Differential Resource Allocation Research Articles

Influence of mate preference and laying order on maternal allocation in a monogamous parrot species with extreme hatching asynchrony

It is well established that in many avian species, prenatal maternal resource allocation varies both between and within clutches and may affect offspring fitness. Differential allocation of maternal resources, in terms of egg weight and yolk composition, may therefore allow the female to adjust brood reduction and to fine-tune reproductive investment in accordance with the expected fitness returns. The adaptive value of such maternal resource allocation is thought to be context-dependent as well as species-specific. We investigated the effects of female preference for her mate on the allocation of prenatal maternal resources in the budgerigar, Melopsittacus undulatus, a monogamous species of parrot that shows an extreme hatching asynchrony. We assessed mate preferences in a two-way preference test and allowed females two breeding rounds: one with the preferred and one with the non-preferred partner. We found no effect of preference on either latency to lay or clutch size, but females mated with the preferred partner laid eggs that contained significantly more yolk. Their eggs also contained significantly more androstenedione but not testosterone. Our results suggest that in this species, female preference may influence maternal resource allocation, and that the functional roles of each androgen in the yolk should be considered separately. In addition, we found a significant effect of laying order on egg and yolk weight as well as on yolk testosterone and androstenedione levels. These measures, however, did not change linearly with the laying order and render it unlikely that female budgerigars compensate for the extreme hatching asynchrony by adjusting within-clutch allocation of prenatal maternal resources.

Irrigation Management Reform in Northern China: Case Studies in Shanxi Province

AbstractIrrigation in northern China is exposed to declining groundwater resources and institutional issues. As a response, authorities have developed measures that include differentiated resource allocation and charging, collective and individual water rights, a block pricing system, prepaid access to water, and real‐time monitoring of resource and use. This paper analyses this alternative management model and its implications at the farm and system levels, using institutional, technical and economic analyses of case studies from Qingxu County, northern China.The results show that the prepaid system helps solve cost‐recovery, free‐riding, agency and resource overuse problems. All water fees are prepaid, therefore fully collected. However, while most operation and maintenance costs are covered, personnel costs are covered in only one case, due to low water fees. The agency problem is also addressed by the continuous monitoring of water resources. Water use value is high compared to actual water fees, owing to high maize yields and reasonable use of supplemental irrigation. This indicates potential for a water price increase, if needed. This paper shows that the new management system at the county level epitomizes China's whole rural financial reform and the realignment of local water institutions with public administrative layers. It finally discusses achievements, pending questions and limitations for long‐term impacts. Copyright © 2015 John Wiley & Sons, Ltd.

Nutritional ecology, growth and density of Acronyctodes mexicanaria(Lepidoptera: Geometridae) on a dioecious plant Buddleja cordata(Scrophulariaceae)

Due to differential resource allocation by male and female plants, herbivores tend to feed more on male plants than on female ones. It is believed that the preferred food gives the organism a better performance. Buddleja cordatais an abundant dioicous plant in the “Pedregal de San Ángel”, México City. This plant is the food of the monophagous geometrid Acronyctodes mexicanaria. The objective of this study was to determine if the dioecy of B. cordataaffects nutritional and performance parameters of A. mexicanaria(consumption, metabolic use of the food, growth, and density of caterpillars on male and female trees). Feeding preference, development time of caterpillars, and 5 variables concerning consumption and growth efficiencies were analyzed for caterpillars collected from male and female trees, and which were fed in the laboratory with leaves from trees of each sex. There was no significant difference between caterpillar density on female and male trees; however, we found that caterpillars preferred feeding on female leaves, and they obtained better nutritional efficiencies and grew more quickly when feeding on female leaves than on male leaves.

What drives masting? The phenological synchrony hypothesis.

Annually variable and synchronous seed production, or masting behavior, is a widespread phenomenon with dramatic effects on wildlife populations and their associated communities. Proximally, masting is often correlated with environmental factors and most likely involves differential pollination success and resource allocation, but little is known about how these factors interact or how they influence seed production. We studied masting in the valley oak (Quercus lobata Née), a California endemic tree, and report evidence that phenological synchrony in flowering driven by microclimatic variability determines the size of the acorn crop through its effects on pollen availability and fertilization success. These findings integrate two of the major factors believed to influence seed production in wind-pollinated species-environmental conditions and pollen limitation-by means of a coherent mechanistic hypothesis for how highly variable and synchronized annual seed production is accomplished. We illustrate how, by means of a simulation based on the mechanism proposed here, climate change may influence masting patterns through its effects on environmental variability.

Exploring the Politics of Differential Resource Allocation: Implications for Policy Design and Leadership Practice

This qualitative case study explores the political and leadership challenges imbedded within the implementation of a district-wide resource reallocation policy. Based on a two-year study of a medium-sized district’s efforts to address changing demographics of families in the district and a widening achievement gap, we draw upon concepts from education finance and the politics of policymaking to better understand the strategies used to introduce and implement a differential resource-allocation formula. Leadership strategies are explored, with a focus on anticipated areas of both internal and external “pushback,” and a discussion of the cycle of political support for equity-focused policy initiatives.

Effects of flower dimorphism and light environment on arbuscular mycorrhizal colonisation in a cleistogamous herb.

Although it is known that floral dimorphism contributes to the maintenance of mixed breeding systems, the consequences of producing progeny of a contrasting genetic background and seeds with differential resource allocation has been practically ignored regarding establishment of belowground organisms-plant interactions. This article evaluates the combined effect of floral dimorphism with cross type and light environment on interactions between Ruellia nudiflora and arbuscular mycorrhizal fungi (AMF). R.nudiflora produces cleistogamous (CL) flowers that exhibit obligate self-pollination and chasmogamous (CH) flowers with facultative self- (CHs) or cross- (CHc) pollination. We evaluated the establishment of the plant-AMF interaction in progeny derived from each floral type, under two light conditions (shaded versus open). We established different scenarios depending on the existence of inbreeding depression (ID) and whether the differential resource allocation (DRA) to CH and CL flowers affected the R.nudiflora-AMF interaction. We predicted that under shaded light conditions there might be an intensification of ID, having a negative effect on AMF colonisation. The percentages of hyphae and vesicles in the harvested roots was significantly higher in the shaded plants (F≥4.11, P<0.05), while progeny of CHc and CHs presented a higher percentage of hyphae and vesicle colonisation compared to CL progeny (F=15.26, P<0.01). The results show that DRA to CH flowers and light availability both determines the establishment of R.nudiflora-AMF interaction. The results also suggest that even under stressful light conditions, endogamy does not affect this interaction, which may explain the success of R.nudiflora as an invasive species.

Antimicrobial and antiinsectan phenolic metabolites of Dalea searlsiae.

Continued interest in the chemistry of Dalea spp. led to investigation of Dalea searlsiae, a plant native to areas of the western United States. Methanol extractions of D. searlsiae roots and subsequent chromatographic fractionation afforded the new prenylated and geranylated flavanones malheurans A–D (1–4) and known flavanones (5 and 6). Known rotenoids (7 and 8) and isoflavones (9 and 10) were isolated from aerial portions. Structure determination of pure compounds was accomplished primarily by extensive 1D- and 2D-NMR spectroscopy. The absolute configurations of compounds 1–5, 7, and 8 were assigned using electronic circular dichroism spectroscopy. Antimicrobial bioassays revealed significant activity concentrated in the plant roots. Compounds 1–6 exhibited MICs of 2–8 μg/mL against Streptococcus mutans, Bacillus cereus, and oxacillin-sensitive and -resistant Staphylococcus aureus. Aerial metabolites 7–10 were inactive against these organisms, but the presence of 7 and 8 prompted investigation of the antiinsectan activity of D. searlsiae metabolites toward the major crop pest Spodoptera frugiperda (fall armyworm). While compounds 1–10 all caused significant reductions in larval growth rates, associated mortality (33–66%) was highest with flavanone 4 and rotenoids 7 and 8. These findings suggest a differential allocation of antimicrobial and antiinsectan plant resources to root and aerial portions of the plant, respectively.

Beyond suicide: action needed to improve self-injury mortality accounting.

Beyond suicide: action needed to improve self-injury mortality accounting.

Nutritional physiology of life-history trade-offs: how food protein-carbohydrate content influences life-history traits in the wing-polymorphic cricket Gryllus firmus.

Although life-history trade-offs result from the differential acquisition and allocation of nutritional resources to competing physiological functions, many aspects of this topic remain poorly understood. Wing-polymorphic insects, which possess alternative morphs that trade off allocation to flight capability versus early reproduction, provide a good model system for exploring this topic. In this study, we used the wing-polymorphic cricket Gryllus firmus to test how expression of the flight capability versus reproduction trade-off was modified across a heterogeneous protein-carbohydrate nutritional landscape. Newly molted adult female long- and short-winged crickets were given one of 13 diets with different concentrations and ratios of protein and digestible carbohydrate; for each cricket, we measured consumption patterns, growth and allocation to reproduction (ovary mass) versus flight muscle maintenance (flight muscle mass and somatic lipid stores). Feeding responses in both morphs were influenced more by total macronutrient concentration than by protein-carbohydrate ratio, except at high-macronutrient concentration, where protein-carbohydrate balance was important. Mass gain tended to be greatest on protein-biased diets for both morphs, but was consistently lower across all diets for long-winged females. When long-winged females were fed high-carbohydrate foods, they accumulated greater somatic lipid stores; on high-protein foods, they accumulated greater somatic protein stores. Food protein-carbohydrate content also affected short-winged females (selected for early reproductive onset), which showed dramatic increases in ovary size, including ovarian stores of lipid and protein, on protein-biased foods. This is the first study to show how the concentration and ratio of dietary protein and carbohydrate affects consumption and allocation to key physiological features associated with the reproduction-dispersal life-history trade-off.

Socioeconomic deprivation independently predicts symptomatic painful diabetic neuropathy in type 1 diabetes

IntroductionPainful peripheral neuropathy in people with type 1 diabetes is a disabling and costly complication. A greater understanding of predisposing factors and prescribing may facilitate more effective resource allocation. MethodsThe Townsend index of deprivation (numerically higher for greater disadvantage) was examined in the pseudonymised records of 1621 (684 females) individuals with type 1 diabetes and related to prevalence of drug treated severe diabetes related neuropathic pain. ResultsTreatment for neuropathic pain was initiated in 280 patients, who were older at 57.1 vs 45.6 years and had greater BMI (29.8 vs 27.8kg/m2; p<0.0001). HbA1C was similar between groups, whilst eGFR was lower in the neuropathic pain group.Amitriptyline was the most commonly prescribed agent (46.8% of total prescriptions). Duloxetine (60mg daily) was prescribed in 9.3% of cases.There were significant differences between the groups for the Townsend index, with a greater proportion (34.3% vs 21.7%) of patients with treated neuropathic pain having a score of ≥1 (X2=19.9, p<0.001).Multivariate logistic regression analyses indicated that each unit increment in Townsend index was associated with a 11% increased odds of requiring neuropathic pain treatment [odds ratio (95% CI) 1.11 (1.05–1.17), p<0.001]. This was independent of age: 1.04 (1.02–1.05), BMI: 1.03 (1.01–1.05), HbA1C: 1.15 (1.05–1.24), male gender: 0.74 (0.55–0.98), systolic BP and eGFR. Inclusion of depression and mixed anxiety/depressive disorder did not change the risk estimates. ConclusionAmitriptyline was the most commonly used agent for treatment of diabetes related neuropathic pain with Duloxetine much less used.A higher level of socioeconomic deprivation may predispose to severe neuropathic pain in diabetes. Differential allocation of resources may benefit this group.

Investigating the drought-stress response of hybrid poplar genotypes by metabolite profiling

Drought stress is perhaps the most commonly encountered abiotic stress plants experience in the natural environment, and it is one of the most important factors limiting plant productivity. Here, we employed untargeted metabolite profiling to examine four drought-stressed hybrid poplar (Populus spp.) genotypes for their metabolite content, using gas chromatography coupled to mass spectrometry. The primary objective of these analyses was to characterize the metabolite profile of poplar trees to assess relative drought resistance and to investigate the underlying biochemical mechanisms employed by the genotypes to combat drought. Metabolite profiling identified key metabolites that increased or decreased in relative abundance upon exposure to drought stress. Overall, amino acids, the antioxidant phenolic compounds catechin and kaempferol, as well as the osmolytes raffinose and galactinol exhibited increased abundance under drought stress, whereas metabolites involved in photorespiration, redox regulation and carbon fixation showed decreased abundance under drought stress. One clone in particular, Okanese, displayed unique responses to the imposed drought conditions. This clone was found to have higher leaf water potential, but lower growth rate relative to the other clones tested. Okanese also had lower accumulation of osmolytes such as raffinose, galactinol and proline, but higher overall levels of antioxidants such as catechin and dehydroascorbic acid. As such, it was proposed that osmotic adjustment as a mechanism for drought avoidance in this clone is not as well developed in comparison with the other clones investigated in this study, and that a possible alternative mechanism for the enhanced drought avoidance displayed by Okanese may be due to differential allocation of resources or better retention of water.

Eyes wide open: enhanced pupil dilation when selectively studying important information

Remembering important information is imperative for efficient memory performance, but it is unclear how we encode important information. The current experiment evaluated two non-exclusive hypotheses for how learners selectively encode important information at the expense of less important information (differential resource allocation and information reduction). To evaluate these hypotheses, we measured changes in learners' pupil diameter and fixation durations while participants performed a selectivity task that involved studying lists consisting of words associated with different point values. Participants were instructed to maximize their score on a free recall task that they completed after studying each list. Participants' pupils dilated more when studying high-valued than low-valued words, and these changes were associated with better memory for high-valued words. However, participants fixated equally on words regardless of their value, which is inconsistent with the information reduction hypothesis. Participants also increased their memory selectivity across lists, but changes in pupil diameter and differences in fixations could not account for this increased selectivity. The results suggest that learners allocate attention differently to items as a function of their value, and that multiple processes and operations contribute to value-directed remembering.

The Effect of Choosing Key Versus Ordinary Schools on Student’s Mathematical Achievement in China

The current study examined the impacts on students’ cognitive performance of the key versus ordinary school system in China, using an analytic approach that combines hierarchical linear modeling with propensity score stratification. The results show that students from key schools score significantly higher on a mathematical achievement test than their counterparts in ordinary schools, after controlling for student characteristics and their family background. The specific magnitude of the school effect varies substantially across the geographic locations of the school. The advantages of key schools over ordinary schools are found to be generally greater among urban schools compared with suburban schools. The results are noteworthy as both key and ordinary schools are state-funded and the system was formed directly by policy initiatives and differential resource allocation. As such, they bear important policy implications on systematic-level school management in general.

Females Paired with New and Heavy Mates Reduce Intra-Clutch Differences in Resource Allocation

Reproductive investment affects both offspring and parental fitness and influences the evolution of life histories. Females may vary their overall primary reproductive effort in relation to the phenotypic characteristics of their mate. However, the effects of male quality on differential resource allocation within clutches have been largely neglected despite the potential implications for mate choice and population dynamics, especially in species exhibiting biparental care and brood reduction. Female southern rockhopper penguins Eudyptes chrysocome paired with heavy mates reduced intra-clutch variation in egg and albumen masses. Females paired with new mates also reduced intra-clutch variation in yolk androgen levels. Since both an increased mass and increased androgen concentrations positively influence chick survival under sibling competition, the chances of fledging the whole clutch are likely to be higher for newly formed pairs with heavy males than for previously formed pairs with light males. Interestingly, total clutch provisioning did not vary with male quality. We show for the first time that females vary intra-clutch variation in resource allocation according to male quality. In species with brood reduction, it may be more adaptive for females to modulate the distribution of resources within the clutch according to breeding conditions, than to change their total clutch provisioning.

Isolating exogenous and endogenous modes of temporal attention.

The differential allocation of information processing resources over time, here termed "temporal attention," may be achieved by relatively automatic "exogenous" or controlled "endogenous" mechanisms. Over 100 years of research has confounded these theoretically distinct dimensions of temporal attention. The current report seeks to ameliorate this oversight by novel application of 2 experimental methodologies. A scheme imported from the animal learning literature (Rescorla's "truly random control" procedure) was used to eliminate any temporal contingency between signals and targets. An auditory stimulus imported from the psychophysical literature (correlated vs. uncorrelated noise) was used to provide a salient signal that entailed no local or global change in intensity. Purely endogenous temporal attention (generated by a reliable signal-target contingency in the absence of a change in intensity) is characterized by robust improvements in speed and accuracy of responding. Purely exogenous temporal attention (generated by an intensity increase in the absence of contingency) is characterized by a brief period of faster responding. When exogenous temporal attention is elicited in the context of endogenous temporal attention, the decrease in response time that follows an intense signal is accompanied by a decrease in response accuracy.

Milk Composition during Lactation Suggests a Mechanism for Male Biased Allocation of Maternal Resources in the Tammar Wallaby (Macropus eugenii)

Recent research has found empirical evidence in support of the Trivers-Willard Hypothesis that offspring sex allocation is correlated with maternal investment. Tammar wallabies birthing sons have higher investment ability; however a mechanism for sex specific differential allocation of maternal resources in wallabies remains elusive. In metatherians the majority of maternal investment is during lactation. To examine if differential allocation occurs during lactation, we measured total milk protein, lipid and carbohydrates, from mothers with male and female pouch young, during phase 2B (100–215 days post partum) and phase 3 (215–360 days post partum) of lactation. Mothers of sons allocated significantly higher levels of protein than mothers of daughters during phase 2B of lactation, however no sex specific difference in maternal allocation was found for lipids, carbohydrates, or any milk component during phase 3 of lactation. We were unable to measure milk production to establish any differences in the amount of milk allocated. However, with the production of more milk comes a dilution effect on milk components. Given that we find no apparent dilution of milk components may suggest equality in milk production. Offspring body weight at 14 months of age was related to protein allocation during phase 2B of lactation, providing a maternal mechanism for differential allocation with fitness consequences. We believe collection of earlier phase 2A (0–100 days post partum) milk may yield important results given that differential investment in metatherians may be most apparent early in lactation, prior to any significant maternal investment, when a decision on termination of investment can be made with very little energetic loss to the mother. Interestingly, small mothers did not birth sons and better maternal condition was associated with raising sons. These data are in support of TWH and demonstrate a potential mechanism through which condition dependent and sex specific maternal investment may occur.

Cost of reproduction in the Queensland fruit fly: Y-model versus lethal protein hypothesis

The trade-off between lifespan and reproduction is commonly explained by differential allocation of limited resources. Recent research has shown that the ratio of protein to carbohydrate (P : C) of a fly's diet mediates the lifespan-reproduction trade-off, with higher P : C diets increasing egg production but decreasing lifespan. To test whether this P : C effect is because of changing allocation strategies (Y-model hypothesis) or detrimental effects of protein ingestion on lifespan (lethal protein hypothesis), we measured lifespan and egg production in Queensland fruit flies varying in reproductive status (mated, virgin and sterilized females, virgin males) that were fed one of 18 diets varying in protein and carbohydrate amounts. The Y-model predicts that for sterilized females and for males, which require little protein for reproduction, there will be no effect of P : C ratio on lifespan; the lethal protein hypothesis predicts that the effect of P : C ratio should be similar in all groups. In support of the lethal protein hypothesis, and counter to the Y-model, the P : C ratio of the ingested diets had similar effects for all groups. We conclude that the trade-off between lifespan and reproduction is mediated by the detrimental side-effects of protein ingestion on lifespan.

Maternal effects on begging behaviour: an experimental demonstration of the effects of laying sequence, hatch order, nestling sex and brood size

Differential resource allocation by females across the laying sequence has been hypothesised as a mechanism through which females could either compensate nestlings that hatch last in asynchronous broods or promote brood reduction. In this study we artificially incubated eggs and cross-fostered offspring to manipulate nestlings’ position in the hatching order, to identify whether the competitive ability of nestlings is dependent on position in the laying sequence. In both control and experimentally reversed broods, first hatched chicks had a higher survival than last hatched siblings. Yet, nestlings that hatched from eggs laid in the second half of a clutch begged with a greater intensity than nestlings hatched from eggs laid in the first half of a clutch. In natural broods, the greater begging competitiveness of nestlings from later-laid eggs led to a moderation of sibling competition and these nestlings achieved the same body size and weight as nestlings from eggs laid in the first half of the clutch. The lack of a substantial difference in the size and condition of surviving nestlings in respect to laying order suggests that differential resource allocation across the egg-laying sequence partially compensates for hatching last in asynchronous broods and reduces the negative effects of the nestling size hierarchy. The effect of laying order, brood size and experimental treatment also differed for male and female nestlings. Our study highlights the need to be aware of the complex and subtle effects of nestling sex and laying sequence when investigating genetic and environmental influences on individual fitness.

Linking reproductive and feeding strategies in the parasitoid Ibalia leucospoides: does feeding always imply profit?

Resource acquisition and allocation to different biological functions over the course of life have strong implications for animal reproductive success. Animals can experience different environmental conditions during their lifetime, and this may play an important role in shaping their life-history and resource allocation strategies. In this study we investigate larval and adult resource allocation to reproductive and survival functions in the parasitoid wasp Ibalia leucospoides (family Ibaliidae). The pattern of larval resource allocation was inferred from the relationship between adult body size and ovigeny index (OI; a relative measure of investment in early reproduction determined as the ratio between the initial egg load and the potential lifetime fecundity); and adult resource allocation was explored through the influence of adult feeding on reproduction, maintenance and metabolism, in laboratory experiments. Food acquisition by this parasitoid in the wild was also examined. The relationship between size and OI was constant, suggesting no differential resource allocation to initial egg load and potential lifetime fecundity with size. This finding is in line with that predicted by adaptive models for the proovigenic egg maturation strategy (OI = 1). Despite of this, I. leucospoides showed a high OI of 0.77, which places this species among the weakly synovigenic ones (OI < 1). Adult feeding had no effect on post-emergence egg maturation. However, wasps extended their lifespan through feeding albeit only when food was provided ad libitum. Although the information we obtained on the feeding behaviour of free-foraging wasps is limited, our results suggest that food intake in the wild, while possible, may not be frequent in this parasitoid. We discuss the results relative to the environmental factors, such as reproductive opportunities and food availability, which may have driven the evolution of larval and adult pattern of resource allocation in parasitoids.

EFFECT OF DIET QUALITY ON NUTRIENT ALLOCATION TO THE TEST AND ARISTOTLE'S LANTERN IN THE SEA URCHIN LYTECHINUS VARIEGATUS (LAMARCK, 1816).

Small adult (19.50 ± 2.01g wet weight) Lytechinus variegatus were fed eight formulated diets with different protein (12 to 36% dry weight as fed) and carbohydrate (21 to 39 % dry weight) levels. Each sea urchin (n = 8 per treatment) was fed a daily ration of 1.5% of the average body weight of all individuals for 9 weeks. Akaike information criterion scores were used to compare six different dietary composition hypotheses for eight growth measurements. For each physical growth response, different mathematical models representing a priori hypotheses were compared using the Akaike Information Criterion (AIC) score. The AIC is one of many information-theoretic approaches that allows for direct comparison of non-nested models with varying number of parameters. Dietary protein level and protein: energy ratio were the best models for prediction of test diameter increase. Dietary protein level was the best model of test with spines wet weight gain and test with spines dry matter production. When the Aristotle's lantern was corrected for size of the test, there was an inverse relationship with dietary protein level. Log transformed lantern to test with spines index was also best associated with the dietary protein model. Dietary carbohydrate level was a poor predictor for growth parameters. However, the protein × carbohydrate interaction model was the best model of organic content (% dry weight) of the test without spines. These data suggest that there is a differential allocation of resources when dietary protein is limiting and the test with spines, but not the Aristotle's lantern, is affected by availability of dietary nutrients.