INFLUENCIA DE VARIABLES CLIMATICAS SOBRE LA INCIDENCIA DE ENFERMEDADES PARASITARIAS
CGL2015-67789-C2-1-P
•
Nombre agencia financiadora Ministerio de Economía y Competitividad
Acrónimo agencia financiadora MINECO
Programa Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia
Subprograma Subprograma Estatal de Generación del Conocimiento
Convocatoria Proyectos de I+D dentro del Subprograma Estatal de Generación del Conocimiento (2015)
Año convocatoria 2015
Unidad de gestión Dirección General de Investigación Científica y Técnica
Centro beneficiario AGENCIA ESTATAL CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS (CSIC)
Centro realización MUSEO NACIONAL DE CIENCIAS NATURALES (MNCN)
Identificador persistente http://dx.doi.org/10.13039/501100003329
Publicaciones
Found(s) 19 result(s)
Found(s) 1 page(s)
Found(s) 1 page(s)
Can the intake of antiparasitic secondary metabolites explain the low prevalence of hemoparasites among wild Psittaciformes?
e_Buah Biblioteca Digital Universidad de Alcalá
- Masello, J. F.
- Martínez González, Francisco Javier
- Calderón, Luciano
- Wink, M.
- Quillfeldt, Petra
- Sanz, V.
- Theuerkauf, J.
- Ortiz Catedral, L.
- Berkunsky, I.
- Brunton, D.
- Díaz Luque, J.A.
- Hauber, M.E.
- Ojeda, V.
- Barnaud, A.
- Casalins, L.
- Jackson, B.
- Mijares, A.
- Rosales, R.
- Seixas, G.
- Serafini, P.
- Silva Iturriza, A.
- Sipinski, E.
- Vásquez, R.A.
- Widmann, P.
- Merino, Santiago
Background: Parasites can exert selection pressure on their hosts through effects on survival, on reproductive success, on sexually selected ornament, with important ecological and evolutionary consequences, such as changes in population viability. Consequently, hemoparasites have become the focus of recent avian studies. Infection varies significantly among taxa. Various factors might explain the differences in infection among taxa, including habitat, climate, host density, the presence of vectors, life history and immune defence. Feeding behaviour can also be relevant both through increased exposure to vectors and consumption of secondary metabolites with preventative or therapeutic effects that can reduce parasite load. However, the latter has been little investigated. Psittaciformes (parrots and cockatoos) are a good model to investigate these topics, as they are known to use biological control against ectoparasites and to feed on toxic food. We investigated the presence of avian malaria parasites (Plasmodium), intracellular haemosporidians (Haemoproteus, Leucocytozoon), unicellular flagellate protozoans (Trypanosoma) and microfilariae in 19 Psittaciformes species from a range of habitats in the Indo-Malayan, Australasian and Neotropical regions. We gathered additional data on hemoparasites in wild Psittaciformes from the literature. We considered factors that may control the presence of hemoparasites in the Psittaciformes, compiling information on diet, habitat, and climate. Furthermore, we investigated the role of diet in providing antiparasitic secondary metabolites that could be used as self-medication to reduce parasite load. Results: We found hemoparasites in only two of 19 species sampled. Among them, all species that consume at least one food item known for its secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, were free from hemoparasites. In contrast, the infected parrots do not consume food items with antimalarial or even general antiparasitic properties. We found that the two infected species in this study consumed omnivorous diets. When we combined our data with data from studies previously investigating blood parasites in wild parrots, the positive relationship between omnivorous diets and hemoparasite infestation was confirmed. Individuals from open habitats were less infected than those from forests., European Commission, Ministerio de Economía, Comercio y Empresa
Experimental manipulation of temperature reduce ectoparasites in nests of blue tits (Cyanistes caeruleus)
e_Buah Biblioteca Digital Universidad de Alcalá
- Castaño Vázquez, Francisco
- Martínez González, Francisco Javier
- Lozano, Marco
- Merino, Santiago
Several models predict changes in the distributions and incidences of diseases associated with climate change. However, studies that investigate how microclimatic changes may affect host?parasite relationships are scarce. Here, we experimentally increased the temperature in blue tit Cyanistes caeruleus nest boxes during their breeding season to determine its effects on the parasitic abundance (i.e. of nestdwelling ectoparasites, blood-sucking flying insects and hemoparasites) in nests and the host condition of nestlings and adults. The temperature was increased using heat mats placed underneath the nest material, which resulted in an average temperature increase of 3ºC and a reduction in relative humidity of about six units. The abundance of mites Dermanyssus gallinoides and blowfly pupae Protocalliphora azurea was significantly reduced in heated nest boxes. Although not statistically significant, a lower prevalence of flea larvae Ceratophyllus gallinae was also found in heated nests. However, heat treatment did not affect hemoparasite infection of adult blue tits or the body condition of adult and nestling blue tits. In conclusion, heat treatment in blue tit nests reduced nest-dwelling ectoparasites yet without any apparent benefit for the host., Ministerio de Economía, Comercio y Empresa
Brighter is darker: the Hamilton–Zuk hypothesis revisited in lizards
e_Buah Biblioteca Digital Universidad de Alcalá
- Megía Palma, Rodrigo Manuel
- Barrientos Yuste, Rafael
- Gallardo, Manuela
- Martínez González, Francisco Javier
- Merino, Santiago
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., Ministerio de Economía, Industria y Competitividad
Multiple color patches and parasites in Sceloporus occidentalis: Differential relationships by sex and infection
e_Buah Biblioteca Digital Universidad de Alcalá
- Megía Palma, Rodrigo Manuel
- Paranjpe, D
- Reguera, Senda
- Martínez González, Francisco Javier
- Cooper, R
- Blaimont, P
- Merino, Santiago
- Sinervo, B.R
Parasites generally have a negative influence on the color expression of their hosts. Sexual selection theory predicts resistant high-quality individuals should show intense coloration, whereas susceptible low-quality individuals would show poor coloration. However, intensely colored males of different species of Old and New World lizards were more often infected by hemoparasites. These results suggest that high-quality males, with intense coloration, would suffer higher susceptibility to hemoparasites. This hypothesis remains poorly understood and contradicts general theories on sexual selection. We surveyed a population of Sceloporus occidentalis for parasites and found infections by the parasite genera Lankesterella and Acroeimeria. In this population, both males and females express ventral blue and yellow color patches. Lankesterella was almost exclusively infecting males. The body size of the males significantly predicted the coloration of both blue and yellow patches. Larger males showed darker (lower lightness) blue ventral patches and more saturated yellow patches that were also orange-skewed. Moreover, these males were more often infected by Lankesterella than smaller males. The intestinal parasite Acroeimeria infected both males and females. The infection by intestinal parasites of the genus Acroeimeria was the best predictor for the chroma in the blue patch of the males and for hue in the yellow patch of the females. Those males infected by Acroeimeria expressed blue patches with significantly lower chroma than the uninfected males. However, the hue of the yellow patch was not significantly different between infected and uninfected females. These results suggest a different effect of Lankesterella and Acroeimeria on the lizards. On the one hand, the intense coloration of male lizards infected by Lankesterella suggested high-quality male lizards may tolerate it. On the other hand, the low chroma of the blue coloration of the infected males suggested that this coloration could honestly express the infection by Acroeimeria., Ministerio de Economía, Comercio y Empresa
Manipulation of parasite load induces significant changes in the structural-based throat color of male Iberian green lizards
e_Buah Biblioteca Digital Universidad de Alcalá
- Megía Palma, Rodrigo Manuel
- Martínez González, Francisco Javier
- Merino, Santiago
The honesty of structural-based ornaments is controversial. Sexual selection theory predicts that the honesty of a sexual signal relies on its cost of production or maintenance. Therefore, environmental factors with negative impact on individuals could generate high costs and affect the expression of these sexual signals. In this sense, parasites are a main cost for their hosts. To probe the effect of parasites on the structural-based coloration of a lacertid species Lacerta schreiberi, we have experimentally removed ticks from a group of male Iberian green lizards using an acaricide treatment (i.e., the broad-use insecticide fipronil). All individuals were radio-tracked and recaptured after 15 days to study changes in coloration in both the ultraviolet (UV)-blue (structural-based) and UV-yellow (structural and pigment-based) ornamentations after manipulation, as well as changes in endo- and ectoparasitic load and body condition. Additionally, after the experiment, we measured the skin inflammatory response to a mitogen. The fipronil treatment was effective in reducing ticks and it was associated with a significant reduction of hemoparasite load. Throughout the season, individuals treated with fipronil tended to maintain the brightness of the UV-blue throat coloration while control lizards tended to increase it. However, individuals treated with fipronil that were not infected with hemoparasites significantly reduced the brightness of the UV-blue throat coloration. Individuals with a higher initial tick load exhibited a lower UV saturation increment (UV-blue) and a higher brightness increment (UV-yellow) during the experiment. Overall these results experimentally support the idea that parasites adversely influence the expression of the structural-based coloration of male Iberian green lizards. This adds evidence to the hypothesis that sexual ornaments in lizards function as honest signals., Ministerio de Economía, Comercio y Empresa, Ministerio de Economía, Comercio y Empresa
Can the intake of antiparasitic secondary metabolites explain the low prevalence of hemoparasites among wild Psittaciformes?
Digital.CSIC. Repositorio Institucional del CSIC
- Masello, Juan F.
- Martínez, Javier
- Calderón, Luciano
- Wink, Michael
- Quillfeldt, Petra
- Sanz, Virginia
- Theuerkauf, Jörn
- Ortiz-Catedral, Luis
- Berkunsky, Igor
- Brunton, Dianne
- Díaz-Luque, José A.
- Hauber, Mark E.
- Ojeda, Valeria
- Barnaud, Antoine
- Casalins, Laura
- Jackson, Bethany
- Mijares, Alfredo
- Rosales, Romel
- Seixas, Gláucia
- Serafini, Patricia
- Silva-Iturriza, Adriana
- Sipinski, Elenise
- Vásquez, Rodrigo A.
- Widmann, Peter
- Widmann, Indira
- Merino, Santiago
[Background] Parasites can exert selection pressure on their hosts through effects on survival, on reproductive success, on sexually selected ornament, with important ecological and evolutionary consequences, such as changes in population viability. Consequently, hemoparasites have become the focus of recent avian studies. Infection varies significantly among taxa. Various factors might explain the differences in infection among taxa, including habitat, climate, host density, the presence of vectors, life history and immune defence. Feeding behaviour can also be relevant both through increased exposure to vectors and consumption of secondary metabolites with preventative or therapeutic effects that can reduce parasite load. However, the latter has been little investigated. Psittaciformes (parrots and cockatoos) are a good model to investigate these topics, as they are known to use biological control against ectoparasites and to feed on toxic food. We investigated the presence of avian malaria parasites (Plasmodium), intracellular haemosporidians (Haemoproteus, Leucocytozoon), unicellular flagellate protozoans (Trypanosoma) and microfilariae in 19 Psittaciformes species from a range of habitats in the Indo-Malayan, Australasian and Neotropical regions. We gathered additional data on hemoparasites in wild Psittaciformes from the literature. We considered factors that may control the presence of hemoparasites in the Psittaciformes, compiling information on diet, habitat, and climate. Furthermore, we investigated the role of diet in providing antiparasitic secondary metabolites that could be used as self-medication to reduce parasite load., [Results] We found hemoparasites in only two of 19 species sampled. Among them, all species that consume at least one food item known for its secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, were free from hemoparasites. In contrast, the infected parrots do not consume food items with antimalarial or even general antiparasitic properties. We found that the two infected species in this study consumed omnivorous diets. When we combined our data with data from studies previously investigating blood parasites in wild parrots, the positive relationship between omnivorous diets and hemoparasite infestation was confirmed. Individuals from open habitats were less infected than those from forests., [Conclusions] The consumption of food items known for their secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, as well as the higher proportion of infected species among omnivorous parrots, could explain the low prevalence of hemoparasites reported in many vertebrates., Laboratory work was supported by the SYNTHESYS Project (ES-TAF 4110 and ES-TAF 4542; http://www.synthesys.info/), financed by the European Community Research Infrastructure Action under the FP7 “Capacities” Programme at the Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain. The extensive fieldwork was carried out with financial support from different organizations. For population number see Table 1. Organizations and grant numbers (if available): 1 (Katala Foundation); 2, 3, 4, 5, 10 and 11 (Loro Parque Fundación (Spain), Polish Ministry of Science and Higher Education (Grant 2P04F 001 29), Conservation des Espèces et Populations Animales (France), La Fondation Nature et Découvertes (France), Fonds für bedrohte Papageien - Zoologische Gesellschaft für Arten und Populationsschutz (Germany); 6, 7, 8 and 9 (New Zealand Department of Conservation, Institute of Natural Sciences (Massey University), Motuihe Island Trust, Landcare Research and National Council of Science from Mexico (CONACYT)); 12, 13 and 14 (World Parrot Trust); 15, 24 and 25 (PIP 112-20150100598 CONICET, PICT 2015-2281 ANPCyT, Argentina, and World Parrot Trust); 16 (Projects 657 and 1365, Instituto Venezolano de Investigaciones Científicas, Venezuela); 17 and 25 (Fundação Neotropica do Brasil, Brazil); 18 and 19 (the City Council of Viedma Río Negro, Argentina, World Parrot Trust, and PQ was supported by the Deutsche Forschungsgemeinschaft (DFG) (Qu 148/1 ff.)); 20 (FONDECYT 1140548, ICM-P05-002, and PFB-23-CONICYT, Chile, to RAV, and Ministerio de Economía y Competitividad and European Regional Development Fund (MINECO/FEDER) CGL2015-67789-C2-1-P / BOS to SM); 21 (PICT 2012-2926 ANPCyT); 22 and 23 (Sociedade de Pesquisa em Vida Selvagem e Educação Ambiental and CEMAVE, Brazil).
Experimental manipulation of temperature reduce ectoparasites in nests of blue tits [Dataset]
Digital.CSIC. Repositorio Institucional del CSIC
- Castaño-Vázquez, Francisco
- Martínez, Javier
- Merino, Santiago
- Lozano, Marco
Several models predict changes in the distributions and incidences of diseases associated with climate change. However, studies that investigate how microclimatic changes may affect host–parasite relationships are scarce. Here, we experimentally increased the temperature in blue tit Cyanistes caeruleus nest boxes during their breeding season to determine its effects on the parasitic abundance (i.e. of nest-dwelling ectoparasites, blood-sucking flying insects and hemoparasites) in nests and the host condition of nestlings and adults. The temperature was increased using heat mats placed underneath the nest material, which resulted in an average temperature increase of 3ºC and a reduction in relative humidity of about six units. The abun¬dance of mites Dermanyssus gallinoides and blowfly pupae Protocalliphora azurea was significantly reduced in heated nest boxes. Although not statistically significant, a lower prevalence of flea larvae Ceratophyllus gallinae was also found in heated nests. However, heat treatment did not affect hemoparasite infection of adult blue tits or the body condition of adult and nestling blue tits. In conclusion, heat treatment in blue tit nests reduced nest-dwelling ectoparasites yet without any apparent benefit for the host., Sponsorship: CGL2015-67789- C2-1-P (MINECO/FEDER)., Peer reviewed
Opposed elevational variation in prevalence and intensity of endoparasites and their vectors in a lizard
Digital.CSIC. Repositorio Institucional del CSIC
- Álvarez-Ruiz, Lola
- Megía-Palma, Rodrigo M.
- Reguera, Senda
- Ruiz, Santiago
- Zamora-Camacho, Francisco J.
- Figuerola, Jordi
- Moreno-Rueda, Gregorio
Studying the causes of parasite geographic distribution is relevant to understand ecological and
evolutionary processes that affect host populations as well as for species conservation.
Temperature is one of the most important environmental variables affecting parasite distribution,
as raising temperatures positively affect development, reproduction, and rate of transmission of
both endo- and ectoparasites. In this context, it is generally accepted that, in mountains, parasite
abundance decreases with elevation. However, empirical evidence on this topic is limited. In the
present study, we analyzed the elevational variation of hemoparasites and ectoparasites of a lizard,
Psammodromus algirus, along a 2,200-m elevational gradient in Sierra Nevada (SE Spain). As predicted,
ectoparasite (mites, ticks, mosquitoes, and sandflies) abundance decreased with elevation.
However, hemoparasite prevalence and intensity in the lizard augmented with altitude, showing a
pattern contrary to their vectors (mites). We suggest that tolerance to hemoparasites may increase
with elevation as a consequence of lizards at high altitudes taking advantage of increased body
condition and food availability, and reduced oxidative stress. Moreover, lizards could have been selected
for higher resistance against hemoparasites at lowlands (where higher rates of replication
are expected), thus reducing hemoparasite prevalence and load. Our findings imply that, in a scenario
of climate warming, populations of lizards at high elevation may face increased abundance of
ectoparasites, accompanied with strong negative effects., This work was funded by the European Union the Spanish government (Ministerio de Ciencia e Innovación and Ministerio de Economía y Ciencia (FEDER-MINECO), projects CGL2009-13185, CGL2014-55969-P, CGL2015-65055-P, and CGL2015-67789. F.J.Z.-C (AP2009-3505) and S.R. (AP2009-1325) were supported by two predoctoral grants from the Ministerio de Ciencia e Innovación (FPU program). F.J.Z.-C was partially supported by a Ramón Areces Foundation postdoctoral fellowship and by a Juan de la Cierva contract., Peer reviewed
evolutionary processes that affect host populations as well as for species conservation.
Temperature is one of the most important environmental variables affecting parasite distribution,
as raising temperatures positively affect development, reproduction, and rate of transmission of
both endo- and ectoparasites. In this context, it is generally accepted that, in mountains, parasite
abundance decreases with elevation. However, empirical evidence on this topic is limited. In the
present study, we analyzed the elevational variation of hemoparasites and ectoparasites of a lizard,
Psammodromus algirus, along a 2,200-m elevational gradient in Sierra Nevada (SE Spain). As predicted,
ectoparasite (mites, ticks, mosquitoes, and sandflies) abundance decreased with elevation.
However, hemoparasite prevalence and intensity in the lizard augmented with altitude, showing a
pattern contrary to their vectors (mites). We suggest that tolerance to hemoparasites may increase
with elevation as a consequence of lizards at high altitudes taking advantage of increased body
condition and food availability, and reduced oxidative stress. Moreover, lizards could have been selected
for higher resistance against hemoparasites at lowlands (where higher rates of replication
are expected), thus reducing hemoparasite prevalence and load. Our findings imply that, in a scenario
of climate warming, populations of lizards at high elevation may face increased abundance of
ectoparasites, accompanied with strong negative effects., This work was funded by the European Union the Spanish government (Ministerio de Ciencia e Innovación and Ministerio de Economía y Ciencia (FEDER-MINECO), projects CGL2009-13185, CGL2014-55969-P, CGL2015-65055-P, and CGL2015-67789. F.J.Z.-C (AP2009-3505) and S.R. (AP2009-1325) were supported by two predoctoral grants from the Ministerio de Ciencia e Innovación (FPU program). F.J.Z.-C was partially supported by a Ramón Areces Foundation postdoctoral fellowship and by a Juan de la Cierva contract., Peer reviewed
Molecular evidence for host–parasite co-speciation between lizards and Schellackia parasites
Digital.CSIC. Repositorio Institucional del CSIC
- Megía-Palma, Rodrigo M.
- Martínez, Javier
- Cuervo, José Javier
- Belliure, Josabel
- Jiménez-Robles, Octavio
- Gomes, Verónica
- Cabido Quintas, Carlos
- Pausas, J. G.
- Fitze, Patrick S.
- Martín Rueda, José
- Merino, Santiago
Current and past parasite transmission may depend on the overlap of host distributions, potentially affecting parasite specificity and co-evolutionary processes. Nonetheless, parasite diversification may take place in sympatry when parasites are transmitted by vectors with low mobility. Here, we test the co-speciation hypothesis between lizard final hosts of the Family Lacertidae, and blood parasites of the genus Schellackia, which are potentially transmitted by haematophagous mites. The effects of current distributional overlap of host species on parasite specificity are also investigated. We sampled 27 localities on the Iberian Peninsula and three in northern Africa, and collected blood samples from 981 individual lizards of seven genera and 18 species. The overall prevalence of infection by parasites of the genus Schellackia was ∼35%. We detected 16 Schellackia haplotypes of the 18S rRNA gene, revealing that the genus Schellackia is more diverse than previously thought. Phylogenetic analyses showed that Schellackia haplotypes grouped into two main monophyletic clades, the first including those detected in host species endemic to the Mediterranean region and the second those detected in host genera Acanthodactylus, Zootoca and Takydromus. All but one of the Schellackia haplotypes exhibited a high degree of host specificity at the generic level and 78.5% of them exclusively infected single host species. Some host species within the genera Podarcis (six species) and Iberolacerta (two species) were infected by three non-specific haplotypes of Schellackia, suggesting that host switching might have positively influenced past diversification of the genus. However, the results supported the idea that current host switching is rare because there existed a significant positive correlation between the number of exclusive parasite haplotypes and the number of host species with current sympatric distribution. This result, together with significant support for host–parasite molecular co-speciation, suggests that parasites of the genus Schellackia co-evolved with their lizard hosts., Ministerio de Economía y Competitividad and European Regional Development Fund (MINECO/FEDER) provided financial support (CGL2012-40026-C02-01 and CGL2015-67789-C2-1-P to SM; CGL2012-40026-C02-02 to J. Martínez; CGL2015-64086-P to JGP; CGL2014-53523-P to J. Martín; CGL2008-01522, CGL2012-32459, and CGL2016-76918 to PSF). Partial support to sample in the Guadarrama Mountains was provided to OJR by project CGL2011-30393 conceded to I. de la Riva. Ministerio de Educación, Cultura y Deporte and the European Regional Development Fund (MEC/FEDER) funded JJC and JB (grant CGL2008-00137/BOS). MEC also funded RM-P (BES-2010-038427)., Peer reviewed
Experimental manipulation of temperature reduce ectoparasites in nests of blue tits Cyanistes caeruleus
Digital.CSIC. Repositorio Institucional del CSIC
- Castaño-Vázquez, Francisco
- Martínez, Javier
- Merino, Santiago
- Lozano, Marco
Several models predict changes in the distributions and incidences of diseases associated with climate change. However, studies that investigate how microclimatic changes may affect host–parasite relationships are scarce. Here, we experimentally increased the temperature in blue tit Cyanistes caeruleus nest boxes during their breeding season to determine its effects on the parasitic abundance (i.e. of nest‐dwelling ectoparasites, blood‐sucking flying insects and hemoparasites) in nests and the host condition of nestlings and adults. The temperature was increased using heat mats placed underneath the nest material, which resulted in an average temperature increase of 3ºC and a reduction in relative humidity of about six units. The abundance of mites Dermanyssus gallinoides and blowfly pupae Protocalliphora azurea was significantly reduced in heated nest boxes. Although not statistically significant, a lower prevalence of flea larvae Ceratophyllus gallinae was also found in heated nests. However, heat treatment did not affect hemoparasite infection of adult blue tits or the body condition of adult and nestling blue tits. In conclusion, heat treatment in blue tit nests reduced nest‐dwelling ectoparasites yet without any apparent benefit for the host., This study was funded by the project CGL2015-67789-C2-1-P (MINECO/FEDER)., Peer Reviewed
Manipulation of parasite load induces significant changes in the structural-based throat color of male iberian green lizards
Digital.CSIC. Repositorio Institucional del CSIC
- Megía-Palma, Rodrigo M.
- Martínez, Javier
- Merino, Santiago
The honesty of structural-based ornaments is controversial. Sexual selection theory predicts that the honesty of a sexual signal relies on its cost of production or maintenance. Therefore, environmental factors with negative impact on individuals could generate high costs and affect the expression of these sexual signals. In this sense, parasites are a main cost for their hosts. To probe the effect of parasites on the structural-based coloration of a lacertid species Lacerta schreiberi, we have experimentally removed ticks from a group of male Iberian green lizards using an acaricide treatment (i.e., the broad-use insecticide fipronil). All individuals were radio-tracked and recaptured after 15 days to study changes in coloration in both the ultraviolet (UV)-blue (structural-based) and UV-yellow (structural and pigment-based) ornamentations after manipulation, as well as changes in endo- and ectoparasitic load and body condition. Additionally, after the experiment, we measured the skin inflammatory response to a mitogen. The fipronil treatment was effective in reducing ticks and it was associated with a significant reduction of hemoparasite load. Throughout the season, individuals treated with fipronil tended to maintain the brightness of the UV-blue throat coloration while control lizards tended to increase it. However, individuals treated with fipronil that were not infected with hemoparasites significantly reduced the brightness of the UV-blue throat coloration. Individuals with a higher initial tick load exhibited a lower UV saturation increment (UV-blue) and a higher brightness increment (UV-yellow) during the experiment. Overall these results experimentally support the idea that parasites adversely influence the expression of the structural-based coloration of male Iberian green lizards. This adds evidence to the hypothesis that sexual ornaments in lizards function as honest signals., Spanish Ministerio de Economía y Competitividad provided financial support (project CGL2012-40026-C02-01 and CGL2015-67789-C2-1-P to SM and project CGL2012-40026-C02-02 to J. M. R. M. was granted by Spanish Ministerio de Educación with grant number [BES-2010-038427]., Peer Reviewed
Multiple color patches and parasites in Sceloporus occidentalis: Differential relationships by sex and infection
Digital.CSIC. Repositorio Institucional del CSIC
- Megía-Palma, Rodrigo M.
- Paranjpe, Dhanashree
- Reguera, Senda
- Martínez, Javier
- Cooper, Robert D.
- Blaimont, Pauline
- Merino, Santiago
- Sinervo, Barry
Parasites generally have a negative influence on the color expression of their hosts. Sexual selection theory predicts resistant high-quality individuals should show intense coloration, whereas susceptible low-quality individuals would show poor coloration. However, intensely colored males of different species of Old and New World lizards were more often infected by hemoparasites. These results suggest that high-quality males, with intense coloration, would suffer higher susceptibility to hemoparasites. This hypothesis remains poorly understood and contradicts general theories on sexual selection. We surveyed a population of Sceloporus occidentalis for parasites and found infections by the parasite genera Lankesterella and Acroeimeria. In this population, both males and females express ventral blue and yellow color patches. Lankesterella was almost exclusively infecting males. The body size of the males significantly predicted the coloration of both blue and yellow patches. Larger males showed darker (lower lightness) blue ventral patches and more saturated yellow patches that were also orange-skewed. Moreover, these males were more often infected by Lankesterella than smaller males. The intestinal parasite Acroeimeria infected both males and females. The infection by intestinal parasites of the genus Acroeimeria was the best predictor for the chroma in the blue patch of the males and for hue in the yellow patch of the females. Those males infected by Acroeimeria expressed blue patches with significantly lower chroma than the uninfected males. However, the hue of the yellow patch was not significantly different between infected and uninfected females. These results suggest a different effect of Lankesterella and Acroeimeria on the lizards. On the one hand, the intense coloration of male lizards infected by Lankesterella suggested high-quality male lizards may tolerate it. On the other hand, the low chroma of the blue coloration of the infected males suggested that this coloration could honestly express the infection by Acroeimeria., Financial support was provided by Spanish Ministerio de Economía y Competitividad (projects CGL2012-40026-C02-01 and CGL2015-67789-C2-1-P (MINECO/FEDER) to SM, and CGL2012-40026-C02-02 to JM, and grant numbers BES-2010-038427 and EEBB-I-14-08326 to RM-P). Ministerio de Educación funded SR with FPU grant number AP-2009-1325 and EST13/00196. Permits for carrying out this investigation and collecting lizards were provided by the UCSC ethics committee (IACUC) and CDFG to RDC. Research at the UCSC was supported by an NSF grant to BS (EF-1241848)., Peer Reviewed
Nest Gasses as a Potential Attraction Cue for Biting Flying Insects and Other Ectoparasites of Cavity Nesting Birds
Digital.CSIC. Repositorio Institucional del CSIC
- Castaño-Vázquez, Francisco
- Merino, Santiago
- Cuezva, Soledad
- Sánchez-Moral, Sergio
The presence of nestlings and other nest dwelling organisms in cavity nests alters the composition of gasses inside the cavity. Differential concentrations of gasses could be used by some parasites as a cue to localize their hosts. Here, we explored temporal variation in the concentration and isotopic signature of carbon dioxide (CO) and methane (CH) inside nest boxes of blue tits (Cyanistes caeruleus) during the nestling period (on days 3, 8, 13, 20, and 21 post-hatching) as well as several variables potentially affecting such variation. Finally, we checked whether differences in gas concentrations affect the abundance of different types of parasites affecting nestlings. Gas concentration and isotopic signature were significantly different between nest boxes and the forest during the nestling period. The CO concentration was higher inside nests than in the forest air, whereas CH concentration was lower. We expected to observe a positive correlation between the abundance of parasites actively seeking nests (i.e., blackflies, biting midges, and blowflies) and differences in gas concentration for those species that use these differences as a cue for host location. We observed that biting midge abundance was positively related to differences in CO between nest and forest air at day 20 of nestling age, indicating that this species can use these differences to locate hosts. We also found a positive relationship between blackfly abundance and differences in CH concentration. However, we hypothesize that the concentration of this gas inside nests may be related with bacterial activity; therefore, this relationship may be due to an effect of bacteria on blackflies and not to the effect of CH as an attraction cue for blackflies., This study was funded by the project CGL2015-67789-C2-1-P, PGC2018-097426-B-C21, and CGL2016-78318- C2-1-R (MINECO/MICINN/FEDER). We also acknowledge institutional support from the Unit of Information Resources for Research at the Unit of Information Resources for Research at the "Consejo Superior de Investigaciones Científicas" (CSIC) for the article-processing charges contribution.
Geographic patterns of stress in insular lizards reveal anthropogenic and climatic signatures
Digital.CSIC. Repositorio Institucional del CSIC
- Megía-Palma, Rodrigo M.
- Arregui, L.
- Pozo, I.
- Zagar, A.
- Serén, N.
- Carretero, M.A.
- Merino, Santiago
Anthropization of insular ecosystems may have negative impacts on native populations of lizards, which provide core ecosystem services on islands. We aimed to identify environmental factors to explain the interlocal variation in faecal glucocorticoids, parasite intensity, and body condition in populations of insular lizards. A cross-sectional design during the summer of 2017 and 2018 was used to sample 611 adult lizards, Gallotia galloti. Interlocal variation of three stress indicators was analysed in response to environmental variables across a wide environmental gradient in Tenerife (Canary Islands): (i) concentration of faecal glucocorticoids, (ii) intensities of infection by hematic parasites, and (iii) body condition. The data, with low spatial autocorrelation, were analysed using multimodel inference and model cross-validation. Bioclimatic variables associated with the extreme hot and dry climate of summer were the most informative predictors. Interlocal variation in faecal corticosterone in males was best fitted to a model that included the maximum temperature of the warmest month, although the best predictor was habitat anthropization. The thermal annual range, associated with extreme thermal events, was positively related to faecal corticosterone in females. Extreme hot temperatures were positively related to the median parasite intensities in both sexes, while the highest mean intensities of infection were found in females from the most xeric coastal localities. None of the predictors tested, including faecal glucocorticoids, explained individual or interlocal variation in body condition. Effects of human pressure and climate change on insular populations of lizards can be additive. However, the uncoupled relationship found between body condition and the faecal glucocorticoid content suggests that current negative effects may be aggravated during drought periods in summer. Given the impact of climate change on islands, our results may be of application to other archipelagos, where lizards also play key ecological roles., This work was supported by research grants MINECO/FEDER (CGL2015-67789-C2-1-P to SM), FCT/FEDER (28014 02/SAICT/2017 to MAC), and state budget by the Slovenian Research Agency (ARRS, Programme P1-0255 to AŽ). RMP enjoys a postdoctoral contract (CEECIND/04084/2017) by ICETA–Instituto de Ciências, Tecnologias e Agroambiente da Universidade do Porto and Fundação da Ciência eTecnologia.
Experimental manipulation of cavity temperature produces differential effects on parasite abundances in blue tit nests at two different latitudes
Digital.CSIC. Repositorio Institucional del CSIC
- Castaño-Vázquez, Francisco
- Schumm, Yvonne R.
- Bentele, Anna
- Quilfeldt, Petra
- Merino, Santiago
Although different predictive models forecast that climate change will alter the distribution and incidence of parasitic diseases, few studies have investigated how microclimatic changes may affect host-parasite relation-ships. In this study, we experimentally increased the temperature inside nest boxes of the blue tit Cyanistes caeruleus during the nestling period at two different latitudes (central Spain and central Germany) to determine its effect on parasite abundance. The two localities have contrasting climate conditions: the southern one in Spain is warmer and drier than the northern one in Germany. Consistent with this, we observed that the parasitic fauna in nests at the two localities differs. The flea species Ceratophyllus gallinae was more abundant in the northern locality, while the blowfly species Protocalliphora azurea and biting midge species of the genus Culicoides were more abundant in the southern one, as were blood parasites. Moreover, dermanyssid mites and blackflies (Simuliidae) were observed only in the southern locality. The temperature inside nest boxes was increased using heat mats placed underneath the nest material during the nestling period (day 3 to day13 post-hatching). Compared with control nests, the average temperature in heated nests increased by 2.24 ◦C and 1.35 ◦C at night in Spain and Germany, respectively. Consequently, the average relative humidity in heated versus control nests decreased 4.93 and 0.82 units in Spain and Germany, respectively. The abundance of blowfly pupae in the heated nests was significantly lower than that of control nests at both localities. The abundance of larval fleas was also lower in the heated nests, but only at the Spanish locality. Infection by the blood parasites Haemo-proteus/Plasmodium was higher in males attending the heated nests in Germany, and the control nests in Spain. Moreover, both male body mass and nestling wing length were negatively related to the abundance of larval fleas. In conclusion, our results indicate that increased temperature at the nestling stage may affect the fitness of blue tits by altering parasite prevalence rates., This study is also a contribution to the research developed at the ‘El Ventorrillo’ field station, and was funded by projects CGL2015-67789-C2-1-P, and PGC2018-097426-B- C21 (MINECO/MICINN/FEDER)., Peer reviewed
Brighter is darker: the Hamilton-Zuk hypothesis revisited in lizards
Digital.CSIC. Repositorio Institucional del CSIC
- Megía-Palma, Rodrigo M.
- Barrientos, Rafael
- Gallardo, Manuela
- Martínez, Javier
- Merino, Santiago
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 high-
performance 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, Ministerio de Economía y Competitividad/European Agricultural Fund for Rural Development funded this research with projects CGL2012-40026-C02 (granted to S.M. and J.M.) and CGL2015-67789-C2-1-P (granted to S.M.). R.M.-P. enjoys a postdoctoral contract (CEECIND/04084/2017) provided by ICETA—Instituto de Ciências, Tecnologias e Agroambiente da Universidade do Porto and Fundação da Ciência e Tecnologia. R.B. enjoys a postdoctoral grant from Comunidad de Madrid (2018T1/AMB10374)
performance 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, Ministerio de Economía y Competitividad/European Agricultural Fund for Rural Development funded this research with projects CGL2012-40026-C02 (granted to S.M. and J.M.) and CGL2015-67789-C2-1-P (granted to S.M.). R.M.-P. enjoys a postdoctoral contract (CEECIND/04084/2017) provided by ICETA—Instituto de Ciências, Tecnologias e Agroambiente da Universidade do Porto and Fundação da Ciência e Tecnologia. R.B. enjoys a postdoctoral grant from Comunidad de Madrid (2018T1/AMB10374)
Interacciones parásito-hospedador en poblaciones de aves silvestres y su relación con variables ambientales
Digital.CSIC. Repositorio Institucional del CSIC
- Castaño-Vázquez, Francisco
Tesis doctoral defendida en la Facultad de Ciencias Biológicas de la Universidad Complutense de Madrid, [EN] The aim of this Thesis is to explore whether an experimental change in temperature can affect the prevalence and abundance of parasites in cavity nesting birds during their breeding period. During the 2015 breeding period, we observed that an experimental increase in temperature inside blue tit (Cyanistes caeruleus) nests negatively affected the abundance of mites (Dermanyssus gallinoides) and blowfly pupae (Protocalliphora azurea). During the breeding season of 2017 we explored whether an experimental increase in temperature inside blue tit nests located at different latitudes (Spain and Germany) significantly affected the abundance of parasites in the nests. Heated treatment reduced significantly the abundance of blowfly pupae in both locations, as well as that of flea larvae in nests from Germany, although not from those in Spain. In addition, we also observed that infections by hemoparasites such as Haemoproteus/Plasmodium in adult birds was significantly higher in blue tit males attending nests where the temperature was increased in Germany and control nests in Spain. In this study, we also found that the abundance of flea larvae was significantly higher in nests in Germany, while the abundance of blowfly pupae and biting midges was higher in Spain. Similarly, we observed that other parasites such as mites and black flies only appeared in nests in Spain, but not in those in Germany. In addition, we found that the weight of males and the length of wing in blue tit nestlings were negative and significantly related to flea larvae abundance. On the other hand, the experimental increase in temperature within European roller (Coracias garrulus) nests during their breeding period was not enough to show significant differences between heated and control nests. However, treatment had a significant effect on relative humidity, being lower during night in heated nests than in control nests. We also found a higher abundance of mites, sandflies and carnid flies in heated nests with lower humidity than in control nests. However, biting midge abundance was significantly lower in heated than in control nests of rollers, being the abundance of black flies similar between both groups. In addition, the abundance of some parasites vary among nests located on different locations (sandstone walls, trees and human constructions. However, we did not find any significant effect of treatment, nest location or abundance of ectoparasites on mean weight and wing length or growth of nestlings at different nestling ages. On the other hand, we explored whether differences in carbon dioxide (CO2) and methane (CH4) between inside and outside of nest cavities could be potentially used by some ectoparasites to locate their hosts. Our results showed that CO2 concentration was higher inside nests than in outside air, being lower CH4 inside nests than outside. In addition, we observed a higher abundance of biting midges in those nests where the differences of concentration between the CO2 of the nest and the outside were higher at 20 days of nestling age, indicating that these dipterans can use the higher differences in the concentration of this gas to locate their hosts. On the other hand, the abundance of blackflies was higher in those nests with higher differences in concentration of CH4 between the nest and the outside air at 8 days of nestling age. However, our main hypothesis about this result is that nests with highest bacterial activity had higher concentrations of CH4 and the black flies used this signal to locate nestlings in their nests. Finally, using data on the abundance of ectoparasites captured in blue tit nests and climatic variables (temperature, precipitation and wind speed) during a ten-year period (2008-2017), we explore whether the magnitude of the change in climate during this period affected the prevalence and abundance of parasites. In addition, we explore the magnitude of the effect of climate change on blood infections in blue tit adults, as well as the relationships between adult infections and vector abundance. During this 10-year period we observed an increase in temperature and wind speed, as well as a reduction in precipitation. Furthermore, we found that the abundance of biting midges, black flies and blowfly pupae in the nests increased over the years, but not the mites and flea larvae. Regardless of the variation in the number of parasites over the years, different relationships were found between parasites and climatic variables. Temperature was positive and significantly related to biting midges, blowfly pupae, mites and flea larvae abundances, although other ectoparasites such as blackflies, were not affected. In addition, wind speed and precipitation negatively affected to the abundance of blowfly pupae and blackflies, indicating that each parasite species respond to external environmental conditions differently. Over the years, we observed a higher abundance of biting midges and black flies in those nests where the clutch size was higher. We also found a positive and significant relationship between the abundance of blood parasites of the genus Haemoproteus and the abundance of biting midges during the first year of life of the birds. However, infections by parasites such as Lankesterella were positive and significantly related to the abundance of mites during the year of birth of birds. Leucocytozoon and Lankesterella infections were also significantly related to climatic variables and Haemoproteus and Lankesterella infections increased over the years. In addition, we found that the body condition of females, males and nestling blue tits were negatively related to flea larvae, blowfly pupae and biting midge abundances respectively. Our results support the idea that changes in environmental conditions in natural systems can affect each parasite species and its hosts in different ways, because they can adapt in different modes to environmental changes. The prediction that an increase in temperature due to climate change will necessarily lead to an increase in parasitic diseases is not supported by our experimental data, at least in the case of several species of parasites. In addition, we have shown that parasites can still use stimuli such as the difference in concentration of some gases between the inside and outside of the nest to locate their hosts., [ES] Durante el periodo de cría del 2015, observamos que un aumento experimental de la temperatura en el interior de los nidos de herrerillo común (Cyanistes caeruleus) afectó negativamente a la abundancia de ácaros (Dermanyssus gallinoides) y pupas de mosca (Protocalliphora azurea). Durante la temporada de cría del 2017 utilizamos esta misma aproximación experimental en dos poblaciones de herrerillo localizadas a distinta latitud (España y Alemania). El tratamiento térmico redujo significativamente la abundancia de pupas de mosca en ambas localidades, así como también la de larvas de pulga en los nidos de Alemania, aunque no en los de España. Además, también observamos que la infección por hemoparásitos como Haemoproteus/Plasmodium en las aves adultas fue significativamente mayor en machos de herrerillo que atendían nidos donde se aumentó la temperatura en Alemania y nidos controles en España. También encontramos que la abundancia de larvas de pulga fue significativamente mayor en los nidos de Alemania, mientras que la abundancia de pupas de mosca y jejenes fue mayor en España. Del mismo modo, observamos que otros parásitos como ácaros y moscas negras sólo aparecieron en los nidos de España, pero no en los de Alemania. Además, encontramos que el peso de los machos y la longitud del ala de los polluelos de herrerillo estuvieron relacionados negativa y significativamente con la abundancia de larvas de pulgas. También sometimos a un incremento experimental de temperatura a nidos de carraca europea (Coracias garrulus). Aunque no hubo diferencias significativas en temperatura entre nidos calentados y controles si hubo un efecto significativo sobre la humedad relativa, siendo menor durante la noche en los nidos calentados que en los controles. Encontramos una mayor abundancia de ácaros, flebotomos y moscas cárnidas en nidos calentados y con menor humedad que en los nidos control. Sin embargo, la abundancia de jejenes fue significativamente menor en los nidos calentados que en los controles, mientras que la abundancia de moscas negras no mostró diferencias significativas entre ambos grupos. Además, la abundancia de algunos parásitos también varió en función de lugar donde se encontraba la caja-nido (taludes, árboles o construcciones humanas). Estos resultados, contrastan con el hecho de que no encontrásemos ningún efecto significativo sobre el peso medio, la longitud del ala o el crecimiento a diferentes edades de los polluelos. Por otro lado, exploramos si las diferencias en dióxido de carbono (CO2) y metano (CH4) entre el interior y el exterior del nido pueden ser potencialmente utilizados por algunos ectoparásitos para localizar a sus hospedadores. Nuestros resultados demostraron que la concentración de CO2 era más elevada dentro de los nidos que en el aire exterior, siendo la de CH4 menor en los nidos que en el exterior. Además, observamos una mayor abundancia de jejenes en aquellos nidos donde las diferencias de concentración entre el CO2 del nido y el exterior fueron más elevadas a los 20 días de edad de los polluelos, indicándonos que estos dípteros pueden utilizar las mayores diferencias de concentración de este gas para localizar a sus hospedadores. Por otro lado, la abundancia de moscas negras fue más alta en aquellos nidos con mayores diferencias de concentración de CH4 a los 8 días de edad de los polluelos. Esto puede deberse a que los nidos con mayor actividad bacteriana tuvieron mayores concentraciones de CH4 y las moscas negras utilizaron esta señal para localizar a los polluelos en sus nidos.
Finalmente, exploramos si la magnitud del cambio en temperatura, precipitación y velocidad del viento durante un periodo de diez años (2008-2017) afectó a la prevalencia y abundancia de ectoparásitos y parásitos sanguíneos en nidos de herrerillo común, así como también de las relaciones entre las infecciones sanguíneas en los adultos y la abundancia vectores. En este estudio observamos un incremento temporal de la temperatura y de la velocidad del viento, así como una reducción de la precipitación. Además, encontramos que la abundancia de jejenes, moscas negras y pupas de mosca, se incrementó a lo largo de los años, aunque no la de ácaros y larvas de pulga. La temperatura se relacionó positiva y significativamente con la abundancia de jejenes, pupas de mosca, ácaros y larvas de pulgas, aunque otros ectoparásitos como las moscas negras no se vieron afectadas. Además, la velocidad del viento y la precipitación afectaron negativamente a la abundancia de pupas de mosca y moscas negras indicando que cada especie de parásito responde a unas condiciones ambientales externas de manera diferente. También observamos una mayor abundancia de jejenes y moscas negras en aquellos nidos donde el tamaño de nidada era mayor. Asimismo, encontramos una relación positiva y significativa entre la abundancia de parásitos sanguíneos del género Haemoproteus y la abundancia de jejenes durante el primer año de vida de las aves. Las infecciones por parásitos como Lankesterella fueron relacionadas positiva y significativamente con la abundancia de ácaros durante el año de nacimiento de las aves. Las infecciones por Leucocytozoon y Lankesterella estuvieron también significativamente relacionadas con variables climáticas y las infecciones por Haemoproteus y Lankesterella se incrementaron a lo largo de los años. Además, encontramos que la condición de las hembras, machos y los polluelos de herrerillo se relacionaron negativamente con la abundancia de larvas de pulgas, pupas de mosca y jejenes respectivamente. Nuestros resultados apoyan la idea de que en los sistemas naturales los cambios en las condiciones ambientales pueden afectar de distinta manera a cada especie de parásito y a sus hospedadores, debido a que cada uno de estos puede adaptarse de distinta forma a unas novedosas condiciones ambientales. La predicción de que un aumento de la temperatura debido al cambio climático necesariamente va a producir un aumento de las enfermedades parasitarias no se sostiene en base a nuestros datos experimentales, al menos en el caso de algunas especies de parásitos. Además, hemos demostrado que los parásitos todavía pueden utilizar estímulos como la diferencia de concentración de algunos gases entre el interior y el exterior del nido para localizar a sus hospedadores., El trabajo de esta Tesis Doctoral ha podido llevarse a cabo con la financiación de los proyectos CGL2015-67789- C2-1-P y PGC2018-097426-B-C21 (Santiago Merino) ambos del Ministerio de Economía y Competitividad (MINECO/FEDER). Además, Francisco Castaño Vázquez ha contado con una beca FPI-CSIC 2016 ref. BES-2016-076285 del Ministerio de Economía y Competitividad., Peer reviewed
Finalmente, exploramos si la magnitud del cambio en temperatura, precipitación y velocidad del viento durante un periodo de diez años (2008-2017) afectó a la prevalencia y abundancia de ectoparásitos y parásitos sanguíneos en nidos de herrerillo común, así como también de las relaciones entre las infecciones sanguíneas en los adultos y la abundancia vectores. En este estudio observamos un incremento temporal de la temperatura y de la velocidad del viento, así como una reducción de la precipitación. Además, encontramos que la abundancia de jejenes, moscas negras y pupas de mosca, se incrementó a lo largo de los años, aunque no la de ácaros y larvas de pulga. La temperatura se relacionó positiva y significativamente con la abundancia de jejenes, pupas de mosca, ácaros y larvas de pulgas, aunque otros ectoparásitos como las moscas negras no se vieron afectadas. Además, la velocidad del viento y la precipitación afectaron negativamente a la abundancia de pupas de mosca y moscas negras indicando que cada especie de parásito responde a unas condiciones ambientales externas de manera diferente. También observamos una mayor abundancia de jejenes y moscas negras en aquellos nidos donde el tamaño de nidada era mayor. Asimismo, encontramos una relación positiva y significativa entre la abundancia de parásitos sanguíneos del género Haemoproteus y la abundancia de jejenes durante el primer año de vida de las aves. Las infecciones por parásitos como Lankesterella fueron relacionadas positiva y significativamente con la abundancia de ácaros durante el año de nacimiento de las aves. Las infecciones por Leucocytozoon y Lankesterella estuvieron también significativamente relacionadas con variables climáticas y las infecciones por Haemoproteus y Lankesterella se incrementaron a lo largo de los años. Además, encontramos que la condición de las hembras, machos y los polluelos de herrerillo se relacionaron negativamente con la abundancia de larvas de pulgas, pupas de mosca y jejenes respectivamente. Nuestros resultados apoyan la idea de que en los sistemas naturales los cambios en las condiciones ambientales pueden afectar de distinta manera a cada especie de parásito y a sus hospedadores, debido a que cada uno de estos puede adaptarse de distinta forma a unas novedosas condiciones ambientales. La predicción de que un aumento de la temperatura debido al cambio climático necesariamente va a producir un aumento de las enfermedades parasitarias no se sostiene en base a nuestros datos experimentales, al menos en el caso de algunas especies de parásitos. Además, hemos demostrado que los parásitos todavía pueden utilizar estímulos como la diferencia de concentración de algunos gases entre el interior y el exterior del nido para localizar a sus hospedadores., El trabajo de esta Tesis Doctoral ha podido llevarse a cabo con la financiación de los proyectos CGL2015-67789- C2-1-P y PGC2018-097426-B-C21 (Santiago Merino) ambos del Ministerio de Economía y Competitividad (MINECO/FEDER). Además, Francisco Castaño Vázquez ha contado con una beca FPI-CSIC 2016 ref. BES-2016-076285 del Ministerio de Economía y Competitividad., Peer reviewed
Experimental manipulation of humidity in a cavity-nesting bird influences ectoparasites’ abundance
Digital.CSIC. Repositorio Institucional del CSIC
- Castaño-Vázquez, Francisco
- Merino, Santiago
- Valera, Francisco
- Veiga, Jesús
Climate change effects on host–parasite interactions have been poorly studied in arid or semi-arid habitats. Here, we conducted an experiment aimed to increase the temperature inside European roller Coracias garrulus nest boxes located in a semi-arid habitat on different nest-site types to look for effects on different ectoparasite abundances and nestling growth. Average nest temperature was slightly higher in heated nests than in control nests, although differences were not statistically significant. However, relative humidity was significantly lower at night in heated nests as compared to control nests. The abundance of sand flies,
mites and carnid flies was significantly higher in heated, less humid, nests while biting midge abundance was significantly lower in heated nests. Other ectoparasites were not significantly affected by treatment. Relative humidity was high even in heated nests, reaching more than 60%. Sand fly abundance was higher in nests located in sandstone walls, while mite abundance was higher in isolated farmhouses. In addition, sand fly prevalence was higher in nests located in isolated farmhouses and sandstone walls. Heat treatment, nest-site type or ectoparasite abundances did not affect the nestling body mass, wing length or their growth at different
nestling ages., This study was funded by the project CGL2015-67789-C2-1-P (MINECO/FEDER). Also, this project is part of the project PGC2018-097426-B-C21 and PGC2018-097426-B-C22 funded by MCIU/AEI/10.13039/501100011033/ and by ‘ERDF A way of making Europe’., Peer reviewed
mites and carnid flies was significantly higher in heated, less humid, nests while biting midge abundance was significantly lower in heated nests. Other ectoparasites were not significantly affected by treatment. Relative humidity was high even in heated nests, reaching more than 60%. Sand fly abundance was higher in nests located in sandstone walls, while mite abundance was higher in isolated farmhouses. In addition, sand fly prevalence was higher in nests located in isolated farmhouses and sandstone walls. Heat treatment, nest-site type or ectoparasite abundances did not affect the nestling body mass, wing length or their growth at different
nestling ages., This study was funded by the project CGL2015-67789-C2-1-P (MINECO/FEDER). Also, this project is part of the project PGC2018-097426-B-C21 and PGC2018-097426-B-C22 funded by MCIU/AEI/10.13039/501100011033/ and by ‘ERDF A way of making Europe’., Peer reviewed
Differential effects of environmental climatic variables on parasite abundances in blue tit nests during a decade
Digital.CSIC. Repositorio Institucional del CSIC
- Castaño-Vázquez, Francisco
- Merino, Santiago
Models on climate change have predicted an increase of temperature over the earth's surface with potential drastic effects on living organisms. We analyzed the relationships between climatic conditions (temperature, rainfall, and wind speed) and the abundance of blood-sucking flying insects (biting midges and blackflies) and nest-dwelling ectoparasites (mites, fleas, and blowflies) collected from blue tit nests during bird breeding seasons for a period of 10 years. Average temperature, rainfall, and wind speed showed significant differences among years. Temperature and wind speed increased during the period of study while rainfall decreased. Biting midge, blackfly, and blowfly abundances increased across years but not flea and mite abundances. Hatching date decreased and brood size increased across years. Independently of year variation, parasites were related to climatic variables. For example, biting midge, blowfly, mite, and flea abundances were positive and significantly related to average temperature. We also found a positive and significant relationship between abundances of Haemoproteus infections and biting midge abundances during the first year of life of birds out of nests. However, abundance and prevalence of Lankesterella infections in yearlings were positive and significantly related to mite abundances during the year of birth of birds. Leucocytozoon and Lankesterella infections were also significantly related to climatic variables and Haemoproteus and Lankesterella infections increased across years. In addition, body condition of adult females and males were negatively related to flea larvae and blowfly abundance respectively. Nestling body condition was also negatively related to biting midge abundance. Changes in climatic conditions across years could therefore affect several parasites of birds but also to birds themselves., This study was funded by the project CGL2015-67789-C2-1-P and PGC2018-097426-B-C21 (MINECO/MICINN/FEDER) MCIU/AEI/10.13039/501100011033/ERDF A way of making Europe.