Santiago Merino - Academia.edu (original) (raw)

Papers by Santiago Merino

Emu, Sep 1, 2016

Fecha de publicación: JUL 2016 Ver información de revista Resumen Blood parasites exert significa... more Fecha de publicación: JUL 2016 Ver información de revista Resumen Blood parasites exert significant selective pressure, which can alter population dynamics, and the introduction of new parasite lineages in a region could lead to the extinction of endemic avian species that have not coevolved with them. The avifauna of the Pampa del Tamarugal in the desert of Atacama, Chile, is highly depauperate, with two species accounting for the greatest numbers: the widespread Rufous-collared Sparrow (Zonotrichia capensis) and the endemic Tamarugo Conebill (Conirostrum tamarugense). We used molecular and microscopic methods to estimate the prevalence of haemoparasites in birds inhabiting the Pampa del Tamarugal. The molecular screening of the samples from the most common species indicated that the Tamarugo Conebill was only infected by parasites of the genus Leucocytozoon (prevalence 3.5%) and the Rufous-collared Sparrow was uninfected. Only two other bird species (of a total of seven) were infected, the House Sparrow (Passer domesticus), by Plasmodium relictum (prevalence 30%), and the Eared Dove (Zenaida auriculata), by Haemoproteus multipigmentatus (prevalence 100%). The occurrence of House Sparrows infected with the Plasmodium haplotype GRW4 (involved in Hawaiian bird extinctions) may entail the risk of potential host-switching, something particularly relevant for the conservation of the endemic and vulnerable Tamarugo Conebill.

The Auk, Oct 1, 2006

AяѠѡџюѐѡ.-We explored two hypotheses that may explain intraspecifi c variability in nest size. Th... more AяѠѡџюѐѡ.-We explored two hypotheses that may explain intraspecifi c variability in nest size. The "thermoregulatory" hypothesis states that species adjust nest size to maintain egg temperature and minimize temperature fl uctuations in the nest. Recently, the suggestion has been made that nest size may refl ect the health status or phenotypic quality of the builder, potentially making it a sexually selected trait ("sexual selection" hypothesis). For two years, we weighed nests of Blue Tit (Cyanistes caeruleus) at initiation of reproduction in a nest-box breeding population in central Spain. We recorded laying date, clutch size, incubation period, and hatching success. We measured and took blood samples of adult females when nestlings reached three days of age. General regression models controlling for potential variables that could aff ect nest weight revealed that prevalence of Trypanosoma avium and immunoglobulin levels in females were signifi cantly related to nest weight in only one of the study years. Females not infected with Trypanosoma avium built heavier nests than infected ones, whereas female immunoglobulin levels were negatively associated with nest weight. Hatching success and duration of the incubation period were not related to nest weight in either year. Thus, our results do not support the thermoregulatory hypothesis and show that certain measures of female health are related to nest-building eff ort in some years, probably depending on environmental conditions.

Evolution, Jan 30, 2020

This study was funded by projects CGL2012-40026-C02-01 and CGL2012-40026-C02-02 from the MEC (Min... more This study was funded by projects CGL2012-40026-C02-01 and CGL2012-40026-C02-02 from the MEC (Ministerio de Economia y Competitividad). We thank 'El Ventorrillo' field station for allowing the use of their facilities. Work in the field area was done with permission from. on s (irector of 'Montes de Valsain'). EPB was supported by a AE grant from the Spanish National Research Council (CSIC). We thank two anonymous reviewers for providing valuable comments on an earlier version of the manuscript.

Behavioral Ecology and Sociobiology, May 23, 2022

Ontogeny is expected to be a determinant factor affecting production of colour patches in lizards... more Ontogeny is expected to be a determinant factor affecting production of colour patches in lizards, while immune challenges or sudden weight loss may impair the maintenance of pigment-based coloration within a breeding season. We translocated males of the lizard Psammodromus algirus between two sampling plots that differed in distance to a road, vegetation structure, and predator abundance. We analysed variation in spectral reflectance of their colour patches the same and the following year. The change in the reflectance of the lizard colour patches within the first breeding season was explained by the interaction between plot and treatment, but not body condition. The maintenance of the breeding coloration was impaired only in those males translocated close to the road, probably reflecting that it is a poor-quality habitat for P. algirus. The following year, lizards that produced a more elaborate coloration were those that increased their body condition and controlled some parasitic infections, although suffered an increase of others. This study shows that colour patch production is plastic in P. algirus. Lizards increasing parasites or losing weight reduced pigmentation, although habitat quality can cushion these negative effects on pigmentation. However, not all parasites constrain the investment in coloration. In fact, some increased in those lizards that allocated more pigments to colour patches. In conclusion, longitudinal studies following experimental manipulation can contribute to understand pigment allocation rules in lizards. Significance statement Pigments involved in colour patches of animals are limiting resources that can be reallocated off the skin to other functions. However, longitudinal evidence of this phenomenon is scarce in reptiles. We designed a manipulative mark-recapture experiment to investigate effects of habitat and parasitic infections on colour patch maintenance (within-year variation) and production (between-year variation) in male free-ranging lizards that were reciprocally translocated between two patches of habitat that differed in quality. During the first year, lizards translocated to the habitat with more predators and worse vegetation impoverished their coloration, while lizards translocated to the more favourable habitat maintained it despite all translocated lizards loose body condition. The next year we detected different effects on the coloration of three different parasites investigated, suggesting that coloration can reflect the virulence of the infections.

Behavioral Ecology and Sociobiology, Mar 1, 2017

Take-down policy If you believe that this document breaches copyright please contact us providing... more Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

The Auk, 2003

Effects of bacteria on avian hosts in the wild have received little attention until recently. Whe... more Effects of bacteria on avian hosts in the wild have received little attention until recently. Whereas the pathogenic effects of bacteria are well known, positive effects of symbiotic bacteria are more rarely considered. Nestling growth has important repercussions for offspring fi tness in avian populations and may be affected by microbial colonization of the gut. Enterococcus faecalis is a common opportunistic pathogen, whereas E. faecium has been used as a growth promoter because it interacts competitively with pathogenic bacteria, E. faecalis included. We followed the growth in tarsus length and mass of 18 Pied Flycatcher (Ficedula hypoleuca) broods. Chicks were weighed and measured on days 4, 8, 10, and 13 after hatching. On day 13, wing length was also measured and cloacal swabs were taken of two chicks in each brood for detection of enterococci. In all, the methods used allowed us to detect six species of bacteria among a possibly much richer community. Most chicks had E. faecalis, whereas E. faecium was less prevalent. There was a negative association between scores for E. faecalis and for the rest of the species pooled. The presence of E. faecalis showed no detectable association with nestling mass or size at any age, whereas the presence of the other species showed signifi cantly positive associations with mass and size on day 13, but not before. Presence of E. faecium on its own was positively associated with nestling mass and size shortly before fl edging. E. faecium may act as a growth promoter in the wild through its competitive interactions with facultative pathogenic bacteria. The presence of some microbes are critically important in avian growth and development.

Behavioral Ecology and Sociobiology, Sep 2, 2016

Host species in populations under strong pressures from parasitic diseases may evolve ornaments t... more Host species in populations under strong pressures from parasitic diseases may evolve ornaments to signal individual host quality to conspecifics. Colour ornaments in lizards result from the interaction of different layers in the skin. When inner layers of melanin and well-arranged iridophores are combined, UV-blue structural colouration results. On the other hand, when layers of erythrophores are densely loaded with carotenoids, a UV-yellow colouration is seen. The expression of carotenoid-based traits has been frequently studied in relation to parasite infections. However, few studies have explored the relationship between parasitic diseases and structural colouration. In this study, we investigated the expression of UV-blue and UV-yellow throat colour patches in males of Lacerta schreiberi in relation to infection by haemoparasites, ixodid ticks and intestinal nematodes. The brightness of the UV-yellow throat patch (a carotenoid-based ornament) was positively correlated with body condition and negatively correlated with the number of attached ticks, supporting Hamilton and Zuk's hypothesis. Additionally, individuals that passed nematode eggs in the faeces had UV-yellow throat patches with higher hue values (more greenish colouration). Strikingly, the individuals infected by haemoparasites of the genus Schellackia showed UV-blue throat patches (a melaninbased ornament) with higher values of both UV-blue chroma and hue (i.e., UV-biased throats) than did uninfected individuals, suggesting a key role for melanin in the nuptial colouration of this lizard species. Thus, the combined information from both UV-blue and UV-yellow throat patches may convey integrative information about individual quality in this lacertid species. Significance statement In this study, we present evidence that the striking throat colouration in males of the endemic Iberian green lizard is related to the presence or load of different parasites. The ornament is composed of one UV-yellow patch and one UVblue patch, which were differentially related to the presence of different parasitic diseases in the individual hosts. These results suggest that different parasitic diseases may differentially constrain the expression of these colour patches. Moreover, the combined display of the two throat patches simultaneously may convey to conspecifics integrative information about the individual quality of the Iberian green lizard.

Ardeola, Sep 1, 2016

In wild bird populations nestlings are commonly infested by ectoparasites. The effects that ectop... more In wild bird populations nestlings are commonly infested by ectoparasites. The effects that ectoparasites exert on host fitness usually become evident after the complete elimination of parasites or a substantial reduction in their abundance. Among the most common elimination methods in ecological studies, the use of chemical insecticides is traditionally preferred. However, the application of several doses is usually needed because the efficiency of insecticides decreases over time. This results in increasing toxicity effects and disturbance of both parents and nestlings. In the present study, we tested the efficacy of Inesfly, a new insecticidal paint. Inesfly acts by releasing active water-soluble compounds progressively over a period, therefore having a longer-lasting effect than other insecticides. By applying this insecticidal paint inside nest-boxes used by blue tits Cyanistes caeruleus during the breeding season, we investigated its effect on the abundance of blackfly (Simuliidae), biting midge (Culicidae), flea (Ceratophyllidae), mite (Dermanyssidae) and blowfly (Calliphoridae) larvae. The insecticide significantly reduced the abundance of Protocalliphora azurea blowflies, while other parasites remained unaffected. Our results show that Inesfly was ineffective against ectoparasites infesting blue tit nest-boxes, blowflies excepted, at least at the dose applied. Finally, no negative effects on nestlings were reported following the use of this insecticide.

§ We iden'fied one specie of Leucocytozoon in adults and juveniles at the beginning of the rehab... more § We iden'fied one specie of Leucocytozoon in adults and juveniles at the beginning of the rehabilita'on s'nt. The prevalence of infec'on varied between birds species. § Our preliminary results show that infec'on levels by these blood parasites decrease during the period spent in the rehabilita'on centre.

Biological Journal of The Linnean Society, Jun 27, 2021

Several studies of lizards have made an erroneous interpretation of negative relationships betwee... more Several studies of lizards have made an erroneous interpretation of negative relationships between spectral brightness and parasite load, and thus provided misleading support for the Hamilton-Zuk hypothesis (HZH). The HZH predicts that infected hosts will produce poorer sexual ornamentation than uninfected individuals as a result of energetic trade-offs between immune and signalling functions. To test whether there is a negative relationship between spectral brightness and pigment content in the skin of lizards, we used spectrophotometry to quantify the changes in spectral brightness of colour patches of two species after chemically manipulating the contents of orange, yellow and black pigments in skin samples. Carotenoids were identified using highperformance liquid chromatography. In addition, we compared the spectral brightness in the colour patches of live individuals with differential expression of nuptial coloration. Overall, the analyses demonstrated that the more pigmented the colour patch, the darker the spectrum. We provide a comprehensive interpretation of how variation in pigment content affects the spectral brightness of the colour patches of lizards. Furthermore, we review 18 studies of lizards presenting 24 intraspecific tests of the HZH and show that 14 (58%) of the tests do not support the hypothesis.

Authorea (Authorea), Feb 17, 2023

Studies exploring the effect of microclimatic changes on host-parasite relationships are scarce, ... more Studies exploring the effect of microclimatic changes on host-parasite relationships are scarce, however, many models predict changes in the distribution and incidence of diseases associated with climate change. In this study, we increased both temperature and relative humidity in blue tit nest-boxes during the breeding season, trying to discern between the effect of both variables on the abundance of ectoparasites reported in previous studies and, also, on the body condition of the nestlings and adults. Temperature and relative humidity were experimentally increased an average of about 2ºC and 15 units respectively. The abundance of blowfly Protocalliphora azurea pupae was significantly reduced in nests with increased temperature as compared to control nests and nests with increased relative humidity, and was also significantly reduced in nests with increased relative humidity as compared to control nests. The abundance of Dermanyssus spp. mites and Ceratophyllus gallinae flea larvae was significantly reduced in nests with increased relative humidity. However, there was no significant effect of the experiment on flying insect vectors abundance (Blackflies and biting midges.). On the other hand, body condition and mass of nestlings were lower in nests with increased relative humidity and nestlings' mass was also lower in heated nests. However, the body condition and mass of the adults was not significantly affected by the experiment. In addition, blowfly Protocalliphora azurea pupae and biting midges Culicoides spp. had a significant negative effect on body condition and mass of nestlings and adults. In conclusion, an increase in temperature, on the one hand, and relative humidity, on the other, reduces the abundance of ectoparasites, which suggests that these parasites are sensitive to sudden changes in the microclimate in which they develop. In addition, these fluctuations negatively affect the body condition and mass of blue tit nestlings despite the concurrent decrease of parasites in nests.

There are two major interpretations of serum IgY concentration in wild birds. On the one hand, it... more There are two major interpretations of serum IgY concentration in wild birds. On the one hand, it has been considered an indication of susceptibility to stress and parasite infection. Therefore, immunoglobulin concentration is expected to change in response to variation in these factors owing to reproductive activities. On the other hand, it has been considered a measure of immune capacity. We measured the IgY level and the lymphocyte proportion at the beginning of incubation and at the end of the nestling period in female pied flycatchers, Ficedula hypoleuca (Pallas, 1764). We assessed the immune response to phytohaemagglutinin (PHA) at the latter stage. We found that the total IgY level remained constant throughout the season. Initially, it was positively associated with the PHA response, lymphocyte proportion, intensity of infection by Haemoproteus spp., and concentration of stress protein HSP70 in peripheral blood. These variables explained nearly 80% of the variation in IgY concentration. In the final phase, only the PHA response was correlated with the IgY level. We discuss the hypothetical mechanisms underlying these associations and the need to control for parasite infection and physiological stress in ecological studies including measurements of immunoglobulin concentration. Résumé : Il y a deux façons principales d'interpréter la concentration d'IgY dans le sérum des oiseaux sauvages. D'abord, elle peut être considérée comme un indice de la susceptibilité au stress at à l'infection par les parasites. Ainsi, la concentration d'immunoglobuline doit changer, croit-on, en réaction à ces facteurs au cours des activités de reproduction. En second lieu, on a suggéré qu'elle pouvait être une mesure de la capacité immunitaire. Nous avons mesuré les concentrations d'IgY, ainsi que les proportions des lymphocytes, chez des gobe-mouches noirs, Ficedula hypoleuca (Pallas, 1764) femelles au début de l'incubation et à la fin de la nidification. À cette dernière période, nous avons évalué leur réaction immunitaire à la phytohémagglutinine (PHA). Les concentrations d'IgY restent constantes au cours de la saison. Dans la phase initiale, elles sont en corrélation positive avec la réaction à la PHA, les proportions de lymphocytes, l'intensité de l'infection à Haemoproteus spp. et à la concentration de la protéine du stress HSP70 dans le sang périphérique. Ces variables expliquent 80 % des variations de concentration d'IgY. Dans la phase finale, seule la réaction à la PHA est en corrélation avec la concentration d'IgY. Nous discutons des mécanismes présumés qui expliquent ces associations, ainsi que de l'importance de tenir compte des infections parasitaires et du stress physiologique dans les études écologiques, en particulier des dosages des concentrations d'immunoglobuline. [Traduit par la Rédaction] Morales et al. 1492

The Auk, Jul 1, 2003

Pollutants and toxic contaminants produced in all parts of the world are transported to remote re... more Pollutants and toxic contaminants produced in all parts of the world are transported to remote regions including Antarctica. Tourism, research and fishing activities on this continent are another source of contamination. Toxic substances affect Antarctic species and some produced genomic damage to the fauna. The genetic damage can be detected by microscopic observation of erythrocytic nuclear abnormalities (ENAs). We counted the number of ENAs in seven populations of three Pygoscelid penguin species, Adélie (Pygoscelis adeliae), Chinstrap (Pygoscelis antarctica) and Gentoo (Pygoscelis papua) and found important differences among species exposed to the same conditions. ENAs were more frequent in Adélie penguins than in the other two species. Inter-population comparisons within species showed remarkable differences in Adélie and Chinstrap penguins but not in Gentoo penguin. Frequency of ENAs in Adélie penguins was the highest in Yalour Island population, intermediate in King George Island population, and the lowest in Torgersen Island and Avian Island populations. In Chinstrap penguins, the highest number of ENAs was found on Deception Island and significant differences were found only between Deception Island and King George Island populations. This information will provide baseline data to be used for assessing the evolution of genomic damage of penguins along the Antarctic Peninsula in the future.

Journal of Avian Biology, 2016

Major histocompatibility complex (MHC) genes are central for the adaptive immune response against... more Major histocompatibility complex (MHC) genes are central for the adaptive immune response against parasites. Here, we investigated potential associations among MHC-I alleles and blood parasite infections in a natural breeding population of a passerine bird, the blue tit Cyanistes caeruleus, in central Spain. We screened both infection status (presence/absence of infection) and infection intensity to the pathogenic blood parasites Haemoproteus and Leucocytozoon. Three MHC-I alleles (UA104, UA108 and UA117) were associated with higher or lower infection intensities by Leucocytozoon. Interestingly, these associations were dependent on age and were found both among young and adult birds. No MHC alleles were associated with infection intensity by Haemoproteus parasites. In addition, no significant relationships were detected between infection status by Haemoproteus and Leucocytozoon infections and MHC alleles. The very high prevalence of these two parasites in our study population (79-100%) poses challenges to identify associations with infection status and also suggests that clearance of infections may be rare. In conclusion, associations between specific MHC-I alleles and Leucocytozoon parasites were related to either high or low infection intensities, and hence increased susceptibility or resistance to infection. (Less)

Organisms Diversity & Evolution, 2015

In this study, several species of Isospora infecting lizards were genetically characterized. Spec... more In this study, several species of Isospora infecting lizards were genetically characterized. Specifically, five described and four newly described species of Isospora were included in a phylogeny of the family Eimeriidae. These species were isolated from hosts originally inhabiting all geographic continents except Europe. Phylogenetic analyses of the 18S ribosomal RNA (rRNA) gene grouped these nine species of Isospora with Lankesterella species and Caryospora ernsti. Therefore, within this clade, different evolutionary strategies in oocyst development and transmission occurred. Although the characteristic endogenous oocyst development of the genus Lankesterella may have arisen only once, the reduction in the number of sporocysts observed in the genus Caryospora occurred at least twice during coccidian evolution, as evidenced by the phylogenetic position of Caryospora bigenetica as the sister taxon of the group formed by reptilian Isospora, Lankesterella, and C. ernsti. Within this group, C. ernsti was the sister taxon to the genus Lankesterella. Overall, our results contradict the proposed monophyly of the genus Caryospora, highlighting the need for a thorough taxonomic and systematic revision of the group. Furthermore, they suggest that the recent ancestor of the genus Lankesterella may have been heteroxenous.

turno cierépl ¡ca Ejemplar de malvasía ca• beciblanca. Es una espe• cie amenazada que sirv para i... more turno cierépl ¡ca Ejemplar de malvasía ca• beciblanca. Es una espe• cie amenazada que sirv para ilustrar el debate de (as reintroducciones de fauna, ante casos como el de la suelta en Doñana, a finales de los añosse tenta, de pollos de esta anátida amenazada pro cedentes de PakistiÍn (fo• to: Gabriel Sierra ISEO BirdLifel• Bibliografía (1) A1maraz, P. yAma!, A. J. (2004). Multi-annual spatial and numeric dynamics 01 the whitehroded duck Oxyuro leucoceplJola in soulhem Eumpe: asonaUty, density dependence and climatic variability. Jovmal alAnimal Ecalogy, 73: 1.013 1.023. (2) Muñoz-fuentes, V. y otros iIlItores (2005). Pllpulation structure and \oss al genetic iversity in tf1e endangered",Me headed duck, O;ryura lelJcocephata. COllservatioo Gell€tic~ 6:999-1.015 (3) Champagnon, J. Yotros autoI'e$ (20U). low penme~tal de Zonas Ári das;, José Ramón Obeso (Universidad de Ov,edoi ¡. Alberto Velando (UJ1JVersi dad de VigO), además de Eduardo de Juana ~preSl den:e ce SEO/B rdUre) y Asunción Ruiz (dlrceo'a ejec~t va oe SEO/BirdLirei. MaSI~lormac;ón, el' w\'Iw.seo.orf,/conocerosl grupos-de-¡'abajoi COtl'1 p-cinn: ficoi Quercus326-AbrillOI3' 81

Journal of Parasitology, Jun 1, 2014

International Journal for Parasitology