Maternal effects on offspring size in a natural population of the viviparous tsetse fly

1. Theory predicts that mothers should adaptively adjust reproductive investment depending on current reserves and future reproductive opportunities. Females in better intrinsic state, or with more resources, should invest more in current reproduction than those with fewer resources. Across the lifespan, investment may increase as future reproductive opportunities decline, yet may also decline with reductions in intrinsic state. 2. Across many species, larger mothers produce larger offspring, but there is no theoretical consensus on why this is so. This pattern may be driven by variation in maternal state such as nutrition, yet few studies measure both size and nutritional state or attempt to tease apart confounding effects of size and age. 3. Viviparous tsetse flies (Glossina species) offer an excellent system to explore patterns of reproductive investment: females produce large, single offspring sequentially over the course of their relatively long life. Thus, per‐brood reproductive effort can be quantified by offspring size. 4. While most tsetse reproduction research has been conducted on laboratory colonies, maternal investment was investigated in this study using a unique field method where mothers were collected as they deposited larvae, allowing simultaneous mother‐offspring measurements under natural conditions. 5. It was found that larger mothers and those with a higher fat content produced larger offspring, and there was a trend for older mothers to produce slightly larger offspring. 6. The present results highlight the importance of measuring maternal nutritional state, rather than size alone, when considering maternal investment in offspring. Implications for understanding vector population dynamics are also discussed.     

No evidence for sex biases in milk macronutrients,energy, or breastfeeding frequency in a sample of filipino mothers

Maternal reproductive investment includes both the energetic costs of gestation and lactation. For most humans, the metabolic costs of lactation will exceed those of gestation. Mothers must balance reproductive investment in any single offspring against future reproductive potential. Among mammals broadly, mothers may differentially invest in offspring based on sex and maternal condition provided such differences investment influence future offspring reproductive success. For humans, there has been considerable debate if there are physiological differences in maternal investment by offspring sex. Two recent studies have suggested that milk composition differs by infant sex, with male infants receiving milk containing higher fat and energy; prior human studies have not reported sex‐based differences in milk composition. This study investigates offspring sex‐based differences in milk macronutrients, milk energy, and nursing frequency (per 24 h) in a sample of 103 Filipino mothers nursing infants less than 18 months of age. We found no differences in milk composition by infant sex. There were no significant differences in milk composition of mothers nursing first‐born versus later‐born sons or daughters or between high‐ and low‐income mothers nursing daughters or sons. Nursing frequency also showed no significant differences by offspring sex, sex by birth order, or sex by maternal economic status. In the Cebu sample, there is no support for sex‐based differences in reproductive investment during lactation as indexed by milk composition or nursing frequency. Further investigation in other populations is necessary to evaluate the potential for sex‐based differences in milk composition among humans. Am J Phys Anthropol 152:209–216, 2013. © 2013 Wiley Periodicals, Inc.     

Maternal investment during pregnancy in wild meerkats

Maternal investment in offspring development is a major determinant of the survival and future reproductive success of both the mother and her young. Mothers might therefore be expected to adjust their investment according to ecological conditions in order to maximise their lifetime fitness. In cooperatively breeding species, where helpers assist breeders with offspring care, the size of the group may also influence maternal investment strategies because the costs of reproduction are shared between breeders and helpers. Here, we use longitudinal records of body mass and life history traits from a wild population of meerkats (Suricata suricatta) to explore the pattern of growth in pregnant females and investigate how the rate of growth varies with characteristics of the litter, environmental conditions, maternal traits and group size. Gestational growth was slight during the first half of pregnancy but was marked and linear from the midpoint of gestation until birth. The rate of gestational growth in the second half of pregnancy increased with litter size, maternal age and body mass, and was higher for litters conceived during the peak of the breeding season when it is hot and wet. Gestational growth rate was lower in larger groups, especially when litter size was small. These results suggest that there are ecological and physiological constraints on gestational growth in meerkats, and that females may also be able to strategically adjust their prenatal investment in offspring according to the likely fitness costs and benefits of a particular breeding attempt. Mothers in larger groups may benefit from reducing their investment because having more helpers might allow them to lower reproductive costs without decreasing breeding success.     

Maternal effects across life stages: larvae experiencing predation risk increase offspring provisioning

1. Maternal provisioning can reduce offspring vulnerability to predators by promoting offspring growth and eliciting of antipredator behaviours. Mothers perceiving predation risk may improve offspring survival if producing larger, higher‐quality offspring. However, empirical evidence suggests that offspring quality is often reduced, probably reflecting predator‐induced physiological costs, or a selfish maternal strategy aimed at producing more offspring by sacrificing their quality. While perception and impact of predators can vary across the prey's life stage, a majority of studies have focused on understanding how reproductive allocation decisions are influenced by the risk of predation during adulthood. 2. In this study, Leptinotarsa decemlineata beetles were used to examine if the risk of predation during the larval stage: (i) impacts the mother's physiological condition, including body mass and metabolic rate; and (ii) alters maternal allocation of reproductive resources to offspring quantity versus quality. 3. Results revealed that L. decemlineata mothers responded to perceived predation risk by producing clutches with fewer but larger eggs, thus increasing offspring provisioning. Surprisingly, while females that had faced predation risk as larva emerged with a similar body mass to control females, they exhibited lower metabolic rates. 4. Although predation risk in L. decemlineata larvae is known to impair their ability to acquire and maintain energy resources, adult females appeared to ameliorate such costs by improving their metabolic efficiency and by allocating more of their limited reproductive resources to produce fewer but better‐quality offspring.     

Costs of reproduction and terminal investment by females in a semelparous marsupial

Evolutionary explanations for life history diversity are based on the idea of costs of reproduction, particularly on the concept of a trade-off between age-specific reproduction and parental survival, and between expenditure on current and future offspring. Such trade-offs are often difficult to detect in population studies of wild mammals. Terminal investment theory predicts that reproductive effort by older parents should increase, because individual offspring become more valuable to parents as the conflict between current versus potential future offspring declines with age. In order to demonstrate this phenomenon in females, there must be an increase in maternal expenditure on offspring with age, imposing a fitness cost on the mother. Clear evidence of both the expenditure and fitness cost components has rarely been found. In this study, we quantify costs of reproduction throughout the lifespan of female antechinuses. Antechinuses are nocturnal, insectivorous, forest-dwelling small (20-40 g) marsupials, which nest in tree hollows. They have a single synchronized mating season of around three weeks, which occurs on predictable dates each year in a population. Females produce only one litter per year. Unlike almost all other mammals, all males, and in the smaller species, most females are semelparous. We show that increased allocation to current reproduction reduces maternal survival, and that offspring growth and survival in the first breeding season is traded-off with performance of the second litter in iteroparous females. In iteroparous females, increased allocation to second litters is associated with severe weight loss in late lactation and post-lactation death of mothers, but increased offspring growth in late lactation and survival to weaning. These findings are consistent with terminal investment. Iteroparity did not increase lifetime reproductive success, indicating that terminal investment in the first breeding season at the expense of maternal survival (i.e. semelparity) is likely to be advantageous for females.     

The effect of maternal and paternal immune challenge on offspring immunity and reproduction in a cricket

Trans‐generational immune priming is the transmission of enhanced immunity to offspring following a parental immune challenge. Although within‐generation increased investment into immunity demonstrates clear costs on reproductive investment in a number of taxa, the potential for immune priming to impact on offspring reproductive investment has not been thoroughly investigated. We explored the reproductive costs of immune priming in a field cricket, Teleogryllus oceanicus. To assess the relative importance of maternal and paternal immune status, mothers and fathers were immune‐challenged with live bacteria or a control solution and assigned to one of four treatments in which one parent, neither or both parents were immune‐challenged. Families of offspring were reared to adulthood under a food‐restricted diet, and approximately 10 offspring in each family were assayed for two measures of immunocompetence. We additionally quantified offspring reproductive investment using sperm viability for males and ovary mass for females. We demonstrate that parental immune challenge has significant consequences for the immunocompetence and, in turn, reproductive investment of their male offspring. A complex interaction between maternal and paternal immune status increased the antibacterial immune response of male offspring. This increased immune response was associated with a reduction in son's sperm viability, implicating a trans‐generational resource trade‐off between investment into immunocompetence and reproduction. Our data also show that these costs are sexually dimorphic, as daughters did not demonstrate a similar increase in immunity, despite showing a reduction in ovary mass.     

Maternal effects are long‐lasting and influence female offspring's reproductive strategy in the swordtail fish Xiphophorus multilineatus

The adaptive benefits of maternal investment into individual offspring (inherited environmental effects) will be shaped by selection on mothers as well as their offspring, often across variable environments. We examined how a mother's nutritional environment interacted with her offspring's nutritional and social environment in Xiphophorus multilineatus, a live‐bearing fish. Fry from mothers reared on two different nutritional diets (HQ = high quality and LQ = low quality) were all reared on a LQ diet in addition to being split between two social treatments: exposed to a large adult male during development and not exposed. Mothers raised on a HQ diet produce offspring that were not only initially larger (at 14 days of age), but grew faster, and were larger at sexual maturity. Male offspring from mothers raised on both diets responded to the exposure to courter males by growing faster; however, the response of their sisters varied with mother's diet; females from HQ diet mothers reduced growth if exposed to a courter male, whereas females from LQ diet mothers increased growth. Therefore, we detected variation in maternal investment depending on female size and diet, and the effects of this variation on offspring were long‐lasting and sex specific. Our results support the maternal stress hypothesis, with selection on mothers to reduce investment in low‐quality environments. In addition, the interaction we detected between the mother's nutritional environment and the female offspring's social environment suggests that female offspring adopted different reproductive strategies depending on maternal investment.     

Maternal Investment in the Swordtail Fish Xiphophorus multilineatus: Support for the Differential Allocation Hypothesis

The differential allocation hypothesis predicts that reproductive investment will be influenced by mate attractiveness, given a cost to reproduction and a tradeoff between current and future reproduction. We tested the differential allocation hypothesis in the swordtail fish Xiphophorus multilineatus, where males have genetically influenced (patroclinous inheritance) alternative mating tactics (ARTs) maintained by a tradeoff between being more attractive to females (mature later as larger courting males) and a higher probability of reaching sexual maturity (mature earlier as smaller sneaker males). Males in X. multilineatus do not provide parental care or other resources to the offspring. Allelic variation and copy number of the Mc4R gene on the Y-chromosome influences the size differences between males, however there is no variation in this gene on the X-chromosome. Therefore, to determine if mothers invested more in offspring of the larger courter males, we examined age to sexual maturity for daughters. We confirmed a tradeoff between number of offspring and female offspring’s age to sexual maturity, corroborating that there is a cost to reproduction. In addition, the ART of their fathers significantly influenced the age at which daughters reached sexual maturity, suggesting increased maternal investment to daughters of courter males. The differential allocation we detected was influenced by how long the wild-caught mother had been in the laboratory, as there was a brood order by father genotype (ART) interaction. These results suggest that females can adjust their reproductive investment strategy, and that differential allocation is context specific. We hypothesize that one of two aspects of laboratory conditions produced this shift: increased female condition due to higher quality diet, and/or assessment of future mating opportunities due to isolation from males.     

Life-history analysis of the Trivers and Willard sex-ratio problem

Phenotypic quality, such as condition or size, often variesbetween individuals. For species with extensive maternal care,the quality of offspring may partially be determined by thequality of their mother. Trivers and Willard (1973) predictedthat high quality females should prefer offspring of the sexwhose reproductive success is most strongly influenced by maternalcare, which in many cases will be sons. Correspondingly, lowquality females should prefer daughters. However, this predictionis not based on a proper analysis of variation in reproductivevalue. Using state-dependent life-history theory, I show herethat high quality females should prefer offspring of the sexwhose reproductive value is most strongly influenced by maternalcare. I also show that when offspring quality is strongly determinedby their mother's quality, but not influenced by their father'squality, high quality females can have higher reproductive valuethan high quality males, even though their reproductive successmay be much lower. In such cases, high quality females shouldprefer daughters and, correspondingly, low quality females shouldprefer sons.[Behav Ecol 7: 316–325 (1996)]     

How effective are maternal effects at having effects?

The well studied trade-off between offspring size and offspring number assumes that offspring fitness increases with increasing per-offspring investment. Where mothers differ genetically or exhibit plastic variation in reproductive effort, there can be variation in per capita investment in offspring, and via this trade-off, variation in fecundity. Variation in per capita investment will affect juvenile performance directly--a classical maternal effect--while variation in fecundity will also affect offspring performance by altering the offsprings' competitive environment. The importance of this trade-off, while a focus of evolutionary research, is not often considered in discussions about population dynamics. Here, we use a factorial experiment to determine what proportion of variation in offspring performance can be ascribed to maternal effects and what proportion to the competitive environment linked to the size-number trade-off. Our results suggest that classical maternal effects are significant, but that in our system, the competitive environment, which is linked to maternal environments by fecundity, can be a far more substantial influence.     

Early-life reproduction is associated with increased mortality risk but enhanced lifetime fitness in pre-industrial humans

The physiology of reproductive senescence in women is well understood, but the drivers of variation in senescence rates are less so. Evolutionary theory predicts that early-life investment in reproduction should be favoured by selection at the cost of reduced survival and faster reproductive senescence. We tested this hypothesis using data collected from preindustrial Finnish church records. Reproductive success increased up to age 25 and was relatively stable until a decline from age 41. Women with higher early-life fecundity (ELF; producing more children before age 25) subsequently had higher mortality risk, but high ELF was not associated with accelerated senescence in annual breeding success. However, women with higher ELF experienced faster senescence in offspring survival. Despite these apparent costs, ELF was under positive selection: individuals with higher ELF had higher lifetime reproductive success. These results are consistent with previous observations in both humans and wild vertebrates that more births and earlier onset of reproduction are associated with reduced survival, and with evolutionary theory predicting trade-offs between early reproduction and later-life survival. The results are particularly significant given recent increases in maternal ages in many societies and the potential consequences for offspring health and fitness.     

COOPERATIVE BREEDING FAVORS MATERNAL INVESTMENT IN SIZE OVER NUMBER OF EGGS IN SPIDERS

The transition to cooperative breeding may alter maternal investment strategies depending on density of breeders, extent of reproductive skew, and allo‐maternal care. Change in optimal investment from solitary to cooperative breeding can be investigated by comparing social species with nonsocial congeners. We tested two hypotheses in a mainly semelparous system: that social, cooperative breeders, compared to subsocial, solitarily breeding congeners, (1) lay fewer and larger eggs because larger offspring compete better for limited resources and become reproducers; (2) induce egg size variation within clutches as a bet‐hedging strategy to ensure that some offspring become reproducers. Within two spider genera, Anelosimus and Stegodyphus, we compared species from similar habitats and augmented the results with a mini‐meta‐analysis of egg numbers depicted in phylogenies. We found that social species indeed laid fewer, larger eggs than subsocials, while egg size variation was low overall, giving no support for bet‐hedging. We propose that the transition to cooperative breeding selects for producing few, large offspring because reproductive skew and high density of breeders and young create competition for resources and reproduction. Convergent evolution has shaped maternal strategies similarly in phylogenetically distant species and directed cooperatively breeding spiders to invest in quality rather than quantity of offspring.     

Cross-generational environmental effects and the evolution of offspring size in the Trinidadian guppy Poecilia reticulata

Abstract The existence of adaptive phenotypic plasticity demands that we study the evolution of reaction norms, rather than just the evolution of fixed traits. This approach requires the examination of functional relationships among traits not only in a single environment but across environments and between traits and plasticity itself. In this study, I examined the interplay of plasticity and local adaptation of offspring size in the Trinidadian guppy, Poecilia reticulata. Guppies respond to food restriction by growing and reproducing less but also by producing larger offspring. This plastic difference in offspring size is of the same order of magnitude as evolved genetic differences among populations. Larger offspring sizes are thought to have evolved as an adaptation to the competitive environment faced by newborn guppies in some environments. If plastic responses to maternal food limitation can achieve the same fitness benefit, then why has guppy offspring size evolved at all? To explore this question, I examined the plastic response to food level of females from two natural populations that experience different selective environments. My goals were to examine whether the plastic responses to food level varied between populations, test the consequences of maternal manipulation of offspring size for offspring fitness, and assess whether costs of plasticity exist that could account for the evolution of mean offspring size across populations. In each population, full‐sib sisters were exposed to either a low‐ or high‐food treatment. Females from both populations produced larger, leaner offspring in response to food limitation. However, the population that was thought to have a history of selection for larger offspring was less plastic in its investment per offspring in response to maternal mass, maternal food level, and fecundity than the population under selection for small offspring size. To test the consequences of maternal manipulation of offspring size for offspring fitness, I raised the offspring of low‐ and high‐food mothers in either low‐ or high‐food environments. No maternal effects were detected at high food levels, supporting the prediction that mothers should increase fecundity rather than offspring size in noncompetitive environments. For offspring raised under low food levels, maternal effects on juvenile size and male size at maturity varied significantly between populations, reflecting their initial differences in maternal manipulation of offspring size; nevertheless, in both populations, increased investment per offspring increased offspring fitness. Several correlates of plasticity in investment per offspring that could affect the evolution of offspring size in guppies were identified. Under low‐food conditions, mothers from more plastic families invested more in future reproduction and less in their own soma. Similarly, offspring from more plastic families were smaller as juveniles and female offspring reproduced earlier. These correlations suggest that a fixed, high level of investment per offspring might be favored over a plastic response in a chronically low‐resource environment or in an environment that selects for lower reproductive effort     

Variation in reproductive investment among and within populations of the scorpion Centruroides vittatus

Although information concerning variation among and within populations is essential to understanding an organism's life history, little is known of such variation in any species of scorpion. We show that reproductive investment by the scorpion Centruroides vittatus varied among three Texas populations during one reproductive season. Females from the Kickapoo population produced smaller offspring and larger litters than females from the Independence Creek or Decatur populations; this pattern remained when adjusting for among population variation in either female mass or total litter mass. Relative clutch mass (RCM) and within-litter variability in offspring mass (V*) did not differ among populations. Among-population variation may result from genetic differences or from phenotypically plastic responses to differing environments. Within populations, the interrelationships among reproductive variables were similar for Decatur and Independence Creek: females investing more in reproduction (measured by total litter mass, TLM) produced larger litters and larger offspring, and V* decreased with increased mean offspring mass (and with decreased litter size at Decatur). At Kickapoo, larger females produced larger litters and had larger TLM; females investing more in reproduction produced larger litters but not larger offspring. Within litter variability in offspring mass was not correlated with any reproductive variables in this latter population. These patterns may be explained by the fractional clutch hypothesis, the inability of females precisely to control investment among offspring or morphological constraints on reproduction.     

DO EMBRYOS INFLUENCE MATERNAL INVESTMENT? EVALUATING MATERNAL‐FETAL COADAPTATION AND THE POTENTIAL FOR PARENT‐OFFSPRING CONFLICT IN A PLACENTAL FISH

The evolution of matrotrophy introduces the potential for genomic conflicts between mothers and embryos. These conflicts are hypothesized to accelerate the evolution of reproductive isolation and to influence the evolution of life-history traits, reproductive structures, and genomic imprinting. These hypotheses assume offspring can influence the amount of maternal investment they receive and that there is a trade-off between maternal investment into individual offspring and maternal survival or fecundity. We used field data and laboratory crosses to test whether these assumptions are met in the matrotrophic poeciliid fish Heterandria formosa . Comparisons of life histories between two natural populations demonstrated a trade-off between the level of maternal investment into individual embryos and maternal fecundity. Laboratory crosses between individuals from these populations revealed that offspring genotype exerts an influence on the level of maternal investment and affects maternal fecundity through higher rates of embryo abortion and lower numbers of full-term offspring. Our results show that the prerequisites for parent–offspring conflict to be a potent evolutionary force in poeciliid fish are present in H. formosa. However, determining whether this conflict has shaped maternal investment in nature will require disentangling any effects of conflict from those of several ecological factors that are themselves correlated with the expected intensity of conflict.     

Linking life‐history theory and metabolic theory explains the offspring size‐temperature relationship

Temperature often affects maternal investment in offspring. Across and within species, mothers in colder environments generally produce larger offspring than mothers in warmer environments, but the underlying drivers of this relationship remain unresolved. We formally evaluated the ubiquity of the temperature–offspring size relationship and found strong support for a negative relationship across a wide variety of ectotherms. We then tested an explanation for this relationship that formally links life‐history and metabolic theories. We estimated the costs of development across temperatures using a series of laboratory experiments on model organisms, and a meta‐analysis across 72 species of ectotherms spanning five phyla. We found that both metabolic and developmental rates increase with temperature, but developmental rate is more temperature sensitive than metabolic rate, such that the overall costs of development decrease with temperature. Hence, within a species’ natural temperature range, development at relatively cooler temperatures requires mothers to produce larger, better provisioned offspring.     

Relationship between reproductive resource allocation and resource capacity in the matriphagous spider, <Emphasis Type="Italic">Chiracanthium japonicum </Emphasis>(Araneae: Clubionidae)

Females of the Japanese foliage spider, Chiracanthium japonicum, are eaten by their offspring at the end of the maternal care period. To examine the patterns of allocation of maternal investment to their offspring associated with female resource capacity, the amounts of female body reserves accumulated before oviposition, reproductive components at the egg-production phase and those at the matriphagy phase were measured using an artificial breeding nest. Regardless of size, female bodies were completely consumed by the offspring, and larger females, i.e. those having larger reserves, produced a larger number of offspring, but not larger offspring. Furthermore, the proportion of reserves allocated to egg production was not affected by the total amount of the reserves, which indicated that the females systematically divided the resources for individual offspring between egg yolk and food for the growth and survival of the offspring. These results suggest that C. japonicum females adjust egg production to their own resource capacity so that they can achieve an investment per individual offspring which is not dependent on resource capacity. Electronic Publication     

Why does offspring size affect performance? Integrating metabolic scaling with life-history theory

Within species, larger offspring typically outperform smaller offspring. While the relationship between offspring size and performance is ubiquitous, the cause of this relationship remains elusive. By linking metabolic and life-history theory, we provide a general explanation for why larger offspring perform better than smaller offspring. Using high-throughput respirometry arrays, we link metabolic rate to offspring size in two species of marine bryozoan. We found that metabolism scales allometrically with offspring size in both species: while larger offspring use absolutely more energy than smaller offspring, larger offspring use proportionally less of their maternally derived energy throughout the dependent, non-feeding phase. The increased metabolic efficiency of larger offspring while dependent on maternal investment may explain offspring size effects—larger offspring reach nutritional independence (feed for themselves) with a higher proportion of energy relative to structure than smaller offspring. These findings offer a potentially universal explanation for why larger offspring tend to perform better than smaller offspring but studies on other taxa are needed.     

Hormonal manipulation of offspring number: maternal effort and reproductive costs

We used exogenous gonadotropin hormones to physiologically enlarge litter size in the bank vole (Clethrionomys glareolus). This method allowed the study design to include possible production costs of reproduction and a trade-off between offspring number and body size at birth. Furthermore, progeny rearing and survival and postpartum survival of the females took place in outdoor enclosures to capture salient naturalistic effects that might be present during the fall and early winter. The aim of the study was to assess the effects of the manipulation on the growth and survival of the offspring and on the reproductive effort, survival, and future fecundity of the mothers. Mean offspring body size was smaller in enlarged litters compared to control litters at weaning, but the differences disappeared by the winter. Differences in litter sizes disappeared before weaning age due to higher mortality in enlarged litters. In addition to the effects of the litter size, offspring performance was probably also influenced by the ability of the mother to support the litter. Experimental females had higher reproductive effort at birth, and they also tended to have higher mortality during nursing. Combined effects of high reproductive effort at birth and high investment in nursing the litter entailed costs for the experimental females in terms of decreased probability of producing a second litter and a decreased body mass gain. Thus, enlarged litter size had both survival and fecundity costs for the mothers. Our results suggest that the evolution of litter size and reproductive effort is determined by reproductive costs for the mothers as well as by a trade-off between offspring number and quality.     

Preparing Offspring for a Dangerous World: Potential Costs of Being Wrong

Adaptive maternal responses to stressful environments before young are born can follow two non-exclusive pathways: either the mother reduces current investment in favor of future investment, or influences offspring growth and development in order to fit offspring phenotype to the stressful environment. Inducing such developmental cues, however, may be risky if the environment changes meanwhile, resulting in maladapted offspring. Here we test the effects of a predator-induced maternal effect in a predator-free postnatal environment. We manipulated perceived predation-risk for breeding female great tits by exposing them to stuffed models of either a predatory bird or a non-predatory control. Offspring were raised either in an environment matching the maternal one by exchanging whole broods within a maternal treatment group, or in a mismatching environment by exchanging broods among the maternal treatments. Offspring growth depended on the matching of the two environments. While for offspring originating from control treated mothers environmental mismatch did not significantly change growth, offspring of mothers under increased perceived predation risk grew faster and larger in matching conditions. Offspring of predator treated mothers fledged about one day later when growing under mismatching conditions. This suggests costs paid by the offspring if mothers predict environmental conditions wrongly.