Physiological, morphological and behavioural responses of self-feeding precocial chicks copying with contrasting levels of water salinity during development

Combined physiological and behavioural responses to salt loads during development have rarely been studied in air-breathing vertebrates able to inhabit hypersaline habitats, but they may be of particular importance in understanding, for example, the differences among species in patterns of habitat use or ontogenetic diet switches. Here, we compared the physiological and behavioural responses of self-feeding precocial chicks developed in contrasting levels of water salinity. The model species was the Black-winged Stilt (Himantopus himantopus) a precocial shorebird that breeds in a range of habitats from freshwater to hypersaline wetlands. Specifically, we compared resting metabolic rate (RMR), heat shock proteins (Hsp70), plasma ions, hematocrit, body mass, body size, growth rate and headshaking behaviour of captive-reared Black-winged Stilt fledglings developed under fresh (0 ½), saline (20 ½), and hypersaline (60 ½) water. Contrary to expectations, none of the physiological and morphological variables measured differed significantly among treatments. Likewise, the RMR of wild and captive-reared fledglings was similar. Surprisingly, the saltgland mass of wild fledglings from freshwater and those from hypersaline habitats was also similar. However, head-shaking, a behavioural response associated to minimize salt intake and to expel the secretions of salt glands, differed according to salinity source: head-shaking rate increased with increasing salinity. The results of this study support the key role of behavioural osmoregulation in avoiding salt stress during development.Trabajo financiado por: Fundacão para a Ciência e Tecnologia. Ayuda SFRH / BD / 74228 / 2010 y UID/MAR/04292/2013 para Afonso Duarte dos Reis Rocha Ministerio de Ciencia e Innovación. Ayuda CGL2011-27485 Junta de Extremadura y Fondos FEDER. Ayuda GR15080peerReviewe

Metabolic plasticity for subcutaneous fat accumulation in a long-distance migratory bird traced by 2H2O

La comilona migratoria de cola negra (Limosa limosa) tradicionalmente utilizaba humedales naturales en la Península Ibérica para prepararse para los vuelos migratorios alimentándose principalmente en estuarios. En las últimas décadas, esta especie se ha vuelto cada vez más dependiente de los campos de arroz, confiando así en una dieta basada en plantas para alimentar. Los ácidos grasos en la dieta (FA) parecen ser determinantes para la composición de la grasa subcutánea acumulada en las aves migratorias. Aún no está claro si la plasticidad metabólica permite la modificación y / o síntesis de la FA, lo que contribuye a un perfil lipídico que permite un rendimiento migratorio exitoso. El agua deuterada se administró a las monitas de cola negra cautivas sometidas a dos dietas (larvas de mosca versus arroz) y se analizó la incorporación de deuterio (2H) en los triglicéridos subcutáneos mediante RMN. Un método de biopsia localizada recientemente desarrollado para muestrear grasa subcutánea se empleó con la posterior liberación exitosa de todas las aves en el medio silvestre. La estructura química promedio reflejó principalmente una mezcla de FA saturada y monoinsaturada de 16 y 18 carbonos, un perfil que se encuentra con frecuencia en las aves migratorias. Se observaron niveles significativamente más altos de FA poliinsaturada, así como niveles detectables de FA n-3, en aves alimentadas con larvas de mosca. El exceso de enriquecimiento con 2H en FA reveló tasas significativamente más altas de lipogénesis de novo fraccional y capacidad de desaturación de FA en aves alimentadas con arroz. Este novedoso y no letal método trazador reveló la capacidad de esta especie para alterar su metabolismo lipídico para compensar una contribución de lípidos en la dieta más deficiente. Debido a su versatilidad, la adaptación de este método a otros escenarios y / u otras especies migratorias se considera factible y rentable.The migrant black-tailed godwit (Limosa limosa) traditionally used natural wetlands in the Iberian Peninsula to prepare for migratory flights by feeding mainly in estuaries. In recent decades, this species has become increasingly dependent on rice fields, thereby relying on a plant-based diet for fuelling. Dietary fatty acids (FA) seem to be determinant to the composition of accumulated subcutaneous fat in migratory birds. It is still unclear whether metabolic plasticity allows for modification and/or synthesis of FA, contributing to a lipid profile that enables a successful migratory performance. Deuterated water was administered to captive black-tailed godwits submitted to two diets (fly larvae versus rice) and the incorporation of deuterium (2H) into subcutaneous triglycerides was analyzed by NMR. A recently developed localized biopsy method for sampling subcutaneous fat was employed with later successful release of all birds into the wild. The average chemical structure reflected mostly a mixture of saturated and monounsaturated 16- and 18-carbon FA, a profile frequently found in migrant birds. Significantly higher levels of polyunsaturated FA, as well as detectable levels of n-3 FA, were observed in fly-larvae-fed birds. Excess 2H-enrichments in FA revealed significantly higher rates of fractional de novo lipogenesis and FA desaturation capacity in rice-fed birds. This novel and nonlethal tracer method revealed the capacity of this species to alter its lipid metabolism to compensate for a poorer dietary lipid contribution. Because of its versatility, adapting this method to other scenarios and/or other migratory species is considered feasible and costeffective.• Fundação para a Ciência e Tecnologia. Beca SFRH / BPD / 90032/2012, para Iván Daniel dos Santos Martins Viegas • Fundação para a Ciência e Tecnologia. Beca SFRH / BD / 69238/2010, para Pedro Miguel Mendes Araujo • Fundação para a Ciência e Tecnologia. Beca SFRH / BD / 74228/2010, para Afonso D. Rocha • Fundação para a Ciência e Tecnologia. Beca SFRH / BPD / 91527/2012, para José Albino Alves • Fundação para a Ciência e Tecnologia. Proyecto de investigación EXCL / DTP-PIC / 0069/2012peerReviewe

Host dispersal shapes the population structure of a tick-borne bacterial pathogen

Birds are hosts for several zoonotic pathogens. Because of their high mobility, especially of longdistance migrants, birds can disperse these pathogens, affecting their distribution and phylogeography. We focused on Borrelia burgdorferi sensu lato, which includes the causative agents of Lyme borreliosis, as an example for tick-borne pathogens, to address the role of birds as propagation hosts of zoonotic agents at a large geographical scale. We collected ticks from passerine birds in 11 European countries. B. burgdorferi s.l. prevalence in Ixodes spp. was 37% and increased with latitude. The fieldfare Turdus pilaris and the blackbird T. merula carried ticks with the highest Borrelia prevalence (92 and 58%, respectively), whereas robin Erithacus rubecula ticks were the least infected (3.8%). Borrelia garinii was the most prevalent genospecies (61%), followed by B. valaisiana (24%), B. afzelii (9%), B. turdi (5%) and B. lusitaniae (0.5%). A novel Borrelia genospecies "Candidatus Borrelia aligera" was also detected. Multilocus sequence typing (MLST) analysis of B. garinii isolates together with the global collection of B. garinii genotypes obtained from the Borrelia MLST public database revealed that: (a) there was little overlap among genotypes from different continents, (b) there was no geographical structuring within Europe, and (c) there was no evident association pattern detectable among B. garinii genotypes from ticks feeding on birds, questing ticks or human isolates. These findings strengthen the hypothesis that the population structure and evolutionary biology of tick-borne pathogens are shaped by their host associations and the movement patterns of these hosts.Peer reviewe

As Aves Marinhas como Indicadores Ecológicos

Sumário da Lição, apresentado para Provas de Agregação em Biologia, na especialidade de Ecologia, da Faculdade de Ciências e Tecnologia da Universidade de Coimbr

Biologia da Conservação

Relatório de Unidade Curricular, apresentado para Provas de Agregação em Biologia, na especialidade de Ecologia, da Faculdade de Ciências e Tecnologia da Universidade de Coimbr

Distribution data and modelling outputs for the Desertas Petrel (Pterodroma deserta)

This set contains a zip file with distribution shapefiles (Kernel Usage Density) of the Desertas Petrel (Pterodroma deserta), the variables used for modelling current distribution and project future potential distribution. All spatial files are in GCS WGS84

Experimental infection by microparasites affects the oxidative balance in their avian reservoir host the blackbird Turdus merula

By draining resources, microparasites can negatively affect the host fitness, which in turn can result in reduced transmission when virulence leads to reductions in host population size. Therefore, for a microparasite to persist in nature, the level of harm it can do to its host is expected to be limited. We tested this hypothesis for tick-borne Borrelia burgdorferi sensu lato (s.l.) infections in the blackbird Turdus merula, one of the most important avian reservoir hosts in Europe. Experimental and observational data were combined to examine the physiological effects caused by B. burgdorferi s.l. infection in blackbirds. Pathogen-free blackbirds were exposed to B. burgdorferi s.l.-infected Ixodes ricinus and I. frontalis nymphs, and compared with a control group (exposed to naïve laboratory-derived I. ricinus nymphs). Their physiological status was evaluated before and after infection with B. burgdorferi s.l., through a set of immunological (erythrocyte sedimentation rate, haptoglobin, white blood cell count and heterophil/lymphocyte ratio), oxidative stress (glutathione peroxidase activity, protein carbonyls and nitric oxide) and general body condition variables (body condition, glucose and haematocrit). Infected males showed higher levels of oxidative damage to proteins (increased levels of protein carbonyls), decreased glutathione peroxidase activity and increased body mass. Infected females had higher levels of glutathione peroxidase activity after infection by B. burgdorferi s.l. than the control group. No significant effects of B. burgdorferi s.l. infection were detected on erythrocyte sedimentation rate, haptoglobin, heterophil/lymphocyte ratio, nitric oxide, glucose and haematocrit. The first experimental study on the effects of B. burgdorferi s.l. on its avian reservoir hosts shows that these bacteria may inflict non-negligible physiological costs. We speculate that during energetically demanding periods, these physiological costs may reduce host fitness and affect pathogen transmission.This research was supported by the Fund for Scientific Research – Flanders Belgium (grant G0.049.10) and the University of Antwerp (KP BOF UA 2015). This study received financial support from Fundação para a Ciência e a Tecnologia - FCT, by the strategic program of MARE (MARE – UID/MAR/04292/2013) and the fellowships to Ana Cláudia Norte (SFRH/BPD/108197/2015 and SFRH/BPD/62898/2009). Dieter Heylen and David Costantini were supported by the Fund for Scientific Research – Flanders Belgium (FWO – postdoctoral fellowships).info:eu-repo/semantics/publishedVersio

Getting under the birds’ skin: tissue tropism of Borrelia burgdorferi s.l. in naturally and experimentally infected avian hosts

Wild birds are frequently exposed to the zoonotic tick-borne bacteria Borrelia burgdorferi sensu lato (s.l.), and some bird species act as reservoirs for some Borrelia genospecies. Studying the tropism of Borrelia in the host, how it is sequestered in different organs, and whether it is maintained in circulation and/or in the host's skin is important to understand pathogenicity, infectivity to vector ticks and reservoir competency.We evaluated tissue dissemination of Borrelia in blackbirds (Turdus merula) and great tits (Parus major), naturally and experimentally infected with Borrelia genospecies from enzootic foci. We collected both minimally invasive biological samples (feathers, skin biopsies and blood) and skin, joint, brain and visceral tissues from necropsied birds. Infectiousness of the host was evaluated through xenodiagnoses and infection rates in fed and moulted ticks. Skin biopsies were the most reliable method for assessing avian hosts' Borrelia infectiousness, which was supported by the agreement of infection status results obtained from the analysis of chin and lore skin samples from necropsied birds and of their xenodiagnostic ticks, including a significant correlation between the estimated concentration of Borrelia genome copies in the skin and the Borrelia infection rate in the xenodiagnostic ticks. This confirms a dermatropism of Borrelia garinii, B. valaisiana and B. turdi in its avian hosts. However, time elapsed from exposure to Borrelia and interaction between host species and Borrelia genospecies may affect the reliability of skin biopsies. The blood was not useful to assess infectiousness of birds, even during the period of expected maximum spirochetaemia. From the tissues sampled (foot joint, liver, spleen, heart, kidney, gut and brain), Borrelia was detected only in the gut, which could be related with infection mode, genospecies competition, genospecies-specific seasonality and/or excretion processes.This study received financial support from Fundação para a Ciência e a Tecnologia by the strategic program of MARE (MARE - UID/MAR/04292/2019), the fellowship to Ana Cláudia Norte (SFRH/BPD/108197/2015) and from the Portuguese National Institute of Health Doutor Ricardo Jorge. Dieter Heylen is funded by the Marie Sklodowska-Curie Actions (EU-Horizon 2020, Individual Global Fellowship, project no. 799609), the Fund for Scientific Research – Flanders (FWO) and the Bill & Melinda Gates Foundation.info:eu-repo/semantics/publishedVersio

Padr?es de mal?ria avi?ria em regi?o tropical e temperada : testando a ?hip?tese da libera??o do inimigo?.

According to the enemy release hypothesis (ERH) the spread of invasive species will be facilitated by release from their enemies as they occupy new areas. However, the ERH has rarely been tested by comparing populations of native (non-invasive, long established) species with expanding or shifting ranges, to the same species as invasive in another area. We tested the ERH with respect to blood parasite levels (prevalence and intensity of Plasmodium spp. and Haemoproteus spp.) of (a) two closely related, widely distributed species of thrush (Turdus leucomelas and T. merula), and (b) an invasive sparrow (Passer domesticus) whose range has expanded from the Old World to the New World since the 18th century. A total of 158 birds were sampled in Portugal and 99 in Brazil. All bird species were parasitized, and 55% of the individuals collected were parasitized, and the mean intensity of infection was of 28 parasites per 10,000 erythrocytes. We assessed whether differences in levels of infection (prevalence and intensity) were due to site (tropical/New World and temperate/Old World) or host species. The ERH was supported: Passer domesticus and Turdus merula had higher levels of parasitism in the Old World than in the New World. Thus, P. domesticus seems to be benefitting from its ?recent? range expansion, compared to T. leucomelas, through ecological release from its native parasites and because the parasites of the recently invaded area seem to be infesting native species instead.De acordo com a hip?tese da libera??o do inimigo (HLI), a dissemina??o de esp?cies invasoras ser? facilitada pela libera??o de seus inimigos ao ocuparem novas ?reas. No entanto, a HLI raramente ? testada comparando-se as popula??es de esp?cies nativas (n?o invasivas, estabelecidas h? muito tempo) que apresentam expans?o ou altera??o de habitats, com popula??es das mesmas esp?cies em habitats que foram invadidos. Testamos a HLI com rela??o aos n?veis de parasitas no sangue (preval?ncia e intensidade de Plasmodium spp. e Haemoproteus spp.). De (a) duas esp?cies estreitamente relacionadas e amplamente distribu?das de Turdus (Turdus leucomelas e T. merula), e (b) um pardal invasor (Passer domesticus) cujo alcance se expandiu do Velho Mundo para o Novo Mundo desde o s?culo 18. Um total de 158 aves foram amostradas em Portugal e 99 no Brasil. Todas as esp?cies foram parasitadas e 55% dos indiv?duos foram parasitados, sendo que a intensidade m?dia da infec??o foi de 28 parasitas por 10.000 eritr?citos. Avaliamos se as diferen?as nos n?veis de infec??o (preval?ncia e intensidade) foram devidas ao local (tropical/Novo Mundo e temperado/Velho Mundo) ou esp?cies hospedeiras. A HLI foi corroborada: Passer domesticus e Turdus merula apresentaram valores mais elevados de parasitismo no Velho Mundo do que no Novo Mundo. Assim, P. domesticus parece estar se beneficiando de sua expans?o ?recente? em compara??o com T. leucomelas, atrav?s da libera??o ecol?gica de seus parasitas nativos porque os parasitas da ?rea recentemente invadida parecem infestar esp?cies nativas