Papers by Vicente García-navas
Journal of evolutionary biology, 2014
Dispersal and local patterns of adaptation play a major role on the ecological and evolutionary t... more Dispersal and local patterns of adaptation play a major role on the ecological and evolutionary trajectory of natural populations. In this study, we employ a combination of genetic (25 microsatellite markers) and field-based information (seven study years) to analyse the impact of immigration and local patterns of adaptation in two nearby (<7 km) blue tit (Cyanistes caeruleus) populations. We used genetic assignment analyses to identify immigrant individuals and found that dispersal rate is female-biased (72%). Data on lifetime reproductive success indicated that immigrant females produced fewer local recruits than their philopatric counterparts whereas immigrant males recruited more offspring than those that remained in their natal location. In spite of the considerably higher immigration rates of females, our results indicate that, in absolute terms, their demographic and genetic impact in the receiving populations is lower than that in immigrant males. Immigrants often brought...
Relatively few bird species show complex social mating systems whose preponderance in a populatio... more Relatively few bird species show complex social mating systems whose preponderance in a population is likely to affect the patterns of parental care observed there. In turn, parental investment is likely to be related to the expression of certain ornaments, which may reveal information on the bearer's individual quality. Here we address both issues in a species characterised by several forms of parental care (both biparental and uniparental care) and in which both sexes possess a yellow breast patch, the rock sparrow (Petronia petronia). In our population, males contributed more to the care of the young in comparison with other populations. Social monogamy was the most frequent mating pattern and the percentage of cases of female (or male) brood desertion was lower with respect to that reported in previous studies, suggesting a flexible behaviour of this species to deal with different social environments. Birds did not pair assortatively with respect to the size of the yellow breast patch and we found no significant relationship between this trait and the frequency with which parents provisioned their chicks. However, we observed a positive relationship between male yellow patch size and nestling tarsus length, which suggests that more ornamented males are better parents. Males, but not females, differentially allocated parental investment in response to female ornamentation, although the benefits that males may gain from choosing more attractive females remain unidentified. Our results on paternal care investment along with previous studies on this species, reinforcing the view that the rock sparrow constitutes a good model to study sexual conflict over parental care under different social environments.
Journal of Evolutionary Biology, 2014
In natural populations, mating between relatives can have important fitness consequences due to t... more In natural populations, mating between relatives can have important fitness consequences due to the negative effects of reduced heterozygosity. Parental level of inbreeding or heterozygosity has been also found to influence the performance of offspring, via direct and indirect parental effects that are independent of the progeny own level of genetic diversity. In this study, we first analysed the effects of parental heterozygosity and relatedness (i.e. an estimate of offspring genetic diversity) on four traits related to offspring viability in great tits (Parus major) using 15 microsatellite markers. Second, we tested whether significant heterozygosity-fitness correlations (HFCs) were due to 'local' (i.e. linkage to genes influencing fitness) and/or 'general' (genome-wide heterozygosity) effects. We found a significant negative relationship between parental genetic relatedness and hatching success, and maternal heterozygosity was positively associated with offspring body size. The characteristics of the studied populations (recent admixture, polygynous matings) together with the fact that we found evidence for identity disequilibrium across our set of neutral markers suggest that HFCs may have resulted from genome-wide inbreeding depression. However, one locus (Ase18) had disproportionately large effects on the observed HFCs: heterozygosity at this locus had significant positive effects on hatching success and offspring size. It suggests that this marker may lie near to a functional locus under selection (i.e. a local effect) or, alternatively, heterozygosity at this locus might be correlated to heterozygosity across the genome due to the extensive ID found in our populations (i.e. a general effect). Collectively, our results lend support to both the general and local effect hypotheses and reinforce the view that HFCs lie on a continuum from inbreeding depression to those strictly due to linkage between marker loci and genes under selection.
Journal of Evolutionary Biology, 2014
Understanding the importance of host genetic diversity for coping with parasites and infectious d... more Understanding the importance of host genetic diversity for coping with parasites and infectious diseases is a long-standing goal in evolutionary biology. Here, we study the association between probability of infection by avian malaria (Plasmodium relictum) and individual genetic diversity in three blue tit (Cyanistes caeruleus) populations that strongly differ in prevalence of this parasite. For this purpose, we screened avian malaria infections and genotyped 789 blue tits across 26 microsatellite markers. We used two different arrays of markers: 14 loci classified as neutral and 12 loci classified as putatively functional. We found a significant relationship between probability of infection and host genetic diversity estimated at the subset of neutral markers that was not explained by strong local effects and did not differ among the studied populations. This relationship was not linear, and probability of infection increased up to values of homozygosity by locus (HL) around 0.15, reached a plateau at values of HL from 0.15 to 0.40 and finally declined among a small proportion of highly homozygous individuals (HL > 0.4). We did not find evidence for significant identity disequilibrium, which may have resulted from a low variance of inbreeding in the study populations and/or the small power of our set of markers to detect it. A combination of subtle positive and negative local effects and/or a saturation threshold in the association between probability of infection and host genetic diversity in combination with increased resistance to parasites in highly homozygous individuals may explain the observed negative quadratic relationship. Overall, our study highlights that parasites play an important role in shaping host genetic variation and suggests that the use of large sets of neutral markers may be more appropriate for the study of heterozygosity-fitness correlations.
Animal Behaviour, 2015
Extended phenotypes as signals are widely distributed among animal taxa. For example, many bird s... more Extended phenotypes as signals are widely distributed among animal taxa. For example, many bird species build eye-catching nests or structures, which can potentially mirror the quality or ability of the builder. Rock sparrow, Petronia petronia, nests are usually overly decorated with feathers belonging to different species. Feather carrying in this and other species seems to play a role beyond their supposed thermoregulatory function, that is, to provide insulation to eggs and developing chicks. In this study, we documented for the first time this intriguing pattern of behaviour in the rock sparrow and experimentally tested its potential role as a sexually selected or status signal by means of a feather supplementation experiment carried out in two distinct populations from Italy and Spain. We found that females were responsible for feather carrying, laid larger clutches and provisioned their young at a lower rate in those nests with experimentally added feathers. Decorated nests sustained fewer intrusions by floater individuals and were defended with greater intensity by both parents than control nests, which supports the role of nest ornamentation as a status signal to conspecifics. Presence of experimental feathers did not significantly increase the frequency with which males provisioned their young but males tended to desert their brood less often and spent more time guarding the brood in experimental nests, indicating that feather presence may also play a role in an intersexual context. Overall, our results allow us to exclude the thermoregulation hypothesis as a likely explanation for the occurrence of these decorations and provide partial evidence for the idea that feather carrying conveys information to the partner and potential competitors. Our study thus supports the notion that nonbodily traits serving a direct (naturally selected) function can also evolve a signalling component.
Proceedings of the Royal Society B: Biological Sciences, 2009
The general hypothesis of mate choice based on non-additive genetic traits suggests that individu... more The general hypothesis of mate choice based on non-additive genetic traits suggests that individuals would gain important benefits by choosing genetically dissimilar mates (compatible mate hypothesis) and/or more heterozygous mates (heterozygous mate hypothesis). In this study, we test these hypotheses in a socially monogamous bird, the blue tit (Cyanistes caeruleus). We found no evidence for a relatednessbased mating pattern, but heterozygosity was positively correlated between social mates, suggesting that blue tits may base their mating preferences on partner's heterozygosity. We found evidence that the observed heterozygosity-based assortative mating could be maintained by both direct and indirect benefits. Heterozygosity reflected individual quality in both sexes: egg production and quality increased with female heterozygosity while more heterozygous males showed higher feeding rates during the broodrearing period. Further, estimated offspring heterozygosity correlated with both paternal and maternal heterozygosity, suggesting that mating with heterozygous individuals can increase offspring genetic quality. Finally, plumage crown coloration was associated with male heterozygosity, and this could explain unanimous mate preferences for highly heterozygous and more ornamented individuals. Overall, this study suggests that non-additive genetic traits may play an important role in the evolution of mating preferences and offers empirical support to the resolution of the lek paradox from the perspective of the heterozygous mate hypothesis.
Parasitology Research, 2012
We genetically analysed malaria parasites (Protozoa) in three Mediterranean blue tit (Cyanistes c... more We genetically analysed malaria parasites (Protozoa) in three Mediterranean blue tit (Cyanistes caeruleus) populations from central Spain. A total of 853 breeding individuals were screened for parasites of the genera Plasmodium and Haemoproteus using a very efficient polymerase chain reaction approach that amplifies a partial segment of the mitochondrial cytochrome b gene of these parasites. We have found six lineages of Plasmodium (SGS1, GRW11, COLL1, DELURB4, GRW04 and BLUTI10) parasitizing the studied populations but we did not detect any infection by Haemoproteus. One of the detected lineages (BLUTI10) has not been previously described in any bird species and this is the first study recording lineages DELURB4 and GRW04 in blue tits. SGS1 (belonging to the morphospecies Plasmodium relictum) was the most frequent lineage (overall prevalence, 24 %), whereas the other lineages showed a much lower prevalence (<4 %). Only a small proportion (12.2 %) of positive amplifications of the most common lineage (SGS1) was detected in blood smears using light microscopy and infection intensities were very low (mean ±SE, 2.0±1.4 parasites/2,000 erythrocytes). We have also found strong inter-population variability in prevalence patterns (12-41 % for lineage SGS1), suggesting important differences in parasite transmission rates among the geographically close studied localities.
Oecologia, 2011
Insectivorous birds rely on a short period of food abundance to feed their young; they must time ... more Insectivorous birds rely on a short period of food abundance to feed their young; they must time their reproduction to match the timing of Lepidoptera larvae, their main prey. Apart from the net result (i.e. birds are timed or mistimed with respect to the food's peak), an important aspect is the possible influence of other factors, such as the seasonality of the environment or the abundance and diversity of species contributing to the caterpillar peak, on birds' phenology and their ability to cope well with unpredictable food supplies. In a 2-year study, we explored the seasonal variation of nestling diet in Mediterranean blue tits Cyanistes caeruleus and how reproductive parameters (nestling condition, provisioning rates) are affected by the phenology and composition of food. We also examined the influence of the synchrony between offspring needs and caterpillar peak in shaping the composition of the nestlings' diet. We found that the effect of synchrony on nestling condition varied between years which may be partially due to differences in food peak attributes. The adequacy of birds' timing in relation to prey phenology affected foraging decisions; those birds that were not able to correctly adjust their timing were forced to rely on less preferred prey (tortricids). In this sense, we found that relative contribution of tortricids (smaller caterpillars but easier to get) and noctuids (preferred prey but more difficult to find) to the diet influenced nestling condition and parental provisioning effort; parents performed fewer feeding events and reared heavier nestlings as the contribution of noctuids to the diet increased. The relationship between the proportion of caterpillars and nestling mass was curvilinear, whereas that parameter was negatively affected by the percentage of pupae. Our results show how changes in diet composition may contribute to explain the effect of mismatching on birds' breeding performance.
Journal of Ornithology, 2011
Previous studies have found strong relationships between calcium availability and eggshell pigmen... more Previous studies have found strong relationships between calcium availability and eggshell pigmentation in the Great Tit (Parus major). According to the ''structural function hypothesis'', protoporphyrins, the pigments responsible for reddish spots on speckled eggs, are deposited in those areas of the shell where calcium deposition is less intense. In the study reported here, which was carried out in three Blue Tit (Cyanistes caeruleus) populations in central Spain, we provide partial experimental support for the association between protoporphyrin eggshell pigmentation and shell thinning. Contrary to our expectations, we did not observe a decrease in the size and intensity of pigment spots for those eggs from calciumsupplemented nests. However, we did find that the provision of calcium-rich material during the egg-laying period led to a more wide distribution of pigment spots and reduced the proportion of eggs with defective shells (deviant pigmentation, dull and rough surface). When only the supplemented nests were considered in the analysis, within the same clutch we also detected differences in the spotting distribution between those eggs laid by female Blue Tits observed to have consumed calcium consumption on the day prior to laying and those observed not to have consumed calcium on the day prior to laying. Clutch size was not affected by the calcium supplementation. Female Blue Tits experimentally supplied with calcium-rich material had a shorter incubation period than control females, and they laid eggs with thicker shells. Eggshell thickness markedly affects the probability of hatching and could explain the lower proportion of unhatched late eggs found in supplemented nests in comparison with control ones. This study highlights the role of calcium in eggshell maculation and its effects on breeding performance of small passerines. We found the spotting distribution to be a good predictor of calcium deficiency. However, our results provide only mixed support for the ''structural function hypothesis'': in our study populations, the thickness of the eggshell was intimately associated with calcium availability, but the relationship between calcium and protoporphyrin deposition remains far from clear.
Journal of Animal Ecology, 2009
We test the consequences, in terms of breeding success and parental effort, of eggshell pigmentat... more We test the consequences, in terms of breeding success and parental effort, of eggshell pigmentation pattern in a hole-nesting bird, the blue tit Cyanistes caeruleus that lays eggs asymmetrically speckled with reddish spots (maculated eggs). 2. We assess the effect of distribution of spots (pigment 'spread') and spot size and pigment intensity (pigment 'darkness') on eggshell physical properties and breeding parameters concerning nestling condition, investment of parents in offspring care and reproductive output in two different habitat types: a deciduous oakwoodland and an evergreen forest. 3. Blue tit clutches with more widely distributed spots showed a thicker eggshell, a shorter incubation period, a lesser amount of mass loss per day and a higher hatching probability than those with spots forming a 'corona' ring. While eggs with larger and darker (more pigment intensity) spots showed a thicker eggshell and a shorter incubation period. In the light of 'signal function hypothesis', these egg traits may reflect female health status and, consequently, this could affect male parental effort. 4. Here we show supports for some of the necessary assumptions of this hypothesis. We found a positive relationship between egg pigment 'spread' and male but not female provisioning rates per day. On the other hand, pigment 'darkness' of blue tits' clutches was positively related to female tarsus length, while pigment 'spread' was positively related to clutch size, male body mass and nestling tarsus length. Our study shows that eggshell pigment 'spread' can be used as an indicator of clutch quality. Further investigations are needed to understand the role of calcium availability as possible causal agent of deviant eggs and its relation to the maculation phenomenon.
Ibis, 2014
In species with biparental care, males and females share the benefits of investing in offspring b... more In species with biparental care, males and females share the benefits of investing in offspring but pay the costs individually. As a result of these evolutionary conflicts of interest between the sexes, it is expected that the two parents should follow different behavioural rules when providing food to the young. Such a discrepancy may be accentuated when parents have to choose between different subsets of offspring (e.g. large and small nestlings). We manipulated the degree of hatching asynchrony in Blue Tits Cyanistes caeruleus and quantified male and female feeding behaviour when nestlings were 7 and 10 days old. First, we tested for a difference in the role of the sexes during the nestling rearing period between experimentally asynchronous and synchronous control broods. We then used experimentally asynchronous broods to assess differences between the sexes in the pattern of food distribution in terms of number of feedings and prey types, between junior and senior siblings. When nestlings in experimental nests were 7 days old, females fed young more often than did males despite facing a trade-off between brooding the smallest nestlings and bringing food to the nest. At this age, there was also a skew in food delivery in favour of senior siblings, whereas food was more evenly distributed across the brood when nestlings were 10 days old. We found no difference in how male and female Blue Tits distributed feeding visits among junior and senior nestlings. However, females fed the smallest nestlings with more spiders in comparison with their senior siblings. This could be related to their more suitable size relative to other prey types, their high content of essential nutrients, or both, and may represent a more cryptic form of parentally biased favouritism. We compare these findings with previous work on other species and discuss why parents did not feed junior siblings more frequently.
Ibis, Apr 1, 2008
Avian life-history studies are often conducted on populations nesting in nestboxes. However, the ... more Avian life-history studies are often conducted on populations nesting in nestboxes. However, the type of nestbox used is a potentially confounding variable, as each model shows specific characteristics. In recent decades, a new commercial model of artificial nestbox made of woodcrete, a mixture of sawdust and additives, has become popular owing to its better protection against predators compared with the classic wooden design. We assess the effect of nestbox type on the breeding ecology of Tree Sparrows Passer montanus, focusing on ...
Ibis, 2011
A common feature of many birds breeding in seasonal environments is that fitnessrelated parameter... more A common feature of many birds breeding in seasonal environments is that fitnessrelated parameters such as nestling mass or survival decline as the breeding season progresses. Consequently, there is a tendency for early breeders to have better reproductive performance than individuals breeding later in the season. This variation could be caused by factors associated with the date of laying, such as changing environmental conditions (date hypothesis), or by differences in parental quality between early and late breeders (parent quality hypothesis). To evaluate the relative importance of both hypotheses, we manipulated hatch dates of Blue Tits Cyanistes caeruleus by exchanging clutches with different incubation stages and assessed the impact on nestling mass, nestling diet and provisioning rates. Mean nestling mass declined significantly over the season. This was the combined result of differences in parental quality, which dominated in the early part of the season, and the influence of hatching date (date effect per se), which prevailed later in the season. Nestling diet composition was apparently uninfluenced by the manipulation, suggesting that deteriorating food supplies are the primary reason for the seasonal variation in the nestling diet. Counter to the date hypothesis, delayed parents did not feed their young less than control pairs did, but in fact exhibited higher provisioning rates. Our results suggest that in this population, parental quality seems to constrain post-hatching reproductive performance and such intrinsic limitations may help to explain why certain individuals breed later.
Bird Study, 2012
Capsule The effect of nestling age (7, 10 and 13 days old) on prey choice by Blue Tits Cyanistes ... more Capsule The effect of nestling age (7, 10 and 13 days old) on prey choice by Blue Tits Cyanistes caeruleus seems to be related to time constraints on food selectivity rather than chick gape-size limitations. Aims To study age differences in the nestling diet of Blue Tits and how the relative contribution of each parent varies as the nestlings grow older. Methods The provisioning activity of Blue Tit parents was recorded using infrared video cameras when chicks were 7, 10 and 13 days old. Results Nestling age had no influence on the percentage of folivorous caterpillars in the diet of nestlings. Male and female parents changed their provisioning strategy with nestling age; this change was similar in adults of both sexes. Blue Tit nestlings received a smaller proportion of spiders and a greater proportion of Tortricid larvae (small, low-mobility caterpillars) as they grew older. At the age of seven days, females brought a lower proportion of Noctuids (large caterpillars) to the nest than their mates. The role of each parent in provisioning young varied with nestling age. Males fed their young at a lower rate when they were seven days old compared with later in the nestling period, whereas females tended to invest more in provisioning effort early in the nestling period in comparison with subsequent age-classes.
Biological Journal of the Linnean Society, 2013
Biological Journal of the Linnean Society, 2012
Carotenoid-based coloration in adult birds has been often regarded as an honest signal of individ... more Carotenoid-based coloration in adult birds has been often regarded as an honest signal of individual quality. However, few studies have demonstrated a link between carotenoid display and the quantity or quality of resources provided to the offspring. The present study investigated the expression of a carotenoid-based ornament, the breast plumage yellowness of the blue tit Cyanistes caeruleus, in relation to the level of parental provisioning effort and the amount of carotenoid-rich prey provided to the young. The study was conducted in two forest types (evergreen and deciduous), which also allowed an exploration of the possible existence of habitat effects on the coloration of breeding birds. It was found that plumage colour intensity (carotenoid chroma) correlated positively with nestling provisioning rates of both males and females, supporting the good parent hypothesis. In addition, carotenoid chroma was positively related with the proportion of Lepidoptera larvae brought to the nest in both sexes. Female but not male coloration was positively linked to breeding success (proportion of fledged young). Nestling coloration did not correlate with that of their parents, nor the frequency with which they were fed. Hue and lightness of nestling's plumage correlated positively with body mass and tarsus length, respectively. The results obtained in the present study indicate that ventral plumage coloration in blue tits may advertise the ingested carotenoids (carotenoid foraging ability) and also their overall parental quality in terms of nestling provisioning rates. This suggests that plumage yellowness can be used as an indicator of foraging ability in this species.
Behavioral Ecology, 2011
In a wide range of animal taxa, males build elaborate mating structures to attract females. For i... more In a wide range of animal taxa, males build elaborate mating structures to attract females. For instance, some bird species use their nests or display sites as nonbodily ornaments (extended phenotypes) in intersexual communication. Recently, it has been proposed that feather carrying constitutes a postmating sexual display. Here, evidence supporting this hypothesis is presented for a species in which such behavior had not been previously reported, the blue tit Cyanistes caeruleus. In our Mediterranean study populations, males carry feathers to the nest and place them outside the nest cup. Here, we show experimentally and by means of observational data that feather carrying by male blue tits induced their mates to increase their clutch size. In addition, males from ornamented nests fed their offspring at a higher rate than those from nests in which this behavior was not detected. Feathercarrying effort was positively associated with male tarsus length. On the other hand, females paired with males engaging in this activity reduced their feeding rates but obtained direct fitness benefits: Ornamented nests resulted in more fledged young with better body condition than those without feathers carried by males. In summary, this study suggests that male feather-carrying ability constitutes an honest signal of their parental quality and a good predictor of breeding success in these blue tit populations.
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Papers by Vicente García-navas