Torrijo de la Cañada, Spain


Torrijo de la Cañada, Spain
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Exposito-Granados M.,EEZA CSIC | Parejo D.,EEZA CSIC | Parejo D.,University of Extremadura | Martinez J.G.,University of Granada | And 5 more authors.
PLoS ONE | Year: 2017

Hosts can counteract parasites through defences based on resistance and/or tolerance. The mechanistic basis of tolerance, which involve defensive mechanisms minimizing parasite damage after a successful parasitic attack, remains poorly explored in the study of cuckoo-host interactions. Here, we experimentally explore the possibility that the risk of great spotted cuckoo Clamator glandarius parasitism may induce tolerance defences in magpie Pica pica hosts through plasticity in life-history traits. We predict that magpies exposed to auditory cues indicating high parasitism risk will more likely exhibit resistance and/or modify their life-history traits to minimize parasitism costs (i.e. tolerance) compared to magpies under low parasitism risk. We found that manipulating the perceived parasitism risk did not affect host resistance (i.e. rejection of parasitic eggs) nor host life-history traits. Unexpectedly, host's egg volume increased over the season in nests exposed to auditory cues of control non-harmful hoopoes Upupa epops. Our results do not provide support for inducible defences (either based on resistance or tolerance) in response to risk of parasitism in magpie hosts. Even so, we encourage studying plastic expression of breeding strategies in response to risk of cuckoo parasitism to achieve a better understanding of the mechanistic basis of tolerance defences. © 2017 Expósito-Granados et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Martinez-Padilla J.,CSIC - National Museum of Natural Sciences | Mougeot F.,EEZA CSIC | Garcia J.T.,IREC CSIC UCLM JCCM | Arroyo B.,IREC CSIC UCLM JCCM | Bortolotti G.R.,University of Saskatchewan
Journal of Raptor Research | Year: 2013

Most of our understanding of the function of colored traits displayed by birds and the mechanisms that produce or maintain them comes from studies on adults. However, colored traits are often displayed by nestlings from a young age, and these traits may influence parent-offspring interactions or sibling competition. The mechanisms that may mediate the expression of those traits during growth are still fairly unknown in raptors. In this study, we examined a possible mediating effect of corticosterone levels on the expression of carotenoid-pigmented traits in nestlings of Common Buzzards (Buteo buteo), specifically the yellow-orange coloration of their cere and legs. We assayed corticosterone levels deposited in feathers, which can provide a reliable and integrated index of stress responses during growth. Carotenoids can be used to color integuments, or diverted to other physiological processes involved in self-maintenance. We hypothesized that corticosterone levels mediate how carotenoids can be diverted to functions other than coloration. We show that carotenoid and corticosterone levels were positively associated, perhaps because of a higher metabolic activity in more-stressed nestlings. Corticosterone levels were negatively correlated with the coloration of cere and legs in females only. Altogether, our results support the hypothesis that corticosterone may influence how carotenoid pigments are allocated for needs other than coloration, although in a sex-specific manner. We encourage further studies exploring how individuals cope with and respond to stressful conditions, in order to better understand the complex interactions between corticosterone, carotenoids, and coloration during nestling growth. © The Raptor Research Foundation, Inc.

Molina-Morales M.,University of Granada | Molina-Morales M.,University of Sheffield | Gabriel Martinez J.,University of Granada | Martin-Galvez D.,University of Sheffield | And 4 more authors.
Journal of Animal Ecology | Year: 2013

Brood parasites usually reduce their host's breeding success, resulting in strong selection for the evolution of host defences. Intriguingly, some host individuals/populations show no defence against parasitism, which has been explained within the frame of three different evolutionary hypotheses. One of these hypotheses posits that intermediate levels of defence at the population level may result from nonrandom distribution of parasitism among host individuals (i.e. structured parasitism). Empirical evidence for structured brood parasitism is, however, lacking for hosts of European cuckoos due to the absence of long-term studies. Here, we seek to identify the patterns of structured parasitism by studying great spotted cuckoo parasitism on individual magpie hosts over five breeding seasons. We also aim to identify whether individual characteristics of female magpies and/or their territories were related to the status of repeated parasitism. We found that 28·3% of the females in our population consistently escaped from cuckoo parasitism. Only 11·3% of females were always parasitized, and the remaining 60·4% changed their parasitism status. The percentage of females that maintained their status of parasitism (i.e. either parasitized or nonparasitized) between consecutive years varied over the study. Females that never suffered cuckoo parasitism built bigger nests than parasitized females at the beginning of the breeding season and smaller nests than those of parasitized females later in the season. Nonparasitized females also moved little from year to year and preferred areas with different characteristics over the course of the breeding season than parasitized females. Overall, females escaping from cuckoo parasitism reared twice as many chicks per year than those that were parasitized. In conclusion, our study reveals for first time the existence of a structured pattern of cuckoo parasitism based on phenotypic characteristics of individual hosts and of their territories. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.

Sanchez-Canete E.P.,EEZA CSIC | Sanchez-Canete E.P.,Centro Andaluz Of Medio Ambiente Ceama | Kowalski A.S.,Centro Andaluz Of Medio Ambiente Ceama | Kowalski A.S.,University of Granada | And 5 more authors.
Biogeosciences | Year: 2013

Knowledge of all the mechanisms and processes involved in soil CO2 emissions is essential to close the global carbon cycle. Apart from molecular diffusion, the main physical component of such CO2 exchange is soil ventilation. Advective CO2 transport, through soil or snow, has been correlated with the wind speed, friction velocity or pressure (p). Here we examine variations in subterranean CO2 molar fractions (χc) over two years within a vertical profile (1.5 m) in a semiarid ecosystem, as influenc. © 2013 Author(s).

Sanchez-Canete E.P.,EEZA CSIC | Sanchez-Canete E.P.,Centro Andaluz Of Medio Ambiente Ceama | Serrano-Ortiz P.,EEZA CSIC | Serrano-Ortiz P.,Centro Andaluz Of Medio Ambiente Ceama | And 4 more authors.
International Journal of Speleology | Year: 2013

Dynamics and drivers of ventilation in caves are of growing interest for different fields of science. Accumulated CO2 in caves can be exchanged with the atmosphere, modifying the internal CO2 content, affecting stalagmite growth rates, deteriorating rupestrian paintings, or creating new minerals. Current estimates of cave ventilation neglect the role of high CO2 concentrations in determining air density - approximated via the virtual temperature (Tv) -, affecting buoyancy and therefore the release or storage of CO2. Here we try to improve knowledge and understanding of cave ventilation through the use of Tv in CO2-rich air to explain buoyancy for different values of temperature (T) and CO2 content. Also, we show differences between T and Tv for 14 different experimental sites in the vadose zone, demonstrating the importance of using the correct definition of Tv to determine air buoyancy in caves. The calculation of Tv (including CO2 effects) is currently available via internet using an excel template, requiring the input of CO2 (%), air temperature (°C) and relative humidity (%).

Martinez-Padilla J.,CSIC - National Museum of Natural Sciences | Redpath S.M.,University of Aberdeen | Zeineddine M.,University of Aberdeen | Mougeot F.,EEZA CSIC
Journal of Animal Ecology | Year: 2014

Long-term studies have been the backbone of population ecology. The red grouse Lagopus lagopus scoticus is one species that has contributed widely to this field since the 1950s. This paper reviews the trajectory and profound impact that these studies have had. Red grouse research has combined long-term studies of marked individuals with demographic studies over wide geographical areas and replicated individual- and population-level manipulations. A main focus has been on understanding the causes of population cycles in red grouse, and in particular the relative importance of intrinsic (behaviour) and extrinsic (climate, food limitation and parasite) mechanisms. Separate studies conducted in different regions initially proposed either the nematode parasite Trichostrongylus tenuis or changes in male aggressiveness in autumn as drivers of population cycles. More recent experiments suggest that parasites are not a necessary cause for cycles and have highlighted that behavioural and parasite-mediated mechanisms are interrelated. Long-term experiments show that parasites and aggressiveness interact. Two outstanding questions remain to be tested experimentally. First, what intrinsic mechanism causes temporal variation in patterns of male aggressiveness? The current favoured mechanism is related to patterns of kin structuring although there are alternative hypotheses. Second, how do the dual, interacting mechanisms, affect population dynamics? Red grouse studies have had an important impact on the field of population ecology, in particular through highlighting: (1) the impact of parasites on populations; (2) the role of intrinsic mechanisms in cyclic dynamics and (3) the need to consider multiple, interacting mechanisms. © 2013 British Ecological Society.

Mougeot F.,EEZA CSIC | Martinez-padilla J.,University of Aberdeen | Bortolotti G.R.,University of Saskatchewan | Webster L.M.I.,University of Aberdeen | Piertney S.B.,University of Aberdeen
Journal of Evolutionary Biology | Year: 2010

Vertebrates commonly use carotenoid-based traits as social signals. These can reliably advertise current nutritional status and health because carotenoids must be acquired through the diet and their allocation to ornaments is traded-off against other self-maintenance needs. We propose that the coloration more generally reveals an individual's ability to cope with stressful conditions. We tested this idea by manipulating the nematode parasite infection in free-living red grouse (Lagopus lagopus scoticus) and examining the effects on body mass, carotenoid-based coloration of a main social signal and the amount of corticosterone deposited in feathers grown during the experiment. We show that parasites increase stress and reduce carotenoid-based coloration, and that the impact of parasites on coloration was associated with changes in corticosterone, more than changes in body mass. Carotenoid-based coloration appears linked to physiological stress and could therefore reveal an individual's ability to cope with stressors. © 2009 The Authors. Journal Compilation © 2009 European Society For Evolutionary Biology.

Miralles I.,EEZA CSIC | Domingo F.,EEZA CSIC | Canton Y.,University of Almeria | Trasar-Cepeda C.,CSIC - National Institute of Agrobiological Sciences | And 2 more authors.
Soil Biology and Biochemistry | Year: 2012

In arid and semi-arid regions, pioneer organisms form complex communities that penetrate the upper millimetres of the bare substrate, creating biological soil crusts (BSC). These thin crusts play a vital role in whole ecosystem functioning because they enrich bare surfaces with organic matter, initiate biogeochemical cycling of elements, modify hydrological cycles, etc., thus enabling the ground to be colonized by vascular plants. Various hydrolase enzymes involved in the carbon (cellulase, β-glucosidase and invertase activities), nitrogen (casein-protease and BAA-protease activities) and phosphorus (alkaline phosphomonoesterase activity) cycles were studied at three levels (crust, middle and deep layers) of three types of BSCs from the Tabernas Desert (SE Spain), representing an ecological gradient ranging from crusts predominated by cyanobacteria to crusts predominated by lichens (Diploschistes diacapsis, Lepraria crassissima). All enzyme activities were higher in all layers of all BSCs than in the bare substrate. The enzymes that hydrolyze low molecular weight substrates were more active than those that hydrolyze high molecular weight substrates (cellulase, casein-protease), highlighting the pioneering characteristics of the BSCs. The hydrolytic capacity developed in parallel to that of ecological succession, and the BSCs in which enzyme activity was highest were those under L. crassissima. The enzyme activity per unit of total organic C was extremely high; the highest values occurred in the BSCs formed by cyanobacteria and the lowest in those formed by lichens, which indicates the fundamental role that the primary colonizers (cyanobacteria) play in enriching the geological substrate with enzymes that enable degradation of organic remains and the establishment of more developed BSCs. The results of the study combine information on different enzyme activities and provide a clear vision of how biogeochemical cycles are established in BSCs, thus confirming the usefulness of enzyme assays as key tools for examining the relationship between biodiversity and ecosystem function in biological soil crusts. © 2012 Elsevier Ltd.

Miralles I.,EEZA CSIC | Domingo F.,EEZA CSIC | Garcia-Campos E.,CSIC - National Institute of Agrobiological Sciences | Trasar-Cepeda C.,CSIC - National Institute of Agrobiological Sciences | And 2 more authors.
Soil Biology and Biochemistry | Year: 2012

The ecology and functional role of biological soil crusts (BSCs) in arid and semi-arid zones have been extremely well studied. However, little is known about the biochemical properties related to the number and activity of the microbiota that form the crusts, even though information about these properties is very important for understanding many of the processes that affect the formations. In this study, several properties related to the activity and number of microorganisms (biomass-C, basal respiration, dehydrogenase activity and nitrogen mineralization potential) were determined at different depths (crusts, 0-0.5 cm; middle, 0.5-3 cm and deep, 3-5 cm layers) in two types of crusts (predominated by cyanobacteria and by lichens) in the Tabernas desert (Almeria, SE Spain). The absolute values of the above-mentioned properties and the values expressed relative to the total organic carbon (TOC) content were both much higher in the crust layers than in the surface horizons of soils under Mediterranean or Atlantic climates. A large part of the TOC in the BSCs was contained in the microbiota and another large part was readily metabolized during incubation of the crusts for 10 days at 25 °C. The net nitrogen mineralization rate was also high, and ammonification predominated in the crust layers, whereas nitrification predominated in the middle and deep layers. In all types of BSCs, the microbiota colonized the deep layers, although with greater intensity in the lichen-dominated BSCs than in the cyanobacterial BSCs. The results also indicate that hydrolytic enzymes are not stabilized on soil colloids and their activity depends only on the active microbiota. © 2012 Elsevier Ltd.

Aviles J.M.,EEZA CSIC | Parejo D.,EEZA CSIC
Journal of Avian Biology | Year: 2012

Vividly coloured chromatic signals play a key role in social and sexual signalling in diurnal birds, but their role is considered negligible in favour of achromatic (i.e. white, pure grey and black colourations) signals in nocturnal species. Here we studied colour variation and potential signalling of the yellow bill - a trait functioning as sexual signal in diurnal raptors during the breeding season in females of a truly nocturnal raptor, the little owl Athene noctua. We found that yellow-red chroma of the bill was highly variable between individuals and positively correlated with female fitness prospects (i.e. brood size at fledging). In addition, we found that females with brighter bills were larger in size and produced owlets with a higher mass at fledging. This study suggests that yellow bill colouration in female little owls may potentially play a role in sexual signalling and may constitute the first evidence of chromatic colour signalling in a nocturnal bird. © 2012 The Authors.

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