1. The consequences of symbiont transmission strategies are better understood than their adaptive causes. 2. Feather mites are permanent ectosymbionts of birds assumed to be transmitted mainly vertically from parents to offspring. The transmission of Proctophyllodes doleophyes Gaud (Astigmata, Proctophyllodidae) was studied in two European populations of pied flycatchers, Ficedula hypoleuca Pallas (Passeriformes, Muscicapidae). 3. The vertical transmission of this mite species is demonstrated here with an acaricide experiment. This study also compared (for two distant populations during 4 years) patterns in reductions in mite intensity in adult birds, from egg incubation to chick-rearing periods, with the predictions of three hypotheses on how host survival prospects and mite intraspecific competition might drive feather mites' transmission strategy. 4. The results are in agreement with previous studies and show that feather mites transmit massively from parents to chicks. 5. The magnitude of the transmission was closer to that predicted by the hypothesis based on intraspecific competition, while a bet-hedging strategy is also partially supported., JD, RJ and JP were supported by the Ministry of Economy and Competitiveness (SVP-2013-067939, Ramon y Cajal research contract RYC-2009-03967, and projects CGL2014-55969-P and CGL2015-70639-P)

Melanin-based colouration of tegument structures may be related to variability in the expression of certain strategies or behaviours within a species, including the propensity to disperse. This is because melanin synthesis may be physiologically linked to certain behaviours and personality traits, as proposed by the hypothesis of the pleiotropy in the melanocortin system (HPMS). During a 28-year period (1988–2015), we studied the melanin-based dorsal colouration of male pied flycatchers (Ficedula hypoleuca) in relation to natal dispersal movements between contrasting (pine and oak) habitats. In addition, the relationship between tonic immobility (TI), a measure of individual fearfulness towards predators, and plumage colour was examined using a shorter time series. Consistent with HPMS, males’ dispersal propensity was related to their plumage colour, with the blackest individuals being more likely to disperse into a new habitat to breed. Blacker males remained for longer in TI than lighter ones. The positive relationship between plumage melanisation and TI might result from the pleiotropic effect of the melanocortin system on glucocorticoid-mediated stress and fearfulness responses as well as on eumelanin synthesis. This study provides solid empirical support for the HPMS in relation to natal dispersal behaviour., Long-term monitoring of the study population has been mainly funded by the Spanish CCYT, most recently by projects CGL2014-55969-P (to F. Valera) and CGL201570639-P (to L.Z. Garamszegi) of the Spanish Ministry of Economy and Competitiveness. CC received financial support from the Spanish Ministry of Economy and Competitiveness (SVP-2013-067686). LP-R was supported by a postdoctoral contract from MINECO through the Severo Ochoa Programme for Centres of Excellence in RandDandI (SEV-2012-0262). DC was supported by projects CGL2009-10652 and CGL2015-70639-P., Peer reviewed

Differentiation of niche by means of resource partitioning facilitates coexistence of species
with similar requirements. Here we analyse the association between different habitats
(i.e. nest types) and two Diptera species of the poorly known Family Carnidae that coexist
during their larval and pupal stage in the nests of troglodytic bird species. We also describe
for the first time the puparium of Hemeromyia anthracina and Hemeromyia longirostris and
offer morphometric data of the puparia of these two species and of Carnus hemapterus. Both
the smaller size and the occurrence of well-developed spiracles allow easy discrimination of
the puparium of C. hemapterus. The puparia of both Hemeromyia species is very similar
and only differ in the distance between the small spiracles. Hemeromyia anthracina and C.
hemapterus coexisted in nest boxes but the former species did not occur in natural sandy cavities
where, in turn, C. hemapterus was highly prevalent. Carnus hemapterus prevalence did
not differ between nest boxes and natural cavities but its abundance was higher in the first
type of nest. This study shows clear associations of the two dipteran species with specific
types of nests. Yet, some conditions are seemingly acceptable for both species., F.V. and E.M. received financial support from the Spanish
Ministry of Economy and Competitiveness (grant no. CGL2014-55969-P) and
the European Regional Development Fund. J.V. was funded by the Spanish
Ministry of Economy, Industry and Competitiveness by means of a predoctoral
grant (grant no. BES-2015-075951)., Peer reviewed

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

[Background] Haemosporidians are the most important vector-borne parasites due to their cosmopolitan distribution and their wide range of hosts, including humans. Identification of their vectors is critical to highlight ecologically and epidemiologically relevant features such as host specificity or transmission routes. Biting midges of the genus Culicoides are considered the main vectors of Haemoproteus spp., yet important information on aspects such as vector feeding preferences or vector-host specificity involving haemosporidian parasites is frequently missing., [Methods] We assessed the abundance of Culicoides circumscriptus and C. paolae and blood sources of the latter at the nests of cavity-nesting bird species (mainly the European roller Coracias garrulus) and in their surroundings. We also explored the prevalence and genetic diversity of avian haemosporidians in parous females of both species., [Results] Both C. circumscriptus and C. paolae were abundant in the study area and common at European roller nests. Culicoides paolae had a diverse ornithophilic diet, feeding on at least seven bird species. Human DNA was also detected in the blood meal of some individuals. Four Haemoproteus lineages, including a new one reported here for the first time, were isolated from parous females of both biting midges., [Conclusions] Culicoides circumscriptus and C. paolae can play a locally important role in the transmission dynamics of Haemoproteus parasites in a community of cavity-nesting bird species in an arid ecosystem., JV was funded by the Spanish Ministry of Economy, Industry and Competitiveness by means of a predoctoral grant (grant no. BES-2015-075951). FV and JF received financial support from the Spanish Ministry of Economy and Competitiveness, and the European Regional Development Fund (CGL2014-55969-P; CGL2015-65055-P). JMP was partially supported by a 2017 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. The Foundation accepts no responsibility for the opinions, statements and contents included in the project and/or the results thereof, which are entirely the responsibility of the authors. We acknowledge support of the publication fees by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI)., Peer reviewed

Peer reviewed

Telomere length is a marker of cellular senescence that relates to different components of individual fitness. Oxidative stress is often claimed as a main proximate factor contributing to telomere attrition, although the importance of this factor in vivo has recently been challenged. Early development represents an ideal scenario to address this hypothesis because it is characterized by the highest rates of telomere attrition of the life and by an arguably high susceptibility to oxidative stress. We tested the effect of oxidative stress on telomere dynamics during early development by exposing pied flycatcher nestlings (Ficedula hypoleuca) to either an oxidative challenge (diquat injections), an antioxidant (vitamin E) or control treatments (PBS injections and supplementation with vehicle substance). We found no effects of treatments on average telomere change during the nestling period. However, vitamin E supplementation, which increased growth, removed the association between initial telomere length and telomere attrition. Diquat-treated nestlings, by contrast, showed no differences in growth or telomere dynamics with respect to controls. These results do not support the hypothesis that oxidative stress is the main direct mechanism explaining telomere attrition in vivo, and highlight the importance of micronutrient intake during early development on telomere dynamics. Studies addressing alternative action pathways of vitamins on growth and telomere dynamics, perhaps via restoration mechanisms, would provide important insights on the proximate factors affecting telomere attrition during this critical phase of life., LP-R was supported by Severo Ochoa (SEV-2012-0262) and SECTI (UCLM) postdoctoral contracts during data collection manuscript and writing, respectively. Funding was provided by Spanish Ministry of Economy and Competitiveness (SMEC); grant number CGL2014-55969-P. Additional funding came from the project “A test of the oxidative cost of a reliable signal,” granted to TR by the internal EBD proposal call Microproyectos and financed by the SMEC, through the Severo Ochoa Program for Centers of Excellence in R+D+I (SEV-2012-0262)., Peer Reviewed

Environmental change associated with urbanization is considered one of the major threats to biodiversity. Some species nevertheless seem to thrive in the urban areas, probably associated with selection for phenotypes that match urban habitats. Previous research defined different >copying styles> in distress behavior during the handling of birds. These behaviors vary along a continuum from >proactive> to >reactive> copers. By studying avian distress behaviors we aimed to broaden our understanding of the relationship between coping styles and urbanization. Using a large-scale comparative study of seven paired rural and urban sites across Europe, we assayed distress behaviors during handling of urban and rural-dwelling populations of the great tit Parus major. We detected no consistent pairwise differences in breath rate between urban and rural habitats. However, urban great tits displayed more distress calling (fear screams) and higher pecking rate (handling aggression) than rural birds. These findings suggest that urban great tits have a more proactive coping strategy when dealing with stressful conditions. This finding is in line with previous studies implying that urban great tits are more explorative, less neophobic, and display shorter flight distances than their rural counterparts, representing further aspects of the same >proactive,> coping strategy. Future research should investigate whether reported differences in distress behavior are due to local adaption caused by natural selection or due to phenotypic plasticity., This work was supported by funds from the Ministry of Economy and Competitivity, Spanish Research Council (CGL-2016-79568-C3-3-P; to JCS. CGL2015-70639-P; to LG. CGL2014-55969-P; to GM-R), from the National Research, Development and Innovation Office (Hungary) (K-115970; to LG), from the Estonian Ministry of Education and Research (institutional research funding IUT no. 34-8; to VT), from the European Research Council (ERC-2013-StG-337365-SHE; to AC), from the OSU-OREME (to AC), from the Deutsche Forschungsgemeinschaft (DFG) (SP 1450/3-1; to PhS), from the European Union a Marie Curie Re-Integration grant (CIG 322217; to CI) and from the Swedish Research council (C0361301; to CI).

Many organisms adjust their reproductive phenology in response to climate change, but phenological sensitivity to temperature may vary between species. For example, resident and migratory birds have vastly different annual cycles, which can cause differential temperature sensitivity at the breeding grounds, and may affect competitive dynamics. Currently, however, adjustment to climate change in resident and migratory birds have been studied separately or at relatively small geographical scales with varying time series durations and methodologies. Here, we studied differential effects of temperature on resident and migratory birds using the mean egg laying initiation dates from 10 European nest box schemes between 1991 and 2015 that had data on at least one resident tit species and at least one migratory flycatcher species. We found that both tits and flycatchers advanced laying in response to spring warming, but resident tit populations advanced more strongly in relation to temperature increases than migratory flycatchers. These different temperature responses have already led to a divergence in laying dates between tits and flycatchers of on average 0.94 days per decade over the current study period. Interestingly, this divergence was stronger at lower latitudes where the interval between tit and flycatcher phenology is smaller and winter conditions can be considered more favorable for resident birds. This could indicate that phenological adjustment to climate change by flycatchers is increasingly hampered by competition with resident species. Indeed, we found that tit laying date had an additional effect on flycatcher laying date after controlling for temperature, and this effect was strongest in areas with the shortest interval between both species groups. Combined, our results suggest that the differential effect of climate change on species groups with overlapping breeding ecology affects the phenological interval between them, potentially affecting interspecific interactions., T.E. acknowledges the funding by the Academy of Finland (project 265859). MM and RM were financially supported by the Estonian Research Council (institutional research funding IUT number 34‐8). I.K. received financial support from the Estonian Ministry of Education and Science (grant PUT1223). The data collection in Russia was financially supported by RSF grant number 14‐50‐00029. JP was supported by projects CGL2014‐55969‐P and CGL2015‐70639‐P of the Spanish Ministry of Economy and Competitiveness.

Host range and parasite specificity determine key epidemiological, ecological and evolutionary aspects of host-parasite interactions. Parasites are usually classified as generalists or specialists based on the number of hosts they feed on. Yet, the requirements of the various stages of a parasite may influence the suitability of a given host species. Here, we investigate the generalist nature of three common ectoparasites (the dipteran Carnus hemapterus and two species of louse flies, Pseudolynchia canariensis and Ornithophila metallica), exploiting two avian host species (the European roller Coracias garrulus and the Rock pigeon Columba livia), that frequently occupy the same breeding sites. We explore the prevalence and abundance of both the infective and the puparial stages of the ectoparasites in both host species. Strong preferences of Pseudolynchia canariensis for pigeons and of Carnus hemapterus for rollers were found. Moderate prevalence of Ornithophila metallica was found in rollers but this louse fly avoided pigeons. In some cases, the infestation patterns observed for imagoes and puparia were consistent whereas in other cases host preferences inferred from imagoes differed from the ones suggested by puparia. We propose that the adult stages of these ectoparasites are more specialist than reported and that the requirements of non-infective stages can restrict the effective host range of some parasites., F.V. received financial support from the Spanish Ministry of Economy and
Competitiveness (grant no. CGL2014-55969-P) and the European Regional
Development Fund. J.V. was funded by the Spanish Ministry of Economy, Industry and
Competitiveness by means of a predoctoral grant (BES-2015-075951)

Nest box supplementation is widely used to increase nest-site availability for cavity nesting animals but the analysis of its effects on individuals breeding in natural cavities is often neglected. This study offers a novel restoration technique to revert abandonment of natural breeding sites by a secondary cavity avian bird, the European roller (Coracias garrulus), and other ecologically similar species. We found that, after a program of nest box supplementation with ensuing monitoring, rollers gradually abandon nesting in natural and seminatural cavities in favor of nest boxes because the latter are of higher quality. We examine whether reducing the entrance size of natural and seminatural cavities improves their suitability for rollers. A 6-year program reduced the diameter of the entrance of sandstone cavities and cavities in bridges. This led to a high occupancy (59%) of manipulated nest-sites. Manipulated sites were most frequently occupied by rollers and little owls (Athene noctua) (31 and 18% of sites, respectively). Manipulation did not affect clutch size or fledgling success. We suggest that nest-site diversity and nesting in natural cavities should be preserved to reduce nest box dependence. Our study illustrates the value of nest boxes when used alongside restoration of natural breeding sites and provides insights for the management of natural cavities., F.V. received financial support from the Spanish Ministry of Science and Innovation (CGL2008‐00562), the Spanish Ministry of Economy, Industry and Competitiveness (CGL2014‐55969), and the European Regional Development Fund. R.V. was supported by a VEGA grant of the Ministry of Education of the Slovak Republic (No. 2/0008/16). J.V. was funded by the Spanish Ministry of Economy, Industry and Competitiveness (predoctoral grant BES‐2015‐075951)

Esta Tesis ha sido desarrollada en la Estación Experimental de Zonas Áridas en Almería. Instituto perteneciente al Consejo Superior de Investigaciones Científicas (EEZA-CSIC). Memoria presentada por Jesús Veiga Neto para optar al título de Doctor por la Universidad de Granada.-- Esta tesis ha sido dirigida por el Dr. Francisco Valera Hernández, de la Estación Experimental de Zonas Áridas (CSIC) y el Dr. Gregorio Moreno Rueda, de la Universidad de Granada., Parasites are strongly influenced by numerous abiotic and biotic factors operating at different temporal and spatial scales. To understand parasites dynamics, host-parasite interactions and the underlying mechanisms of such interactions it is necessary to study how those factors influence parasites and their relationships with the hosts at the various scales.
Here we study the effect of off-host and host-related factors on the relationship between a cavity-nesting bird species, the European roller (Coracias garrulus) and its ectoparasites, mainly the haematophagous fly Carnus hemapterus. The main factors considered in this study involve habitat characteristics at the mesoscale (the host nest and the immediate surroundings) like nest-site type (a major source of habitat heterogeneity in our study area) as well as host and parasite density, breeding phenology of the host (i.e. seasonal effects) and host total brood mass (as a surrogate of cues for the parasites). We study the effect of these factors on the colonization success and distribution (prevalence and abundance) of the most common ectoparasite (Carnus hemapterus). However, since a given host species usually harbours several parasite species, the approach “one host-one parasite” overlooks the effect of the interactions among parasites that mainly occur at the infracommunity level. Therefore, we also explore the effect of the above-mentioned factors on the ectoparasite infracommunity of the European roller.
Our study is performed in a semi-arid environment, therefore contributing to our knowledge of host-parasite interactions in such habitats that are underrepresented in the scientific literature.
Both to fill the gaps on the basic biology of the study species and to build up our study on solid foundations, we also explore basic aspects of the natural history of Carnus hemapterus such as the characteristics of the pupal stage of the ectoparasite or its life span during the dispersal stage (closely related to colonization success).
We found that carnid flies have a very short life span during the dispersal stage (less than four days), in spite of which they are able to colonize ca. 100% of the host nests. Its longevity during this period increases with body size, environmental humidity and with access to food (flowers). Nest-site type influences colonization success of carnid flies, so that it is higher in nest boxes on sandstone cliffs-farmhouses than in nest boxes on trees. Colonization success also increased with host density and host brood mass but decreased as the season progressed. Interestingly, parasite density had no effect on host colonization success. Nest-site type also explained differences among nests in composition of the ectoparasite infracommunity and in abundance of various ectoparasite species. These variables were not affected by the spatial structure, nor by brood mass. However, host breeding phenology affects the ectoparasite infracommuity differences in abundance, acting mainly over Carnus hemapterus.
Our results also reveal that it is necessary to consider the non-infective stages of parasites when analysing host-parasite relationships since they are important for understanding habitat selection criteria, host-range and processes regulating coexistence with other species. In our study system, the observed patterns of prevalence and abundance of imagoes and pupae of three supposedly generalist ectoparasites (Carnus hemapterus and the louse flies Pseudolynchia canariensis and Ornithophila metallica) suggest that, for some parasite species, the requirements of non-infective stages may be more restrictive than the ones of the parasitic stages.
Since some of the ectoparasites here studied are vectors of haemoparasites and since the identification of associations host-vector-pathogens is critical for understanding the ecology of diseases, we studied the likely vectorial role of biting midges (Fam. Ceratopogonidae). We found that Culicoides paolae and C. circumscriptus were common visitors in nests of various species of troglodyte birds. These midges feed on various bird species and harbour four lineages of Haemoproteus. Thus, they can play an important role in the transmission of Haemoproteus in the study area.
Finally, this study reveals that the infracommunity of ectoparasites of a cavity-nesting bird species in a semi-arid environment is rich (made up of at least species of 8 different families, including a recently introduced species, C. paolae), with some species being particularly abundant.
We conclude that socioenvironmental characteristics at small scale are major determinants of the spatial distribution of nest-based ectoparasites in an arid environment., Este trabajo ha sido posible gracias a la concesión de una beca predoctoral de formación de personal investigador (BES-2015-075951) del Ministerio de Economía, Industria y Competitividad asociada al proyecto CGL2014-55969-P, financiado con fondos FEDER y del Ministerio de Economía, Industria y Competitividad., Peer reviewed

Nombre de la variable y descripción: Year (Año de toma de datos / Year), LayingDate (Fecha de puesta / laying date), Habitat (Habitat (Robledal:1 / Pinar: 2) / Habitat (Oak:1 / Pine: 2)), Mate (Pareja única, con hembra primaria (Mon) o hembra secundaria con ayuda (SecA) o secundaria sin ayuda (SecNoA)/ female mating as primary (Mon), secondary with male help (SecA) or secondary without help (SecNopA)), Age (Edad / Age), MaxPApril (Precipitación máxima de abril / Maximum precipitation in April), MaxPMay (Precipitación máxima de May / Maximum precipitation in May), NAOw (Índice de NAO en invierno / NAO index in winter), PrecipMinLD (Precipitación mínima durante la fecha de puesta / Minimum precipitation during laying), MaxTApril (Temperatura máxima de abril / Maximum temperature in April), TempMaxPreLD (Temperatura máxima durante el período prepuesta / Maximum temperature during prelaying period), PrecipMinPreLD (Precipitación mínima durante el período prepuesta / Minimum precipitation during prelaying period), TempMinLD (Temperatura mínima durante la fecha de puesta / Minimum temperature during laying), MinTMay (Temperatura mínima de Mayo / Maximum temperature in May), MinTApril (Temperatura mínima de Abril / Minimum temperature in April), Female (Identidad de la hembra / Female identity)., The origin of natural selection is found in the environmental heterogeneity that determines a variation in relative fitness among phenotypes. However, individuals in wild populations are exposed not a single but to a plethora of biotic and abiotic environmental factors. Surprisingly, the relative influence of multiple environmental conditions on relative fitness of phenotypes has rarely been tested in wild populations. Identifying the main selection agent(s) is crucial when the target phenotype is tightly linked to reproduction and when temporal variation in selection is expected to affect evolutionary response. By using individual-based information from a short-lived migratory passerine, the pied flycatcher (Ficedula hypoleuca), we studied the relative influence of 28 temperature- and precipitation-based factors at local and global scales on selection on breeding time (egg laying) at the phenotypic level over 29 breeding seasons. Selection penalised late breeders using number of recruits as proxy of fitness. Minimum temperatures in April and May were the environmental drivers that best explained selection on laying date. In particular, there was negative directional selection on laying date mediated by minimum temperature in April being strongest in colder years. In addition, non-linear selection on laying date was shaped by minimum temperatures in May, with selection on laying date changing from null to negative as the breeding season advances. The intensity of selection on late breeders increased when minimum temperatures in May were highest. Our results illustrate the complex influence of environmental factors on selection on laying date in wild bird populations. Despite minimum temperature in April being the only variable that changed overtime, its increase did not induce a shift in laying date in the population. In this songbird population stabilizing selection has led to a three-decade stasis in breeding time. We suggest that the influence of local climatic variables on selection in addition to global climatic trends, may constrain phenotypic change., Financiación: PID2019-104835GB-I00; CGL2015-70639-P/BOS; CGL2014-55969-P; CGL2015-70639-P; ARAID., Peer reviewed

© 2022, The Author(s). Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/., Mating system theory predicts that social polygyny—when one male forms pair bonds with two females—may evolve by female choice in species with biparental care. Females will accept a polygynous male if the benefit of mating with a male providing high-quality genes or rearing resources outweighs the cost of sharing mate assistance in parental care. Based on this rationale, we hypothesise that the population frequency of social polygyny (FSP) varies due to changes in mate sharing costs caused by changing environmental conditions. We predicted that: (1) polygamous females (i.e. mated with a polygynous male) pay a survival cost compared to monogamous females; (2) FSP would be higher in years with better rearing conditions and (3) the difference in survival rates between monogamous and polygamous females would be small following years with higher FSP. We tested these predictions using regression and multistate analyses of capture-recapture data of pied flycatchers, Ficedula hypoleuca, in central Spain collected over 26 years (1990–2016). Monogamous females had a higher mean survival rate than polygamous females (prediction 1), but there was no difference in survival between polygynous and monogamous males. In addition, FSP was positively associated with annual reproductive success (a proxy of the quality of rearing conditions—prediction 2). Finally, following years with high FSP, the survival of polygamous females was similar to that of monogamous females (prediction 3), while the chance of breeding in a polygamous state for 2 years in a row increased for both males and females. Our findings suggest that fluctuating environmental conditions may be a necessary but neglected aspect of understanding social polygyny mechanisms., Spanish Ministry of Economy and Competitiveness CGL2014-55969-P and CGL2015-70639-P, Hungarian National Research, Development and Innovation Office. K-129215, Spanish MECD (FJCI-2015-24579), ARAID foundation, National Research, Development and Innovation Office (NKFIH) grant nr. K-139992., Peer reviewed

Parent–offspring conflict over food allocation can be modeled using two theoretical frameworks: passive (scramble competition) and active choice (signaling) resolution models. However, differentiating between these models empirically can be challenging. One possibility involves investigating details of decision-making by feeding parents. Different nestling traits, related to competitive prowess or signaling cryptic condition, may interact additively or non-additively as predictors of parental feeding responses. To explore this, we experimentally created even-sized, small broods of pied flycatchers and manipulated nestling cryptic quality, independently of size, by vitamin E supplementation. We explored how interactions between nestling cryptic condition, size, signals, and spatial location predicted food allocation and prey-testing by parents. Parents created the potential for spatial scramble competition between nestlings by feeding from and to a narrow range of nest locations. Heavier supplemented nestlings grew faster and were more likely to access profitable nest locations. However, the most profitable locations were not more contested, and nestling turnover did not vary in relation to spatial predictability or food supply. Postural begging was only predicted by nestling hunger and body mass, but parents did not favor heavier nestlings. This suggests that size-mediated and spatial competition in experimental broods was mild. Pied flycatcher fathers allocated food in response to nestling position and begging order, while mothers seemingly followed an active choice mechanism involving assessment of more complex traits, including postural intensity interacting with order, position, and treatment, and perhaps other stimuli when performing prey-testings. Differences in time constraints may underlie sex differences in food allocation rules., This work was supported by the Spanish Ministry of Economy and Competitiveness (SMEC) (grant number CGL2014-55969-P to L.P.-R. and T.R.), internal EBD proposal call Microproyectos (grant number SEV-2012-0262 to TR), a Severo Ochoa (grant number SEV-2012-0262 to L.P.-P.) and by a predoctoral contract funded by “Fondo Social Europeo” at the University of Castilla-La Mancha (grant number 2019-PREDUCLM-11785 to D.P.-P.)., Peer reviewed

Mediterranean woodland environments are characterised by high spatial and temporal heterogeneity, which means the inhabiting species face a wide variety of selective pressures. Species may respond differently to habitat heterogeneity and so distinct eco-evolutionary scenarios may be responsible for the inter-habitat variability in reproductive strategies observed in certain species. The inter-forest variability of some reproductive traits in passerines has been examined by comparing forest patches or separated fragments. However, there is still little information regarding how such highly mobile animals adjust their breeding performance across continuous and heterogeneous woodlands. Here we studied the reproductive performance of a population of Blue Tits (Cyanistes caeruleus) in an area of continuous Mediterranean woodland that included two mountain slopes and four different types of forest, ranging from deciduous oak forests to perennial non-oak forests. We studied the habitat heterogeneity and inter-forest phenotypic variation in terms of reproductive performance and adult and nestling biometry, besides also exploring the effects of ectoparasites on Blue Tit reproduction. Eggs were laid earliest in deciduous Pyrenean Oak (Quercus pyrenaica) forests, while clutch size and the number of fledglings were highest in the humid Pyrenean Oak forest, which had the greatest tree coverage and most humid climate, and lowest in the coniferous Scots Pine (Pinus sylvestris) forest. There were no inter-forest differences in hatching (percentage of nests with at least one egg hatched) and fledging (percentage of nests in which at least one nestling fledged) success. Similarly, there were no inter-forest differences in adult and nestling biometry, but adults that raised more fledglings had a lower body mass, while males whose females laid larger clutches had smaller tarsi. Most ectoparasites did not affect Blue Tit reproduction, although Culicoides had a negative impact on nestling body mass. These results suggest that Blue Tits can adjust their reproductive effort to the forest where they breed even across a very small spatial scale. Different eco-evolutionary scenarios, such as phenotypic plasticity or genetic structuring and local adaptation, might explain the phenotypic differentiation in the reproductive strategies observed over small areas in woodlands., Peer reviewed

The role of plumage ornamentation as a signal of parasite infection is a key issue in the evolution of animal behaviour. Despite the undeniable role of host–parasite interactions in sexual selection, it is still unclear how parasites influence the variance in the expression of females displaying multiple ornaments. Here, by taking advantage of a long-term and individual-based, monitored population of pied flycatchers, Ficedula hypoleuca, in a Mediterranean area, we investigated the variation in the expression of wing patch (size) and forehead patch (occurrence and size) in relation to infections with haemosporidian parasites in breeding adult females. Haemosporidian infection was related to wing patch size, and this association varied in direction and magnitude depending on the origin of birds (locally born versus immigrant) and the type of breeding habitat (oakwood versus pine plantation). Specifically, differences in wing patch size were most evident among immigrant females breeding in the pine plantation, with noninfected females expressing larger wing patches than infected ones. Regarding the forehead patch, its occurrence was also modulated by haemosporidian infection through two-way interactions with bird origin (lower occurrence in locally born females) and breeding habitat type (lower occurrence among infected than uninfected females in the oakwood, whereas the opposite was true in the pine plantation). Only bird age predicted forehead patch size. Therefore, in addition to haemosporidian infection, the expression of these ornaments was related to extrinsic (breeding habitat) and intrinsic (age, origin) factors, which suggests the existence of trade-offs between physiological responses to infection and the expression of secondary sexual traits. Overall, our results suggest that plumage ornaments provide independent and reliable information on the haemosporidian infection status of female pied flycatchers., This research was supported by projects CGL2006-07481/BOS (to J. C. Senar), CGL2009-10652 (to J. C. Senar), CGL2011-29694 (to J. Potti) and CGL2014- 55969-P (to F. Valera) from the Spanish Ministry of Education and project PAC05-006-2 (to J. A. Dávila) from Universidad de Castilla-La Mancha (UCLM, Spain). During writing, E.G.B. was supported by a Margarita Salas Contract financed by the European Union-NextGenerationEU and the Recovery, Transformation and Resilience Plan (Spanish Ministry of Universities). C.C. was supported by the grant ref. RYC2021-033977-I funded by MCIN/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR. J.M. was supported by a postdoctoral researcher contract for scientific excellence under the Plan Propio de I+D+i of the Universidad de Castilla – La Mancha (UCLM). D.C. was supported by a Talent Attraction fellowship from the Autonomous Community of Madrid (CAM), Spain (2022-T1_AMB-24025) and the project PID2022-141763NA-I00, funded by MCIN/AEI (https://doi.org/10.13039/501100011033)., Funding for open access charge: Universidad de Granada / CBUA., Peer reviewed

Ascertaining the feeding behavior of vectors is a key for understanding epidemiology of the infections they transmit. For some host–vector–parasite systems, this information is biased towards human and peridomestic habitats, frequently underestimating the likely role of wildlife. In addition, studies on vector interactions often focus on a one-to-one host–vector relationship, even though it is crucial to analyze how multiple vector species interact with multiple hosts. These biases particularly affect our knowledge of sandflies, the main vector of Leishmania spp. and various phleboviruses, that are rarely explored in non-peridomestic habitats and in the context of multiple interactions with various hosts. To reveal the multihost/multivector network involving phlebotomine sandflies in a semiarid and poorly populated area of Spain, we sampled the sandfly community close to avian nests by means of two trapping methods (Centers for Disease Control (CDC) and sticky traps) during 3 years and identified the blood-meal source of all engorged sandflies. We detected six phlebotomine species with Phlebotomus perniciosus, P. papatasi, and Sergentomyia minuta being the most abundant ones. We identified 13 blood source species, with humans being the most common one, followed by Coracias garrulus (European roller) and Sus scrofa (likely wild boar). Five of the six sandfly species fed largely on wild mammals, although, three also fed on wild birds. Phlebotomus sergenti only fed on birds based on this analysis. Phlebotomus papatasi and P. sergenti were common visitors of bird nests suggesting an endophagic behavior. A network analysis showed a highly-connected and poorly-specialized network wherein sandflies shared most of the blood source and showed an opportunistic feeding behavior with marked anthropophilia. Our results obtained close to avian nests show that sandfly populations are maintained by various wild animals, which will greatly complicate the management and control of the pathogens they transmit to humans and domestic animals., J. Veiga was funded during this study by the Spanish Ministry of Economy, Industry and Competitiveness by means of a predoctoral grant (Grant BES-2015-075951), by the Margarita Salas program funded by Spanish Ministry of Universities (managed by University of Granada), and by the Juan de la Ciervan program (Grant FJC2021-048057-I) funded by MCIN/AEI/Agencia Estatal de Investigación and the European Union «NextGenerationEU/PRTR». F. Valera received financial support from the Spanish Ministry of Economy and Competitiveness, the European Regional Development Fund, MCIN/AEI/Agencia Estatal de Investigación and by the European Union “NextGenerationEU”/PRTR (Grants CGL2014-55969-P, PGC2018-097426-B-C22, and TED2021-130035B-100). DNA sequencing and molecular data analysis of blood meals was financed by the Canada First Research Excellence Fund, through the Food From Thought Program awarded to Dr. Paul Hebert at the Centre for Biodiversity Genomics, University of Guelph, Ontario, Canada. The open access charge was funded by Universudad de Granada/CBUA., Peer reviewed

Female and male hosts may maximise their fitness by evolving different strategies to compensate for the costs of parasite infections. The resulting sexual dimorphism might be apparent in differential relationships between parasite load and body condition, potentially reflecting differences in energy allocation to anti-parasitic defences. For example, male lacertids with high body condition may produce many offspring while being intensely parasitised. In contrast, female lacertids may show a different outcome of the trade-offs between body condition and immunity, aiming to better protect themselves from the harm of parasites. We predicted that females would have fewer parasites than males and a lower body condition across parasitaemia levels because they would invest resources in parasite defence to mitigate the costs of infection. In contrast, the male strategy to maximise access to females would imply some level of parasite tolerance and, thus, higher parasitaemia. We analysed the relationship between the body condition of lizards and the parasitemias of Karyolysus and Schellackia, two genera of blood parasites with different phylogenetic origins, in 565 females and 899 males belonging to 10 species of the Lacertidae (Squamata). These lizards were sampled over a period of 12 years across 34 sampling sites in southwestern Europe. The results concerning the Karyolysus infections were consistent with the predictions, with males having similar body condition across parasitaemia levels even though they had higher infection intensities than females. On the other hand, females with higher levels of Karyolysus parasitaemia had lower body condition. This is consistent with the prediction that different life strategies of male and female lacertids can explain the infection patterns of Karyolysus. In contrast, the parasitaemia of Schellackia was consistently low in both male and female hosts, with no significant effect on the body condition of lizards. This suggests that lizards of both sexes maintain this parasite below a pathogenic threshold., Spanish Ministerio de Economía y Competitividad and European Regional Development Fund (MINECO/ERDF) provided financial support: CGL2012-40026-C02-01 and CGL2015-67789-C2-1-P to S.M., CGL2012-40026-C02-02 to J. Martínez, CGL2014-53523-P to J. Martín, CGL2008-01522, CGL2012-32459
and CGL2016-76918 to P.S.F., CGL2011-30393 to I.D.l.R., MCI-CGL2011-24150/BOS and CGL-2014-55969-P
to G.M.-R. Spanish Ministerio de Educación y Ciencia and the European Regional Development Fund (MEC/ERDF) funded J.J.C. (CGL2008-00137/BOS). Spanish Ministerio de Ciencia e Innovación (MICIN/ERDF) provided financial support to S.M. and R.M.-P. (PGC2018-097426-B-C21). The study was conducted under licences from all responsible authorities (numbers: 10/033298.9/13, 10/373043.9/12, 10/380311.9/12,
10/315072.9/11, 10/040449.9/13, 10/165944.9/18, PROEX 271/19, 10/356576.9/20, 2012/272, 372/2013-VS
(FAU13_038), DGMEN/SEN/avp_13_025_aut, Biod/MLCE-68564, EP/CYL/101/2013, EP/SG/625/2011, EP/SG/213/2013, SGYB/EF/FJRH Re-9H/13, INAGA/5000201/24/2013/04434, CSVZ5-4ZBJN-02QA1-DYREG,
EHV/24/2010/105-106, LCE/mp24/2012/426, 276/HCEFLCD/DLCDPN/DPRN/CFF, 500201/24/2013/5692(1098), 2013/025426(74/CS/13), GMN/GyB/JMIF, ENSN/JSG/JEGT/MCF, ENSN/JSG/BRL/MCF, SGMN/GyB/JMIF, and SSA/SI/MD/ps) including also Dirección General de Gestión del Medio Natural (Junta de Andalucía), Departamento de Desarrollo Rural y Medio Ambiente (Gobierno de Navarra), Préfet des Pyrénées-Atlantiques (Service Patrimoine, Ressources, Eau, Biodiversité, Division Continuité Écologique et Gestion des Espèces; 41-2016), and Instituto da Conservação da Natureza e das Florestas (ICNF; 733/2020/CAPT)., Peer reviewed

Individuals experience changes in multiple traits across their lifespan, often peaking before senescence-driven declines. Many species display secondary sexual traits that can vary with age due to physiological and selective processes, influencing individual fitness and sexual selection. Using 13 years of longitudinal data from a pied flycatcher (Ficedula hypoleuca) population, we analyzed age-related variation in wing and forehead patches in both sexes. Wing patch size increased with age due to both within- and between-individual effects, with sex-specific patterns. Forehead patch size showed sex-dependent age effects: quadratic in females, linear in males, with only males exhibiting within-individual changes. In females, forehead patch occurrence followed a quadratic age pattern, influenced by selective (dis)appearance and reproductive timing. These results show that age-related ornament expression arises from different processes across traits and sexes, highlighting potential trade-offs between reproduction and ornamentation. This study underscores the role of both sexes' ornaments in selection and life-history strategies., We would like to thank all the people who helped us in the field over the three decades of study. Permission for working in protected areas was granted by the Consejerías de Medio Ambiente de la Comunidad de Madrid and Comunidad de Castilla-La Mancha. This research received support from projects CGL2006-07481/BOS (to J.C. Senar), CGL2009-10652 (to J.C. Senar), CGL2011-29694 (to J. Potti), CGL2014-55969-P (to F. Valera), and PID2019-104835GB-I00 (to J. Martinez-Padilla) from the Spanish Ministry of Science. More recently, this work has been supported by the Autonomous Community of Madrid (CAM), Spain (project: 2022-T1_AMB-24025 to David Canal) and the Spanish Ministry of Science and Innovation (projects: PID2022-141763NA-I00 to David Canal and PID2022-138133NB-I00 to J. Martinez-Padilla). E.G.B. was supported by a Margarita Salas Contract financed by the European Union-NextGenerationEU and the Recovery, Transformation, and Resilience Plan (Spanish Ministry of Universities). J.M.P. was supported by the ARAID Foundation. CC was supported by the grant ref. RYC2021-033977-I funded by MCIN/AEI and the European Union NextGenerationEU/PRTR. D.C. received support from a CAM Talent Attraction grant associated with project 2022-T1_AMB-24025 and the project PID2022-141763NA-I00 funded by MCIN/AEI/10.13039/501100011033. We are grateful to two anonymous reviewers for their insightful comments on an earlier version of the article., Peer reviewed

Memoria presentada por Daniel Parejo Pulido para optar al grado de Doctor con mención internacional por la Universidad de Castilla – La Mancha., Instituto de Investigación en Recursos Cinegéticos (CSIC-UCLM-JCCM) Doctorado en Ciencias Agrarias y Ambientales: Departamento de Ciencia y Tecnología Agroforestal y Genética Universidad de Castilla – La Mancha., [EN] The current understanding of begging signals and parent-offspring conflict over parental investment is largely shaped by influential models of scramble competition and signalling of need in avian broods. Godfray’s model of differential benefits, in particular, has become the dominant paradigm, inspiring extensive theoretical and empirical research. This model posits that offspring signal their need honestly, with those in greater need signalling more intensely due to higher benefits from food, allowing parents to allocate resources efficiently through an active choice mechanism. The system stabilizes via a signalling cost, creating a highly informative separating equilibrium. However, this model has faced significant criticism regarding its applicability to natural systems. While much of this criticism is theoretical, few empirical studies rigorously test the model’s assumptions, with many This thesis aims to experimentally test several assumptions and predictions of Godfray’s model that have been subject to criticism.researchers instead assuming its validity without question., [ES] La comprensión actual de las señales de petición y el conflicto entre padres e hijos por la transferencia de recursos está en gran medida influenciada por los modelos de competencia igualitaria y de señalización de la necesidad en familias de aves altriciales. En particular, el modelo de Godfray de beneficios diferenciales se ha convertido en el paradigma dominante, inspirando una amplia investigación teórica y empírica. Este modelo propone que las crías indican de forma sincera su nivel de necesidad, siendo las más necesitadas las que solicitan con mayor intensidad debido a los mayores beneficios que reciben por el alimento, permitiendo que los padres asignen recursos de manera eficiente a través de un mecanismo de elección activa. El sistema se estabiliza mediante un coste de señalización, lo que conlleva a un equilibrio de separación de señales bien diferenciadas muy informativo. Sin embargo, este modelo se ha enfrentado a numerosas críticas relacionadas con su aplicabilidad en los sistemas naturales. Aunque gran parte de estas críticas son teóricas, pocos estudios empíricos han ensayado rigurosamente los supuestos del modelo, y muchos investigadores asumen su validez sin cuestionarla.
Esta tesis tiene como objetivo principal ensayar experimentalmente ciertos supuestos y predicciones controvertidas del modelo de Godfray que han sido objeto de críticas., Los objetivos de esta tesis se llevaron a cabo gracias a la financiación proveniente de los siguientes proyectos y ayudas: - Proyecto ref. CGL2014-55969-P del Ministerio de Economía y Competitividad. - Proyecto ref. CGL2017-83843-C2-1-P del Ministerio de Ciencia y Universidades. - Proyecto ref. PGC2018-099596-B-I00 cofinanciado por el Ministerio de Ciencia, Innovación y Universidades, la Agencia Española de Investigación (10.13039/501100011033) y por FEDER – Una manera de hacer Europa. - Proyecto ref. PID2021-126673NB-I00 del Ministerio de Ciencia e Innovación. - Microproyectos EBD, Programa Severo Ochoa para Centros de Excelencia; Ref. SEV-2012-0262. Daniel Parejo Pulido fue beneficiario durante la tesis de un contrato predoctoral del Plan Propio de la Universidad de Castilla – La Mancha (referencia: 2019-PREDUCLM-11785) cofinanciado por el “Fondo Social Europeo”, seguido de un contrato asociado al Programa INVESTIGO asociado al Plan de Recuperación, Transformación y Resiliencia del Ministerio de Trabajo y Economía Social, la Junta de Comunidades de Castilla – La Mancha y el Consejo Superior de Investigaciones Científicas (CSIC), cofinanciado por los fondos NextGenerationEU., Peer reviewed

[EN] Reproductive parameters of the European roller (Coracias garrulus) in Almería. The data are linked to the article Vaclav et al. Reproductive flexibility in a single-brooded migrant: Can the European roller (Coracias garrulus) adapt to extreme weather events? Journal of Avian Biology: in press., [ES] Parámetros reproductores de Carraca europea (Coracias garrulus) en Almería. Los datos están vinculados al artículo Vaclav et al. Reproductive flexibility in a single-brooded migrant: Can the European roller (Coracias garrulus) adapt to extreme weather events? Journal of Avian Biology: en prensa., - VEGA grant from the Ministry of Education of the Slovak Republic (No. 2/0111/24).
- Projects CGL2008-00562, CGL2014-55969, PGC2018-097426-B-C22 and TED2021-130035B-100 (funded by MCIN/AEI/ 10.13039/501100011033/FEDER, “ERDF A way of making Europe”, and the European Union “NextGenerationEU”/PRTR).
- Juan de la Cierva program (FJC2021-048057-I) funded by MICIU/AEI/10.13039/501100011033 and the European Union “NextGenerationEU”/PRTR., Peer reviewed

Global climate change has intensified extreme weather events, including short-duration but intense rainfall, which can significantly impact avian reproduction. This study examines the effects of extreme rainfall on the reproductive phenology and performance of the European roller Coracias garrulus, a single-brooded migratory bird, in a semiarid ecosystem. We analysed breeding parameters during 2023, characterised by exceptionally intense and concentrated rainfall, and compared them with long-term data (2006–2024). Our results indicate that breeding phenology in 2023 exhibited significant shifts. Rollers initiated egg-laying approximately five days earlier than the long-term average in the early breeding season, while late-season laying was delayed by approximately 11 days. The prolonged breeding season was marked by a high incidence of breeding failures, particularly during incubation. Moreover, we observed an unprecedented surge in apparent replacement breeding attempts, a rare phenomenon in this single-brooded species. Despite these challenges, overall population productivity remained consistent with long-term averages because successful breeding was heavily concentrated in resilient nest substrates, nest boxes and sandstone burrows, which buffered the weather's impact and compensated for catastrophic failures in stone cavities. Our findings underscore the European roller's capacity for reproductive flexibility, but also suggest the significant fitness costs and constraints associated with these adaptive responses. These results highlight the need for conservation strategies that consider climate-induced phenological shifts and the importance of nest box designs optimised to mitigate the interacting adverse effects of extreme rainfall and subsequent heatwaves., RV was supported by a VEGA grant from the Ministry of Education of the Slovak Republic (no. 2/0111/24). FC-V was supported by the postdoctoral contract "Margarita Salas" (CT18/22) funded by MICIU/AEI/10.13039/501100011033 and the European Union “NextGenerationEU”/PRTR. FV received financial support from the projects CGL2008-00562, CGL2014-55969, PGC2018-097426-B-C22, and TED2021-130035B-100 (funded by MCIN/AEI/ 10.13039/501100011033/FEDER, “ERDF A way of making Europe”, and the European Union “NextGenerationEU”/PRTR). JV received financial support from the Juan de la Cierva program (FJC2021-048057-I) funded by MICIU/AEI/10.13039/501100011033 and the European Union “NextGenerationEU”/PRTR., Peer reviewed

There is increasing evidence that female ornamentation is not merely a genetic by-product of male ornamentation and has evolved through sexual and/or social selection processes. However, the magnitude and direction of phenotypic selection on ornamental traits may fluctuate according to environmental conditions and life-history traits such as conspecific density and natal dispersal, affecting the covariation between ornament expression and fitness. Natal dispersal is assumed to be costly due to unfamiliarity and local maladaptation to the new environment. Since both dispersal and the expression/maintenance of ornamental traits are behavioural and energetically costly, selection pressures on ornamental traits are expected to differ depending on dispersal strategies. Breeding density, as a proxy of sexual and social competition, is also expected to influence the selection dynamics on ornaments. Here, we used a 34-year individual-based dataset of pied flycatchers (Ficedula hypoleuca) to analyse phenotypic selection on the occurrence and size of a heritable ornamental trait (the white forehead patch) in females in relation to their natal dispersal behaviour and overall breeding density. We found no differences in the relative number of recruits produced by female with and without a forehead patch. Moreover, neither dispersal nor breeding density influenced the magnitude or direction of phenotypic selection on the white forehead patch in female pied flycatchers. Lastly, we documented a temporal change in female ornament size, which may be explained by a genetic correlation between the sexes. We encourage further work to fully understand the factors that shape the temporal dynamics in female ornamentation., This research received support from projects CGL2006-07481/BOS (to J.C. Senar), CGL2009-10652 (to J.C. Senar), CGL2011-29694 (to J. Potti), CGL2014-55969-P (to F. Valera), and PID2019- 104835GB-I00 (to J. Martinez-Padilla) from the Spanish Ministry of Science. More recently, this work has been supported by the Autonomous Community of Madrid (CAM), Spain (project: 2022-T1_AMB-24025 to David Canal) and the Spanish Ministry of Science and Innovation (projects: PID2022-141763NA-I00 and CNS2024-154721 to David Canal and PID2022-138133NB-I00 to J.M.-P.). I.R. was supported by the project CNS2024-154721. C.C. was supported by the grant ref. RYC2021-033977-I funded by MCIN/AEI and the European Union NextGenerationEU/PRTR., Peer reviewed

Global climate change has intensified extreme weather events, including short-duration but intense rainfall, which can significantly impact avian reproduction. This study examines the effects of extreme rainfall on the reproductive phenology and performance of the European roller Coracias garrulus, a single-brooded migratory bird, in a semiarid ecosystem. We analysed breeding parameters during 2023, characterised by exceptionally intense and concentrated rainfall, and compared them with long-term data (2006–2024). Our results indicate that breeding phenology in 2023 exhibited significant shifts. Rollers initiated egg-laying approximately five days earlier than the long-term average in the early breeding season, while late-season laying was delayed by approximately 11 days. The prolonged breeding season was marked by a high incidence of breeding failures, particularly during incubation. Moreover, we observed an unprecedented surge in apparent replacement breeding attempts, a rare phenomenon in this single-brooded species. Despite these challenges, overall population productivity remained consistent with long-term averages because successful breeding was heavily concentrated in resilient nest substrates, nest boxes and sandstone burrows, which buffered the weather's impact and compensated for catastrophic failures in stone cavities. Our findings underscore the European roller's capacity for reproductive flexibility, but also suggest the significant fitness costs and constraints associated with these adaptive responses. These results highlight the need for conservation strategies that consider climate-induced phenological shifts and the importance of nest box designs optimised to mitigate the interacting adverse effects of extreme rainfall and subsequent heatwaves.

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.

Individuals experience changes in multiple traits across their lifespan, often peaking before senescence-driven declines. Many species display secondary sexual traits that can vary with age due to physiological and selective processes, influencing individual fitness and sexual selection. Using 13 years of longitudinal data from a pied flycatcher (Ficedula hypoleuca) population, we analyzed age-related variation in wing and forehead patches in both sexes. Wing patch size increased with age due to both within- and between-individual effects, with sex-specific patterns. Forehead patch size showed sex-dependent age effects: quadratic in females, linear in males, with only males exhibiting within-individual changes. In females, forehead patch occurrence followed a quadratic age pattern, influenced by selective (dis)appearance and reproductive timing. These results show that age-related ornament expression arises from different processes across traits and sexes, highlighting potential trade-offs between reproduction and ornamentation. This study underscores the role of both sexes' ornaments in selection and life-history strategies.

Female and male hosts may maximise their fitness by evolving different strategies to compensate for the costs of parasite infections. The resulting sexual dimorphism might be apparent in differential relationships between parasite load and body condition, potentially reflecting differences in energy allocation to anti-parasitic defences. For example, male lacertids with high body condition may produce many offspring while being intensely parasitised. In contrast, female lacertids may show a different outcome of the trade-offs between body condition and immunity, aiming to better protect themselves from the harm of parasites. We predicted that females would have fewer parasites than males and a lower body condition across parasitaemia levels because they would invest resources in parasite defence to mitigate the costs of infection. In contrast, the male strategy to maximise access to females would imply some level of parasite tolerance and, thus, higher parasitaemia. We analysed the relationship between the body condition of lizards and the parasitemias of Karyolysus and Schellackia, two genera of blood parasites with different phylogenetic origins, in 565 females and 899 males belonging to 10 species of the Lacertidae (Squamata). These lizards were sampled over a period of 12 years across 34 sampling sites in southwestern Europe. The results concerning the Karyolysus infections were consistent with the predictions, with males having similar body condition across parasitaemia levels even though they had higher infection intensities than females. On the other hand, females with higher levels of Karyolysus parasitaemia had lower body condition. This is consistent with the prediction that different life strategies of male and female lacertids can explain the infection patterns of Karyolysus. In contrast, the parasitaemia of Schellackia was consistently low in both male and female hosts, with no significant effect on the body condition of lizards. This suggests that lizards of both sexes maintain this parasite below a pathogenic threshold.

8 p., Parasitoid wasps may act as hyperparasites and sometimes regulate the populations of their hosts by a top-down dynamic. Nasonia vitripennis (Walker, 1836) is a generalist gregarious parasitoid that parasitizes several host flies, including the blowfly Protocalliphora Hough, 1899 (Diptera, Calliphoridae), which in turn parasitizes bird nestlings. Nonetheless, the ecological factors underlying N. vitripennis prevalence and parasitoidism intensity on its hosts in natural populations are poorly understood. We have studied the prevalence of N. vitripennis in Protocalliphora azurea (Fallén, 1817) puparia parasitizing wild populations of pied flycatcher (Ficedula hypoleuca) and blue tit (Cyanistes caeruleus) birds in two Mediterranean areas in central and southern Spain. We found some evidence that the prevalence of N. vitripennis was higher in moist habitats in southern Spain. A host-dependent effect was found, since the greater the number of P. azurea puparia, the greater the probability and rate of parasitoidism by the wasp. Our results also suggest that N. vitripennis parasitizes more P. azurea puparia in blue tit nests than in pied flycatcher nests as a consequence of a higher load of these flies in the former. Based on the high prevalence of N. vitripennis in P. azurea puparia in nature, we propose that this wasp may regulate blowfly populations, with possible positive effects on the reproduction of both bird species., Ministerio de Economía y Competitividad, FEDER

Wild birds are hosts of Culicoides from as early on as the nesting stage when constrained to their nests. However, the environmental factors which determine the abundance and composition of Culicoides species within each bird nest are still understudied. We sampled Culicoides from Eurasian blue tit (Cyanistes caeruleus) nests found in two types of forest located in southern Spain. Firstly, we monitored the abundance of Culicoides species in bird nests from a dry Pyrenean oak deciduous forest and a humid mixed forest comprising Pyrenean and Holm oaks throughout two consecutive years. During the third year, we performed a cross-fostering experiment between synchronous nests to differentiate the role of rearing environment conditions from that of the genetically determined or maternally transmitted cues released by nestlings from each forest. We found 147 female Culicoides from 5 different species in the birds’ nests. The abundance of Culicoides was higher in the dry forest than in the humid forest. Culicoides abundance, species richness, and prevalence were greater when the nestlings were hatched later in the season. The same pattern was observed in the cross-fostering experiment, but we did not find evidence that nestling’s features determined by the forest of origin had any effect on the Culicoides collected. These results support the notion that habitat type has a strong influence on the Culicoides affecting birds in their nests, while some life history traits of birds, such as the timing of reproduction, also influence Culicoides abundance and species composition.