Fluctuating Asymmetry Spotted Wing Drosophila (Diptera: Drosophilidae) Exposed to Sublethal Doses of Acetamiprid and Nicotine

Long-term exposure to low concentrations of toxic substances can cause several adverse consequences ranging from molecular to morphological. Sublethal doses may also lead to increased tolerance in the offspring of surviving individuals. One of the consequences of such stress is deviations from the ideal body symmetry during development, reflected by increased levels of fluctuating asymmetry (FA). This research aimed to verify FA in the wing veins of insects belonging to the Drosophilidae family-Drosophila suzukii, a fruit pest controlled by the insecticide acetamiprid, a neonicotinoid. To determine whether FA varied depending on insecticides present in the diet, multigenerational cultures of D. suzukii were carried out on media supplemented with different concentrations (below the LC50) of two insecticides. Nicotine was used as a positive control. Fecundity decreased, the number of insects decreased, and breeding did not continue beyond the tenth generation. However, the FA level at different concentrations was similar, and high FA values were observed even at lower acetamiprid concentrations. We did not see significant changes in FA levels in subsequent generations. D. suzukii proved extremely sensitive to acetamiprid, and FA is a good index of this sensitivity.

Long-term Exposure to Industrial Chemical Contamination Affects the Magnitude of Predator-induced Immunosuppression in a Free-living Passerine

Industrial chemical contamination is known to have immuno-toxic effects on birds. It may also interfere with natural stressful conditions to further disrupt the immune responses, but these possible interactive effects are still poorly documented in free-living birds. Using the phytohaemagglutinin skin-swelling test, we assessed how the T-cell mediated immune response varied according to the perceived risk of predation in hybrid sparrows, Passer domesticus × Passer hispaniolensis, originating from two sites differentially impacted by industrial chemical contamination, in southern Tunisia. Results showed that T-cell mediated immune response decreased with increasing perceived risk of predation, but the extent of this predator-associated immunosuppression was weaker in birds from the contaminated site compared to those from the control site. The immune response of birds living in the contaminated site was so weak that it could not be further weakened by a predator-related stress. Overall, these results support the idea that chemical contamination interferes with natural environmental stressors, such as predators, thus entailing profound disruption of the immune responses, with possible deleterious repercussions on the ability of birds to cope with diseases.

Does environmental metal pollution affect bird morphometry? A case study on the tree sparrow Passer montanus

Morphological characteristics are the leading indicators of the health status of birds. To explore the effects of heavy metals on bird morphometry in natural populations, tree sparrows (Passer montanus) were studied in a polluted site [Baiyin (BY)] and a relatively unpolluted site [Liujiaxia (LJX)]. This study aimed to examine whether morphological variables, the fluctuating asymmetry (FA) of the wing, tarsus, and toe length, were associated with heavy metals (Cu, Zn, Pb, and Cd) and Ca levels in different tissues and feces of adults and nestlings. Results showed that adults collected from BY contained relatively higher heavy metal concentrations and lower Ca concentrations in different tissues than those from LJX. Smaller body sizes and higher FA levels of adults and nestlings were found in BY than in LJX. Although higher heavy metal concentrations in some tissues were associated with smaller morphological characteristics of adults, the effects were not obvious in nestlings. The most correlated heavy metal with as many characteristics was heavy metal in primary feather in both sites, and the most affected characteristic was body mass in BY. The FA values of adults and nestlings in BY were positively affected by heavy metal concentrations in different tissues and feces. The growth rate of wing and tarsus length of nestlings in BY were negatively affected by the FA values of wing and tarsus length, respectively. Taken together, environmental metal pollution might affect the morphological characteristics of tree sparrows. These findings suggest that the morphological characteristics of tree sparrows, especially FA, can be used as indicators of metal pollution, underscoring the importance of measuring morphological characteristics in avian ecotoxicology field studies.

Insect Fluctuating Asymmetry: An Example in Bolivian Peridomestic Populations of Triatoma infestans (Klug, 1834) (Hemiptera: Reduviidae)

Fluctuating asymmetry (FA) is a morphometric tool used to measure developmental instability in organisms which have been exposed to stress or other adverse conditions. Phenotypic variability in response to stressors are the result of interactions between genomes and the environment, acting in a noisy developmental system. Most of the organisms have bilateral symmetry with a repetition of structures in different positions or orientations; asymmetrical variation has been a morphological response associated with insecticide application inducing disturbances in endocrinal system product of the chemicals. Triatoma infestans (is the main vector of Chagas disease in South America. The availability of food sources varies for populations of T. infestans living in different habitats; insects that inhabit the intradomicile feed preferentially on human blood, whereas insects that develop in the peridomicile feed on the blood of the other mammals and birds. The following research evaluate the FA to the different ecotopes in two geographical areas of Chuquisaca Bolivia; Yamparáez/Sotomayor of the high inter-Andean valleys and Huacaya/Imbochi of the boreal Chaco and a CIPEIN laboratory strain population. A combination of advanced morphometrics tools and multivariate analysis were used to quantify the levels of asymmetry produced by pyretroid near to the peridomiciles in Bolivia. Populations from Yamparáez/Sotomayor were found to have higher levels of FA which the combination of environmental conditions such as low temperatures avoid greater permanence in the habitat and more exposition to insecticide. A better understanding of the combination of these tools will allow researchers to implement better public policies to regulate insecticide applications and to understand how certain organisms adapt to multiple stressors.

Eusociality is linked to caste-specific differences in metabolism, immune system, and somatic maintenance-related processes in an ant species

The social organization of many primate, bird and rodent species and the role of individuals within that organization are associated with specific individual physiological traits. However, this association is perhaps most pronounced in eusocial insects (e.g., termites, ants). In such species, genetically close individuals show significant differences in behavior, physiology, and life expectancy. Studies addressing the metabolic changes according to the social role are still lacking. We aimed at understanding how sociality could influence essential molecular processes in a eusocial insect, the black garden ant (Lasius niger) where queens can live up to ten times longer than workers. Using mass spectrometry-based analysis, we explored the whole metabolome of queens, nest-workers and foraging workers. A former proteomics study done in the same species allowed us to compare the findings of both approaches. Confirming the former results at the proteome level, we showed that queens had fewer metabolites related to immunity. Contrary to our predictions, we did not find any metabolite linked to reproduction in queens. Among the workers, foragers had a metabolic signature reflecting a more stressful environment and a more highly stimulated immune system. We also found that nest-workers had more digestion-related metabolites. Hence, we showed that specific metabolic signatures match specific social roles. Besides, we identified metabolites differently expressed among behavioral castes and involved in nutrient sensing and longevity pathways (e.g., sirtuins, FOXO). The links between such molecular pathways and aging being found in an increasing number of taxa, our results confirm and strengthen their potential universality.

Fluctuating asymmetry as biomarker of pesticides exposure in the Italian wall lizards (Podarcis siculus)

The extensive use of pesticides in agricultural environments produces drastic effects on wildlife, hence the need for less invasive indicators of environmental stress to monitoring the impact of agriculture treatments on biological systems. Fluctuating asymmetry (FA), as measure of developmental instability, has recently been proposed as reliable biomarker of populations stress due to environmental disturbance. We investigate femoral pores (FP) and dorsal head shape (HS) traits in populations of the Italian wall lizard inhabiting agricultural environments to examine whether different pesticide exposures (conventional, organic and control) can cause distinctive degree of FA. High-resolution photographs of FP and HS were taken in the field with a digital camera. The number of FP were counted twice on both sides and HS was analysed using geometric morphometrics with 25 landmarks and 12 semilandmarks. Individuals under conventional management showed higher levels of FA compared to control ones, and females exhibited higher FA levels than males for the FP. However, no significant difference was found for the HS trait. Our study provided evidence that FA may have a real potential as biomarker of population stress in wall lizards, highlighting the importance in the choice of the experimental design and the traits adopted for estimating DI.

Breaking Symmetry: Fluctuating Asymmetry and Geometric Morphometrics as Tools for Evaluating Developmental Instability under Diverse Agroecosystems

Fluctuating asymmetry (FA), in contrast with other asymmetries, is the bilateral asymmetry that represents small, random developmental differences between right and left sides. After nearly a century of using traditional morphometrics in the estimation of FA, geometric morphometrics (GM) now provides new insights into the use of FA as a tool, especially for assessing environmental and developmental stress. Thus, it will be possible to assess adaptation to various environmental stressors as particular triggers for unavoidable selection pressures. In this review, we describe measures of FA that use geometric morphometrics, and we include a flow chart of the methodology. We also describe how this combination (GM + FA) has been tested in several agroecosystems. Nutritional stress, temperature, chemical pollution, and population density are known stressors experienced by populations in agroecosystems.

Weather effects on breeding parameters of two insectivorous passerines in a polluted area

Direct and indirect effects of environmental pollution affect negatively to birds' breeding performance in both urban and industrial environments, but much less is known on how pollution and natural stress factors work together. In our long-term study (1991-2018), we explored whether industrial pollution and associated habitat changes increase the sensitivity of breeding parameters (hatching and fledging success, nestling growth) to temperature and precipitation in two insectivorous bird species, the great tit (Parus major) and the pied flycatcher (Ficedula hypoleuca). We found that both species are rather weather sensitive in terms of their fledging success, but especially in the F. hypoleuca, the negative effect was strengthened in a polluted environment. For both study species, all the breeding parameters, except growth of F. hypoleuca nestlings, were inferior in the polluted area and negatively affected by cold weather. Independent of pollution, the duration of rainy spells during the nestling period had an overall negative effect on fledging success of F. hypoleuca, and this effect became stronger at cold temperatures. The length of rainy spells was, however, positively associated with nestling wing length in both species, possibly because of better availability of some important food resources for wing growth in more humid conditions. The weather-pollution interactions in our study populations were not overwhelmingly strong, but those found in F. hypoleuca show that such interactions exist, they are species-specific and in our study system most likely associated to pollution-related resource (e.g. food) limitation. Higher sensitivity of F. hypoleuca to low temperatures is likely related to its less well-insulated nests and higher dependence on aerial prey, the availability of which is especially reduced during cold and rainy spells. Our study indicates that anthropogenic stress, such as pollution, has synergistic effects with natural stress factors affecting passerine birds' breeding performance.

Changes in Morphometric Traits of Ground Beetles Along Urbanization Gradients

Urbanization has a significant impact on abiotic and biotic factors in nature. We examined the morphometric characters of four carabid species (Abax parallelepipedus, Carabus scheidleri, Carabus violaceus, and Pterostichus oblongopunctatus) along urbanization gradients in and around the cities of Vienna (Austria) and Debrecen (Hungary). We found significant differences among urban, suburban, and rural areas in the parameters of antennomers, the maxillary palpus, the labial palpus, and the length of the tibia and the elytra of the carabids studied. We also found significant differences between males and females based on the parameters of antennomers, the maxillary palpus, the labial palpus, the femur, and the elytra. An interaction between urbanization and sex was found in the case of antennomers, the maxillary palpus, the labial palpus, the femur, and the elytra. Our findings suggested that in the cases of species from Carabini tribus the parameters of antennomers, the maxillary palpus, and the elytra could be useful for assessing the effects of urbanization because these morphometric characters responded sensitively to the environmental stress, whereas the most useful parameters are those of antennomers and the tibia for the species of Pterostichini tribus. Our findings also revealed that females are more sensitive to environmental stress than males.

Effects of experimental lead exposure on physiological indices of nestling great tits Parus major: haematocrit and heterophile-to-lymphocyte ratio

Lead (Pb) is recognized as one of the most toxic trace elements that can induce a wide range of negative health effects in wildlife. Because the investigation of basic environment-sensitive physiological indicators is easy to perform in wild birds, they have been considered as valuable bioindicators of lead contamination. The harmfulness of lead poisoning can depend on the type of exposure, and in most studies of birds, an effect of chronic lead exposition has been considered. In this study, we investigated whether a single exposure to specific doses of lead affected such physiological indices as haematocrit and the heterophil-to-lymphocyte ratio (H/L ratio). For this purpose, we conducted an experiment based on intentional lead supplementation, with the use of two different doses, applied to randomly chosen great tit (Parus major) nestlings from randomly selected broods. A few days after the exposure (when the nestlings were 15 days old), we determined haematocrit and the H/L ratio as potentially sensitive physiological indicators of lead intoxication. We found that the treatment with lead resulted in a significant decline in haematocrit level. In addition, we found that the age when lead exposure occurred can be considered as an important factor influencing haematocrit variation. A decrease in haematocrit was observed on consecutive days of nestling life. In contrast, the H/L ratio did not show any significant response to lead exposure. These results clearly show that the assessment of haematocrit level for nestling great tits can provide a simple and rapid method of indirect evaluation of physiological effects of lead intoxication caused by a single exposure.

Fluctuating asymmetry and feather growth bars as biomarkers to assess the habitat quality of shade coffee farming for avian diversity conservation

Shade coffee farming has been promoted as a means of combining sustainable coffee production and biodiversity conservation. Supporting this idea, similar levels of diversity and abundance of birds have been found in shade coffee and natural forests. However, diversity and abundance are not always good indicators of habitat quality because there may be a lag before population effects are observed following habitat conversion. Therefore, other indicators of habitat quality should be tested. In this paper, we investigate the use of two biomarkers: fluctuating asymmetry (FA) of tarsus length and rectrix mass, and feather growth bars (average growth bar width) to characterize the habitat quality of shade coffee and natural forests. We predicted higher FA and narrower feather growth bars in shade coffee forest versus natural forest, indicating higher quality in the latter. We measured and compared FA in tarsus length and rectrix mass and average growth bar width in more than 200 individuals of five bird species. The extent of FA in both tarsus length and rectrix mass was not different between the two forest types in any of the five species. Similarly, we found no difference in feather growth between shade coffee and natural forests for any species. Therefore, we conclude our comparison of biomarkers suggests that shade coffee farms and natural forests provide similar habitat quality for the five species we examined.

Bone density and asymmetry are not related to DDT in House Sparrows: Insights from micro-focus X-ray computed tomography

In organisms, DDT (Dichlorodiphenyltrichloroethane) and its metabolites, DDE (Dichlorodiphenyldichloroethylene) and DDD (Dichlorobischlorophenylethane) are endocrine mimics. They can influence bone density and other bone structural features. This study was conducted on House Sparrows (Passer domesticus) caught from the Free State - and the Limpopo Provinces of South Africa (SA). The sites were chosen based on spraying patterns of DDT for malaria control or non-spraying. The bone mineral densities of the femurs as well as the lengths of the left- and right leg bones were determined using micro-focus X-ray computed tomography (μ-XCT). The concentrations of DDT and its metabolites in the liver were determined with gas-chromatography mass-spectrometry to provide baseline concentrations of DDT in the body, allowing comparison of the various groups of birds. There was no asymmetry between the lengths of the bones of the left- and the right legs. DDT concentrations in the liver did not correlate with bone lengths. In addition, there were no significant differences between the relative densities of the left- and right leg bones with increase of concentrations of DDT. The concentrations of DDT and its metabolites did not have a significant effect on the measured bone parameters of House Sparrows. It is possible that the concentrations of DDT and its metabolites in the environments were too low to be injurious to the birds and/or tolerance to the insecticide has developed in the birds over more than six decades of almost continuous application of DDT.

Measure of environmental stress on Porcellio laevis Latreille, 1804 sampled near active Tunisian industrial areas

This study aimed to observe the type of asymmetry exhibited by Porcellio laevis sampled from 15 sites belonging to Tunisian industrialized areas. Physicochemical parameters such as pH, organic matter and CaCO₃ contents were measured in soils. Moreover, Cd, Pb, Zn, and Cu concentrations were determined in both soils and woodlice. Additionally, 10 metrical traits were measured to evaluate the type of asymmetry on individuals: the basis, the second and the third articles of the antenna, the first article of the flagellum of the antenna and the merus, the carpus, and the propodus of the sixth and the seventh pereopods. Among the 531 measured individuals, 432 exhibited fluctuating asymmetry (FA) while the remaining individuals exhibited antisymmetry or directional asymmetry. The data obtained were analyzed using a multivariate statistical analysis. Contrary to our hypothesis, the results showed that individuals from contaminated sites have a low FA level, whereas those from uncontaminated sites have a high FA level, particularly females but with some exceptions. Variations in FA level in the traits and populations studied and its usefulness as a stress indicator were discussed.

Carapace asymmetry: A possible biomarker for metal accumulation in adult olive Ridleys marine turtles?

The Olive Ridley marine turtle (Lepidochelys olivacea) is characterized by individual morphological variability in the number and shape of scutes. The influence of pollutants on developmental instability and one of its consequences, the asymmetry of individuals, has been demonstrated in several species, especially invertebrates and some birds. However, the use of this asymmetry as a biomarker of contamination in adult individuals has never been explored. We developed an index to quantify developmental instability (DIx) based on the number and relative size of costal carapace scutes. The link between DIx and inorganic elements concentrations was explored in various tissues of stranded turtles from the Southern Mexican Pacific. The relationships between adult contamination and DIx could directly or indirectly reflect (i) the disruption of metal elimination in the adult stage dependent on embryonic perturbation and thus determining DIx, (ii) the difference in metal absorption dependent on DIx status, or (iii) DIx linked to other unknown factors.

Ultrastructural Alterations of Midgut Epithelium, But Not Greater Wing Fluctuating Asymmetry, in Paper Wasps (Polistes dominula) from Urban Environments

Polistes paper wasps can be used to monitor trace metal contaminants, but the effects of pollution on the health of these insects are still unknown. We evaluated, in a south-eastern area of Spain, whether workers of Polistes dominula collected at urban and rural sites differ in health of midgut tissue and in fluctuating asymmetry, an estimate of developmental noise. We found that wasps collected at the urban sites had abundant lead (Pb)-containing spherites, which were less visible in wasps from the rural sites. Evident ultrastructural alterations in the epithelium of the midgut of the wasps collected at the urban sites included broken and disorganized microvilli, a high amount and density of heterochromatin in the nucleus of epithelial cells, cytoplasmic vacuolization and mitochondrial disruptions. Altogether, these findings suggest a negative effect on the transmembrane transport and a less efficient transcription. On the contrary, a healthy epithelium was observed in wasps from the rural sites. These differences may be preliminarily linked with levels of lead pollution, given that wasps from urban sites had double the Pb concentrations of wasps from rural sites. Level of fluctuating asymmetry was unrelated to wasp origin, thus suggesting no link between developmental noise and Pb-driven pollution.

Enclosure design for flock-level, chronic exposure of birds to air contaminant mixtures

The objective of this study was to design an enclosure suitable for studying the ecotoxicological effects of vehicle emissions on groups of wild birds without compromising welfare. Two, adjacent enclosures sheltered from sunlight, wind and rain, were bird-proofed and wrapped with thick polyethylene sheeting. Emissions were directed into the treatment enclosure from the exhaust of a light-duty gasoline truck, using flexible, heat-proof pipe, with joins sealed to prevent leakage. During active exposure, the engine was idled for 5 h/day, 6 days/week for 4 weeks. Fans maintained positive pressure (controls) and negative pressure (treatment), preventing cross-contamination of enclosures and protecting investigators. Four sets of passive, badge-type samplers were distributed across each enclosure, measuring nitrogen dioxide, sulfur dioxide and volatile organic compounds (NO₂, SO₂ and VOCs, respectively), and were complemented by active monitors measuring VOCs and particulate matter (2.5 µm diameter, PM_2.5). We found that the concentrations of NO₂, SO₂ and PM_2.5 were not different between treatment and control enclosures. Volatile organic compounds (e.g. benzene, toluene, ethylbenzene and xylenes) were approximately six times higher in the treatment enclosure than control (13.23 and 2.13 µg m^-1, respectively). In conclusion, this represents a successful, practical design for studying the effects of sub-chronic to chronic exposure to realistic mixtures of vehicle exhaust contaminants, in groups of birds. Recommended modifications for future research include a chassis dynamometer (vehicle treadmill), to better replicate driving conditions including acceleration and deceleration.

Fluctuating asymmetry rather than oxidative stress in Bufo raddei can be an accurate indicator of environmental pollution induced by heavy metals

Oxidative stress (OS) and fluctuating asymmetry (FA) as risk markers for environmental stress are widely used to predict changes in the health and fitness of many animals exposed to pollutants. However, from the perspective of protecting declining amphibians, it remains to be verified which one would be a reliable indicator for amphibians exposed to long-term heavy metal pollution under natural conditions. In this study, the OS and FA of Bufo raddei exposed to natural heavy metal pollution were analyzed to determine which marker is more accurate for indicating heavy metal-induced stress. Three years of data were collected during the breeding season of B. raddei from Baiyin (BY), which has been mainly contaminated with Cu, Zn, Pb, and Cd compounds for a long period, and from Liujiaxia (LJX), which is a relatively unpolluted area. Unexpectedly, although significant accumulation of the four heavy metals was found in the kidney and liver of B. raddei from BY, the levels of superoxide dismutase, glutathione peroxidase, and malondialdehyde in these two organs were found to be irregular, with low repeatability in both BY and LJX. However, significant differences in the levels of FA were observed in B. raddei populations from these two areas over the past 3 years (P < 0.01). The degrees of FA in B. raddei populations from BY and LJX were assessed as degree 4 and 1, respectively. In short, this study suggested that FA was a more reliable and effective indicator than OS to monitor and predict long-term environmental stress on anuran amphibians.

Mercury exposure may influence fluctuating asymmetry in waterbirds

Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds. Environ Toxicol Chem 2017;36:1599-1605. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Vitamin profiles in two free-living passerine birds under a metal pollution gradient - A calcium supplementation experiment

Vitamin and carotenoid deficiency may impair development in free-living vertebrates, because of the importance of these micronutrients to growth, antioxidant defense and calcium regulation. Micronutrient and calcium insufficiency can be intensified by metal pollution which can interfere with nutrient homeostasis or indirectly reduce food availability. Furthermore, absorption of dietary heavy metals is dependent on food calcium and vitamin levels. We investigated the effect of calcium on plasma vitamin and carotenoid profiles and how these affected growth and survival in two passerine birds with different calcium turnover living along a metal pollution gradient. Vitamins (A, D₃ and E) and carotenoids were quantified from blood plasma of great tit (Parus major) and pied flycatcher (Ficedula hypoleuca) nestlings. Metal concentrations in soil and in feces from the same nestlings were used to assess the exposure to air pollution. Additionally, we examined the vitamin level variation between developmental stages (eggs and nestlings within the same brood). Our results showed that generally higher concentrations of vitamins and carotenoids circulate in blood of great tits than in pied flycatchers. In general, birds inhabiting the polluted zone presented lower concentrations of the studied micronutrients. Calcium supplementation and metal pollution decreased vitamin A concentration in pied flycatcher, but not in great tit, while vitamin A affected growth and survival in great tit and pied flycatcher respectively. Our results suggest that populations under exposure to metal pollution may experience increased vitamin A deficiency, and that the two passerine species, while obtaining similar micronutrients in food, respond differently to environmental disturbance of nutrients.

Strong nonlinear selection against fluctuating asymmetry in wild populations of a marine fish

Theoretical links between fluctuating asymmetry (FA) and fitness have led many to use FA as a proxy for average fitness. However, studies examining whether asymmetry actually correlates with individual fitness in wild populations are relatively rare and often use simple measures of association (e.g., correlation coefficients). Consequently, the pattern of selection on asymmetry in the wild is seldom clear. We examined selection on FA of pectoral fin morphology in two wild populations of a marine fish (the kelp perch; Brachyistius frenatus). As expected, variance in signed FA in each initial sample was significantly greater than that found in the surviving population, indicating selection against FA. Our estimate of the fitness surface confirmed perfect symmetry as the phenotypic optimum and indicated strong, nonlinear selection against asymmetry. No difference in the form of selection was detected between populations. However, the level of FA in the initial samples varied among populations, leading to an overall difference in the level of selective mortality. Our results suggest that selection on asymmetry in wild populations may be strongly nonlinear, and indicate that the demographic costs of asymmetry may play a substantial role in the dynamics of populations.

Corticosterone levels in relation to trace element contamination along an urbanization gradient in the common blackbird (Turdus merula)

In a rapidly urbanizing world, trace element pollution may represent a threat to human health and wildlife, and it is therefore crucial to assess both exposition levels and associated effects of trace element contamination on urban vertebrates. In this study, we investigated the impact of urbanization on trace element contamination and stress physiology in a wild bird species, the common blackbird (Turdus merula), along an urbanization gradient (from rural to moderately urbanized areas). Specifically, we described the contamination levels of blackbirds by 4 non-essential (Ag, Cd, Hg, Pb) and 9 essential trace elements (As, Co, Cr, Cu, Fe, Mn, Ni, Se, Zn), and explored the putative disrupting effects of the non-essential element contamination on corticosterone levels (a hormonal proxy for environmental challenges). We found that non-essential trace element burden (Cd and Pb specifically) increased with increasing urbanization, indicating a significant trace element contamination even in medium sized cities and suburban areas. Interestingly, the increased feather non-essential trace element concentrations were also associated with elevated feather corticosterone levels, suggesting that urbanization probably constrains birds and that this effect may be mediated by trace element contamination. Future experimental studies are now required to disentangle the influence of multiple urban-related constraints on corticosterone levels and to specifically test the influence of each of these trace elements on corticosterone secretion.

Condition and Health of Rufous Bush Robin (Cercotrichas galactotes) Nestlings in a Polluted Oasis Habitat in Southern Tunisia

We investigated whether the proximity to the Gabès-Ghannouche factory complex of phosphate treatment, in south-eastern Tunisia, was associated with notable changes in the condition and health of Rufous bush robin (Cercotrichas galactotes) nestlings hatched in the neighbouring oasis habitat. Results demonstrated that excrements of nestlings hatched in one oasis close to the factory complex contained higher concentrations of lead and zinc than the excrements of nestlings from one oasis situated 20 km away. Furthermore, when effects of age and nestling number in the nest were controlled, nestlings hatched near the factory complex showed reduced tarsus length, rectrix length, haematocrit level and haemoglobin concentration, but higher levels of fluctuating asymmetry compared to those from the more distant oasis. Overall, results suggest that the proximity to the factory complex was associated with increased exposure to metals and deterioration in nestling condition and development.

Long-term recovery of clutch size and egg shell quality of the pied flycatcher (Ficedula hypoleuca) in a metal polluted area

We explored if breeding parameters and egg shell quality of an insectivorous passerine, pied flycatcher Ficedula hypoleuca, have fully recovered after c.a. 99% decrease in dust emissions from a non-ferrous smelter in the course of the 23 year study period. Some potentially important population characteristics (density, phenology, age) and environmental variables (habitat, inter-specific competition) were taken into account in the analysis. We found marked increase in reproductive parameters (egg shell quality, clutch size, hatchability, and fledgling number) in the metal polluted area especially in 1990's when metal-rich dust emissions from the smelter were markedly reduced. Still clutch sizes and fledgling numbers remain below the levels of the reference area. There is currently very little evidence of direct toxic effects of metals in our study population but full recovery of breeding parameters may not be reached until the full recovery of food chains, which is likely to be a slow process.

A review on exposure and effects of arsenic in passerine birds

Arsenic (As) is a metalloid of high concern because of its toxic effects for plants and animals. However, it is hard to find information on this metalloid in passerines. This review presents a comprehensive overview of As exposure and effects in birds, and more particularly in passerines, as a result of an extensive search of the literature available. Internal tissues are the most frequently analyzed matrices for As determination in passerines (37.5% of the reviewed studies used internal tissues), followed by feathers and eggs (32.5% each), feces (27.5%), and finally blood (15%). A clear tendency is found in recent years to the use of non-destructive samples. Most studies on As concentrations in passerines have been done in great tit (Parus major; 50%), followed by pied flycatcher (Ficedula hypoleuca; 22.5%). Some factors such as diet and migratory status are crucial on the interspecific differences in As exposure. More studies are needed to elucidate if intraspecific factors like age or gender affect As concentrations in different tissues. The literature review shows that studies on As concentrations in passerines have been done mainly in the United States (30%), followed by Belgium (22.5%), and Finland (20%), making evident the scarce or even lack of information in some countries, so we recommend further research in order to overcome the data gap, particularly in the southern hemisphere. Studies on humans, laboratory animals and birds have found a wide range of effects on different organ systems when they are exposed to different forms of As. This review shows that few field studies on As exposure and effects in passerines have been done, and all of them are correlative so far. Arsenic manipulation experiments on passerines are recommended to explore the adverse effects of As in free-living populations at similar levels to those occurring in the environment.

CAPSULE

This review summarizes the most interesting published studies on As exposure and effects in passerines.

No delayed behavioral and phenotypic responses to experimental early-life lead exposure in great tits (Parus major)

Early-life exposure to pollutants, such as lead, may have long-lasting consequences on health, behavior, and cognition. However, experiments on delayed effects of specific pollutants are very rare in wild animals. We experimentally exposed wild nestling great tits (Parus major) to dietary lead (high, low, or control group) in levels relevant to exposure levels of wild populations in Europe and studied delayed effects on phenotypic and behavioral traits in captivity. We also included a group of birds from a vicinity of a copper smelter, exposed to a mixture of toxic metals and altered food supply during development. This experimental setup allowed us to compare the strength of direct (exposure to lead per se) and indirect (pollution-related changes in diet) effects of pollutants. Our experimental lead treatment significantly increased lead levels in bone and feces compared with controls. However, we found no carry-over effect of early-life dietary lead on morphology, plumage coloration, or heat shock proteins. Treatment did not affect activity, exploration, neophobia, or success in learning and spatial memory task. We conclude that with the exposure levels and relatively short exposure period used, delayed effects on the measured traits were not found. However, it is important to further study other types of behavioral traits and ultimately fitness effects.

The use of haemoglobin concentrations to assess physiological condition in birds: a review

Total blood haemoglobin concentration is increasingly being used to assess physiological condition in wild birds, although it has not been explicitly recognized how reliably this parameter reflects different components of individual quality. Thus, I reviewed over 120 published studies linking variation in haemoglobin concentrations to different measures of condition and other phenotypic or ecological traits. In most of the studied avian species, haemoglobin concentrations were positively correlated with other commonly used indices of condition, such as body mass and fat loads, as well as with quality of the diet. Also, chick haemoglobin concentrations reliably reflected the intensity of nest infestation by parasitic arthropods, and haemoglobin was suggested to reflect parasitism by haematophagous ectoparasites much more precisely than haematocrit. There was also some evidence for the negative effect of helminths on haemoglobin levels in adult birds. Finally, haemoglobin concentrations were found to correlate with such fitness-related traits as timing of arrival at breeding grounds, timing of breeding, egg size, developmental stability and habitat quality, although these relationships were not always consistent between species. In consequence, I recommend the total blood haemoglobin concentration as a relatively robust indicator of physiological condition in birds, although this parameter is also strongly affected by age, season and the process of moult. Thus, researchers are advised to control fully for these confounding effects while using haemoglobin concentrations as a proxy of physiological condition in both experimental and field studies on birds.

Spatial and temporal variation of lead, cadmium, and zinc in feathers of great tit and blue tit nestlings in Central Poland

In this study, we examined heavy-metal concentrations in feathers of nestling great tits Parus major and blue tits Cyanistes caeruleus at two different sites (urban parkland vs. deciduous forest) located in the Łódź agglomeration in relation to interyear variation. We found that tit species did not differ significantly in lead and cadmium concentrations. Zinc concentration was significantly higher in blue tits. We also found that lead and cadmium levels in blue tit nestlings and the level of lead in great tit nestlings were higher in the parkland site than in the woodland site. We explain habitat variation in heavy-metal concentrations in feathers of nestlings by different levels of contamination at study sites. For both tit species, significant variation in heavy-metal amounts accumulated by nestlings was found between years with the lowest value in a year with the lowest value of rainfall. We suggest that the interyear variation may be accounted for by differences in rainfall, thus influencing quantities of trace elements bioavailable in the environment.

Experimental manipulation of dietary lead levels in great tit nestlings: limited effects on growth, physiology and survival

We manipulated dietary lead (Pb) levels of nestlings in wild populations of the great tit (Parus major L) to find out if environmentally relevant Pb levels would affect some physiological biomarkers (haematocrit [HT], fecal corticosterone metabolites [CORT], heat shock proteins [HSPs], erythrocyte delta-aminolevulinic acid dehydratase activity [ALAd]), growth (body mass, wing length), phenotype (plumage coloration) or survival of nestlings. The responses to three experimental manipulation (control, low and high: 0, 1 and 4 μg/g body mass/day) are compared with those in a P. major population breeding in the vicinity of a heavy metal source, a copper smelter. Our Pb supplementation was successful in raising the fecal concentrations to the levels found in polluted environments (high: 8.0 μg/g d.w.). Despite relatively high range of exposure levels we found only few effects on growth rates or physiology. The lack of blood ALAd inhibition suggests that the circulating Pb levels were generally below the toxic level despite that marked accumulation of Pb in femur (high: 27.8 μg/g d.w.) was observed. Instead, birds in the metal polluted environment around the smelter showed decreased growth rates, lower HT, higher CORT, less colorful plumage and lower survival probabilities than any of the Pb treated groups. These effects are likely related to decreased food quality/quantity for these insectivorous birds at the smelter site. In general, the responses of nestlings to metal exposure and/or associated resource limitation were not gender specific. One of the stress proteins (HSP60), however, was more strongly induced in Pb exposed males and further studies are needed to explore if this was due to higher accumulation of Pb or higher sensitivity of males. In all, our results emphasize the importance of secondary pollution effects (e.g. via food chain disruption) on reproductive output of birds.

Lizards from urban areas are more asymmetric: using fluctuating asymmetry to evaluate environmental disturbance

The increase in human activities that leads to wildlife decline and species extinction poses an urgent need for simple indicators of environmental stress in animal populations. Several studies have suggested that fluctuating asymmetry (FA) can be an easy, direct measure of developmental instability because it is associated to environmental stress and, as such, it can be a useful indicator of population disturbance. We examined three different morphological traits in urban and rural populations of the common wall lizard (Podarcis muralis) to test whether anthropogenic disturbance causes an increase in FA. Compared to rural populations, urban ones showed higher levels of FA in all analyzed traits, thus providing evidence that FA can respond to anthropogenic disturbance. However, we also found significant differences in FA among traits, where femoral pores and subdigital lamellae, traits with a functional relevance, were more stable developmentally compared to supracilliar granules which have no evident function. Unsigned FA [abs(right-left)] exhibited significant, but weak, positive correlations among traits, indicating that developmental noise does not have a uniform effect across characters and thus questioning the view of developmental stability as an organism-wide property. The degree of signed FA (right-left) was more similar between structurally associated traits, possibly as an outcome of morphological integration. In conclusion, our results demonstrate that FA can be a reliable indicator of disturbance provided that it is analyzed on multiple traits simultaneously and examined at the population level.

Breeding performance of blue tits (Cyanistes cæruleus ultramarinus) in relation to lead pollution and nest failure rates in rural, intermediate, and urban sites in Algeria

The breeding parameters and the egg and nestling morphology of Cyanistes caeruleus populations from rural, intermediate, and urban sites in Algeria and the relationships of those variables with lead contamination were studied during three consecutive years. Breeding success was explained only by predation and vandalism rates. Predation was higher in the rural area, whereas vandalism was higher in the urban site. The other measured breeding parameters and egg characteristics were relatively insensitive to study site. The morphology of urban nestlings exhibited a trend toward smaller body size and mass compared to individuals from intermediate and rural sites. Although lead concentrations were higher in the tissues of urban birds than in intermediate and rural individuals, we did not detect a clear influence of this variable on nestling morphology. We conclude that urbanization influenced blue tit breeding parameters through predation and vandalism and nestling morphology through mechanisms other than lead pollution.

Eye of the Beholder: Symmetry Perception in Social Judgments Based on Whole Body Displays

External bilateral symmetry is a biological marker of normal development and is considered a signal of health and attractiveness across species. Because most human interactions are dynamic, it was hypothesized that observers would be able to perceive spatiotemporal symmetry—symmetry in motion—in human point-light walkers. It was also hypothesized that observers would rate symmetrical walkers as healthy and attractive. Symmetrical and asymmetrical figures were presented to adult participants ( n = 22) in motion and as static images with motion implied. Static symmetry was readily perceived, and symmetrical figures were judged significantly healthier and more attractive than asymmetrical figures. However, observers were unable to discriminate symmetry in dynamic presentations. These data provide preliminary evidence of a temporal summation window for a dynamic symmetry perception.

The use of a lacertid lizard as a model for reptile ecotoxicology studies--part 1 field demographics and morphology

At the European level, lacertid lizards have been proposed as potential model species for reptile ecotoxicology. We studied demographic and morphological aspects of natural field subpopulations of Podarcis bocagei inhabiting similar agricultural habitats which were either regularly exposed to pesticides, or not. Parameters examined in this study included population size and density, sex ratio, adult body size, fluctuating asymmetry in femoral pores and parasite prevalence. In general, we detected few statistically significant differences between the exposed and reference subpopulations. Although field situations are ecologically complex and factors other than pesticides may be acting, the absence of observable effects on field subpopulations is probably indicative that lizards are coping or compensating for this level of exposure.

Breeding performance of passerines in a polluted oasis habitat in southern Tunisia

We investigated the breeding performance of passerines nesting in the oases close to Gabès city, one of the most industrialised areas in Tunisia, in relation to habitat pollution. Using data on nest survival, clutch size and chick productivity of four insectivorous passerine species, we assessed whether the proximity to Gabès-Ghannouche factory complex of phosphate treatment was associated with reduced breeding performance. Our results show evidence of decreased breeding performance near the factory complex, but this decrease was more perceptible when comparing one oasis situated at the vicinity of the factory complex (polluted oasis) with one control oasis situated tens of kilometres faraway, than when comparing sites situated hundreds of metres apart within the polluted oasis. Overall, these results would indicate that passerines offer suitable models for biomonitoring programmes in the Gabès region and underline once more the usefulness of passerines as reliable biomonitors of terrestrial ecosystems.

Variation of basal EROD activities in ten passerine bird species--relationships with diet and migration status

Inter-specific differences in animal defence mechanisms against toxic substances are currently poorly understood. The ethoxyresorufin-O-deethylase (EROD) enzyme plays an important role in defence against toxic chemicals in a wide variety of animals, and it is an important biomarker for environmental contamination. We compared basal hepatic EROD activity levels among ten passerine species to see if there is inter-specific variation in enzyme activity, especially in relation to their diet and migration status. Migratory insectivores showed higher EROD activity compared to granivores. We hypothesize that the variable invertebrate diet of migratory insectivores contains a wider range of natural toxins than the narrower diet of granivores. This may have affected the evolution of mixed function oxidases (MFO) system and enzyme activities. We further tested whether metabolic rates or relative liver size were associated with the variation in detoxification capacity. We found no association between EROD activity and relative (per mass unit) basal metabolic rate (BMR). Instead, EROD activity and relative liver mass (% of body mass) correlated positively, suggesting that a proportionally large liver also functions efficiently. Our results suggest that granivores and non-migratory birds may be more vulnerable to environmental contaminants than insectivores and migratory birds. The diet and migration status, however, are phylogenetically strongly connected to each other, and their roles cannot be fully separated in our analysis with only ten passerine species.

Avifauna associada a um trecho urbano do rio Sorocaba, Sudeste do Brasil

Este estudo teve como objetivo caracterizar a avifauna associada ao rio Sorocaba, um típico rio urbano, do sudeste do Brasil. Ele atravessa a cidade com o mesmo nome, ao longo do qual, várias atividades humanas são realizadas como recreação e pesca. Lá, várias espécies de aves devem encontrar locais para descanso, alimentação e nidificação. As aves foram observadas semanalmente, de setembro de 2008 a setembro de 2009 por meio de 16 pontos fixos (A1 a A16). O levantamento quantitativo registrou 65 espécies (32 passeriformes e 33 não - passeriformes), sendo que a família mais bem representada foi Tyrannidae (n = 9). As espécies mais freqüentes foram Egretta thula, Amazonetta brasiliensis, Vanellus chilensis, Pitangus sulphuratus, Ardea alba e Pygochelidon cyanoleuca (FO = 100%). Os maiores valores do índice pontual de abundância foram 46,5 (1626 contatos) para Pgochelidon cyanoleuca, 14,4 (500 contatos) para Phalacrocorax brasilianus e 12,9 (452 contatos) para Amazonetta brasiliensis. As categorias tróficas mais representativas foram dos insetívoros (n = 26), piscívoros (n = 11) e onívoros (n = 10). A análise de agrupamento revelou a existência de três pares de pontos muito semelhantes (100 e 95% semelhança). Diferenças conspícuas na composição da fauna de aves ao longo da área estudada foram detectadas, provavelmente devido às suas características ambientais e do grau de perturbação humana. Além disso, diferenças significativas nos avistamentos foram observadas entre as estações de seca e chuva, provavelmente em função das atividades reprodutivas e migratórias e do aumento na disponibilidade de recursos alimentares, que supostamente ocorrem no período chuvoso. Neste sentido, práticas conservacionistas devem permitir a manutenção a heterogeneidade de habitats, recuperação da vegetação ripária, praias e banhados, assim como o planejamento efetivo das atividades humanas em seu entorno.

Metal pollution indirectly increases oxidative stress in great tit (Parus major) nestlings

Metals can cause oxidative stress by increasing the formation of reactive oxygen species (ROS), when there are insufficient amount of antioxidants to defend against the growing amount of free radicals. We aimed to find out the most reliable biomarkers to detect pollution-related oxidative stress in wild birds by comparing oxidative stress status in great tit (Parus major) nestlings at populations in polluted and unpolluted areas. We also studied with experimental manipulations whether dietary carotenoid levels have any role in great tits' antioxidant defence and whether their carotenoid-based plumage colour was connected to an oxidative stress status. We used antioxidants (GSH, carotenoids) and several antioxidant enzymes (GP, GR, GST, SOD, and CAT) as indicators of the oxidative stress. We found no direct connections between dietary metal exposure and antioxidant or antioxidant enzyme levels. The activity of GP was, however, slightly higher in the polluted environment. This was due to poorer condition and subsequently higher level of oxidative stress in the nestlings in the polluted area. We also found a positive association between GP and an ambient temperature during the nestling period, which may be due to higher metabolic activity of partly poikilothermic nestlings in warm weather. The activity of GST was positively related to the number of nestlings at the sampling time. Fledging success was better in an unpolluted area, where also the nestling body mass was higher. Carotenoid treatment increased the plasma carotenoid concentrations 2.1 fold in carotenoid-supplemented birds, but was not associated with the oxidative stress biomarkers or metal levels. The yellow plumage colour was associated with dietary carotenoid levels in both study areas, but not with the metal exposure or the oxidative stress status. Our results suggest that at the exposure levels found in our study area, the enzyme activities do not indicate metal-related oxidative stress. Instead, GP can be used as an indicator of growth related oxidative stress, which is greater in the polluted area. The activity of this enzyme was, however, not directly related to metal exposure, but more likely to some secondary pollution-related change in the nestling condition.

Are great tits (Parus major) inhabiting the vicinity of a pulp mill healthy? Impacts on physiology and breeding performance

The evaluation of pollution effects on wildlife provides biologically meaningful information concerning environmental quality and possible impacts on populations and can be used as an early warning of environmental change. We aimed to assess the potential effects of exposure to atmospheric pollution from pulp mill emissions on the morphology, physiology, and reproductive performance of the great tit (Parus major). Great tits from a population inhabiting the vicinity of a pulp mill had significantly higher feather mercury levels and were physiologically distinct from other birds not under the direct influence of the pollution source. This distinction, due to significantly higher levels of red blood cell-glutathione peroxidase antioxidant activity, in birds from the vicinity of the pulp mill, was observed both in autumn and winter and was repeatable between years. No detectable effects were observed on breeding performance or nestling morphology and physiology. The effects of pollution in this study seem to be related to increased levels of oxidative stress.

Pollution and its impact on wild animals: a meta-analysis on oxidative stress

Oxidative stress is the unifying feature underlying the toxicity of anthropogenic pollution (e.g., heavy metals, polycyclic aromatic hydrocarbons, and nitrogen-oxides) and the ultimate culprit in the development of many diseases. Yet, there has been no attempt to summarize the published data on wild terrestrial animals to reveal general trends regarding the effects of pollution on oxidative stress. The main findings of this meta-analysis reveal that, as predicted, there is an overall increase in oxidative stress when exposed to pollution. This is mainly due to a weak overall increase of oxidative damages, although there is some variation across taxa. The reduced form of glutathione (GSH) and its associated enzymes are the most reliable biomarkers. This result is important when choosing biomarkers and when using less-invasive sampling of endangered species, or for longitudinal approaches. To be able to predict future population outcomes, possible treatments, but also evolutionary responses to a changing environment, a greater integration of biotic factors such as temperature, bioavailability of toxic elements, and species-specific responses are needed.

Prenatal exposure to corticosterone impairs embryonic development and increases fluctuating asymmetry in chickens (Gallus gallus domesticus)

1. The level of corticosterone in fertilised eggs from hens (Gallus gallus domesticus) was manipulated experimentally to elucidate whether stress in laying hens is harmful to the chicks, as manifested by impaired survival and reduced growth, and whether bilateral asymmetry may represent an indicator of environmental stress in poultry. 2. Three hundred and fifty eggs were randomly divided into 4 groups; 1. untreated, 2. control, 3. 10 ng corticosterone/ml and 4. 20 ng corticosterone/ml. Each of the eggs in groups 2, 3 and 4 were injected with 100 microl ethanol-saline solution (25% ethanol in saline) containing 0, 0.6 and 1.2 microg corticosterone, respectively. After the injections, the final concentration of ethanol in the egg (albumen and yolk) was 0.03%, and the concentration of added corticosterone was 0, 10 and 20 ng/ml, respectively, in groups 2, 3 and 4. All the eggs were treated on developmental d 1. 3. Corticosterone injections resulted in greater embryonic mortality, earlier termination of foetal development and reduced growth. Moreover, chicks developing in eggs with an elevated concentration of corticosterone displayed reduced developmental stability as evidenced by increased fluctuating asymmetry (FA) in tarsus length. 4. In conclusion, an increased concentration of corticosterone in the egg was detrimental to survival and growth of the chicks. Prenatal stress also generated bilateral asymmetry, and illustrates the potential application of FA as an indicator of environmental stress in poultry.

Lead exposure and biological effects in pied flycatchers (Ficedula hypoleuca) before and after the closure of a lead mine in northern Sweden

Mining activities affect the surrounding environment by increasing exposure to metals. In this study, metal accumulation and its effects on reproduction and health of pied flycatcher (Ficedula hypoleuca) nestlings were monitored before and up to five years after a lead mine and enrichment plant closed down. The lead concentration in moss, nestling blood, liver and feces all indicated decreased lead exposure by at least 31% after closure, although only blood lead decreased significantly. Although the birds responded fairly well to the changed atmospheric deposition (based on moss samples), concentrations were still higher compared with birds in a reference area, and breeding was affected at the mine (smaller clutches and higher mortality). Surviving nestlings suffered from lower hemoglobin levels, mean cell hemoglobin concentrations and inhibited delta-aminolevulinic acid dehydratase activity. Lead poisoning contributed to poor health and adverse reproductive effects, but other factors (e.g. increased parasitic load) probably also affected the birds.

Haematological status of wintering great tits (Parus major) along a metal pollution gradient

In the long-term biomonitoring of wild populations inhabiting polluted areas, the use of non-destructive biomarkers as markers of condition is very important. We examined the possible effects of metal pollution on the haematological status of adult great tits (Parus major) along a well-established pollution gradient near a non-ferrous smelter in Belgium. We measured blood and feather metal concentrations and assessed the haematological status (amount of red blood cells, haemoglobin concentration, haematocrit, mean corpuscular volume and mean corpuscular haemoglobin) of adult great tits during winter at four study sites. Metal concentrations in blood and feathers indicated that cadmium and lead were the most important metals in the pollution gradient under study. Measurements of haematological parameters revealed that haemoglobin concentration, haematocrit, mean corpuscular volume and mean corpuscular haemoglobin were lower in great tits from the more polluted sites. These parameters were significantly negatively correlated with blood lead concentration. The amount of red blood cells, however, did not significantly differ among study sites. Our results indicate that the haematological status of great tits is negatively affected by metal pollution and may therefore be used as a successful biomarker for monitoring the negative impact of metal exposure in the wild.

Fluctuating wing asymmetry and hepatic concentrations of persistent organic pollutants are associated in European shag (Phalacrocorax aristotelis) chicks

In aquatic birds, high body burdens of persistent organic pollutants (POPs) have been associated with developmental effects related to growth, increased fluctuating wing asymmetry, and disruption of the thyroid hormone, vitamin A (retinol) and vitamin E (tocopherol) homeostasis. The aim of the present study was to examine if morphological variables (body mass, liver mass, wing length, tarsus length and head length), fluctuating asymmetry of the wings and tarsus, growth rates and endocrine variables (thyroid hormones, retinol and tocopherol) were associated with hepatic levels of POPs (PCBs, OCPs and PBDEs) in 21 day old chicks of European shag (Phalacrocorax aristotelis). Partial Least Squares (PLS) analysis showed that fluctuating asymmetry of wing bone length (FA(WBL)) was affected by PCB-105, -118, -138, -153, and -180 (r(2)x=0.88, r(2)y=0.35, q(2)=0.29). Bivariate correlation confirmed significant positive relationships between FA(WBL) and each of these PCB congeners. In the PLS model no other biological variables were significantly affected by any of the POPs. Levels of POPs were much lower in the shag chicks than in eggs and in hatchlings from the same breeding colony, most likely due to growth dilution of the compounds. We suggest that the effects of the PCBs on FA(WBL) may be due to effects of these compounds on bone growth and bone structure. FA(WBL) may have functional effects on the fitness if it persists after fledging.