Volatiles of symbiotic bacterial origin explain ectoparasitism and fledging success of hoopoes.

BACKGROUND: Some parasites use olfactory cues to detect their hosts and, since bacterial symbionts are partially responsible for animal odours, they could influence host parasitism. By autoclaving nest materials of hoopoe (Upupa epops) nests before reproduction started, we explored the hypothetical links between host-associated bacteria, volatiles and parasitism. During the nestling stage, we (i) estimated the level of ectoparasitism by chewing lice (Suborder Mallophaga) in adult hoopoe females and by Carnus haemapterus flies in nestlings, and (ii) characterized microbial communities and volatile profiles of nest environments (nest material and nest cavity, respectively) and uropygial secretions. RESULTS: Experimental nests had less diverse bacterial communities and more diverse volatile profiles than control nests, while occupants experienced lower intensity of parasitism in experimental than in control nests. The experiment also affected beta diversity of the microbial communities of nest material and of the volatiles of the nestling uropygial secretions. Moreover, microbial communities of uropygial secretions and of nest materials covaried with their volatile profiles, while the volatile profile of the bird secretions explained nest volatile profile. Finally, a subset of the volatiles and bacteria detected in the nest material and uropygial secretions were associated with the ectoparasitism intensity of both adult females and nestlings, and with fledging success. CONCLUSIONS: These results show that a component of animal odours is linked with the microbial communities of the host and its reproductive environment, and emphasize that the associations between bacteria, ectoparasitism and reproductive success are partially mediated by volatiles of bacterial origin. Future work should focus on mechanisms underlying the detected patterns.

Extra Nestlings That Are Condemned to Die Increase Reproductive Success in Hoopoes.

AbstractThe adaptive value of routinely laying more eggs than can be successfully fledged has intrigued evolutionary biologists for decades. Extra eggs could, for instance, be adaptive as insurance against hatching failures. Moreover, because recent literature demonstrates that sibling cannibalism is frequent in the Eurasian hoopoe (Upupa epops), producing extra offspring that may be cannibalized by older siblings might also be adaptive in birds. Here, directed to explore this possibility in hoopoes, we performed a food supplementation experiment during the laying period and a clutch size manipulation during the hatching stage. We found that females with the food supplement laid on average one more egg than control females and that the addition of a close-to-hatch egg at the end of the hatching period increased the intensity of sibling cannibalism and enhanced fledging success in hoopoe nests. Because none of the extra nestlings from the experimental extra eggs survived until fledging, these results strongly suggest that hoopoes obtain fitness advantages by using temporarily abundant resources to produce additional nestlings that will be cannibalized. These results therefore suppose the first experimental demonstration of the nutritive adaptive function of laying extra eggs in vertebrates with parental care.

Psychometric evaluation of the Spanish version of the Pediatric Quality of Life Eosinophilic Esophagitis Questionnaire (Peds QL-EoE Module ™).

BACKGROUND: The Paediatric Eosinophilic Oesophagitis Module (PedsQL-EoE) was developed in English as a valid and reliable questionnaire to assess health-related quality of life (HRQoL) in children with EoE. The aim of this study was to evaluate the validity and reliability of the PedsQL-EoE that was previously adapted to Spanish by our group. METHODS: This cross-sectional multicentre study was conducted in 36 paediatric gastroenterology units. Groups with and without dietary restrictions were studied separately. The PedsQL-EoE consists of 33 items divided into seven factors. Age-specific versions of the PedsQL-EoE were sent by e-mail to children and parents. Statistical analysis was used to study the questionnaire structure by means of exploratory factor analysis and interitem correlations. Confirmatory factor analysis (CFA) was applied to verify the proposed model as well as its psychometric properties through SMSR (standardized root mean square), outer loadings and R-square. To study construct validity and reliability, Cronbach´s alpha coefficient, convergent validity (AVE), discriminant validity (HTMT) and intraclass correlation coefficients (ICC) were used. RESULTS: A total of 341 children and 394 parents participated with 307 matched answers. The median age was 12 years, and 75% were male. The questionnaire structure explained 68% and 66% of the total variance for parents and children, respectively. Five items showed negative correlations and were removed from the questionnaire. CFA applied to the new model supported the following construct: SMRS was less than 0.08, outer loadings measured above 0.5, and R2 explained more than 89% of the total variance. Once the modifications were performed, good internal consistency was demonstrated, with Cronbach's alpha values > 0.7, AVE values > 0.5 and HTMT < 0.9 with good child/parent agreement (ICC = 0.80). The most robust model of the PedsQL-EoE module was formed by seven factors: Symptoms I (6 items), Symptoms II (4 items), Treatment (4 items), Worries (3 items), Communication (5 items), Food and Eating (3 items) and Food Feelings (3 items). CONCLUSIONS: The final PedsQL-EoE Module version, after the removal of five items, is a valid and reliable tool to be used in children with EoE. The Spanish validated version appears to be a useful instrument for measuring the impact of EoE on Spanish children´s quality of life.

Hiperfiltración glomerular en el paciente traumático grave / Glomerular hyperfiltration in patients with severe trauma

Antecedentes y objetivo El aclaramiento renal aumentado o hiperfiltración glomerular (HFG) puede afectar significativamente a los resultados clínicos de los fármacos eliminados por vía renal al promover la exposición subterapéutica al fármaco. La agresión sufrida en los pacientes que presentan trauma grave supone un predisponente a manifestar HFG y la identificación de estos pacientes sigue siendo un desafío clínico. El objetivo principal de este estudio fue describir la prevalencia de HFG en una cohorte de pacientes críticos traumatizados en la primera semana de ingreso. Materiales y métodos Estudio prospectivo observacional de una cohorte de pacientes adultos ingresados en la UCI de Anestesiología del Complejo Hospitalario Universitario de Albacete (España) tras sufrir un trauma grave o politraumatismo. Se calculó el aclaramiento de creatinina (ClCr) en muestra de recolección de orina 4h a las 24, 72 y 168h de ingreso aplicando la fórmula ClCr: [Diuresis en ml (orina/4h)×Creatinina en orina (mg/dl)]÷[240 (minutos)×Creatinina en plasma (mg/dl)]. Un CrCl por encima de 130ml/min fue considerado HFG. Los análisis se realizaron con el software estadístico R versión 4.0.4. Resultados Se incluyeron 85 pacientes. La edad mediana de los pacientes fue de 51 años (RIQ 26); 68 pacientes fueron varones (78,82%). El 75,29% de los pacientes fueron politraumatizados; 61 pacientes (71,76%) presentaron HFG en algún momento de la determinación del ClCr. A las 24h de ingreso el 56,34% de los pacientes presentaron HFG con ClCr medio de 195,8ml/min, el 61,11% de los pacientes lo presentaban a las 72h con ClCr medio de 186ml/min y el 56,52% presentaban HFG a las 168h de ingreso con ClCr medio de 207ml/min. Se encontró una relación positiva importante (p=0,07) entre la HFG manifestada a las 72h y a las 168h. Se observó relación estadísticamente significativa entre este fenómeno con edades más jóvenes, puntuaciones ISS más bajas y creatininas plasmáticas más bajas (AU)

Background and objective Augmented renal clearance or glomerular hyperfiltration (GHF) can significantly affect the clinical outcomes of renally eliminated drugs by promoting subtherapeutic drug exposure. The aggression suffered in patients who suffer severe trauma is a predisposition to manifest GHF and the identification of these patients remains a clinical challenge. The main objective of this study was to describe the prevalence of GHF in a cohort of critically ill trauma patients. Materials and methods Prospective observational study of a cohort of adult patients admitted after suffering severe trauma or polytrauma in the Anesthesiology ICU of the University Hospital of Albacete (Spain). Creatinine clearance (ClCr) was calculated in a 4-h urine collection sample at 24, 72 and 168h after admission applying the formula: CrCl: [diuresis in ml (urine/4h)×creatinine in urine (mg/dl)]÷[240 (min)×creatinine in plasma (mg/dl)]. A CrCl above 130ml/min was considered GHF. The analyzes were performed with the statistical software R version 4.0.4. Results Eighty-five patients were included. The median age of the patients was 51 years (IQR 26). Sixty-eight patients were male (78.82%). 75.29% of the patients were polytraumatized. Sixty-one patients (71.76%) presented GHF at some point in the CrCl determination. At 24h of admission, 56.34% of the patients presented GHF with a mean CrCl of 195.8ml/min, 61.11% of the patients presented it at 72h with a mean CrCl of 186ml/min and 56.52% presented GHF at 168h of admission with a mean CrCl of 207ml/min. A significant positive relationship (p=0.07) was found between GHF manifested at 72h and at 168h. We observed a statistically significant relationship between this phenomenon with younger ages, lower ISS scores and lower plasma creatinines (AU)

Defensive tolerance to parasitism is correlated with sexual selection in swallows.

Parasite-mediated sexual selection has been the topic of extensive research and enthusiastic debate for more than three decades. Here, we suggest that secondary sexual characters may not only signal parasite resistance but also defensive tolerance. We exemplify this possibility by analysing information on two sexually selected traits, annual reproductive success, and ectoparasitism in a barn swallow Hirundo rustica population followed for more than 30 years. For each individual, we estimated the slope of the association between reproductive success and parasitism as an index of tolerance and subsequently explored the association with the expression of the sexually selected traits. In accordance with expectations of parasites playing a role in sexual selection, tail length was negatively related to load of chewing lice and nest size was positively related to tolerance to chewing lice. We discuss the importance of considering defensive tolerance for understanding the role of parasite-mediated sexual selection.

Glomerular hyperfiltration in patients with severe trauma.

BACKGROUND AND OBJECTIVE: Augmented renal clearance or glomerular hyperfiltration (GHF) can significantly affect the clinical outcomes of renally eliminated drugs by promoting subtherapeutic drug exposure. The aggression suffered in patients who suffer severe trauma is a predisposition to manifest GHF and the identification of these patients remains a clinical challenge. The main objective of this study was to describe the prevalence of GHF in a cohort of critically ill trauma patients. MATERIALS AND METHODS: Prospective observational study of a cohort of adult patients admitted after suffering severe trauma or polytrauma in the Anesthesiology ICU of the University Hospital of Albacete (Spain). Creatinine clearance (ClCr) was calculated in a 4-h urine collection sample at 24, 72 and 168 h after admission applying the formula; CrCl: [Diuresis in ml (urine/4 h) × Creatinine in urine (mg/dl)] ÷ [240 (minutes) × Creatinine in plasma (mg/dl)]. A CrCl above 130 mL/min was considered GHF. The analyses were performed with the statistical software R version 4.0.4. RESULTS: 85 patients were included. The median age of the patients was 51 years (IQR 26), 78.82% male. 68 patients were male (78.82%). 75.29% of the patients were polytraumatized. 61 patients (71.76%) presented GHF at some point in the CrCl determination. At 24 h of admission, 56.34% of the patients presented GHF with a mean CrCl of 195.8 ml/min, 61.11% of the patients presented it at 72 h with a mean CrCl of /min and 56.52% presented GHF at 168 h of admission with a mean CrCl of 207 ml/min. A significant positive relationship (p = 0.07) was found between GHF manifested at 72 h and at 168 h. We observed a statistically significant relationship between this phenomenon with younger ages, lower ISS scores and lower plasma creatinines. CONCLUSIONS: GHF are a common condition in critically ill patients admitted for severe trauma. We recommend the use of CrCl to assess renal function and make dosage adjustments. Studies are required to understand the clinical impact of these phenomena on drug elimination and to be able to establish the ideal dosage in those cases.

Microbial infection risk predicts antimicrobial potential of avian symbionts.

Symbiotic bacteria on animal hosts can prevent pathogenic bacterial infections by several mechanisms. Among them, symbiotic bacteria can indirectly enhance host's immune responses or, directly, produce antimicrobial substances against pathogens. Due to differences in life-style, different host species are under different risks of microbial infections. Consequently, if symbiotic bacteria are somewhat selected by genetically determined host characteristics, we would expect the antimicrobial properties of bacterial symbionts to vary among host species and to be distributed according to risk of infection. Here we have tested this hypothesis by measuring the antimicrobial ability of the bacterial strains isolated from the uropygial-gland skin of 19 bird species differing in nesting habits, and, therefore, in risk of microbial infection. In accordance with our predictions, intensity and range of antimicrobial effects against the indicator strains assayed varied among bird species, with hole-and open-nesters showing the highest and the lowest values, respectively. Since it is broadly accepted that hole-nesters have higher risks of microbial infection than open nesters, our results suggest that the risk of infection is a strong driver of natural selection to enhance immunocompetence of animals through selecting for antibiotic-producing symbionts. Future research should focus on characterizing symbiotic bacterial communities and detecting coevolutionary processes with particular antibiotic-producing bacteria within-host species.

Functional explanation of extreme hatching asynchrony: Male Manipulation Hypothesis.

Hatching asynchrony in birds is considered an adaptation to facilitate brood reduction because under conditions of food scarcity, the smallest nestling usually dies soon after hatching, thereby minimizing parental effort. However, in species with extreme hatching asynchrony, the last hatchlings paradoxically experience a very low probability of survival and death can take so long that it can hardly be considered an adaptation. Here, we propose and experimentally tested a new adaptive hypothesis explaining the brood reduction paradox, namely the "Male Manipulation Hypothesis". Our hypothesis suggests that by inducing asynchronous hatching, females increase the feeding requirements of the brood, which will induce males to increase provisioning effort. In addition, females may extend the period of male manipulation by feeding the smallest nestling just enough to sustain life. Our study showed that male common blackbirds ( Turdus merula) increased their effort (i.e., number of food items per hour) in experimental asynchronous broods compared to synchronous broods, while females reduced their contribution, as predicted by the hypothesis.

Made-up mouths with preen oil reveal genetic and phenotypic conditions of starling nestlings.

Animal coloration results from pigments, nanostructures, or the cosmetic use of natural products, and plays a central role in social communication. The role of cosmetic coloration has traditionally been focused in scenarios of sexual selection, but it could also take place in other contexts. Here, by using spotless starlings (Sturnus unicolor) as a model system, we explore the possibility that nestlings cosmetically use their intensely yellow-colored uropygial secretion to signal their genetic and/or phenotypic quality. In agreement with the hypothetical cosmetic use of the uropygial secretion, (i) video recorded nestlings collected secretion with the bill at the age of feathering, (ii) cotton swabs turned to the color of secretion after rubbing with them nestlings' gape, and (iii) gape and skin colorations correlated positively with that of secretion. Furthermore, we found that (iv) secretion coloration has a genetic component, and (v) associated positively with Vitamin E supplementation and (vi) with plasma carotenoid concentration, which highlights the informative value of nestling secretion. Finally, (vii) coloration of begging-related traits and of secretion of nestlings predicted parental feeding preferences. Consequently, all these results strongly suggest that the cosmetic use of colored uropygial secretion might also play a role in parent-offspring communication, complementing or amplifying information provided by the flamboyant colored gapes and skin of nestlings. The use of makeups by offspring for communication with relatives has been scarcely explored and we hope that these results will encourage further investigations in birds and other taxa with parental care.

Avian sibling cannibalism: Hoopoe mothers regularly use their last hatched nestlings to feed older siblings.

Sibling cannibalism is relatively common in nature, but its evolution in birds and certain other vertebrates with extended parental care had been discarded. Here, however, we demonstrate its regular occurrence in two European populations of the Eurasian hoopoe (Upupa epops) and explore possible adaptive and non-adaptive explanations. Results showed that sibling cannibalism was more frequently detected in Spain (51.7%) than in Austria (5.9%). In these two populations, the hoopoes laid similar clutch sizes, resulting in similar fledging production, but hatching failures were more frequent in the northern population. Consequently, having more nestlings condemned to die in the southern population may explain the higher incidence of sibling cannibalism. In accordance with this interpretation, hatching span and failure, but not breeding date, explained the probability of sibling cannibalism in the Spanish hoopoes, while all three variables predicted brood reduction intensity. Furthermore, experimental food supply reduced the probability of sibling cannibalism, but not the intensity of brood reduction. Finally, females allocated fewer resources to the smallest nestlings when they were going to starve, but not necessarily when they were going to be used as food for their siblings. These results suggest that hoopoes produce extra eggs that, in the case of reduced hatching failure and food scarcity, produce nestlings that are used to feed older siblings. These findings provide the first evidence that sibling cannibalism occurs regularly in a bird species, thus expanding our evolutionary understanding of clutch size, hatching asynchrony, parent-offspring conflict, infanticide, and sibling cannibalism in the animal kingdom.

Microbially Mediated Chemical Ecology of Animals: A Review of Its Role in Conspecific Communication, Parasitism and Predation.

Microbial symbionts are nowadays considered of pivotal importance for animal life. Among the many processes where microorganisms are involved, an emerging research avenue focuses on their major role in driving the evolution of chemical communication in their hosts. Volatiles of bacterial origin may underlie chemical communication and the transfer of social information through signals, as well as inadvertent social information. We reviewed the role of microorganisms in animal communication between conspecifics, and, because the microbiome may cause beneficial as well as deleterious effects on their animal hosts, we also reviewed its role in determining the outcome of the interactions with parasites and predators. Finally, we paid special attention to the hypothetical role of predation and parasitism in driving the evolution of the animal microbiome. We highlighted the novelty of the theoretical framework derived from considering the microbiota of animals in scenarios of communication, parasitism, and predation. We aimed to encourage research in these areas, suggesting key predictions that need to be tested to better understand what is one of the main roles of bacteria in animal biology.

Hemorragias intracraneales en pacientes críticos COVID-19: reporte de tres casos / Intracranial hemorrhages in critical COVID-19 patients: report of three cases

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Autoclaving Nest-Material Remains Influences the Probability of Ectoparasitism of Nestling Hoopoes (Upupa epops).

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 reproductive seasons suffered less from ectoparasites than those hatched in the control nest-boxes with nonautoclaved nest-material. Moreover, we found a positive association between the bacterial density of nest-material during the nestling phase and ectoparasitism intensity that was only apparent in nest-boxes with autoclaved nest-material. However, contrary to our expectations, nest bacterial load was positively associated with fledgling success. These results suggest a link between the community of microorganisms of nest-material remains and the intensity of ectoparasitism, and, on the other hand, that the nest bacterial environment during reproduction is related to fledging success. Here, we discuss possible mechanisms explaining the experimental and correlative results, including the possibility that the experimental autoclaving of nest material affected the microbiota of females and nestlings' secretion and/or nest volatiles that attracted ectoparasites, therefore indirectly affecting both the nest bacterial environment at the nestling stage and fledging success.

The gut microbiota of brood parasite and host nestlings reared within the same environment: disentangling genetic and environmental effects.

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.

Antimicrobial activity of nest-lining feathers is enhanced by breeding activity in avian nests.

The use of feathers as nest material has been proposed as a kind of self-medication strategy because antimicrobial-producing microorganisms living on feathers may defend offspring against pathogenic infections. In this case, it is expected that density of antimicrobial-producing bacteria, and their antimicrobial effects, are higher in feathers that line the nests than in eggshells. Moreover, we know that feather pigmentation and breeding activity may influence density and antimicrobial production of bacteria. To test these predictions, we analyzed bacterial densities and antimicrobial activity of bacterial colonies isolated from bird eggshells and nest-lining feathers against bacterial strains comprising potential pathogens. Samples were collected from spotless starling (Sturnus unicolor) nests, and from artificial nests to isolate the effects of breeding activity on bacterial communities. The composition of feathers lining the nests was experimentally manipulated to create groups of nests with pigmented feathers, with unpigmented feathers, with both types of feathers or without feathers. Although we did not detect an effect of experimental feather treatments, we found that bacterial colonies isolated from feathers were more active against the tested bacterial strains than those isolated from eggshells. Moreover, bacterial density on feathers, keratinolytic bacteria on eggshells and antimicrobial activity of colonies isolated were higher in starling nests than in artificial nests. These results suggest that antimicrobial activity of bacteria growing on nest-lining feathers would be one of the mechanisms explaining the previously detected antimicrobial effects of this material in avian nests, and that breeding activity results in nest bacterial communities with higher antimicrobial activity.

Correction: Ruiz-Rodríguez et al. Gut Microbiota of Great Spotted Cuckoo Nestlings Is a Mixture of Those of Their Foster Magpie Siblings and of Cuckoo Adults. Genes 2018, 9, 381.

The authors wish to make the following changes in their paper [...].