Juan José Soler - Academia.edu (original) (raw)

Papers by Juan José Soler

The ISME Journal, 2020

Gut microbiota are essential for host health and survival, but we are still far from understandin... more Gut microbiota are essential for host health and survival, but we are still far from understanding the processes involved in shaping their composition and evolution. Controlled experimental work under lab conditions as well as human studies pointed at environmental factors (i.e., diet) as the main determinant of the microbiota with little evidence of genetic effects, while comparative interspecific studies detected significant phylogenetic effects. Different species, however, also differ in diet, feeding behavior, and environmental characteristics of habitats, all of which also vary interspecifically, and, therefore, can potentially explain most of the detected phylogenetic patterns. Here, we take advantage of the reproductive strategy of avian brood parasites and investigate gut microbiotas (esophageal (food and saliva) and intestinal) of great spotted cuckoo (Clamator glandarius) and magpie (Pica pica) nestlings that grow in the same nests. We also estimated diet received by each nestling and explored its association with gut microbiota characteristics. Although esophageal microbiota of magpies and great spotted cuckoos raised within the same environment (nest) did not vary, the microbiota of cloacal samples showed clear interspecific differences. Moreover, diet of great spotted cuckoo and magpie nestlings explained the microbiota composition of esophageal samples, but not of cloaca samples. These results strongly suggest a genetic component determining the intestinal microbiota of host and parasitic bird species, indicating that interspecific differences in gut morphology and physiology are responsible for such interspecific differences.

Biology, 2020

Nest bacterial environment influences avian reproduction directly because it might include pathog... more Nest bacterial environment influences avian reproduction directly because it might include pathogenic- or antibiotic-producing bacteria or indirectly because predators or ectoparasites can use volatile compounds from nest bacterial metabolism to detect nests of their avian hosts. Hoopoes (Upupa epops) do not build nests. They rather reuse holes or nest-boxes that contain remains of nest-materials from previous breeding seasons. Interestingly, it has been recently described that the nest’s bacterial environment partly affects the uropygial gland microbiota of hoopoe females and eggshells. Blood-sucking ectoparasites use chemical cues to find host nests, so we experimentally tested the hypothetical effects of microorganisms inhabiting nest-material remains before reproduction regarding the intensity of ectoparasitism suffered by 8-day-old nestling hoopoes. In accordance with the hypothesis, nestlings hatched in nest-boxes with autoclaved nest-material remains from the previous reprodu...

Frontiers in Ecology and Evolution, 2020

Journal of Avian Biology, 2019

Nest re‐use in birds has the potential cost of infection by parasites and pathogens but may also ... more Nest re‐use in birds has the potential cost of infection by parasites and pathogens but may also be a source of beneficial symbiotic bacteria transmitted horizontally. Eurasian hoopoes Upupa epops host antibiotic‐producing bacteria in their uropygial gland but only while breeding, which suggests that the nest‐hole may be a source of those symbionts. Interestingly, hoopoes do not build nests, thus might prefer for reproduction nest holes with soft materials from previous reproductions. Here, we tested experimentally this preference by installing in the field new nest boxes that were left empty or filled with either sawdust or a mixture of sawdust and hoopoe's nest material from the previous year. We explored the experimental effect on the composition of the uropygial secretion bacterial community, on eggshell bacterial loads, and on several proxies of reproductive success. Hoopoes bred significantly more often in nest boxes with nest material than in empty ones, but the type of n...

Microbial ecology, Jul 13, 2016

Microbial symbiont acquisition by hosts may determine the effectiveness of the mutualistic relati... more Microbial symbiont acquisition by hosts may determine the effectiveness of the mutualistic relationships. A mix of vertical and horizontal transmission may be advantageous for hosts by allowing plastic changes of microbial communities depending on environmental conditions. Plasticity is well known for gut microbiota but is poorly understood for other symbionts of wild animals. We here explore the importance of environmental conditions experienced by nestling hoopoes (Upupa epops) during the late nesting phase determining microbiota in their uropygial gland. In cross-fostering experiments of 8 days old nestlings, "sibling-sibling" and "mother-offspring" comparisons were used to explore whether the bacterial community naturally established in the uropygial gland of nestlings could change depending on experimental environmental conditions (i.e., new nest environment). We found that the final microbiome of nestlings was mainly explained by nest of origin. Moreover, c...

Annales Zoologici Fennici, 2004

Female insects have a limited energy budget to invest in reproduction. Clutch size and egg size a... more Female insects have a limited energy budget to invest in reproduction. Clutch size and egg size are two traits typically involved in energy budget trade-offs, and an optimum clutch size is generally predicted. This trade-off, however, is influenced by many factors including the probability of egg parasitism. We studied this possibility in the pine processionary moth (Thaumetopoea pityocampa), which frequently suffers from parasitoids. We found support for a trade-off between clutch size and egg size in this species, but the intermediate clutch size did not correspond to higher hatching success. We suggest that the lack of an optimum clutch size in relation to hatching success was mediated by parasitoids: parasitoids preferentially selected small clutches containing larger eggs. In addition, we experimentally tested whether the scales that coat egg batches reduce the effect of parasitism. Egg batches with experimentally removed scales showed a significantly higher parasitism rate than control batches, which demonstrates that scales protect egg batches from parasitoids. We discuss three possible explanations for our results.

Oecologia, 1999

Certain kinds of hosts are commonly regarded as being more suitable than other for rearing Europe... more Certain kinds of hosts are commonly regarded as being more suitable than other for rearing European cuckoos (Cuculus canorus) ± insectivores that lay small eggs and have open, shallow nests ± although empirical tests of cuckoo host selection are lacking. We analysed host use by the European cuckoo in 72 British passerines that are potential hosts and for which there was information available on life-history variables and variables related to cuckoo-host coevolution, such as rate of parasitism, rejection rate of non-mimetic model eggs and degree of cuckoo-egg mimicry of host eggs. The relative population size of the host species aected parasitism rate most strongly, followed by relatively short duration of the nestling period, and the kind of nest, with cuckoos selecting open-nesting hosts. However, the eect of the nestling period could be related to host body size and the kind of nest used, because hole-nesting species normally have longer nestling periods than open-nesters. We re-analysed the data excluding hole nesters and corvid species (species with larger body mass), but the results remained identical. The European cuckoo may bene®t from selecting hosts with short nestling periods because such hosts provide food for their nestlings at a very high rate. When only those species known as cuckoo hosts were analysed, the variable that best accounted for the parasitism rate was duration of the breeding season. Therefore, availability of potential hosts in both time and space is important for cuckoos in selecting hosts.

Naturwissenschaften, 2011

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. Th... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.

Journal of Theoretical Biology, 1998

Journal of Avian Biology, 2012

Brood parasitic nestlings usually exhibit an exaggerated begging behaviour, which is mainly attri... more Brood parasitic nestlings usually exhibit an exaggerated begging behaviour, which is mainly attributed to reduced inclusive fi tness costs since they typically share the nest with unrelated individuals. However, energetic costs also constrain begging expression and accordingly a relation between food requirements and intensity of begging behaviour could also exist in brood parasites, just as in nesting bird species. Here, we tested this hypothesis in the great spotted cuckoo Clamator glandarius and its main host, the magpie Pica pica , by studying the eff ect of an appetite enhancer, cyproheptadine hydrochloride, on nestling provisioning and development (size, body mass and cell-mediated immune response). To study nestling provisioning, neck-collars were meticulously placed around nestling necks allowing normal respiration but avoiding the ingestion of food delivered by adult magpies during ca 2.5 h. Loss in body mass during neck-collar trials was used as a proxy for energetic begging costs, while the amount of food received during these trials and growth during the whole nestling period were used as variables refl ecting short-and long-term eff ects of the experimental treatment. During neck-collar trials, we found that experimental nestlings of both species received more food than control nestlings. However, experimental magpies, but not cuckoos, lost more body mass than control nestlings. Th ese results suggest a short-term benefi cial eff ect of an escalated begging behaviour in both species that would be energetically cheaper for cuckoos than for magpies. We found positive long-term eff ects of the appetite enhancer only in magpies (in terms of tarsus and wing length at fl edging, but not in terms of immune response and body mass); suggesting that exaggerated begging would be benefi cial for hosts only. We discuss the possible eff ect of begging behaviour on the risk of predation and on inclusive fi tness, but also the possibility that our results may be explained by some kind of limitation in the capability of food assimilation by parasitic species.

Ibis, 2008

Two Jackdaw Corvus monedula colonies were given supplementary food before and during breeding in ... more Two Jackdaw Corvus monedula colonies were given supplementary food before and during breeding in 1983. Breeding density and cavity use were compared with those of the same colonies in previous years, when no food was provided. Predation rate and reproductive parameters were compared with those in the same colonies in previous years and with those of two control colonies, without experimental food. Jackdaws preferred safe cavities with small minimum nest‐entrance dimensions and avoided those with a high risk of nest predation. In experimental (fed) colonies, however, there was a tendency to use all cavities, which resulted in an increased breeding density. No nests were preyed upon by Ravens Corvus corax in the experimental colonies because supplemental food favoured group defence by increasing colony size and by increasing the time the Jackdaws spent in the colony. Additional food advanced laying date, increased clutch size independently of laying date and increased fledging success...

Ibis, 2012

Selection pressures due to parasitism play an important role in driving the evolution of life his... more Selection pressures due to parasitism play an important role in driving the evolution of life history traits of birds in general and of behaviour at the nest in particular. Eggshell bacterial load has been shown to predict hatching failure (i.e. the probability of embryo infection) but the relationships between the bacterial environment of the nest and life history characteristics of birds remain poorly investigated. We explored interspecific variation in eggshell bacterial load of mesophilic bacteria, Enterococcus spp., Staphylococcus spp. and Enterobacteriaceae groups across 24 bird species and assessed whether bacterial load is associated with breeding traits. Interspecific variation was much higher than intraspecific variation for all measures of bacterial load even after controlling for annual variation. Thus, we were able to assess the correlation between bacterial community characteristics and life history traits. After correcting for phylogenetic effects, we found that nest ...

Environment International, 2009

Large-scale studies are essential to assess the emission patterns and spatial distribution of org... more Large-scale studies are essential to assess the emission patterns and spatial distribution of organohalogenated pollutants (OHPs) in the environment. Bird eggs have several advantages compared to other environmental media which have previously been used to map the distribution of OHPs. In this study, largescale geographical variation in the occurrence of OHPs, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), was investigated throughout Europe using eggs of a terrestrial residential passerine species, the great tit (Parus major). Great tit eggs from 22 sampling sites, involving urban, rural and remote areas, in 14 European countries were collected and analysed (5-8 eggs per sampling site). The environmentally most important congeners/compounds of the analysed pollutants were detectable in all sampling locations. For PCBs, PBDEs and OCPs, no clear geographical contamination pattern was found. Sum PCB levels ranged from 143 ng/g lipid weight (lw) to 3660 ng/g lw. As expected, PCB concentrations were significantly higher in the sampled urban compared to the remote locations. However, the urban locations did not show significantly higher concentrations compared to the rural locations. Sum PBDEs ranged from 4.0 ng/g lw to 136 ng/g lw. PBDEs were significantly higher in the urbanized sampling locations compared to the other locations. The significant, positive correlation between PCB and PBDE concentrations suggests similar spatial exposure and/or mechanisms of accumulation. Significantly higher levels of OCPs (sum OCPs ranging from 191 ng/g lw to 7830 ng/g lw) were

Environment International, 2013

Large-scale international monitoring studies are important to assess emission patterns and enviro... more Large-scale international monitoring studies are important to assess emission patterns and environmental distributions of organohalogenated contaminants (OHCs) on a worldwide scale. In this study, the presence of OHCs was investigated on three continents (Europe, North America and Australasia), using eggs of starlings (Sturnus vulgaris and Sturnus unicolor) to assess their suitability for large-scale monitoring studies. To the best of our knowledge, this is the first study using bird eggs of the same species as a biomonitor for OHCs on an intercontinental scale. We found significant differences in OHC concentrations of the eggs among sampling locations, except for hexachlorocyclohexanes (HCHs). Mean concentrations of sum polychlorinated biphenyls (PCBs) in eggs ranged from 78±26 ng/g lipid weight (lw) in Australia to 2900±1300 ng/g lw in the United States. The PCB profile was dominated by CB 153 and CB 138 in all locations, except for New Zealand, where the contribution of CB 95, CB 101 and CB 149 was also high. The highest mean sum polybrominated diphenyl ether (PBDE) concentrations were found in Canada (4400±830 ng/g lw), while the lowest mean PBDE concentrations were measured in Spain (3.7±0.1 ng/g lw). The PBDE profile in starling eggs was dominated by BDE 47 and BDE 99 in all countries, but in Belgium, the higher brominated PBDEs had a higher contribution compared to other countries. For the organochlorine pesticides (OCPs), dichlorodiphenyltrichloroethanes (DDTs) ranged from 110±16 ng/g lw in France to 17,000±3400 ng/g lw in New Zealand, while HCHs and hexachlorobenzene were generally in low concentrations in all sampling locations. Chlordanes were remarkably high in eggs from the United States (2500±1300 ng/g lw). The OCP profile in all countries was largely dominated by p,p′-DDE. In general, the worldwide trends we observed in starling eggs were in accordance with the literature on human and environmental OHC data, which suggests that there is potential for using starling eggs as a biomonitoring tool on a large geographical scale.

Biological Journal of the Linnean Society, 2010

Many bird species use feathers as lining material, and its functionality has traditionally been l... more Many bird species use feathers as lining material, and its functionality has traditionally been linked to nest insulation. However, nest lining feathers may also influence nest detection by predators, differentially affect reproductive investment of mates in a post-mating sexual selection process, and affect the bacterial community of the nest environment. Most of these functions of nest lining feathers could affect hatching success, but the effect might vary depending on feather coloration (i.e. pigmented versus white feathers). This would be the case if coloration is related to: (1) thermoregulatory properties; (2) attractiveness of feathers in the nest for mates; (3) eggshell bacterial density. All of these hypothetical scenarios predict that feathers of different colours would differentially affect the hatching success of birds, and that birds should preferentially choose the most beneficial feather colour for lining their nests. Results from two different experiments performed with a population of Danish barn swallow, Hirundo rustica, were in accordance with these predictions. First, H. rustica preferentially selected white experimentally offered feathers for lining their nests. Second, the experimental manipulation of the feather colour composition of nests of H. rustica had a significant effect on hatching success. Experimental nests with more white feathers added at the beginning of incubation had a lower probability of hatching failures, suggesting differential beneficial effects of lining nests with feathers of this colour. We discuss the relative importance of hypothetical functional scenarios that predicted the detected associations, including those related to sexual selection or to the community of microorganisms associated with feathers of different colours.

Behavioral Ecology and Sociobiology, 1995

When brood parasites are about to lay an egg, they have to decide which nest to parasitize. The b... more When brood parasites are about to lay an egg, they have to decide which nest to parasitize. The best nest in which to lay will depend on the parenting ability of the host. We have studied selection of magpie

Behavioral Ecology, 2004

Post-mating sexually selected signals are expected to indicate parental quality. The good parent ... more Post-mating sexually selected signals are expected to indicate parental quality. The good parent model assumes that expression of the sexual character positively reflects parental ability, resulting in a potential link between the exaggeration of the character and nestling-fitness traits. We tested this prediction in a population of a monogamous passerine, the magpie (Pica pica), for which nest size is known to act as a post-mating sexually selected signal. We provided a food supplement to half of the magpie nestlings in each nest, keeping the other half as control nestlings. We found that food-supplemented nestlings experienced a significantly higher T-cell-mediated immune response and a tendency to an increased condition index. In accordance with the good parent model, we found that nest size was positively related to T-cell mediated immune response for control magpie, whereas this relationship was nonexistent in food-supplemented nestlings. In addition, the difference in T-cell mediated immune response between food-supplemented and control nestlings of the same nest was principally explained by nest size. Based on our results, we discuss that magpie pairs with large nests provided their nestlings with higher quality food as compared to pairs with smaller nests, nest size thereby being an indicator of parental ability. To our knowledge, this is the first study showing a link between a post-mating sexually selected signal and nestling immunocompetence, a trait closely related to fitness in birds.

Behavioral Ecology, 2007

Nest-building behavior has been suggested to represent a postmating sexually selected signal in p... more Nest-building behavior has been suggested to represent a postmating sexually selected signal in passerine birds, an hypothesis that has received both comparative and experimental support. Because selection pressure due to parasites and diseases should be particularly high during nest building, mainly due to energetic costs and depression of the immune system associated with this reproductive phase, we predicted a positive association between nest-building effort and immunity. Nest-building effort would reflect the ability to produce efficient immune responses of builders only if individuals with a superior immune system would display exaggerated nest-building effort. We tested this prediction by studying the relationship between volume of nest material used for nest construction and, at the intraspecific level, estimates of innate humoral immune response in barn swallows Hirundo rustica. At the interspecific level, we used responses to the mitogenic phytohemagglutinin as an indicator of adaptive immune response of European passerine species. As predicted, we found, after controlling for several potential confounding factors, that volume of nest material was positively related to immune response both at the intra-and at the interspecific level. Alternative hypotheses explaining the comparative results are discussed.