Feeding Effort Research Articles

Are brood sex ratios adaptive? – The effect of experimentally altered brood sex ratios on parental feeding behaviour

Correlations between brood sex ratios (BSRs) and parental or environmental quality have been found in many species. This phenomenon is called sex ratio adjustment, and is expected to evolve if certain factors affect the fitness return from the offspring in a sex-dependent way. However, it is seldom studied whether biased sex ratios are indeed adaptive. We manipulated BSRs in a cross-fostering experiment, and investigated parental costs in terms of feeding rate and survival in the collared flycatcher (Ficedula albicollis). In our population, male nestlings can grow faster under good conditions, but are more sensitive to adverse conditions. Assuming that the sensitivity of the males results from their larger energy requirement, we predicted increased costs in broods with male-biased experimental BSR. Assuming that BSR adjustment is adaptive and related to parental care giving capacity, we expected higher feeding and survival rate by parents that originally had more sons, and predicted that low quality parents are less able to adjust their feeding rates to the needs of their foster broods or pay higher survival cost. However, we found that the manipulated BSR and its interaction with original BSR affected neither the feeding rate nor the survival of the parents. Only male feeding rate was correlated with original BSR, however, contrary to our prediction: males with female-biased original BSR fed their foster chicks more frequently. Our results, with those of a previous report about the effects of the experiment on nestlings, do not support that the observed BSRs are adaptive in our population.Significance statementMany hypotheses propose that higher vertebrates adaptively adjust the primary sex ratio of their offspring to individual or environmental quality. While the potential adaptive value of the observed patterns is regularly discussed, studies that specifically test the adaptivity of sex ratio adjustment are very scarce and correlative. Using a special cross-fostering experiment, we investigated whether original brood sex ratios are related to the rearing capacity of the parents, and experimental sex ratios are related to the rearing costs in terms of feeding effort or survival. We found no effect of experimentally altered brood sex ratios on either parental feeding effort or survival. Furthermore, contrary to the adaptive scenario, males that had female-biased broods originally had higher feeding rates. So far, we have found no evidence that the sex ratio adjustment is adaptive in the collared flycatcher.

Analisis Memberi Makan Banyak Orang Dan Implementasinya Pada Masa Kini (2 Raja-Raja 4:42-44)

This article discusses the importance of feeding many people and its implementation today. Nowadays, challenges such as poverty, hunger and unequal access to food are still serious problems in various places. This article aims to analyze the importance of feeding many people and present several implementations that can be done to overcome this problem, and also provide teaching that can influence and encourage people to help each other and foster a sense of empathy with others. In this research, the author analyzes and interprets text from the Bible 2 Kings 4:42-44. This book tells about the history of the reign of several Kings in the Kingdom of Israel and the Kingdom of Judah, especially in this verse which focuses on the Miracle performed by the Prophet Elisha on one hundred people through God's blessing. Teaching in Christianity teaches the values of compassion, social care, and service to others. Through a qualitative approach, this paper explores how Christian values such as responsibility, love and kindness can be applied in feeding efforts involving large numbers of people. The results of this paper highlight the important role of Christian teachings in shaping food programs, both in supporting communities in need and managing food programs that are in accordance with Christian religious values and relevant to current social dynamics.

Activity budget and seasonal activity shifts in sympatric lemurs: Increased lean season effort in a cathemeral frugivore contrasts with energy conservation in a diurnal folivore.

One of the most fundamental aspects of a species' behavioral strategy is its activity budget; for primates this generally involves the allocation of available time among resting, feeding, traveling, and social behavior. Comparisons between species, populations, or individuals can reveal divergences in adaptive strategies and current stressors, and reflect responses to such diverse pressures as predation, thermoregulation, nutrition, and social needs. Further, variation across seasons is an important part of behavioral strategies to survive food scarcity; this can involve increasing or decreasing effort. We documented activity over the 24-h cycle for the cathemeral, frugivorous Eulemur fulvus and the diurnal, folivorous Propithecus diadema across 13-18 months at Tsinjoarivo, Madagascar. Their activity budgets were dominated by resting (E. fulvus: 74.1%; P. diadema: 85.2%), followed by feeding (15.8%, 12.4%), traveling (9.31%, 1.74%) and social activities (0.76%, 0.70%), respectively. The lower feeding and higher resting in P. diadema likely reflect slower gastrointestinal transit and higher reliance on microbial fermentation to extract energy from fibrous food. The two species showed opposite lean season strategies. E. fulvus increased activity, with more feeding but less travel time, consistent with a shift to less-profitable fruits, and some leaves and flowers, while increasing feeding effort to compensate ("energy maximizing"). P. diadema showed less variation across months, but the lean season still evoked reduced effort across the board (feeding, travel, and social behavior), consistent with a "time minimizing" strategy prioritizing energy conservation and microbe-assisted digestion. Understanding these divergent shifts is key to understanding natural behavior and the extent of behavioral flexibility under stressful conditions. Finally, the complex patterns of fruit availability (intra- and interannually) and the species' behavioral responses across months underscore the need to move beyond simplistic "lean/abundant season" and "fruit/leaf" dichotomies in understanding underlying energetic strategies, and species' vulnerability to habitat change.

Reproductive biology of the Whitehead’s Broadbill (Calyptomena whiteheadi)

ABSTRACT Whitehead’s Broadbill, Calyptomena whiteheadi, an endemic species on the island of Borneo, has a declining population, raising the question of whether reproduction might be a factor limiting population growth. We studied breeding biology based on 52 nests in Kinabalu Park, Sabah, Malaysian Borneo in 2009–2020. Length of the egg-laying season was 99 days with a median of 22 March. Clutch size was typical of tropical songbirds at 2.0 ± 0.13 eggs (SE). Nest success was relatively high at 52%, and daily nest predation rate was relatively low at 0.013 ± 0.004 (SE). Concordantly, length of incubation and nestling periods were relatively long at 19.0 ± 0.26 d and 26.8 ± 0.3 d (SE), respectively. Similarly, the growth rate constants (K) for mass, wing length and tarsus length were slow at 0.252, 0.161 and 0.188, respectively. Slow growth might result in part from their frugivorous diet, as we show using seed traps, but they are reported to include insects in their diets and food provided to their young. Feeding effort, as reflected by the number of fruit seeds dropped below the nest, increased through the nestling period. Brooding effort of parents for nestlings was high on hatch day and decreased until Day 10–15 when it stopped. Food and parental care efforts do not seem to cause their slow growth. Ultimately, our study population has reproductive success that suggests it is not limiting population growth, but studies are needed in other locations to determine if it is a problem elsewhere.

Exploring the infant feeding experiences of mothers living in selected Tshwane informal settlements: a qualitative study

Objective: The study aimed to explore and describe the infant feeding experiences of mothers of children aged 3 to 24 months, living in two selected informal settlements in Tshwane, South Africa. Design: This exploratory qualitative study gathered data via six focus-group discussions (FGDs). These were facilitated using a semi-structured questionnaire guide with probes. Data were then transcribed, coded and thematically analysed. Setting: The study was conducted in the two selected informal settlements in the west of Tshwane, South Africa. Subjects: Biological mothers (n = 28) of infants and young children aged 3 to 24 months, living in the selected informal settlements participated. The mothers had to be living with their child with some responsibility for their daily care and feeding. Results: Three themes with six sub-themes were identified following thematic analysis. First was the mothers’ experience of infant feeding, which included their interpretations and practices of exclusive breastfeeding and complementary feeding. Second, mothers received infant feeding support from their elders based on common beliefs. The support received from healthcare workers was sometimes perceived negatively. However, healthcare workers based at healthcare facilities were important sources of exclusive breastfeeding and complementary feeding information. Third were the setting-related factors that negatively affected the mothers’ ability to access nutritious food for themselves and their infants. These included household food insecurity, plus environmental and household factors affecting food storage and preparation. Conclusion: Mothers experienced several challenging circumstances affecting their infant feeding efforts. These findings highlight the need to strengthen targeted infant feeding counselling and support for mothers living in resource-constrained environments.

The Use of Removed Mesquite Brush as a Fiber Replacement in Silage Production.

Simple SummaryMesquite is considered an invasive browse species in most of the American Southwest, spreading rapidly into Texas and leading to disruption of native grasslands. Management efforts generate a significant volume of organic debris. Incorporation of this organic material into livestock feeding efforts would represent a sustainable solution to this ecological problem. Our objectives were to (1) determine the nutritive value and fermentation characteristics of silage produced with mesquite biomass, and (2) evaluate potential pre-treatment methods of mesquite biomass prior to ensiling. Inclusion of mesquite biomass in a bermudagrass-based silage was shown to increase fiber concentrations, decrease crude protein and in vitro digestibility, and decrease fermentation quality (pH and volatile fatty acids [VFA]). However, 250 g kg−1 inclusion of mesquite was shown to be similar to grass silage alone. There was no effect of lactic acid bacteria inoculation, though increasing length of incubation did increase VFA production and decrease silage pH. Pre-treatment of mesquite biomass with acid or alkali did not improve ensiling properties. Results are interpreted to mean that mesquite biomass may be effectively incorporated into silage at levels up to 250 g kg−1.Mesquite (Prosopis L.) is considered an invasive browse species in most of the American Southwest. Mechanical intervention removes yields an excess of organic debris. Anecdotal evidence in the past has supported using such browse as feed for livestock. Thus, our objectives were to (1) determine the nutritive value and fermentation characteristics of silage produced with mesquite biomass, and (2) evaluate solvent treatment of mesquite biomass prior to ensiling. In Experiment 1, we evaluated mesquite inclusion rate (0, 250, 500, 750, or 1000 g kg−1 DM), length of fermentation (28, 56, or 84 d), and silage inoculant. In Experiment 2, we evaluated the effects of mesquite pre-treatment with acid (H2SO4) or alkali (NaOH) solutions. Concentrations of NDF, ADF, and ADL, as well as IVTD, decreased (p < 0.05) with increasing mesquite inclusion. However, 250 g mesquite kg−1 DM did not differ from grass silage. There was no effect (p > 0.05) of inoculation, though increasing length of incubation did increase (p < 0.05) VFA production and decrease (p < 0.05) silage pH. Solvent treatment did not improve ensiling properties. Results are interpreted to mean that mesquite biomass may be effectively incorporated into silage at levels up to 250 g kg−1.

Allostatic Load in Gambel’s White Crowned Sparrow, Zonotrichia leucophrys gambelii: Relationships With Glucocorticoids

Regulation of energetic expenditure in a changing environment, considered here as allostatic load, is central to organism-environment interactions. The value of responses that modify behavior or physiology in coping strategies is often measured in terms of energetic benefits. In this study, the total energetic cost incurred by Gambel’s white-crowned sparrows, Zonotrichia leucophrys gambelii, was assessed using heart-rate transmitters. The use of heart rate was validated as a proxy for metabolic rate via flow-through respirometry. Applying heart rate as an indicator of allostatic load, we confirmed that ambient temperature under wintering conditions influences allostatic load. However, baseline corticosterone, proposed to mediate physiological responses to variation in allostatic load, does not appear to vary with heart rate or temperature in captivity, or with temperature under ambient conditions in the field. The relationship between allostatic load and plasma corticosterone levels was also investigated by manipulating feeding effort for captive Gambel’s white-crowned sparrows using a sand-excavation challenge that approximated a type of foraging work that these birds normally perform in the wild. This experiment was designed to test the hypothesis that experimentally increased allostatic load induces elevation in baseline corticosteroids. We did not find support for this hypothesis. We suggest that the adrenocortical response to increased allostatic load may be limited to overload or environmental conditions that meaningfully threaten energy imbalance, indicating new targets for further research.

An experimental test of chronic traffic noise exposure on parental behaviour and reproduction in zebra finches.

ABSTRACTChronic traffic noise is increasingly recognised as a potential hazard to wildlife. Several songbird species have been shown to breed poorly in traffic noise exposed habitats. However, identifying whether noise is causal in this requires experimental approaches. We tested whether experimental exposure to chronic traffic noise affected parental behaviour and reproductive success in zebra finches (Taeniopygia guttata). In a counterbalanced repeated-measures design, breeding pairs were exposed to continuous playback of one of two types of highway noise previously shown to be either neutral (control) or aversive. Parental nest attendance positively correlated with feeding effort and was higher for the aversive than the control sound and this effect was more pronounced for parents attending larger broods. However, neither noise condition affected offspring number, growth or body mass. The absence of an effect held when we combined our data with data from two other comparable studies into a meta-analysis. We discuss whether the increased nest attendance could be a compensatory strategy that alleviated detrimental noise effects on the chicks, and whether it could be caused by impaired parent-offspring or within-pair communication. Future work should test these hypotheses and investigate potential long-term costs of increased parental engagement.

Masticatory and ingestive effort in Procolobus verus, a small-bodied African colobine.

The olive colobus (Procolobus verus) is the smallest extant colobine. Based on the axiom that folivory is associated with larger body mass, the olive colobus is expected to be less folivorous than its sister taxon Piliocolobus badius, but previous studies show that the opposite is true. Here we test the hypothesis that masticatory and ingestive effort in the olive colobus is greater due to allometric factors related to bite force scaling and throughput of ingested foods. We analyzed oral processing data collected on olive colobus in the Taï Forest, Ivory Coast, between May 2016 and May 2018. We compare these with previously published data on P. badius and Colobus polykomos from Taï. In terms of overall feeding effort, olive colobus invest more effort (i.e., chewing cycles) than the larger colobines. When contrasts are restricted to commonly consumed foods, this greater energetic investment is not consistently observed. Ingestion of young leaves is associated with a reduced number of masticatory cycles in all three colobine species. A slightly elevated average effort in the olive colobus during young leaf feeding suggests this food source is more challenging in smaller monkeys, but mature leaf processing effort is generally the same among Taï colobines. Thus, for olive colobus, leaf ductility may be more problematic than leaf toughness in terms of masticatory effort. While there may be an allometric cost to being a small colobine, food selectivity is an important mitigating factor.

Begging and feeding responses vary with relatedness and sex of provisioners in a cooperative breeder

Begging behaviour can provide information on offspring hunger levels and be used by parents to adjust food provisioning efforts. In cooperative breeders, helpers also provide care by feeding the young. However, how helpers of different sex and relatedness to the offspring respond to begging behaviour has rarely been studied in cooperatively breeding species, which limits our understanding of the indirect and/or direct benefits that helpers may obtain by responding to offspring demand. Here, we used a cooperatively breeding bird, the sociable weaver, Philetairus socius , to investigate how nest intervisit intervals of breeders and different types of helpers, distinguished by sex and relatedness, varied with acoustic begging. Moreover, we tested whether these different classes of provisioners experienced distinct levels of begging. Our results show that only breeding males, but not breeding females or helpers of any sex and relatedness to the nestlings, returned faster to the nest to feed after experiencing more begging calls. When contrasted directly, we confirmed a statistically supported difference in responses to begging between male and female breeders. Surprisingly, second-order relatives experienced more begging calls than the other classes of more related helpers and breeders. These results show that we might find differences in how provisioners respond to begging levels when classifying group members according to their potential fitness gains. In sociable weavers, the benefits and costs of adjusting feeding efforts to begging seem to differ with sex and life history stage. Experimental and more detailed investigations on begging–feeding interactions are necessary to understand the origin and prevalence of these differences across cooperatively breeding systems. • We investigated breeders and helpers' feeding responses to offspring begging. • Breeding males, but not females, fed faster after experiencing more begging calls. • Feeding by helpers of different sex and relatedness did not vary with begging. • Second-order related helpers experienced more begging calls than other provisioners.

Large-scale supplemental feeding alters lay date and nest survival in Eastern Bluebirds but not in two species of chickadees

Abstract Wild bird feeding is a popular and growing activity, with approximately half of households participating in nations including the United States, Canada, the United Kingdom, New Zealand, and Australia. Supplemental feeding can increase survival and reproductive success of birds (which is often a goal of supplemental feeding efforts), but it raises concerns about phenological mismatch and possible increased risk of nest predation. Our objectives were to test whether access to supplemental food during the breeding season was correlated with (1) advanced egg-laying phenology, (2) increased clutch size, or (3) improved nest survival of 3 cavity-nesting species (Carolina Chickadee [Poecile carolinensis], Black-capped Chickadee [P. atricapillus], and Eastern Bluebird [Sialia sialis]) at a large spatial scale (the United States and Canada; spanning 22° latitude and 55° longitude). We examined data from 24,528 nest attempts submitted to NestWatch from 2014 to 2019. For Eastern Bluebirds, birds with access to supplemental insects initiated clutches 5.83 ± 0.89 (mean ± SE) days earlier than birds without access to food subsidies, whereas predicted nest survival was 5% greater for birds with access to supplemental insects (probability of nest success = 0.79, 95% CI: 0.77–0.81) than for birds without (0.74, 95% CI: 0.72–0.75). Clutch size of Eastern Bluebirds did not differ between birds with and without access to supplemental insects. For chickadees, supplemental feeding (of seeds, suet, insects, or fruit) was not correlated with phenology, clutch size, or nest survival. Our results suggest that supplemental feeding of insects can be an effective tool for increasing nest survival in Eastern Bluebirds and potentially other food-limited insectivores. However, the efficacy of supplemental feeding for improving reproductive success varies across taxa, likely related to diet. Despite widespread feeding of Black-capped and Carolina Chickadees, supplemental food had no discernable effect on timing of egg-laying, clutch size, or nest survival.

Positive association between experimental cortisol increases and cage-measures of feeding behavior in wild-caught gerbils

Abstract Glucocorticoid hormone levels vary within a forager based upon environmental stressors such as illumination and riskier habitats, and a forager’s response to environmental variables depends upon its glucocorticoid levels. Here, we report on a laboratory experiment in which we manipulated cortisol in Allenbyi’s gerbils (Gerbillus andersoni allenbyi) to test the relationship between cortisol and behavior. We then quantified the resulting blood cortisol levels and feeding behavior in gerbils. Thirty gerbils were injected with 21-day slow-release cortisol pellets drawn from 5 different dosages. We quantified the physiological response to pellet implantation in gerbils by measuring cortisol level in blood serum using ELISA (Enzyme Linked Immunosorbent Assay). We fed gerbils daily by mixing millet seeds into the sand inside rodent cages and measured the remaining seeds the following day to quantify feeding efforts. Some evidence supports that subcutaneous supplementation of glucocorticoids (GCs) in the gerbils led to higher blood serum levels. Cortisol levels varied according to time period of measurement. Gerbils that received lower dosages consumed most of the food presented to them when compared to those receiving the highest doses. In this manner, we delineate a pattern on cortisol hormone level variation over time following dosing and consequences in feeding behavior.

Blue tit Cyanistes caeruleus males increase their reproductive effort when subject to a flea experimental manipulation

Parasites exert a strong selection pressure on their hosts as manifested in behavioural antiparasite traits to reduce negative impacts on fitness. The numerous nest‐dwelling ecto‐parasites residing in avian nests make altricial birds excellent model‐systems for investigating the relationship between parasites and their hosts. Here, we experimentally increased natural levels of hen fleas Ceratophyllus gallinae in blue tit Cyanistes caeruleus nests during incubation, and tested their effects on parental incubation behaviours and reproductive performance. Our experimental addition of fleas resulted in an increase in feeding effort of males to incubating females. Frequency of male feedings was also positively related to clutch size. These results suggest that males increase their reproductive effort in flea manipulated and large broods. This will, at least partly, compensate female costs in nests with high ecto‐parasite density and many nestlings. Furthermore, nestling mass at day six in experimental nests decreased with brood size, which was not the case in nests with a natural level of fleas. In line with male incubation feeding, parents may try to compensate for the costs inflicted by the fleas but can only partly compensate when brood size is large.

Loss of Extra-pair Paternity is not Associated with Decreased Paternal Investment in Mixed-paternity Broods or Unrelated Nestlings in the Varied Tit, Parus varius

Males of socially monogamous bird species may be faced with providing costly care for unrelated offspring when nests have extra-pair young (EPY). Theoretical models predict that cuckolded males should lower their parental investment as the likelihood of paternity decreases. However, empirical data are not always in support of this prediction. Here, we explore parental behaviours within the context of extra-pair patenity (EPP) in a population of the varied tit Parus varius in China. The results showed that 39.5% of nests were cuckolded and 16.4% of chicks were sired by extra-pair males. We found no evidence that male and female varied tits reduced their feeding rates or relative feeding effort to EPP broods, or that they decreased provisioning for EPY in mixed broods. There was also no direct effect of EPP on the reproductive success of breeding adults and the body condition nestlings near fledging. The lack of reliable cues of EP copulations (EPC)s by social mates available for the males, and/or the absence of strictly environmental pressure on males that would favor discrimination may account for a lack of an adjustment in feeding effort. The absence of discrimination between own and EPP chicks in parental care suggests that females pay no fitness cost as a result of EPCs, which may explain the high frequency of EPY in nests.

Foraging efforts and behaviour of the European Turtle doves (Streptopelia turtur) during the breeding season

During the breeding season, many avian species face spatial and seasonal variation in the availability of food resources required to rear chicks. Reduction of food abundance is often identified as the most important factor determining population trends and breeding success in bird species, such as the vulnerable European Turtle dove Streptopelia turtur. During the breeding periods, the increase of food requirements in chicks should increase foraging effort to maintain the amount of food required for optimal chick development. To investigate the feeding effort of Turtle doves during the breeding season, we monitored foraging and drinking rates, in different wild habitats and farmlands, from March to September 2016-2017 in Midelt, Morocco. Similarly, breeding chronology, including nesting, laying, and chicks' fledging, were monitored in the same habitats to evaluate the correlation between breeding efforts and foraging rates. We found that Turtle doves feed actively from the arrival to departure dates. Foraging activities were intense during breeding phases, mainly laying and chicks' growth periods. Equally, Doves feed intensively during the end of the breeding season before migration departures. Besides, Doves feed actively during the morning and evening to avoid the hottest periods as a strategy to save metabolic water.

Coloration of spotless starling nestlings shows genetic and environmentally determined characteristics while begging for food

Abstract Similar to other signals, coloration of traits expressed by nestlings while they are begging for food are assumed to reflect their phenotypic conditions, and, therefore, they should be environmentally determined. However, these colorations are also species specifics and, thus, a genetic component explaining the evolution of nestling coloration should exist; a possibility rarely explored in the literature. Cross‐fostering experiments allowed us to quantify genetic and environmental components of coloration of mouth, flanges and skin in a spotless starling Sturnus unicolor population. In addition, by supplementing some nestlings within each brood with non‐pigmented antioxidants (Vitamin E or Vitamin complex), we explored the effects of food supplementation on coloration of begging‐related traits and plasma carotenoid concentration. We detected significant genetic components of colorations of skin and mouth, but not of flanges or plasma carotenoid concentration. Moreover, experimental supplementation with Vitamin E affected UV coloration of mouth, flanges and skin, while vitamin‐complex supplementation exclusively affected flange coloration. Furthermore, coloration of flanges, but not that of other traits, predicted plasma carotenoid concentration suggesting a direct link between these two traits. All these results suggest that coloration of begging‐related traits is a multifaceted signal informing parents about genetic characteristics, and of short‐term needs of nestlings, including antioxidative capacity, that parents could use to adjust feeding efforts, and deciding which chick to feed. Future research should focus on the parents' perspective, taking into account their feeding effort and feeding preferences in relation to genetically and/or environmentally determined coloration of begging‐related traits. A free Plain Language Summary can be found within the Supporting Information of this article

Dynamics of a discrete-time stoichiometric optimal foraging model

In this paper, we discretize and analyze a stoichiometric optimal foraging model where the grazer's feeding effort depends on the producer's nutrient quality. We systematically make comparisons of the dynamical behaviors between the discrete-time model and the continuous-time model to study the robustness of model predictions to time discretization. When the maximum growth rate of producer is low, both model types admit similar dynamics including bistability and deterministic extinction of the grazer caused by low nutrient quality of the producer. Especially, the grazer is benefited from optimal foraging similarly in both discrete-time and continuous-time models. When the maximum growth rate of producer is high, dynamics of the discrete-time model are more complex including chaos. A phenomenal observation is that under extremely high light intensities, the grazer in the continuous-time model tends to perish due to poor food quality, however, the grazer in the discrete-time model persists in regular or irregular oscillatory ways. This significant difference indicates the necessity of studying discrete-time models which naturally include species' generations and are thus more popular in theoretical biology. Finally, we discuss how the shape of the quality-based feeding function regulates the beneficial or restraint effect of optimal foraging on the grazer population.

Hoopoe Upupa epops male feeding effort is related to female cosmetic egg colouration

Avian eggshell colouration might function as a post‐mating sexually selected signal of female quality, influencing male parental investment and, hence, reproductive success. This hypothesis has been tested for intrinsic eggshell pigments as biliverdin (blue‐green colouration) and/or protoporphyrin (brown coloured spots), but never for colourations applied post‐laying. Post‐laying staining colouration due to, for instance, uropygial secretion of the female could reflect its phenotypic properties and, thus, might be a cue for male investment in reproduction. In hoopoes, the uropygial gland of incubating females hosts symbiotic bacteria that are responsible for the brown colour of their uropygial secretion and of the eggshells, as they cover their bluish‐grey eggshells with gland secretion after laying. The secretion protects embryos from pathogenic trans‐shell infections and, thus, egg colouration may function as a cue or even as a post‐mating sexually selected signal of antimicrobial potential in hoopoes. In a wild hoopoe population breeding in nest boxes in Spain, we test this hypothesis by exploring whether egg colour predicts male parental investment. In accordance with the hypothesis, we found that the amount of food provided by males to incubating females was higher in nests with less saturated eggshell colours. This relationship was affected by female body condition. High quality females in terms of body condition and/or in secretion colour obtained better males in terms of provisioning effort during incubation. Given that eggshell saturation is negatively related to density of bacterial symbionts in uropygial secretions, one possibility is that males may regulate their parental investment in accordance to the expected characteristics of mutualistic bacteria hosted in uropygial glands and deposited on eggshells. We discuss alternative explanations for our results, concluding that the post‐mating sexual selection hypothesis is the most likely but experimental modification of egg colour is needed to test it further.

A longitudinal study of maternal feeding and children's picky eating

This study aimed to estimate the rate of persistent picky eating (PE) in children 3–8 years of age, and to characterize children with PE and their mothers. From a base sample of 1055 mothers of children 3.4 ± 1.3 years old, we selected those who described their children as picky eaters (PEs; n = 185, 17.5%) for a longitudinal study. 109 PE dyads participated, as well as a matched comparison group of dyads without PE (n = 106). At T1 mothers self-reported on trait anxiety, perfectionism, attachment style; as well as on the child's behavioral problems, their temperament, and their executive function. The participants were re-evaluated twice, at two-year intervals (T2 and T3). At T2 the mothers self-reported on their personality, on their child feeding practices, and reported their child's eating behavior. At T3 the mothers self-reported on their feeding style and the children self-reported on a pictorial frequent food questionnaire. PE persisted throughout T2 and T3 in 22.5% of T1 PE children in the longitudinal study, or in 3.94% of the base sample. The child characteristics that distinguished the PE and non-PE groups at T1 predicted 9–10% of the variance of T3 PE. Maternal feeding practices at T2 contributed 1–2% to the explained variance. It can be concluded that for the overwhelming majority of children, PE is a passing phase. Maternal feeding practices have limited long-term influence on children's PE. Unless PE is persistent and severe, parents would best be advised to relax their feeding efforts.

Flexible feeding patterns of copepod Centropages tenuiremis in fluctuating conditions: a possible survival strategy to cope with disturbance

Centropages tenuiremis is a species with a wide distribution range in disturbed coastal waters. However, due to a lack of dietary information, it remains unclear as to how they maintain such dominance in fluctuating conditions. In this study, C. tenuiremis was collected from the Daya Bay Nuclear Power Plant both in inlet and outfall regions at 06:00, 12:00 and 18:00 on April 27, 2011 and their in situ diet was analyzed using a PCR protocol targeting 18S ribosomal genes. Thirty-four species of prey organisms were identified totally, including Dinophyta, Baciliariophyta, Viridiplantae, Rhizaria, Apicomplexa, Chordata, Mollusca, Arthropoda and Fungi, indicating an obvious omnivorous feeding habit of C. tenuiremis. Centropages tenuiremis obviously exhibited spatial and temporal variations in diet composition. More plant prey (land plants and phytoplankton) were consumed in the morning (~50%), while more animal prey (metazoans and protozoans) were ingested at midday and night (60%–70%). Furthermore, a more diverse diet was detected in the outfall region (10–11 taxa), where the temperatures were relatively higher and more fluctuating, than in the control region (5–10 taxa). This finding indicated that C. tenuiremis could potentially expand its food spectrum under stressful condition. Specifically, C. tenuiremis exhibited phytoplankton preference (58.62%–67.64%) in the outfall region with a lower omnivory index (0.27–0.35) than in the control region (0.51–0.95). However, phytoplankton density was lower than that in the control region, suggesting a possible herbivorous tendency of C. tenuiremis under elevated temperatures to balance the energy acquirement and feeding effort. The flexible food choices of C. tenuiremis observed here could effectively buffer environmental fluctuations and might be an important survival strategy in coastal ecosystems.