It has been proposed recently that labile state variables (e.g. energy reserves) can have a key role in the development and maintenance of consistent between-individual behavioural variation (i.e. animal personality) within population. In male Carpetan rock lizards (Iberolacerta cyreni), the provitamin D3 component of femoral gland secretion acts as an honest signal in sexual communication. Further, vitamin D3 has many important metabolic functions in reptiles. Therefore, by employing a factorial experiment with food (high vs. low) and vitamin D3 (supplemented vs. control) treatments in wild-caught reproductive male I. cyreni, we tested whether changing labile components of individual state affected (i) behavioural consistency (the degree of between-individual difference) and (ii) behavioural type (mean behaviour). Animal personality in activity was present in all treatments; however, personality was present only in the high food × vitamin D3 supplementation treatment in shelter use and it was present in all but the low food × placebo treatment in risk taking. Lizards (i) decreased activity in the high food treatment, (ii) increased shelter use in the vitamin D3 supplementation treatment and (iii) increased risk taking in the low food × vitamin D3 supplementation treatment. We conclude that short-term changes in individual state affect both behavioural consistency and behavioural type of reproductive male I. cyreni. Unfavourable conditions resulted in decreased behavioural consistency, while high-state individuals became less active in general. Individuals with high specific (vitamin D3) but low general (energy reserves) state took higher risk. We discuss several evolutionary explanations for the reported patterns., LZG was supported by funds from The Ministry of Economy and Competitiveness (Spain) (CGL2015-70639-P), PL and JM were supported by the Ministerio de Economía y Competitividad project MINECO CGL2014-53523-P, The research also received support from the SYNTHESYS Project http://www.synthesys.info/, which is financed by European Community Research Infrastructure Action under the FP7 “Capacitie” Program., Peer reviewed

Understanding the background mechanisms affecting the emergence and maintenance of
consistent between-individual variation within population in single (animal personality) or
across multiple (behavioural syndrome) behaviours has key importance. State-dependence
theory suggests that behaviour is `anchored' to individual state (e.g. body condition, gender,
age) and behavioural consistency emerges through behavioural-state feedbacks. A number
of relevant state variables are labile (e.g. body condition, physiological performance) and
expected to be affected by short-term environmental change. Yet, whether short-term environmental
shifts affect behavioural consistency during adulthood remains questionable.
Here, by employing a full-factorial laboratory experiment, we explored if quantity of food (low
vs. high) and time available for thermoregulation (3h vs. 10h per day) had an effect on activity
and risk-taking of reproductive adult male European green lizards (Lacerta viridis). We
focussed on different components of behavioural variation: (i) strength of behavioural consistency
(repeatability for animal personality; between-individual correlation for behavioural
syndrome), (ii) behavioural type (individual mean behaviour) and (iii) behavioural predictability
(within-individual behavioural variation). Activity was repeatable in all treatments. Risktaking
was repeatable only in the low basking treatments. We found significant betweenindividual
correlation only in the low food × long basking time group. The treatments did not
affect behavioural type, but affected behavioural predictability. Activity predictability was
higher in the short basking treatment, where it also decreased with size ( age). Risk-taking
predictability in the short basking treatment increased with size under food limitation, but
decreased when food supply was high. We conclude that short-term environmental change
can alter various components of behavioural consistency. The effect could be detected in
the presence/absence patterns of animal personality and behavioural syndrome and the
level of individual behavioural predictability, but not in behavioural type, Peer reviewed

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

[Access and reuse conditions] This database and its components are subject to a Creative Commons Attribution International licence 4.0., The cost of reproduction is a key concept in life-history trade-offs. However, our understanding of the reproductive costs is biased towards measures of reproductive effort obtained before offspring independence. During the post-fledging dependence period (PFDP) is well known that parents feed and protect their offspring. However, the effort devoted to this reproductive activity has never been considered under the scheme of the costs of reproduction, and the potential fitness benefits and costs, for offspring and parents respectively, of the duration of PFDP remain barely known. We estimated the duration of the PFDP during 5 years using wild common kestrels (Falco tinnunculus) and studied its association with survival probability and future parental reproductive performance. Our results show that longer PFDPs increased the survival probability of fledglings, probably due to the benefits obtained by parental care. Also, we found that providing longer PFDPs was associated with reduced clutch sizes but not number of fledglings the subsequent breeding season in males. We suggest that increased parental expenditure on offspring during the PFDP may represent a potential cost of reproduction in breeding males., The long-term monitoring associated to this study was funded by projects CGL2004- 04479/BOS, CGL2007-61395/BOS, CGL2010-15726/BOS and CGL2015-70639-P from the Ministerio de Economía y Competitividad, Peer reviewed

All relevant data are deposited at URI: http://hdl.handle.net/10261/169111; DOI: http://dx.doi.org/10.20350/digitalCSIC/8561., The cost of reproduction is a key concept in life-history trade-offs. However, our understanding of the reproductive costs is biased towards measures of reproductive effort obtained before offspring independence. During the post-fledging dependence period (PFDP), it is well known that parents feed and protect their offspring. However, the effort devoted to this reproductive activity has never been considered in the context of of the costs of reproduction. Moreover, the potential fitness benefits and costs for offspring and parents, respectively, of the duration of the PFDP are largely unknown. We estimated the duration of the PFDP over 5 years using wild common kestrels (Falco tinnunculus) and studied its association with survival probability and future parental reproductive performance. Our results show that longer PFDPs increase the survival probability of fledglings, probably due to the benefits obtained from parental care. In addition, we found that providing longer PFDPs was associated with reduced clutch sizes but not the number of fledglings in the subsequent breeding season in males. We suggest that increased parental expenditures on offspring during the PFDP may represent a potential cost of reproduction in breeding males., The long-term monitoring associated to this study was funded by projects CGL2004-04479/BOS, CGL2007-61395/BOS, CGL2010-15726/BOS and CGL2015-70639-P from the Ministerio de Economía y Competitividad., Peer reviewed

The expression of elaborate sexual displays is associated with individual quality ensuring reliable information about the bearers. However, the associated cost of expressing enhanced sexual traits is expected to change according to environmental circumstances. Specifically, the cost of maintaining or producing a signal is predicted to increase when environmental conditions are unfavorable, which may lead to a reduction in signal expression as shown in several species. Here, we compared the calling behavior of male red grouse Lagopus lagopus scoticus living in an area of experimentally increased intra-sexual competition to that of males living in a control area. Levels of intra-sexual competition were experimentally manipulated by testosterone implants in a subset of captured males. In addition, we compared the association between two sexual traits, calling behavior and comb size, of males living in these two areas. Although call frequency was not affected by different levels of intra-sexual competition, males from the control area performed shorter calls than individuals from the treatment area. Additionally, a positive association between comb size and call duration was found only for males in the area of lower aggressiveness. We suggest that environmental conditions influence the expression of multiple plastic sexual traits, depending on the costs and the information conveyed about different individual qualities., RT was supported by a PhD grant from the Spanish Ministry of Education (FPU, grant no. AP2009-0762). PV was supported by an Intra-European Marie Curie fellowship (European Union Seventh Framework Programme, FP7/2007-2013, grant agreement no. 252499). JM-P was supported by a JAE-doc fellowships and a research grant (CGL2015-70639-P, Ministerio de Economía y Competitividad)., Peer Reviewed

Order of birth has profound consequences on offspring across taxa during development and can have effects on individuals later in life. In birds, differential maternal allocation and investment in their progeny lead to variance in the environmental conditions that offspring experience during growth within the brood. In particular, laying and hatching order have been proposed to influence individual quality during the growing period, but little is known about the fitness consequences that these two factors have for offspring from a lifetime perspective. We explored the effect of laying and hatching order on post‐fledgling survival (measured as recruitment probability) and lifetime reproductive success (LRS) in Common Kestrels Falco tinnunculus, using a long‐term and individual‐based dataset. First‐hatched chicks showed higher survival probability and LRS than their siblings. This effect was not due to body condition of the individuals at adulthood, the quality of their mates or the reproductive outcome compared with later‐hatched individuals. Instead, first‐hatched chicks had a higher recruitment probability. This could be explained by the higher body condition attained by first‐hatched chicks at the end of the nesting period, perhaps due to an enhanced competitive advantage for food over their siblings at the time of hatching. Laying order, in contrast to hatching order, appeared to have little or no effect on LRS. Our results suggest that hatching order within siblings predicts fitness, and that better early‐life conditions during growth experienced by first‐hatched chicks improve first survival and then recruitment, resulting in an enhanced LRS., This study was financed by the Spanish Ministerio de Economía y Competitividad (Projects: CGL2004‐04479/BOS; CGL2007‐61395/BOS; CGL2010‐15726/BOS; CGL2015‐70639‐P). Suggestions from R. Kimball and two anonymous referees greatly improved an early version of this paper. This study was conducted in accordance with all applicable laws and rules set forth by the Spanish Government and all licences granted by Junta de Castilla y León., Peer Reviewed

To provide reliable information about individual-specific characteristics, sexual signals should be consistently displayed within an individual at least within a particular social context or time window. However, some male traits, like bird song, depict extreme within-individual variations even within a very short time frame. To investigate the extent by which acoustic displays in male collared flycatchers (Ficedula albicollis) reveal consistent individual-specific attributes or more flexible characteristics, we assessed the repeatability of various song traits at different sampling regimes (within-day, between-day, and between-year contexts). Repertoire size showed considerably high and significant repeatability (R > 0.25) in all temporal contexts suggesting that it can potentially indicate an individual attribute that is shaped by genetic background, permanent environmental effects, or long-term experience. Song rate, song length, mean frequency and frequency bandwidth, tempo of syllables, and within-song complexity had small-to-moderate repeatability (R < 0.25) that was significant for the within-day scenario only. Environmental effects can confound repeatability estimates, as males that changed nest boxes between song recordings performed with lower consistency than those that systematically sang on the same territory. Hence, the characteristics of particular songs could reveal aspects that are sensitive to changes in the environment rendering a signal function to the within-individual variance of songs. The consistency of acoustic signals and their sensitivity to the environment determines what kind of information can be conveyed to the receivers., This study was supported by funds from The Ministry of Economy and Competitiveness (Spain) (CGL2015-70639-P), the Hungarian Scientific Research Fund (K-75618, K-101611, K-105517), the National Research, Development and Innovation Office (NKFIH, K-115970, and PD-115730), the Erdők a Közjóért Alapítvány, and the Pilisi Parkerdő Zrt. GH was also funded by the János Bólyai Research Scholarship of the Hungarian Academy of Sciences., 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).

Understanding and forecasting the effects of environmental change on wild populations requires knowledge on a critical question: do populations have the ability to evolve in response to that change? However, our knowledge on how evolution works in wild conditions under different environmental circumstances is extremely limited. We investigated how environmental variation influences the evolutionary potential of phenotypic traits. We used published data to collect or calculate 135 estimates of evolvability of morphological traits of European wild bird populations. We characterized the environmental favourability of each population throughout the species’ breeding distribution. Our results suggest that the evolutionary potential of morphological traits decreases as environmental favourability becomes high or low. Strong environmental selection pressures and high intra-specific competition may reduce species’ evolutionary potential in low-and highfavourability areas, respectively. This suggests that species may be least able to adapt to new climate conditions at their range margins and at the centre. Our results underscore the need to consider the evolutionary potential of populations when studying the drivers of species distributions, particularly when predicting the effects of environmental change. We discuss the utility of integrating evolutionary dynamics into a biogeographical perspective to understand how environmental variation shapes evolutionary patterns. This approach would also produce more reliable predictions about the effect of environmental change on population persistence and therefore on biodiversity., We acknowledge funding from the Spanish Ministerio de Economía y Competitividad (grants nos. CGL2012-34685, CGL2015-70639-P and CGL2016-76173-P) and thanks to the ERA-Net BiodivERsA, with the national funder FCT (Project: BIODIVERSA/0003/2011). A.E. has a contract funded by the project 1098/2014 (Organismo Autónomo Parques Nacionales, Spain)., Peer reviewed

Null-hypothesis testing (NHT) based on statistical significance is the most conventional statistical framework, on which neuroscientists rely for the analysis of their data. However, this approach can provide misleading results if p-values are wrongly interpreted, as often done in practice. Misconceptions can arise, in particular, when i) wrong null-hypothesis is chosen for reference; ii) the assumptions of the statistical model are not met; iii) p-values are interpreted as the probability of the null- or alternative hypotheses or as the measure of the importance of findings; iv) statistical thresholds guide scientific conclusions and decision making; v) one applies multiple testing or p-hacking. In this commentary, we address these issues by bringing into the focus the uniform distribution of p-values with the hope of enhancing the appreciation and proper use of the NHT approach among neuroscientists. We propose guidelines for the correct interpretations of p-values that brain and behavioural scientists may adopt to improve both the transparency of statistical reports and the value of scientific conclusions drawn from them., LZG was supported by funds from The Ministry of Economy and Competitiveness (Spain, CGL2015-70639-P) through the >Programa Estatal de Investigación Científica y Técnica de Excelencia>(CGL2015-70639-P), and the National Research, Development and Innovation Office (Hungary, NKFIH, K-115970).

Members of the genus Stenus (Coleoptera, Staphylinidae) possess a unique adhesive labial prey-capture apparatus as an adaptation to their predatory behaviour. In order to examine the relationships between the morphology of the prey-capture apparatus, its adhesive performance and the prey-capture success, we combined force measurements, morphological and behavioural investigations of representatives of 14 Central European species of this genus. The direct relationship between these traits was studied by using phylogenetic generalized least squares and a molecular phylogeny generated from mitochondrial cytochrome c oxidase I partial sequences. Force measurements revealed strong interspecific differences in the adhesive forces generated during the predatory attack; these differences entail significant differences in the prey-capture success. The interspecific differences in adhesive performance were functionally correlated with the pad morphology and divergences in the compressive forces generated during the predatory strike. Allometric analyses revealed that the pad area scaled with positive allometry with respect to body size, whereas the adhesive forces scaled with negative allometry with respect to body size, that is, the pads' efficiency decreased with body size. Our experimental approach demonstrates a direct functional relationship between the morphology of the prey-capture device of Stenus beetles and its performance in a natural behavioural context., This study was partly financed by the German Science Foundation (project PAK 478: BE 2233/10–1). LZG was supported by funds from The Ministry of Economy and Competitiveness (Spain) (CGL2015-70639-P) and The National Research, Development and Innovation Office (NKFIH, K-115970).

Color patterns, such as bars or dots that cover the body surface of animals are generally thought to play roles in signaling and camouflage. In birds, however, the macroscopic aspects of plumage coloration are less well understood, as past studies typically described plumage colorations by using spectrophotometric analyses. To provide insight into the evolution of plumage patterns as sexual signals, we characterized interspecific and intersexual variations in the plumage patterns of estrildid finches and tested their associations with other courtship signals and life-history traits using a comparative phylogenetic approach. Our results support the idea that plumage patterns in estrildids are favored by sexual selection because large-sized conspicuous plumage patterns are possessed by species with an elaborate courtship dance. These plumage patterns may also play roles in social signaling because patterns are more conspicuous in species with intraspecific brood parasitism. We predict that pattern traits can be favored by mate choice or intrasexual competition when they can serve as honest indicators of individual condition. As our results are consistent between the sexes, we suggest that the same selective force is acting on the evolution of plumage patterns in males and females in parallel. Finally, we also found a trade-off between large size and vivid color patterns, suggesting that too conspicuous patterns are costly, presumably because of the risk of catching the eyes of potential predators. Therefore, plumage patterns are also shaped by natural selection., This study was supported by the JSPS Grant-in-Aid for Young Scientists (23680027 and 16H06177) and Hokkaido University WinGS Global Networking Award 2015 to Masayo Soma, and by the Ministry of Economy and Competitiveness (Spain) (CGL2015-70639-P) and the National Research, Development and Innovation Office (Hungary) (K-115970) to L.Z.G.

The comparison of acoustic complexity across individuals is often essential for understanding the evolution of acoustic signals. In many animal taxa, as a proxy of acoustic complexity, repertoire size is intensively studied; however, its estimation is challenging in species with large repertoires, as this process is time-consuming and may involve considerable subjectivity for the classification of signal elements. Here, we propose a novel application of the minimum spanning tree (MST) method for comparing individuals’ signal complexity, an approach that does not require classification process. We suggest that the differences in the MST length predict the differences in the repertoire sizes between individuals. To evaluate these proposals, first, we performed a simulation study investigating the effect of the practically important variables (repertoire size, number of acoustic parameters, sample size, distribution of element types and within-group variance) on the MST length. Second, we compared repertoire size estimates from the same song data from male collared flycatchers obtained using the fully manual, computer-aided manual and MST methods. In our simulation study, we found that the repertoire size strongly correlated with MST length. We also found significant effects of sample size, number of parameters and within-group variance, as well as how uniformly the samples were distributed between the groups, on the MST length. Our empirical data also revealed a strong correlation between the computer-aided manual estimation of repertoire sizes and MST length, which was comparable to the correlation between the estimations of repertoire size obtained using the two different manual methods. Therefore, we suggest using the MST method to compare the acoustic complexity among individuals in birds and other animals, with the practical restrictions suggested by our simulation results., This study was supported by funds from the Ministry of Economy and Competitiveness (Spain; CGL2015-70639-P); Hungarian Scientific Research Fund (K-75618, K-105517); National Research, Development and Innovation Office (NKFIH; K-115970, PD-115730), Erdők a Közjóért Alapítvány; and Pilisi Parkerdő Zrt.

Despite growing appreciation of the importance of considering a pace-of-life syndrome (POLS) perspective to understand how animals interact with their environment, studies relating behavior to life history under altered environmental conditions are still rare. By means of a comparative analysis of flight initiation distances (i.e., the distance at which an animal takes flight when a human being is approaching) across > 300 bird species distributed worldwide, we document here the existence of a POLS predicted by theory where slow-lived species tend to be more risk-averse than fast-lived species. This syndrome largely emerges from the influence of body mass, and is highly dependent on the environmental context. Accordingly, the POLS structure vanishes in urbanized environments due to slow-lived species adjusting their flight distances based on the perception of risk. While it is unclear whether changes in POLS reflect plastic and/or evolutionary adjustments, our findings highlight the need to integrate behavior into life history theory to fully understand how animals tolerate human-induced environmental changes., [Significance statement] Animals can often respond to changing environmental conditions by adjusting their behavior. However, the degree to which different species can modify their behavior depends on their life history strategy and on the environmental context. Species-specific perception of risk is a conspicuous example of adjustable behavior tightly associated with life history strategy. While there is a general tendency of higher risk aversion in rural than city-dwelling birds, it is dependent on the species’ life history strategy. Slow-lived species are more prone to adjust their flight initiation distances based on the perception of risk, allowing humans to approach closer in urban than rural environments. Behavior must therefore be taken into account together with life history to reliably assess species’ vulnerability at the face of ongoing environmental change., DS was supported by the project CGL2013-47448-P from the Spanish Government, AGV by project 2013–4834 from the Swedish Research Council and project IA201716 from PAPIIT, UNAM, IMC by the Fonds de Recherches du Quebec—Nature et Technologies (FQRNT) programme and by Harvard University, and LZG was supported by funds from The Ministry of Economy and Competitiveness (Spain) (CGL2015-70639-P) and The National Research, Development and Innovation Office (Hungary) (K-115970).

The hypothesis of pace-of-life syndromes (POLS) predicts relationships between traits including life history traits and risk-taking behaviour that can be mediated by the trade-off between current and future reproductive value. However, alternative causal mechanisms may also generate covariance among these traits without trade-offs. We investigated the relationships between survival to the next year, current reproductive investment and risk-taking behaviour (flight initiation distance) in male collared flycatchers, Ficedula albicollis, using long-term data. We used structural equation modelling (SEM) to uncover whether the associations among traits are mediated by a common latent factor that determines how individuals balance the trade-off between current and future reproductive value. As trade-offs could be concealed when there are differences in resource acquisition between individuals, we also included potential causes of these differences, body mass and body size, in the analysis. We found that risk-taking behaviour was positively related to reproductive investment and negatively to survival to the next year as could be predicted if investment into a risky behaviour is traded against future prospects. However, the most supported SEM model also suggested that survival to the next year was positively related to current reproductive investment, contrary to predictions of a hypothesis based on trade-off. These results remained qualitatively similar when controlling for body condition. In conclusion, we only could derive partial support for the POLS hypothesis. We suggest that aspects of individual quality, and not only trade-offs, should also be considered when interpreting the relationships between life history and behavioural traits., [Significance statement] We investigated the association between two life history components (survival to the next year and current reproductive effort) and risk-taking behaviour, relying on long-term records from a passerine bird, to investigate the predictions of the pace-of-life syndrome (POLS) hypothesis. Using structural equation modelling, we found support for a causal model that implies that risk-taking negatively affects survival to the next year and that survival to the next year and current reproductive effort are strongly and positively associated. Controlling for the effect of body condition did not fundamentally change these relationships. We could not find conclusive evidence for the investigated traits being mediated by a common underlying factor, as generally predicted by the POLS hypothesis. However, the sign of the relationship between risk-taking behaviour and survival to the next year was as predicted by the POLS hypothesis., This study was supported by funds from the Hungarian National Research, Development and Innovation Office (K-75618, K-101611, K-105517, K-115970) and by funds from the Ministry of Economy and Competitiveness in Spain (CGL2015-70639-P).

Behavioural consistency within and across behaviours (animal personality and behavioural syndrome, respectively) has been vigorously studied in the last decade, leading to the emergence of “animal personality” research. It has been proposed recently that not only mean behaviour (behavioural type), but the environmentally induced behavioural change (behavioural plasticity) might also differ between individuals within populations. While case studies presenting between-individual variation in behavioural plasticity have started to accumulate, the mechanisms behind its emergence are virtually unknown. We have recently demonstrated that ecologically relevant environmental stimuli during ontogeny are necessary for the development of animal personality and behavioural syndromes. However, it is unknown whether between-individual variation in behavioural plasticity is hard-wired or induced. Here, we tested whether experience with predation during development affected predator-induced behavioural plasticity in Rana dalmatina tadpoles. We ran a common garden experiment with two ontogenetic predation treatments: tadpoles developed from hatching in either the presence or absence of olfactory predator stimuli. Then, we assayed all tadpoles repeatedly for activity and risk-taking both in the absence and presence of olfactory predator stimuli. We found that (a) between-individual variation in predator-induced behavioural plasticity was present only in the group that developed in the presence of olfactory stimuli from predators and (b) previous experience with predatory stimuli resulted in lower plastic response at the group level. The latter pattern resulted from increased between-individual variation and not from universally lower individual responses. We also found that experience with predation during development increased the predictability (i.e. decreased the within-individual variation unrelated to environmental change) of activity, but not risk-taking. In line with this, tadpoles developing under perceived predatory risk expressed their activity with higher repeatability. We suggest that ecologically relevant environmental stimuli are not only fundamental for the development of animal personality and behavioural syndromes, but also for individual variation in behavioural plasticity. Thus, experience is of central importance for the emergence of individual behavioural variation at many levels.

Behaviour shown in a novel environment has important consequences for fitness in many animals. It is widely studied with standard tests by placing the individuals into an unfamiliar experimental area, that is the so-called open-field or novel environment test. The biological relevance of traits measured under such artificial conditions is questionable and could be validated by establishing a link with variables that truly reflect exploration in the wild. Our aim in this field study was to characterize behaviours measured in an artificial novel environment (an aviary) and assess the biological relevance of them in the collared flycatcher (Ficedula albicollis). Therefore, we measured the repeatability and the association of multiple behavioural traits, as well as their relationship with breeding dispersal (that reflects exploration in the wild). We found evidence for non-zero repeatability for number of crosses between the quarters, number of hops and perching latency in the aviary, and these repeatabilities were high when assessed at shorter time windows. Additionally, birds with short perching latency in the novel environment were more likely residents and bred closer to their breeding nest box in the previous year, which may suggest that latency to perch is connected to dispersal in the wild. In sum, our results indicate that behaviours assessed in an artificial environment are individual-specific at least on smaller timescales, and at least, one component of these behaviours is correlated with an ecologically relevant trait.

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

© 2022 The Authors. Journal of Evolutionary Biology published by John Wiley & Sons Ltd on behalf of European Society for Evolutionary Biology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The moral rights of the named author(s) have been asserted., Most studies of phenotypic selection in the wild have focussed on morphological and life‐history traits and looked at abiotic (climatic) variation as the main driver of selection. Consequently, our knowledge of the effects of biotic environmental variation on phenotypic selection on sexual traits is scarce. Population density can be considered a proxy for the intensity of intrasexual and intersexual competition and could therefore be a key factor influencing the covariation between individual fitness and the expression of sexual traits. Here, we used an individual‐based data set from a population of pied flycatchers (Ficedula hypoleuca) monitored over 24 years to analyze the effect of breeding density on phenotypic selection on dorsal plumage colouration, a heritable and sexually selected ornament in males of this species. Using the number of recruits as a fitness proxy, our results showed overall stabilizing selection on male dorsal colouration, with intermediate phenotypes being favoured over extremely dark and dull individuals. However, our results did not support the hypothesis that breeding density mediates phenotypic selection on this sexual trait. We discuss the possible role of other biotic factors influencing selection on ornamental plumage., DC received financial support from the Hungarian Academy of Sciences (MTA Premium Postdoctoral Research Program; ID: 2019‐353) and the Spanish Ministry of Education and Science (I3PBDP2005). J.M.‐P. is funded by ARAID foundation and funded by Spanish Ministry of Science, Innovation and Universities (research grant: PID2019‐104835GB‐I00). CC received financial support from the Spanish Ministries of Economy and Competitiveness (SVP‐2013‐067686) and Science, Innovation and Universities (FJC2018‐038412‐I). During writing, we were supported by project CGL2015‐70639 of the Spanish Ministry of Economy and Competitiveness., Peer reviewed

Temporal changes in environmental conditions may play a major role in the year-to-year variation in fitness consequences of behaviours. Identifying environmental drivers of such variation is crucial to understand the evolutionary trajectories of behaviours in natural contexts. However, our understanding of how environmental variation influences behaviours in the wild remains limited. Using data collected over 14 breeding seasons from a collared flycatcher (Ficedula albicollis) population, we examined the effect of environmental variation on the relationship between survival and risk-taking behaviour, a highly variable behavioural trait with great evolutionary and ecological significance. Specifically, using annual recapture probability as a proxy of survival, we evaluated the specific effect of predation pressure, food availability, and mean temperature on the relationship between annual recapture probability and risk-taking behaviour (measured as flight initiation distance [FID]). We found a negative trend, as the relationship between annual recapture probability and FID decreased over the study years and changed from positive to negative. Specifically, in the early years of the study, risk-avoiding individuals exhibited a higher annual recapture probability, whereas in the later years, risk-avoiders had a lower annual recapture probability. However, we did not find evidence that any of the considered environmental factors mediated the variation in the relationship between survival and risk-taking behaviour., K-115970/Hungarian National Research, Development and Innovation Office
CGL2015-70639-P/Ministry of Economy and Competitiveness in Spain
Eötvös Loránd University
PID2019-104835GB-I00/ARAID Foundation and the Ministry of Science and Innovation
2019-353/Hungarian Academy of Sciences, Peer reviewed

The study of host–parasite co-evolution is a central topic in evolutionary ecology. However, research is still fragmented and the extent to which parasites influence host life history is debated. One reason for this incomplete picture is the frequent omission of environmental conditions in studies analyzing host–parasite dynamics, which may influence the exposure to or effects of parasitism. To contribute to elucidating the largely unresolved question of how environmental conditions are related to the prevalence and intensity of infestation and their impact on hosts, we took advantage of 25 years of monitoring of a breeding population of pied flycatchers, Ficedula hypoleuca, in a Mediterranean area of central Spain. We investigated the influence of temperature and precipitation during the nestling stage at a local scale on the intensity of blowfly (Protocalliphora azurea) parasitism during the nestling stage. In addition, we explored the mediating effect of extrinsic and intrinsic factors and blowfly parasitism on breeding success (production of fledglings) and offspring quality (nestling mass on day 13). The prevalence and intensity of blowfly parasitism were associated with different intrinsic (host breeding date, brood size) and extrinsic (breeding habitat, mean temperature) factors. Specifically, higher average temperatures during the nestling phase were associated with lower intensities of parasitism, which may be explained by changes in blowflies’ activity or larval developmental success. In contrast, no relationship was found between the prevalence of parasitism and any of the environmental variables evaluated. Hosts that experienced high parasitism intensities in their broods produced more fledglings as temperature increased, suggesting that physiological responses to severe parasitism during nestling development might be enhanced in warmer conditions. The weight of fledglings was, however, unrelated to the interactive effect of parasitism intensity and environmental conditions. Overall, our results highlight the temperature dependence of parasite–host interactions and the importance of considering multiple fitness indicators and climate-mediated effects to understand their complex implications for avian fitness and population dynamics., This research received support from 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, as well as project PAC05-006-2 (to J.A. Dávila) from the Universidad de Castilla-La Mancha (Spain). During the writing process, 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). D.C. received support through a Talent Attraction fellowship from the Autonomous Community of Madrid (CAM), Spain (2022-T1_AMB-24025), and the projects PID2022-141763NA-I00, CGL2015-70639-P, and PID2019-104835GB-I00, funded by MCIN/AEI (doi: 10.13039/501100011033). 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.P. was supported by the ARAID Foundation. Funding for open access charge: Universidad de Granada/CBUA., Peer reviewed

Several hypotheses predict that the major histocompatibility complex (MHC) drives mating preference in females. Olfactory, colour or morphological traits are often found as reliable signals of the MHC profile, but the role of avian song mediating MHC-based female choice remains largely unexplored. We investigated the relationship between several MHC and acoustic features in the collared flycatcher (Ficedula albicollis), a European passerine with complex songs. We screened a fragment of the class IIB second exon of the MHC molecule, of which individuals harbour 4–15 alleles, while considerable sequence diversity is maintained at the population level. To make statistical inferences from a large number of comparisons, we adopted both null-hypothesis testing and effect size framework in combination with randomization procedures. After controlling for potential confounding factors, neither MHC allelic diversity nor the presence of particular alleles was associated remarkably with the investigated qualitative and quantitative song traits. Furthermore, genetic similarity among males based on MHC sequences was not reflected by the similarity in their song based on syllable content. Overall, these results suggest that the relationship between features of song and the allelic composition and diversity of MHC is not strong in the studied species. However, a biologically motivated analysis revealed that individuals that harbour an MHC allele that impairs survival perform songs with broader frequency range. This finding suggests that certain aspects of the song may bear reliable information concerning the MHC profile of the individuals, which can be used by females to optimize mate choice., This study was supported by funds from the Ministry of Economy and Competitiveness in Spain (CGL2015-70639-P), the Hungarian Scientific Research Fund (K75618, K101611), the National Research, Development and Innovation Office in Hungary (K105517, K115970, PD115730, PD124043) and the Polish Ministry of Science and Higher Education (N N304 401338). The project was also supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences to ES., Peer reviewed

Qualitative and quantitative assessments of bird song repertoires are important in studies related to song learning, sexual selection and cultural evolution. Despite methods for automatic analysis, it is still necessary to engage in manual cutting, segmenting and clustering of bird song elements in many cases. Here, we describe a program, the Ficedula Toolbox, which has been made available for free to the bird song research community and has recently come into extensive use. The main advantages of this package are the opportunity to conduct all processing steps in one framework and the option of carrying out computer-aided manual clustering. Output files are ready for further analyses, such as estimation of repertoire size, sequential analysis and repertoire overlap calculation. With this program, findings based on empirical data from the Collared Flycatcher (Ficedula albicollis) song show high inter-observer similarity, and thus, reproducible results. The toolbox may be especially applicable to the analysis of song in species with moderately high repertoires., This study was supported by funds from the Ministry of Economy and Competitiveness, Spain (CGL2015-70639-P) and the National Research, Development and Innovation Office Hungary (NKFIH, K-115970 and PD-115730)., Peer reviewed