I am a researcher at EBD-CSIC (Doñana Biological Station) in Sevilla, Spain. I am interested in the evolution of cooperation and conflict in animal societies, particularly bird families, and the evolution of communicative signals. My research topics include parental care, parent-offspring conflict, honest signalling, brood parasitism, and sibling aggression and cooperation. Phone: +34954232340 Address: Avda. Américo Vespucio s/n, 41092 Sevilla, Spain
Some theoretical models predict that nestling begging must be a costly activity to transmit relia... more Some theoretical models predict that nestling begging must be a costly activity to transmit reliable information to parents about offspring hunger. One candidate cost is oxidative stress, which could impair growth or immune function. This hypothesis predicts that nestlings in a poor oxidative status should pay higher costs for a given amount of begging, hence beg at lower rates for a similar degree of hunger. To test this prediction, we experimentally induced a transient alteration of the oxidative status of Barn Swallow (Hirundo rustica) nestlings by administering them either a single dose of a pro-oxidant substance (BSO) or an antioxidant (vitamin E), and recorded their begging behaviour. Chicks treated with vitamin E increased their begging rates in the hours following treatment. However, and contrary to prediction, BSO nestlings did not decrease begging compared to controls. These inconsistent results are difficult to explain by the hypothesis that begging performance is mediate...
Hematological profiles are routinely used to assess the health status of animals. Several methods... more Hematological profiles are routinely used to assess the health status of animals. Several methods have been developed for blood cell counting, but they are typically expensive and/or time-consuming. Here, we present a free image-processing software, Mizutama, developed for counting cells in photographs of blood smears. Mizutama uses the thresholding method to transform original photographs into grayscale trinary images. Following a number of parameters, Mizutama searches in the image for cells of a given size, with a nucleus size relative to cytoplasm surface area. The software is not only easy, versatile, and intuitive to handle but also fast when counting cells in photographs. Moreover, we show that it is highly accurate, failing to detect only ca. 1.4% of avian red cells in ordinary microscopic photographs. The Mizutama application may greatly facilitate the counting of erythrocytes and other blood cells in physiological studies, saving time and money.
Some theoretical models predict that nestling begging must be a costly activity to transmit relia... more Some theoretical models predict that nestling begging must be a costly activity to transmit reliable information to parents about offspring hunger. One candidate cost is oxidative stress, which could impair growth or immune function. This hypothesis predicts that nestlings in a poor oxidative status should pay higher costs for a given amount of begging, hence beg at lower rates for a similar degree of hunger. To test this prediction, we experimentally induced a transient alteration of the oxidative status of Barn Swallow (Hirundo rustica) nestlings by administering them either a single dose of a pro-oxidant substance (BSO) or an antioxidant (vitamin E), and recorded their begging behaviour. Chicks treated with vitamin E increased their begging rates in the hours following treatment. However, and contrary to prediction, BSO nestlings did not decrease begging compared to controls. These inconsistent results are difficult to explain by the hypothesis that begging performance is mediated by the oxidative status of nestlings because chicks with an impaired oxidative status (the BSO group) begged the same as controls. Alternatively, vitamin E may alleviate the inhibitory effects on begging of stress responses mediated by glucocorticoids. This study suggests that oxidative costs of begging are minor or absent in this species. Future studies should consider alternative explanations for an association between oxidative status, antioxidant supplementation and begging behaviour, particularly those involving glucocorticoids. Keywords Begging • Honest signalling • Oxidative stress • Hirundo rustica • Vitamin E • BSO • Glucocorticoids Zusammenfassung Entstehen den Nestlingen von Rauchschwalben durch Betteln oxidative Kosten? Es gibt theoretische Modelle, die besagen, dass das Betteln von Nestlingen vermutlich eine kostenintensive Art ist, um den Eltern zuverlässige Information über den Hunger der Jungen zu geben. Ein möglicher Kostenfaktor wäre oxidativer Stress, der das Wachstum oder das Immunsystem beeinträchtigen könnte. Diese Hypothese besagt, dass Nestlingen in einem schlechten oxidativen Zustand höhere Kosten für ein bestimmtes Maß an Betteln entstehen und sie deshalb bei gleichem Hunger besser weniger häufig betteln sollten. Um dies zu testen, führten wir experimentell eine vorübergehende Veränderung des Oxidationsstatus von Nestlingen der Rauchschwalbe (Hirundo rustica) herbei, indem wir ihnen entweder eine einmalige Dosis einer pro-oxidativen Substanz (BSO) oder eines Antioxidans (Vitamin E) verabreichten und ihr Bettelverhalten aufzeichneten. Die mit Vitamin E behandelten Küken bettelten in den Stunden nach der Behandlung häufiger. Aber entgegen der Vorhersage bettelten die BSO-Küken im Vergleich zu den Kontrollen nicht weniger. Diese widersprüchlichen Ergebnisse Communicated by I. Moore.
Parent–offspring conflict over food allocation can be modeled using two theoretical frameworks: p... more 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. Hea...
Altricial nestlings in structured families show a diverse array of behavioural mechanisms to comp... more Altricial nestlings in structured families show a diverse array of behavioural mechanisms to compete for food, ranging from signalling scrambles to aggressive interference. Rates of filial infanticide are moderately high in white storks. It has been hypothesized that this unusual behaviour is an adaptive parental response to the absence of efficient mechanisms of brood reduction (aggression or direct physical interference) by nestlings. To test this latter assumption, we analyzed video recordings of 41 complete feeding episodes at 32 broods during the first half of the nestling period, when nestlings complete 90% of growth and chick mortality and size asymmetries are highest. Parents delivered food to all nestlings simultaneously by regurgitating on the nest floor. No direct (bill to bill) feeding was recorded. Senior nestlings were never observed to limit their junior nestlings from eating food, either by aggression or physical interference. Experimental feeding tests revealed that heavier nestlings handled prey items more efficiently and ate food at a higher speed. The high degree of tolerance shown by senior nestlings is unusual among birds with similar ecological and phylogenetic affinities, such as herons. Tolerance by seniors cannot be easily explained by absence of parental favouritism or proximate factors known to affect the occurrence of sibling aggression in other species (rate of food transfer, brood size, hatching asynchrony or length of nestling period)
Este es un libro (primero publicado por autores de lengua española) que trata sobre las estrategi... more Este es un libro (primero publicado por autores de lengua española) que trata sobre las estrategias que los seres vivos emplean para maximizar su eficacia biológica, abordadas desde los cuatro enfoques clásicos que constituyen la esencia de la Etología: las causas inmediatas o mecanismos, la ontogenia, la filogenia y la función adaptativa
Abstract. White stork, Ciconia ciconia, chicks were observed to abandon their natal nests prior t... more Abstract. White stork, Ciconia ciconia, chicks were observed to abandon their natal nests prior to independence and to be adopted by neighbouring foster parents in approximately 40 % of broods at three breeding colonies. Nest switching coincided with a decrease in feeding rates by parents and an increase in aggression by siblings triggered by the flight exercises of nestmates, and mainly aVected the eldest chicks in larger broods. Chicks that abandoned their natal nests moved into broods containing both fewer and younger chicks, and thus experienced a decrease in aggression rate compared with their natal broods. Adopted chicks may also have increased their food intake as a consequence of nest switching. Resident chicks suVered from lower feeding rates during adoption and had lower mass increments than chicks in non-fostering broods of comparable age and size. Both adults and chicks were highly aggressive against trespassing chicks. The probability of aggression was a good predictor ...
Datasets as supporting information to article "Vitamin E supplementation –but not induced ox... more Datasets as supporting information to article "Vitamin E supplementation –but not induced oxidative stress- influences telomere dynamics during early development" to be published in Frontiers in Ecology and Evolution. The Readme files describe variables in the corresponding dataset.
Some theoretical models predict that nestling begging must be a costly activity to transmit relia... more Some theoretical models predict that nestling begging must be a costly activity to transmit reliable information to parents about offspring hunger. One candidate cost is oxidative stress, which could impair growth or immune function. This hypothesis predicts that nestlings in a poor oxidative status should pay higher costs for a given amount of begging, hence beg at lower rates for a similar degree of hunger. To test this prediction, we experimentally induced a transient alteration of the oxidative status of Barn Swallow (Hirundo rustica) nestlings by administering them either a single dose of a pro-oxidant substance (BSO) or an antioxidant (vitamin E), and recorded their begging behaviour. Chicks treated with vitamin E increased their begging rates in the hours following treatment. However, and contrary to prediction, BSO nestlings did not decrease begging compared to controls. These inconsistent results are difficult to explain by the hypothesis that begging performance is mediate...
Hematological profiles are routinely used to assess the health status of animals. Several methods... more Hematological profiles are routinely used to assess the health status of animals. Several methods have been developed for blood cell counting, but they are typically expensive and/or time-consuming. Here, we present a free image-processing software, Mizutama, developed for counting cells in photographs of blood smears. Mizutama uses the thresholding method to transform original photographs into grayscale trinary images. Following a number of parameters, Mizutama searches in the image for cells of a given size, with a nucleus size relative to cytoplasm surface area. The software is not only easy, versatile, and intuitive to handle but also fast when counting cells in photographs. Moreover, we show that it is highly accurate, failing to detect only ca. 1.4% of avian red cells in ordinary microscopic photographs. The Mizutama application may greatly facilitate the counting of erythrocytes and other blood cells in physiological studies, saving time and money.
Some theoretical models predict that nestling begging must be a costly activity to transmit relia... more Some theoretical models predict that nestling begging must be a costly activity to transmit reliable information to parents about offspring hunger. One candidate cost is oxidative stress, which could impair growth or immune function. This hypothesis predicts that nestlings in a poor oxidative status should pay higher costs for a given amount of begging, hence beg at lower rates for a similar degree of hunger. To test this prediction, we experimentally induced a transient alteration of the oxidative status of Barn Swallow (Hirundo rustica) nestlings by administering them either a single dose of a pro-oxidant substance (BSO) or an antioxidant (vitamin E), and recorded their begging behaviour. Chicks treated with vitamin E increased their begging rates in the hours following treatment. However, and contrary to prediction, BSO nestlings did not decrease begging compared to controls. These inconsistent results are difficult to explain by the hypothesis that begging performance is mediated by the oxidative status of nestlings because chicks with an impaired oxidative status (the BSO group) begged the same as controls. Alternatively, vitamin E may alleviate the inhibitory effects on begging of stress responses mediated by glucocorticoids. This study suggests that oxidative costs of begging are minor or absent in this species. Future studies should consider alternative explanations for an association between oxidative status, antioxidant supplementation and begging behaviour, particularly those involving glucocorticoids. Keywords Begging • Honest signalling • Oxidative stress • Hirundo rustica • Vitamin E • BSO • Glucocorticoids Zusammenfassung Entstehen den Nestlingen von Rauchschwalben durch Betteln oxidative Kosten? Es gibt theoretische Modelle, die besagen, dass das Betteln von Nestlingen vermutlich eine kostenintensive Art ist, um den Eltern zuverlässige Information über den Hunger der Jungen zu geben. Ein möglicher Kostenfaktor wäre oxidativer Stress, der das Wachstum oder das Immunsystem beeinträchtigen könnte. Diese Hypothese besagt, dass Nestlingen in einem schlechten oxidativen Zustand höhere Kosten für ein bestimmtes Maß an Betteln entstehen und sie deshalb bei gleichem Hunger besser weniger häufig betteln sollten. Um dies zu testen, führten wir experimentell eine vorübergehende Veränderung des Oxidationsstatus von Nestlingen der Rauchschwalbe (Hirundo rustica) herbei, indem wir ihnen entweder eine einmalige Dosis einer pro-oxidativen Substanz (BSO) oder eines Antioxidans (Vitamin E) verabreichten und ihr Bettelverhalten aufzeichneten. Die mit Vitamin E behandelten Küken bettelten in den Stunden nach der Behandlung häufiger. Aber entgegen der Vorhersage bettelten die BSO-Küken im Vergleich zu den Kontrollen nicht weniger. Diese widersprüchlichen Ergebnisse Communicated by I. Moore.
Parent–offspring conflict over food allocation can be modeled using two theoretical frameworks: p... more 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. Hea...
Altricial nestlings in structured families show a diverse array of behavioural mechanisms to comp... more Altricial nestlings in structured families show a diverse array of behavioural mechanisms to compete for food, ranging from signalling scrambles to aggressive interference. Rates of filial infanticide are moderately high in white storks. It has been hypothesized that this unusual behaviour is an adaptive parental response to the absence of efficient mechanisms of brood reduction (aggression or direct physical interference) by nestlings. To test this latter assumption, we analyzed video recordings of 41 complete feeding episodes at 32 broods during the first half of the nestling period, when nestlings complete 90% of growth and chick mortality and size asymmetries are highest. Parents delivered food to all nestlings simultaneously by regurgitating on the nest floor. No direct (bill to bill) feeding was recorded. Senior nestlings were never observed to limit their junior nestlings from eating food, either by aggression or physical interference. Experimental feeding tests revealed that heavier nestlings handled prey items more efficiently and ate food at a higher speed. The high degree of tolerance shown by senior nestlings is unusual among birds with similar ecological and phylogenetic affinities, such as herons. Tolerance by seniors cannot be easily explained by absence of parental favouritism or proximate factors known to affect the occurrence of sibling aggression in other species (rate of food transfer, brood size, hatching asynchrony or length of nestling period)
Este es un libro (primero publicado por autores de lengua española) que trata sobre las estrategi... more Este es un libro (primero publicado por autores de lengua española) que trata sobre las estrategias que los seres vivos emplean para maximizar su eficacia biológica, abordadas desde los cuatro enfoques clásicos que constituyen la esencia de la Etología: las causas inmediatas o mecanismos, la ontogenia, la filogenia y la función adaptativa
Abstract. White stork, Ciconia ciconia, chicks were observed to abandon their natal nests prior t... more Abstract. White stork, Ciconia ciconia, chicks were observed to abandon their natal nests prior to independence and to be adopted by neighbouring foster parents in approximately 40 % of broods at three breeding colonies. Nest switching coincided with a decrease in feeding rates by parents and an increase in aggression by siblings triggered by the flight exercises of nestmates, and mainly aVected the eldest chicks in larger broods. Chicks that abandoned their natal nests moved into broods containing both fewer and younger chicks, and thus experienced a decrease in aggression rate compared with their natal broods. Adopted chicks may also have increased their food intake as a consequence of nest switching. Resident chicks suVered from lower feeding rates during adoption and had lower mass increments than chicks in non-fostering broods of comparable age and size. Both adults and chicks were highly aggressive against trespassing chicks. The probability of aggression was a good predictor ...
Datasets as supporting information to article "Vitamin E supplementation –but not induced ox... more Datasets as supporting information to article "Vitamin E supplementation –but not induced oxidative stress- influences telomere dynamics during early development" to be published in Frontiers in Ecology and Evolution. The Readme files describe variables in the corresponding dataset.
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