Integration of a battery of biomarkers to evaluate the health status of field-collected frogs of Leptodactylus luctator living in ecosystems with different anthropogenic disturbances.

Amphibians are the most threatened group of vertebrates because they have certain biological and ecological characteristics that make them sensitive to environmental changes. The aim of this study was to evaluate the health status of field-collected adult frogs of Leptodactylus luctator (Amphibia, Anura) living in sites with different anthropogenic disturbances (florihorticulture, petrochemical industry and sewage discharges) and a reference site without any detectable influence of such activities. To this end, a battery of 21 biomarkers (hematological, biochemical and individual biomarkers) was studied using a multivariate approach that allows us to evaluate the relationship between them and provide information on their usefulness. The frogs at the florihorticulture, petrochemical and sewage discharges sites exhibited several biomarkers far from homeostasis. In addition, we identified 11 of 21 biomarkers that were useful indicators of the health status of the frogs and allowed discrimination between study sites in the following order: lymphocytes (98 %), neutrophils (45 %), hemoglobin (42 %), monocytes (41 %), fat body index (35 %), eosinophils (35 %), hepatosomatic index (33 %), mean corpuscular hemoglobin (32 %), thrombocytes (27 %), catalase in liver (26 %), and GST in liver (26 %). The results suggest that hematological biomarkers contribute the most to site separation, whereas biochemical biomarkers contribute the least. The integral interpretation of the results also allowed us to diagnose the different health status of L. luctator: The frogs from the petrochemical industry were the most negatively affected, followed by the frogs from the sewages discharges and finally the frogs from the florihorticulture and reference sites. This is the first field study with anurans in which so many biomarkers were examined.

Realistic scenarios of pesticide exposure alters multiple biomarkers in BOANA PULCHELLA (ANURA) Adult Frogs.

Imazethapyr, a post-emergent herbicide used in worldwide soybean and corn crops, induces genetic and biochemical alterations in aquatic vertebrates. This study examined the relationship between biomarkers at different organization levels and imazethapyr real-life route exposure in Boana pulchella adults. Frogs were exposed to imazethapyr-based formulation Pivot® H (10.59%) at concentrations representing possible acute routes: field runoff (S1:10 mg.L-1), exposure after direct foliar application (S2:100 mg.L-1) and during direct foliar application (S3:1000 mg.L-1). Post-exposure, endpoints levels were evaluated: organism alterations, biochemical activities and cytogenetic assays. Forty-eight hours post-exposure, antioxidant enzymes decrease, micronuclei induction and DNA damage were observed in all scenarios, while cholinesterase activity increase and body condition reduction were observed in frog-exposed to S3. Ninety-six hours post-exposure, frogs showed glutathione-S-transferase inhibition in S1, micronuclei induction in S2 and S3, and DNA-damage increase in S3. Herbicides routes of exposures in real-life could indicate that authorized applications have a risk to amphibian populations.

Multiple Level Effects of Imazethapyr on Leptodactylus latinasus (Anura) Adult Frogs.

Imazethapyr is an herbicide that is used in a variety of crops worldwide, including soybean and corn. The aim of the present study was to evaluate the biomarkers responses of adult Leptodactylus latinasus exposed to the formulation Pivot® H (10.59% imazethapyr) in the laboratory at concentrations and under conditions that simulate two potential field exposure scenarios: an immersion in field runoff (Scenario 1: 10 mg/L) and a direct exposure to the droplets emitted by spray noozles (Scenario 2: 1000 mg/L). In both scenarios, the experimental procedure involved completely immersing the frogs over a period of 15 s. Different endpoints were evaluated at several ecotoxicological levels 48 and 96 h after the herbicide exposure. These included individual (biometric indices and behavior alterations), histological (liver pigments and lesions), biochemical (catalase, glutathione system and cholinesterase activities) and genotoxic effects (micronuclei induction and nuclear abnormalities). Forty-eight hours after imazethapyr exposure, frogs submitted to Scenario 1 presented an inhibition of liver glutathione-S-transferase activity, whereas histological alterations and increased hepatic cholinesterase levels were observed in frogs exposed under Scenario 2. Ninety-six hours after exposure to the imazethapyr formulation, frogs from the Scenario 1 treatment presented a decrease in liver melanin and hemosiderin, increased hepatic catalase activity and micronuclei induction. For their part, frogs exposed to Scenario 2 presented a decrease in the hepatosomatic index, an increase in liver alterations, melanin reduction and micronuclei induction. The multivariate analysis enables correlations to be made between biomarkers of different organizational level in exposed anurans. Our result indicates that real exposure to imazethapyr formulations under field conditions may pose a risk to Leptodactylus latinasus populations living in the agroecosystems.

Sensitivity analysis of the Pesticide in Water Calculator model for applications in the Pampa region of Argentina.

Despite the widespread use of pesticides in the Pampa region of Argentina, mathematical models are rarely employed to predict pesticide fate due to the lack of regionally tested models and the absence of readily available databases to run such models. The objective of the current study was to perform a sensitivity analysis of the Pesticide in Water Calculator (PWC) model for the Pampa Region of Argentina. The sensitivity analysis was performed while simulating applications of 2,4-D (mobile, low Kd) and glyphosate (soil-binding, high Kd) in five localities of the Pampa region: Anguil, Paraná, Marcos Juárez, Pergamino and Tres Arroyos. The sensitivity of the various parameters involved in PWC modelling was evaluated though a two-steps sensitivity analysis which included a first screening of less sensitive parameters with Morris method, followed by a fully global sensitivity analysis of the remaining parameters using Sobol method. When ran under soil and climate conditions typical of the Pampa region of Argentina, PWC was most sensitive to 25% of the parameters evaluated. The sensitive parameters identified depended mainly on the nature of the pesticide molecule being modelled; the location and endpoint considered having much less influence on the sensitivity results. Sensitive parameters belonged to two main grand categories: (i) degradation rates of the pesticide in soil and water, and (ii) parameters descriptive of soil binding, runoff and erosion. The sensitivity analysis of the model PWC performed in the current study represents a crucial first step towards the development and expansion of probabilistic pesticide risk assessment in Argentina, and provides important parameterization criteria that will help obtaining more certain modelling results from PWC in Argentina and elsewhere.

Evaluation of various types of supplemental food for two species of predatory mites, Amblyseius swirskii and Neoseiulus cucumeris (Acari: Phytoseiidae).

Although phytoseiids are best known as predators of phytophagous mites and other small arthropods, several species can also feed and reproduce on pollen. In laboratory assays, we assessed the profitability of two types of dietary supplements (three pollen species-cattail, maize and apple-and eggs of the Mediterranean flour moth, Ephestia kuehniella) for the two species of predatory mites most commonly used as biocontrol agents in horticulture in Canada, Neoseiulus cucumeris and Amblyseius swirskii. We measured the effects of each diet on phytoseiid fitness parameters (survival, development, sex ratio, fecundity) and, as a means of comparison, when fed larvae of the common targeted pest species, western flower thrips Frankliniella occidentalis. A soluble protein assay was also performed on the alternative food sources as protein content is often linked to high nutritive value according to the literature. All food sources tested were suitable for N. cucumeris and A. swirskii, both species being able to develop from egg to adult. The dietary supplements had a beneficial impact on biological parameters, mostly resulting in shorter development times and higher survival rates when compared to thrips larvae. Amblyseius swirskii exhibited a wider dietary range than N. cucumeris. Overall, flour moth eggs, cattail pollen and apple pollen are food sources of equal quality for A. swirskii, whereas apple and cattail pollen are better when it comes to N. cucumeris. In contrast, maize pollen is a less suitable food source for N. cucumeris and A. swirskii. Soluble protein content results did not match the prediction under which the most beneficial food source would contain the highest concentration in protein.

Apple pollen as a supplemental food source for the control of western flower thrips by two predatory mites, Amblyseius swirskii and Neoseiulus cucumeris (Acari: Phytoseiidae), on potted chrysanthemum.

It has been shown that pollen as a dietary supplement may increase the establishment (development and reproduction) and survival of phytoseiid predatory mites, and therefore the pest control these mites can provide. In this study, the role of apple pollen as a supplemental food source was assessed as a means to increase the efficiency of two predatory mite species, Neoseiulus cucumeris and Amblyseius swirskii, for control of western flower thrips, Frankliniella occidentalis, under greenhouse conditions. The impact of apple pollen on thrips populations and predator establishment on a greenhouse chrysanthemum crop was determined over a 4-week period. The two mite species were released separately and in combination with and without pollen with two control treatments (thrips only and thrips + pollen). The introduction of A. swirskii together with pollen application provided the best control of thrips (adults and immatures). The establishment of N. cucumeris was very low in the crop during the greenhouse trial. This could be attributable, in part, to their response to extreme temperature ranges that were encountered during the greenhouse cage trials. The use of A. swirskii alone and the mixed population of the two predatory mite species without pollen resulted in the lowest frequencies of plants with heavy damage, followed by the same treatments with the addition of apple pollen.

Host behaviour manipulation as an evolutionary route towards attenuation of parasitoid virulence.

By definition, insect parasitoids kill their host during their development. Data are presented showing that ladybirds not only can survive parasitism by Dinocampus coccinellae, but also can retain their capacity to reproduce following parasitoid emergence. We hypothesize that host behaviour manipulation constitutes a preadaptation leading to the attenuation of parasitoid virulence. Following larval development, the parasitoid egresses from the host and spins a cocoon between the ladybird's legs. Throughout parasitoid pupation, the manipulated host acts as a bodyguard to protect the parasitoid cocoon from predation. The parasitoid has evolved mechanisms to avoid killing the host prematurely so that its own survival is not compromised. Bodyguard manipulation may thus constitute a selective trait for the evolution of true parasitism in some host-parasitoid associations.

Oviposition pattern of early and late-emerging genotypes of Delia radicum (Diptera: Anthomyiidae) at different temperatures.

The cabbage maggot, Delia radicum L., has a bimodal pattern of emergence caused by the presence in populations of early and late-emerging genotypes that differ in their pupal development time. These genotypes could also express different egg-laying strategies. To examine oviposition patterns between genotypes and, particularly, their response to temperature, the egg-laying activity of females and egg mortality from each genotype were evaluated at temperatures from 12 to 30°C. Several criteria were used to describe the oviposition pattern: longevity of females, preoviposition period, lifetime fecundity, number of oviposition bouts, duration and number of eggs for each oviposition bout, duration of an oviposition cycle, and time interval between oviposition bouts. All criteria were similar between genotypes, except the preoviposition period and time interval between oviposition bouts. The preoviposition period was 1-4 d longer for the early emerging genotype than for the late-emerging genotype at temperatures <25°C, but similar at temperatures ≥25°C. The time interval between oviposition bouts of early emerging genotype was a few hours longer than for the late-emerging genotype at all temperatures. All oviposition pattern criteria responded to temperature, except the duration of oviposition bouts (≍6.5 d) and egg mortality (≍11%). The duration of a bout could be a compromise between oogenesis duration and the risks associated with egg deposition. According to these results, early and late-emerging genotypes express similar egg-laying strategies for all temperatures tested.

Parsing handling time into its components: implications for responses to a temperature gradient.

The functional response is a key element of predator-prey interactions, and variations in its parameters influence interaction strength and population dynamics. Recent studies have used the equation of the metabolic theory of ecology (MTE) to quantify the effect of temperature on the parameter Th, called "handling time," and then predict the responses of predators and communities to climate change. However, our understanding of the processes behind Th and how they vary with temperature remains limited. Using a ladybeetle-aphid system, we compared estimates of Th to direct observations of handling time across a temperature gradient. We found estimated Th values to be greater than observed Th values, suggesting that predation rate is not limited by the time available for handling prey. We next estimated the corrected digestion time, i.e., digestion time corrected for gut capacity, by subtracting observed to estimated Th values. We finally plotted the relationships between temperature and handling or digestion rates. As predicted by MTE, the corrected digestion rate increased exponentially with warming whereas, in contrast to MTE prediction, the relationship between handling rate and temperature was hump shaped. The parameter Th is thus confusing because it combines handling and digestive processes that have different thermal responses. This may explain why general patterns in the relationship between Th and temperature have been difficult to identify in previous studies.

Inconsistent genetic structure among members of a multitrophic system: did bruchid parasitoids (Horismenus spp.) escape the effects of bean domestication?

Anthropogenic range expansion and cultural practices have modified the distribution, abundance and genetic diversity of domesticated organisms, thereby altering multitrophic assemblages through space and time. The putative Mesoamerican domestication centre of the common bean, Phaseolus vulgaris L., in Mexico allows investigating the effects of plant domestication on the genetic structure of members of a multitrophic system. The aim of this study was to compare the evolutionary history of Horismenus parasitoids (Hymenoptera: Eulophidae) to those of their bruchid beetle hosts (Coleoptera: Bruchidae) and their domesticated host plant (P. vulgaris), in the context of traditional agriculture in Mexico. We analyzed the population genetic structure of four Horismenus species in Mexico using mitochondrial COI haplotype data. The two most abundant parasitoid species were Horismenus depressus and Horismenus missouriensis. Horismenus missouriensis were infected by Wolbachia endosymbionts and had little to no population differentiation (F(ST) = 0.06). We suspect the mitochondrial history of H. missouriensis to be blurred by Wolbachia, because differentiation among infected vs. non-infected individuals exists (F(ST) = 0.11). Populations of H. depressus were found to be highly differentiated (F(ST) = 0.34), but the genetic structuring could not be explained by tested spatial components. We then compared the genetic structure observed in this parasitoid species to previously published studies on bruchid beetles and their host plants. Despite extensive human-mediated migration and likely population homogenization of its two Acanthoscelides bruchid beetle hosts, H. depressus populations are structured like its host plant, by a recent dispersal from a diverse ancestral gene pool. Distinct evolutionary dynamics may explain inconsistent patterns among trophic levels. Parasitoids likely migrate from wild bean populations and are poorly adapted to bean storage conditions similar to their bruchid beetle hosts. Integrating several trophic levels to the study of evolutionary history has proven to be fruitful in detecting different ecological responses to human-mediated disturbances and host parasite interactions.

Effect of soil temperature and moisture on survival of eggs and first-instar larvae of Delia radicum.

Edaphic factors such as soil temperature and moisture influence soil-dwelling insects, whose most vulnerable stages typically are eggs and young larvae. In this study, the survival of eggs and first-instar larvae of the cabbage maggot, Delia radicum L., was measured under laboratory conditions after exposure to a range of soil temperatures and moistures. When eggs were exposed to constant temperature (20-29°C) and humidity (5-200% [wt:wt]), temperature had no significant effect on survival, whereas humidity <25% [wt:wt] caused egg mortality. The gradual exposure of eggs to high temperatures resulted in low mortality below 33°C, but <5% of eggs survived at 40°C. When first-instar larvae were exposed to constant temperature (17-29°C) and humidity (5-100% [wt:wt]), both factors as well as their interaction had a significant effect on larval survival, which was nil at 5% (wt:wt) for all temperatures but increased from 21.9 to 42.8% at 17°C and from 34.1 to 55.0% at 29°C, for soil moisture contents of 15% and 100% (wt:wt), respectively. Eggs of D. radicum are resistant to low soil moisture and high temperature conditions. Larval survival tends to increase with an increase in soil temperature and moisture. It is suggested that soil temperature be integrated into insect development simulation models instead of air temperature, to build more effective models for cabbage maggot management.

Prey DNA detection success following digestion by intraguild predators: influence of prey and predator species.

Intraguild predation (IGP) has been increasingly recognized as an important interaction in ecological systems over the past two decades, and remarkable insights have been gained into its nature and prevalence. We have developed a technique using molecular gut-content analysis to compare the rate of IGP between closely related species of coccinellid beetles (lady beetles or ladybirds), which had been previously known to prey upon one another. We first developed PCR primers for each of four lady beetle species: Harmonia axyridis, Coccinella septempunctata, Coleomegilla maculata and Propylea quatuordecimpunctata. We next determined the prey DNA detection success over time (DS(50) ) for each combination of interacting species following a meal. We found that DS(50) values varied greatly between predator-prey combinations, ranging from 5.2 to 19.3 h. As a result, general patterns of detection times based upon predator or prey species alone are not discernable. We used the DS(50) values to correct field data to demonstrate the importance of compensation for detection times that are specific to particular predator-prey combinations.

Temperature influences the handling efficiency of an aphid parasitoid through body size-mediated effects.

It is well known that increasing the ambient temperature increases the metabolic rate and consequently, the foraging rate of most insects. However, temperature experienced during the immature stages of insects affects their adult size (an inverse relationship). Because body size is generally correlated to foraging success, we hypothesized that temperature indirectly influences the foraging efficiency of adult insects through developmental effects. We first investigated the role of parasitoid: host body size ratio on the handling time of Aphidius colemani (Viereck) (Hymenoptera: Braconidae), then tested the prediction that increasing temperature during immature development increases the handling time of adults. As expected, parasitoids took longer to handle large aphids than small aphids. However, large parasitoids did not have shorter handling times than small parasitoids except when attacking large (adult) aphids. Developmental temperature had the predicted effect on parasitoids: Individuals reared at 25°C were smaller than those insects reared at 15°C. Parasitoids reared at 15°C had similar short handling times for both first instar and adult aphids, whereas parasitoids reared at 25°C took longer to handle adult aphids than first instar aphids. The size-mediated effect of temperature through development on parasitoid efficiency was opposite to the more familiar direct effect of temperature through metabolic rate. We conclude that the net effect of temperature on foraging insects will depend on its relative influence on immature and adult stages.

Providing humanistic care: dentists' experiences in deprived areas.

Communication barriers severely reduce the effectiveness of oral health care provision to people living in poverty. Our objective was to identify specific approaches and skills developed by dentists for more effective treatment of people living in poverty and addressing their needs. We conducted qualitative research based on in-depth interviews with eight dentists practicing in disadvantaged communities of Montreal, Canada. Analyses consisted of interview debriefing, transcript coding, and data interpretation. Results revealed that, over years of practice, these dentists had developed a five-faceted socio-humanistic approach that involved: (1) understanding patients' social context; (2) taking time and showing empathy; (3) avoiding moralistic attitudes; (4) overcoming social distances; and (5) favoring direct contact with patients. This approach is original, and, even though participants found it successful, it should be evaluated in terms of its impact for access to services and patients' experience of care.

[The anaesthesia and critical care specialty and new hospital management in France: an inquiry in university and general hospitals]. / La discipline anesthésie-réanimation et les pôles d'activité médicale (PAM) : résultats d'une enquête auprès des CHU et CHG.

OBJECTIVE: To know: (1) how French public services of anaesthesia and critical care (ACC) have applied the new principles of hospital management and (2) whether or not it has impacted the different components of ACC. STUDY DESIGN: National questionnaire at the end of 2008, i.e., after 2 years of new hospital management. MATERIAL: Heads of ACC services in general (GH) and university hospitals (UH). METHODS: Eighteen closed questions and open opinions analyzed. Comparisons of percentages (Chi(2) - Yates): linear correlation. RESULTS: Percentages of responses were 70% (n=51) for UH and 37% (n=146) for GH. The new management principles were mainly applied. The different clinical and academic components of the ACC specialty (ACC, emergency medicine, pain management) mainly remained associated in UH. In GH, the new management induced constant and various changes. They were mainly judged as defeating the object of the ACC speciality in GH, especially in those of lower and mild sizes. CONCLUSION: The general tendency is that the ACC specialty was able to maintain the family ties of its different components in the UH. However, this principle was not a cornerstone of the new management in the GH.

How people on social assistance perceive, experience, and improve oral health.

Oral diseases are highly prevalent among people on social assistance. Despite benefiting from public dental coverage in North America, these people rarely consult the dentist. One possible reason is rooted in their perception of oral health and the means to improve it. To respond to this question, largely unexplored, we conducted qualitative research through 8 focus groups and 15 individual interviews in Montreal (Canada). Thematic analysis revealed that people on social assistance: (a) define oral health in a social manner, placing tremendous value on dental appearance; (b) complain about the decline of their dental appearance and its devastating impact on self-esteem, social interaction, and employability; and (c) feel powerless to improve their oral health and therefore contemplate extractions and complete dentures. Our research demonstrates that perception of oral health strongly influences treatment preference and explains low and selective use of dental services in this disadvantaged population.

Host tree age as a selective pressure leading to local adaptation of a population of a polyphagous Lepidoptera in virgin boreal forest.

We tested the hypothesis that host tree age may act as a selective factor and lead to local adaptation of the hemlock looper (Lambdina fiscellaria), a geometrid Lepidoptera that has a wide geographical distribution and has evolved in different eco-zones characterized by different levels of floristic composition, age structure and fragmentation level. Considering that hemlock looper outbreaks mainly occurred in old forests, we compared the biological performances of two populations. The first population was collected in the northern virgin boreal forest, which is dominated by mature and overmature coniferous stands that have not suffered from human disturbance. The other population was collected in the southern mixed-wood forest, which is more diversified and has been modified by forest harvesting. Larvae were reared under controlled conditions on foliage from three age classes of balsam fir trees: juvenile, mature and overmature. Although we measured significant variations of biological performances between the two populations, no significant effect of the age of the balsam fir trees could be detected for males from both populations or for females from the southern population. However, northern females were strongly affected by the age of balsam fir trees on which they fed, as their pupal weight was 12% higher and their fecundity increased by 27% on overmature trees compared with juvenile ones. These results indicate that under the same selective pressure, females adapt their strategy to maximize their fitness, and thus they appear as the driving force of evolution through the local adaptation concept. Furthermore, the two populations evolved in distinct habitats and their adaptation reflects selective pressures occurring inside their original environment. This is the first report on local adaptation of an herbivore that is mediated by host tree age. Changes in forest age structure may have a considerable impact on insect local adaptation and presumably on their population dynamics.

Geographic biotype and host-associated local adaptation in a polyphagous species, Lambdina fiscellaria (Lepidoptera: Geometridae) feeding on balsam fir on Anticosti Island, Canada.

The debate about mechanisms underlying the evolution of host specialization by herbivorous insects remains open. Natural selection may act locally and lead to different patterns of geographic variation in life history traits of polyphagous herbivores. The hypothesis of genetically-based trade-offs in offspring performance on different hosts has been proposed but this has rarely been demonstrated. Under laboratory conditions, the biological performance of two populations of the hemlock looper Lambdina fiscellaria (Guenée), a highly polyphagous lepidopteran, was compared when reared on three different tree host species: balsam fir, eastern hemlock and sugar maple. One population originated from Anticosti Island, Québec, Canada, where the insect has evolved without having access to two of the three tree species tested, the other being from the mainland where all tree species are present. When reared on balsam fir foliage, which was naturally available to each population, larvae from Anticosti Island underwent four instars compared with five for the mainland population, indicating the existence of geographic biotypes in L. fiscellaria. When reared on the foliage of non-naturally available host trees, larvae from Anticosti Island had a higher incidence of supernumerary instars. This is a unique example where local adaptation to environmental conditions of an insect herbivore is expressed through a differential number of larval instars. Moreover, the Anticosti Island population showed a higher growth related index on the host available to both populations indicating that a fitness trade-off was the evolutionary process underlying the local adaptation of this population on balsam fir.

Dental caries experience: a two-generation study.

The life-course framework stresses the importance of social, psychosocial, and biological factors in early life on the development of later disease. From this perspective, the association between edentulousness of mothers and their children's caries risk has not been studied. Therefore, a sample of 6303 mother-child pairs was randomly selected in Quebec (Canada). Mothers (6039 dentate and 264 edentulous) completed a self-administered questionnaire, and their children, aged 5 to 9 years, were clinically examined. Bivariate analyses and multiple logistic regressions showed that edentulous mothers' children are more likely to experience caries on both primary [OR=1.7 (1.3-2.3)] and permanent [OR=1.4 (1.0-2.0)] dentitions when compared with dentate mothers' children. These results are independent of socio-economic status, age, gender, and children's oral-health-related behaviors. Our study is the first to show that edentulous mothers' children constitute a group at risk of caries. It also highlights the need for a better understanding of the mother-child transmission of risk.

[Migration, ethics and public health in Quebec]. / Migration, éthique et santé publique au Québec.

This article analyses the ethical issues of migration in relation to public health in Quebec. There are two objectives: to describe the progression of analysis of the migration phenomenon in public health over the last thirty years and to state the ethical debate it raises. The progression of analysis of the migration phenomenon has been characterised by various approaches: intercultural, acculturation, transcultural, and migratory journey. Although these approaches have contributed to the development of knowledge about the reality of immigration, they have also, in spite of themselves, generated stigmatisation, discrimination and the proliferation of prejudices. Generally, findings that have emerged when migration is taken into account indicate an imbalance of power. For some, to focus on the phenomenon of migration promotes the power imbalance while for others, to disregard it masks the issue.