococcus faecium

The antimicrobial resistance crisis has persisted despite broad attempts at intervention. It has been proposed that an important driver of resistance is selection imposed on bacterial populations that are not the intended target of antimicrobial therapy. But to date, there has been limited quantitative measure of the mean and variance of resistance following antibiotic exposure. Here we focus on the important nosocomial pathogen Enterococcus faecium in a hospital system where resistance to daptomycin is evolving despite standard interventions. We hypothesized that the intravenous use of daptomycin generates off-target selection for resistance in transmissible gastrointestinal (carriage) populations of E. faecium. We performed a cohort study in which the daptomycin resistance of E. faecium isolated from rectal swabs from daptomycin-exposed patients was compared to a control group of patients exposed to linezolid, a drug with similar indications. In the daptomycin-exposed group, daptomycin resistance of E. faecium from the off-target population was on average 50% higher than resistance in the control group (n = 428 clones from 22 patients). There was also greater phenotypic diversity in daptomycin resistance within daptomycin-exposed patients. In patients where multiple samples over time were available, a wide variability in temporal dynamics were observed, from long-term maintenance of resistance to rapid return to sensitivity after daptomycin treatment stopped. Sequencing of isolates from a subset of patients supports the argument that selection occurs within patients. Our results demonstrate that off-target gastrointestinal populations rapidly respond to intravenous antibiotic exposure. Focusing on the off-target evolutionary dynamics may offer novel avenues to slow the spread of antibiotic resistance.

This study shows that systemic daptomycin use causes selection for daptomycin resistance in gastrointestinal populations of vancomycin-resistant Enterococcus faecium, highlighting the importance of off-target selection on the evolution of antimicrobial resistance.     

Interactions of anthelmintic drugs in Caenorhabditis elegans neuro-muscular ion channel mutants

Due to the increasing development of anthelmintic resistance in nematodes worldwide, it is important to search for anthelmintic compounds with new modes of action and also to investigate the possibility to combine compounds with possible synergistic effects. There might also be the chance to take advantage of the fact that nematode populations which have developed resistance against one anthelmintic class might respond hypersusceptibly to another drug class. The aim of this study was to investigate responses of Caenorhabditis elegans populations with mutations in neuro-muscular ion channels to different anthelmintic classes. Furthermore, potential synergistic effects between two anthelmintic compounds from different classes, i.e. emodepside and tribendimidine, were studied. Although there was neither a synergistic nor an antagonistic effect between emodepside and tribendimidine, other types of interactions could be identified. The C. elegans GABA_A-receptor (GABA_A-R) unc-49 mutants, showing decreased emodepside susceptibility, were more susceptible to tribendimidine than wild-type C. elegans. In contrast, the reverse phenomenon – hypersusceptibility to emodepside in tribendimidine resistant acetylcholine-receptor (AChR) loss of function mutants – was not observed. Moreover, the slo-1 mutant strain (completely emodepside resistant) also showed hypersusceptibility to piperazine. Interestingly, neither the GABA_A-R unc-49 mutants nor the AChR mutants showed decreased susceptibility against piperazine, although there were some studies that indicated an involvement of GABA_A-R or AChR in the piperazine mode of action. In conclusion, the present study provides evidence suggesting that interactions between commercially available anthelmintic drugs with different modes of action might be a relatively common phenomenon but this has to be carefully worked out for each anthelmintic and each anthelmintic drug combination. Moreover, results obtained in C. elegans will have to be confirmed using parasitic nematodes in the future.     

Collaborative and competitive motivations uniquely impact infants' racial categorization

Human history has been plagued by violent inter-group conflicts. Such conflicts are arguably grounded on group biases – particularly, a tendency to favor “ingroups” over “outgroups” – manifested in adults, children, and infants. A question these findings prompt is what motivates social categorization? Here it is shown that priming 14-month-old infants (N?=?144) with collaborative or competitive interactions affects their capacity to form racial categories, and that this effect varies according to the gender of the exemplars being categorized. Specifically, whereas racial categorization of women was facilitated by collaboration, racial categorization of men was facilitated by competition. The presence of these differential effects in infancy is consistent with the idea that social categorization is driven by fundamental functions of group relations.     

Evaluation of antibody serology to determine current helminth and Plasmodium falciparum infections in a co-endemic area in Southern Mozambique

BackgroundSoil-transmitted helminths (STH), Schistosoma spp. and Plasmodium falciparum are parasites of major public health importance and co-endemic in many sub-Saharan African countries. Management of these infections requires detection and treatment of infected people and evaluation of large-scale measures implemented. Diagnostic tools are available but their low sensitivity, especially for low intensity helminth infections, leaves room for improvement. Antibody serology could be a useful approach thanks to its potential to detect both current infection and past exposure.MethodologyWe evaluated total IgE responses and specific-IgG levels to 9 antigens from STH, 2 from Schistosoma spp., and 16 from P. falciparum, as potential markers of current infection in a population of children and adults from Southern Mozambique (N = 715). Antibody responses were measured by quantitative suspension array Luminex technology and their performance was evaluated by ROC curve analysis using microscopic and molecular detection of infections as reference.Principal findingsIgG against the combination of EXP1, AMA1 and MSP2 (P. falciparum) in children and NIE (Strongyloides stercoralis) in adults and children had the highest accuracies (AUC = 0.942 and AUC = 0.872, respectively) as markers of current infection. IgG against the combination of MEA and Sm25 (Schistosoma spp.) were also reliable markers of current infection (AUC = 0.779). In addition, IgG seropositivity against 20 out of the 27 antigens in the panel differentiated the seropositive endemic population from the non-endemic population, suggesting a possible role as markers of exposure although sensitivity could not be assessed.ConclusionsWe provided evidence for the utility of antibody serology to detect current infection with parasites causing tropical diseases in endemic populations. In addition, most of the markers have potential good specificity as markers of exposure. We also showed the feasibility of measuring antibody serology with a platform that allows the integration of control and elimination programs for different pathogens.     

Fluorometric determination of the neutral lipid content of microalgal cells using Nile Red

The fluorophore Nile Red (9-diethylamino-5H-benzo[α]phenoxazine-5-one) has been used to determine neutral lipid in microalgal cells. Cellular fluorescence of stained cells and gravimetrically or chromatographically determined lipid were linearly correlated when Nile Red was excited at 488 – 525 nm and the fluorescent emision measured at 570 – 600 nm. Nile Red is a vital stain which allowed flow cytometric sorting of live microalgal populations based on their lipid content.     

Low parasite infestations in high densities: The paradox of woodpigeons in urban areas

The type of habitat occupied by avian populations has a marked effect on the parasitises they host. The growth of cities and urban areas in recent decades has favoured some species of birds adapted to these types of habitats – urban exploiters – although the effects of urbanisation on the parasitism of wildlife are not always well known. This study compares the ectoparasites characteristic of two differentiated populations of woodpigeons, one located in a predominantly urban environment and the other in a rural one. Most of the species found were chewing lice, with Columbicola claviformis and Campanulotes bidentatus being dominant. Despite the higher density of the urban population, woodpigeon individuals were characterised by a lower abundance of chewing lice, as well as the presence of ectoparasites typical of feral pigeons such as Hohorstiella lata and the hippoboscids fly, Pseudolynchia canariensis. Similarly, birds with lower weights showed a higher parasitic load, which became more noticeable in urban woodpigeons. The lower ectoparasite load of urban hosts represents a health advantage compared with rural populations, which could be one of the causes of greater growth and reproductive success in urban populations of woodpigeons.