Lorenzo Pérez-Rodríguez

University of Castilla-La Mancha · Instituto de Investigación en Recursos Cinegéticos (IREC)

Colorful traits play an important role in animal communication. Melanin‐based colorations are the most extended color traits in animals and are produced by two types of endogenous melanic pigments: eumelanins and pheomelanins, the last ones being the least studied in the context of communication. The production of pheomelanin requires a semi‐essent...

Carotenoid-based coloration is an indicator of the fitness of birds, as carotenoids act as a limiting resource obtained through the diet. In many altricial birds, this carotenoid-based coloration is found in the nestling' mouth flanges, signaling their physical condition and acting as a visual indicator for parent-offspring communication. To invest...

Exploring the evolutionary architecture of female sexual traits and their potential evolvability is important to understand their possible role as post-mating sexual signals. Egg colouration has been proposed to be one of these post-mating sexual signals, honestly advertising female quality in birds, especially in blue-green laying species. In this...

Symptoms of illness offer insights into an organism’s condition, altering social signals that affect others’ behavior. Nestling birds employ begging signals to solicit parental care, but the extent to which begging reflects nestling health beyond hunger remains controversial. We investigated how experimentally induced changes in health affect beggi...

Glucocorticoid (GC) hormones have traditionally been interpreted as indicators of stress, but the extent to which they provide information on physiological state remains debated. GCs are metabolic hormones that amongst other functions ensure increasing fuel (i.e. glucose) supply on the face of fluctuating energetic demands, a role often overlooked...

Nestlings normally exhibit a mix of traits that attract parental care, such as postural and vocal begging and carotenoid‐based mouth colouration. These signals are hypothesised to be signs of nestling needs (vocal begging) and quality (mouth colouration). Therefore, we hypothesised that broods, where nestlings beg for less time and display more sat...

The number and quality of social bonds can have major consequences for fitness. For example, in socially monogamous species with biparental care, pair bond quality has been linked to the latency to breed as well as the number and survival of offspring. Given these benefits, what mechanisms prevent some individuals from forming strong pair bonds? Ma...

Las poblaciones de aves se encuentran en un declive generalizado, por lo que las técnicas de monitoreo eficientes, rápidas y no invasivas pueden ayudar a la conservación de las aves al predecir el éxito reproductivo a corto plazo. Sin embargo, estas técnicas suelen consumir tiempo, ser costosas o tener efectos negativos en el éxito reproductivo de...

El estrés oxidativo es un fenómeno complejo que ha sido el foco de intensa investigación desde diferentes campos del conocimiento. Desde hace más de veinte años ha atraído también la atención de los ecólogos del comportamiento. En este artículo pretendemos describir (1) los métodos más simples y útiles para su medición, (2) los procedimientos más v...

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...

A central issue in avian ecology deals with the trade‐off between investment life‐history components, such as reproductive effort, and parasite and disease resistance. During reproduction, differences in the particular needs of males and females may further affect the outcome of such trade‐off. However, most studies performed to date on avian speci...

Interlocus sexual conflict (IRSC) occurs because of shared interactions that have opposite effects on male and female fitness. Typically, it is assumed that loci involved in IRSC have sex-limited expression and are thus not directly affected by selective pressures acting on the other sex. However, if loci involved in IRSC have pleiotropic effects i...

Food selection is a key aspect of a bird's life history strategy, so understanding how birds respond to variation in food abundance is relevant to evaluating their general ecology and survival, and also the potential consequences of the degradation of environments impacted by livestock. We studied the dietary ecology of Vermilion Fly-catchers (VEFL...

The red-legged partridge is increasingly recognized as a good study model in ecophysiology and evolutionary biology. Most research in these fields has focused on the expression of coloured social signals. The fact that this species expresses the two main types of coloured ornaments among vertebrates (i.e. carotenoid- and melanin-based) has attracte...

Floaters constitute the sexually mature but non-breeding part of populations. Despite being ubiquitous in most species, knowledge about floaters is scarce. Ignoring this significant number of individuals may strongly bias our understanding of population dynamics and sexual selection processes. We used the spotless starling ( Sturnus unicolor ) to e...

It has been proposed that blue‐green egg coloration is a condition‐dependent female sexual trait that may modify paternal care in a post‐mating sexual selection scenario. This pattern may arise because the pigment responsible for eggshell colouration (biliverdin) may be a costly and limited resource, whose availability is linked to female health st...

The active acquisition of plumage cosmetic coloration by iron oxides has been described in several bird species (notably the Bearded Vulture Gypaetus barbatus, but also in cranes, pelicans and other vulture species), but its function remains controversial. We tested the hypothesis that iron oxide acquired through mud bathing may protect feathers fr...

Parental condition transfer effects occur when the parents' physiological state during reproduction affects offspring performance. Oxidative damage may mediate such effects, yet evidence that oxidative damage experienced by parents during reproduction negatively affects offspring fitness is scarce and limited to early life stages. We show in Japane...

Resumen La condición corporal puede influir en diferentes procesos fenológicos que, a su vez, pueden ser desempeñados diferencialmente según la edad y sexo de los individuos. Presentamos la biometría, condición corporal, estado reproductivo y muda de la tijereta sabanera (Tyrannus s. savana), un migrante austral del Neotrópico. En La Pampa, Argenti...

Urbanization constitutes one of the major transformations of natural habitats, creating new areas characterized by multiple potential wildlife stressors. Birds that live in highly anthropized zones are confronted with physiological and behavioural challenges caused by these stressors. Here, we investigated if several health parameters differed betw...

Maternal allocation of androgens to the egg yolk allows mothers to adaptively manipulate offspring phenotype. Increases of egg androgen levels have often been shown to induce sex-specific effects. Some previous studies suggest that females specifically may suffer a fitness reduction after early exposure to high androgen levels. In this study, we ex...

Ecophysiological studies have highlighted the relevance of the avian immune system in individual fitness prospects in the wild. However, studies on the ontogeny of avian immunity are scarce. We analyse age-related changes in the cellular constitutive immunity throughout nestling development, as well as its relationship with sex and brood size. We f...

Increases in DNA degradation have been detected in numerous situations in which organisms are exposed to pollutants. However, outside of the ecotoxicological literature, few studies have investigated whether there exists important variation in DNA integrity in free-living, healthy animals. Using the alkaline version of the comet assay to estimate D...

Sexual steroids can play an important role as life-history organizers. In males, high circulating testosterone levels induce physiological/behavioral costs and benefits, leading to trade-offs. However, studies simultaneously testing the impact of these levels in both fitness components (survival and fecundity) during lifetime are scarce and limited...

El precioso color rojo de las perdices nos llama tanto la atención debido probablemente a los mismos mecanismos evolutivos que han formado parte de nuestra propia historia como especie animal. El rojo lo asociamos en parte a la agresividad y al sexo. Lo asociamos nosotros y, casi con toda seguridad, también las perdices. En las siguientes líneas de...

Female birds can influence offspring development by adjusting egg size or by a differential allocation of egg resources. Such maternal effects can be expected to be shaped by natural selection, given the costs connected to the allocation of maternal resources. Among egg components, yolk androgens play an important role in affecting offspring life-h...

Sexual selection promotes the evolution of conspicuous animal ornaments. To evolve as signals, these traits must reliably express the “quality” of the bearer, an indicator of individual fitness. Direct estimates of individual fitness may include the contribution of longevity and fecundity. However, evidence of a correlation between the level of sig...

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 hy...

Stress during early development can induce substantial long‐term effects in organisms. In the case of birds, despite growth compensations, nestlings reared under harsh conditions typically show reduced survival chances in adulthood. It has been proposed that environmental early‐life stressors could affect longevity via effects on telomere length, p...

Oxidative stress can contribute to an acceleration of telomere erosion leading to cellular senescence and ageing. Increased investment in reproduction is known to accelerate senescence, generally resulting in reduced future reproductive potential and survival. To better understand the role of oxidative status and telomere dynamics in the conflict b...

Limited resources trigger trade-offs in resource allocation. Reproduction is one of the most demanding activities in terms of energy, and costs related to reproduction can be apparent either as reduced future reproduction or as survival. However, costs are not always detected, because individual heterogeneity in quality and resource acquisition may...

Colour patterns (e.g. irregular, spotted or barred forms) are widespread in the animal kingdom, yet their potential role as signals of quality has been mostly neglected. However, a review of the published literature reveals that pattern itself (irrespective of its size or colour intensity) is a promising signal of individual quality across species...

Avian embryos are exposed to yolk androgens that are incorporated into the egg by the ovulating female. These steroids can affect several aspects of embryo development, often resulting in increases in overall size or the speed of growth of different traits. However, several studies suggest that they also entail immune costs to the offspring. In thi...

Conditions experienced during early development can affect the fitness of an organism. During early life, oxidative stress levels can be particularly high due to the increased metabolism and the relatively immature antioxidant system of the individual, and this may have medium- and long-term fitness consequences. Here we explore variations between...

Stress is ubiquitous in the life of animals and a key determinant of their well-being and fitness. By quantifying levels of feather corticosterone in growing feathers (CORTf), we measured integrated stress responses in a monogamous game bird, the red grouse Lagopus lagopus scoticus. We investigated the effects of parasites and social mate choice on...

The carotenoid-based ornaments displayed by many birds often play key roles in social and sexual signalling, revealing information about individual quality. However, the proximate regulation of the honesty of sexual traits remains controversial. Understanding the mechanisms of coloured trait production and maintenance requires an accurate descripti...

Female birds may adjust their offspring phenotype to the specific requirements of the environment by differential allocation of physiologically active substances into yolks, such as androgens. Yolk androgens have been shown to boost embryonic development, growth rate and competitive ability of nestlings, but they can also entail immunological costs...

Avian egg yolks contain various amounts of maternally derived androgens that can modify offspring phenotype and adjust their development to posthatching environment. Seemingly adaptive variation in yolk androgen levels with respect to breeding density conditions or male attractiveness has been found in numerous studies. One important consideration...

Ectoparasites may imply a cost in terms of oxidative stress provoked by the inflammatory responses in hosts. Ectoparasites may also result in costs for nestlings and brooding females because of the direct loss of nutrients and reduced metabolic capacity resulting from parasite feeding activities. These responses may involve production of reactive o...

Lipid peroxidation products are widely used as markers of oxidative damage in the organism. To properly interpret the information provided by these markers, it is necessary to know potential sources of bias and control confounding factors. Here, we investigated the relationship between two indicators of lipid mobilization (circulating levels of tri...

A key aspect in the study of plumage traits with a potential role in communication is the cost associated with trait production and maintenance, expressed in terms of oxidative stress. In the Iberian Pied Flycatcher (Ficedula hypoleuca iberiae (Witherby, 1928)), males and some females exhibit a white forehead patch and both sexes present conspicuou...

Nest-dwelling ectoparasites may result in costs for nestlings of cavity nesters in terms of compromised growth and condition before fledging. The reduction or elimination of nest ectoparasites to study their effects on avian hosts can be conducted through physical methods like heat-treatment or through chemical methods using insecticides. Pyrethroi...

In a reliable signalling system, individual quality is expected to mediate the costs associated with ornamental displays, with relatively lower costs being paid by individuals of higher quality. These relative costs should depend not only on individual quality, but also on levels of intra-sexual competition. We explored the current and delayed effe...

Environmental conditions and individual strategies in early life may have a profound effect on fitness. A critical moment in the life of an organism occurs when an individual reaches independence and stops receiving benefits from its relatives. Understanding the consequences of individual strategies at the time of independence requires quantificati...

Begging in birds is a complex behaviour used by nestlings to solicit feeds from caregivers. Besides calling when parents are present, nestlings of some species also perform less conspicuous repeat calls when parents are absent. The fact that these calls are produced when parents are not at the nest does not mean that parents cannot hear them when t...

Abstract Many animal species show ornaments with yellow-orange-red colors produced by carotenoid pigments. Such traits have evolved as reliable signals of individual quality because of the costs inherent to their production or maintenance. In animal tissues, carotenoids are often found combined with free fatty acids, as carotenoid esters, which may...

Carotenoids are organic pigments that are found in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms like algae, bacteria, and fungi. There are over 600 known carotenoids; they are divided into two classes, xanthophylls (which contain oxygen) and carotenes (which are purely hydrocarbons, and contain no oxygen). All...

Animal coloration is key in natural and sexual selection, playing signifi-cant roles in intra-and interspecific communication because of its linkage to individual behaviour, genetics and physiology. Simple animal traits such as the area or the colour intensity of homogeneous patches have been profusely studied. More complex patterns are widespread...

Carotenoids are large lipophilic compounds that can only be produced by plants, fungi and bacteria. Although animals cannot synthesize them de novo, many taxa accumulate them in exposed parts of the body for communication purposes. In many birds, carotenoids are responsible for the bright yellow-red coloration of integuments or plumages, and these...

In many birds, nestlings exhibit brightly colored traits that are pigmented by carotenoids. Carotenoids are diet limited and also serve important health-related physiological functions. The proximate mechanisms behind the expression of these carotenoid-pigmented traits are still poorly known, especially in nestlings with sexual size dimorphism. In...

Carotenoid-based ornaments (many yellow–orange– red colourations) may signal the genetic or parental quality of the bearer. Thus, their expression could influence the amount of resources/energy that the mate will invest in the production of offspring, thereby optimising its reproductive fitness. The differential allocation hypothesis (DAH) predicts...

Plumage coloration, particularly when carotenoid-based, is important in social signaling in birds. Although feather color is a relatively stable trait, individuals may modify it with “cosmetic” substances such as preen oils. In addition, dirt accumulation may influence plumage coloration and further affect signal perception by receivers. Here, we a...

Black-billed magpies (Pica pica) are considered as a nest predator of game and non-game birds in Europe. In rural areas of Spain magpie control is commonly used as a management tool in small game hunting estates. Cage-traps with a magpie as a decoy are the legal method most commonly used for controlling magpies in Spain although its performance has...

Oxidative stress is the imbalance between the production of pro-oxidant substances and the level of antioxidant defenses, which leads to oxidative damage. It has been proposed that senescence is the result of accumulated oxidative damage throughout life. In birds, the sources of individual variability in oxidative stress are still poorly understood...

Many animal ornaments may have evolved as signals advertising the quality of the bearer. The honesty of the information content of these signals would rely on the costs associated with their expression, these being relatively greater for low-quality than for high-quality individuals. Given the physiological functions of carotenoids, carotenoid-base...