Patient Parents: Do Offspring Decide on the Timing of Fledging in Zebra Finches?

Parent–offspring conflict over parental care is predicted to become most pronounced during offspring transition to independence when offspring are predicted to attempt to extend care for longer than parents are selected to provide it. However, on the proximate level, it is difficult to determine who plays the most important role in this process, parents or offspring. For several vertebrate taxa, it has been documented that parents end brood care by abandoning offspring after a fixed period or else show high flexibility in the duration of care, but teasing apart the role of offspring and parents underlying this flexibility has been difficult. Here, we studied the decision to fledge in captive zebra finches (Taeniopygia guttata), an altricial songbird. We experimentally delayed the time of fledging to determine who decides about the end of feeding inside the nest, parents or offspring. The experiment indicates that parents do not primarily rely on phenotypic offspring traits in their decision to feed offspring in the nest, but appear to adjust the duration of parental care as long as offspring are in the nest which parents may take as an indicator of offspring need and locomotor abilities. Delayed‐fledging offspring appeared not to suffer a disadvantage in terms of age at the onset of independent feeding. Our study suggests that, in zebra finches, offspring play a major role in determining the time of fledging and leave the nest on their own, possibly to reduce the risk of nest predation, or to evade sibling competition in the nest.     

Interaction between parental care and sibling competition: parents enhance offspring growth and exacerbate sibling competition

Species with elaborate parental care often also show intense sibling competition over resources provided by parents, suggesting joint evolution of these two traits. Despite this, the evolution of elaborate parental care and the evolution of intense sibling competition are often studied separately. Here, we examine the interaction between parental food provisioning and sibling competition for resources through the joint manipulation of the presence or absence of parents and brood size in a species with facultative parental care: the burying beetle Nicrophorus vespilloides. The effect of the interaction between the presence or absence of parents and brood size was strong; brood size had a strong effect on growth when parents provided care, but no effect when parents were absent. As in previous studies, offspring grew faster when parents were present than when parents were absent, and offspring grew faster in smaller broods than in larger broods. Our behavioral observations showed that brood size had a negative effect on both the amount of time parents spent providing resources to individual offspring and the offspring's effectiveness of begging, confirming that the level of sibling competition increased with brood size. Furthermore, offspring in larger broods shifted more from begging toward self-feeding as they grew older compared to offspring in small broods. Our study provides novel insights into the joint evolution of parental care and sibling competition, and the evolution of offspring begging signals. We discuss the implications of our results in light of recent theoretical work on the evolution of parental care, sibling competition, and offspring begging signals.     

What are the benefits of parental care? The importance of parental effects on developmental rate

The evolution of parental care is beneficial if it facilitates offspring performance traits that are ultimately tied to offspring fitness. While this may seem self‐evident, the benefits of parental care have received relatively little theoretical exploration. Here, we develop a theoretical model that elucidates how parental care can affect offspring performance and which aspects of offspring performance (e.g., survival, development) are likely to be influenced by care. We begin by summarizing four general types of parental care benefits. Care can be beneficial if parents (1) increase offspring survival during the stage in which parents and offspring are associated, (2) improve offspring quality in a way that leads to increased offspring survival and/or reproduction in the future when parents are no longer associated with offspring, and/or (3) directly increase offspring reproductive success when parents and offspring remain associated into adulthood. We additionally suggest that parental control over offspring developmental rate might represent a substantial, yet underappreciated, benefit of care. We hypothesize that parents adjust the amount of time offspring spend in life‐history stages in response to expected offspring mortality, which in turn might increase overall offspring survival, and ultimately, fitness of parents and offspring. Using a theoretical evolutionary framework, we show that parental control over offspring developmental rate can represent a significant, or even the sole, benefit of care. Considering this benefit influences our general understanding of the evolution of care, as parental control over offspring developmental rate can increase the range of life‐history conditions (e.g., egg and juvenile mortalities) under which care can evolve.     

Implications of caring for an aging parent.

The burden of care for the aged often falls on their adult children, who are themselves stressed by the developmental tasks of middle age. These people are frequently unprepared for the role of caregiver, in which they become parents to their own parents. The author describes the potentially turbulent effect of this role and discusses the origin of the stresses that the caregiver may experience. Doctors need to recognize and deal with the negative feelings, such as resentment, anger, frustration, ambivalence, guilt and demoralization, that may arise in adult children who care for their parents. These emotions must be put into proper context if the mental and physical health of the caregivers as well as the vital support they provide for their elderly parents are to be maintained.     

Sexual conflict over parental investment in repeated bouts: negotiation reduces overall care

Understanding the evolution of parental care is complicated by the occurrence of evolutionary conflicts of interest within the family, variation in the quality and state of family members, and repeated bouts of investment in a family of offspring. As a result, family members are expected to negotiate over care. We present a model for the resolution of sexual conflict in which parents negotiate over repeated bouts of care. Negotiation is mediated by parents deciding at the start of each bout how much care to give on the basis of the state (mass) of offspring, which reflects the amount of care previously received. The evolutionarily stable pattern of care depends on whether the parents care together for the whole family, or each cares alone for part of the divided family. When they care together, they provide less care in the first bout, more in the last bout, and less care overall, resulting in lower parental and offspring fitness. Our results emphasize that negotiation over parental care may occur as a means of avoiding exploitation owing to sexual conflict, even in the absence of variation in the quality of either sex of parent, and lead to a reduction in fitness.     

The benefits of uniparental versus biparental mouth brooding in Galilee St. Peter's fish

In Galilee St. Peter's fish Sarotherodon galilaeus the care system is naturally labile; biparental, male-only and female-only care all exist in one population. This unusual flexibility facilitates comparisons between the forms of care. The costs of parental care were considered in a previous study. Here, the benefits of parental care were quantified by observing wild fish, both held in pond enclosures and free-swimming in Lake Kinneret, Israel. Parental care was shown to be essential for offspring survival in St. Peter's fish. The reproductive success of parents who shared incubation duties was nearly twice as high as that of parents caring alone. However, per brood (or mouth cavity) reproductive success was 20% higher for uniparental parents. Both sexes were equally capable and efficient in care; when both sexes cared, they each incubated a similar number of eggs and released a similar number of fry. The results are discussed in terms of the relationship between caring Strategies and clutch size.     

Do maternal food deprivation and offspring predator cues interactively affect maternal effort in fish?

The state of the environment parents are exposed to during reproduction can either facilitate or impair their ability to take care of their young. Thus, the environmental conditions experienced by parents can have a transgenerational impact on offspring phenotype and survival. Parental energetic needs and the variance in offspring predation risk have both been recognized as important factors influencing the quality and amount of parental care, but surprisingly, they are rarely manipulated simultaneously to investigate how parents adjust care to these potentially conflicting demands. In the maternally mouthbrooding cichlid Simochromis pleurospilus, we manipulated female body condition before spawning and exposure to offspring predator cues during brood care in a two‐by‐two factorial experiment. Subsequently, we measured the duration of brood care and the number and size of the released young. Furthermore, we stimulated females to take up their young by staged predator attacks and recorded the time before the young were released again. We found that food‐deprived females produced smaller young and engaged less in brood care behaviour than well‐nourished females. Final brood size and, related to this, female protective behaviour were interactively determined by nutritional state and predator exposure: well‐nourished females without a predator encounter had smaller broods than all other females and at the same time were least likely to take up their young after a simulated predator attack. We discuss several mechanisms by which predator exposure and maternal nutrition might have influenced brood and offspring size. Our results highlight the importance to investigate the selective forces on parents and offspring in combination, if we aim to understand reproductive strategies.     

Effects of parental care on offspring growth in the Korean wood-feeding cockroach, <Emphasis Type="Italic">Cryptocercus kyebangensis</Emphasis>

The objective of this study was to measure the possible effects of prolonged parental care on offspring growth in Korean wood-feeding cockroaches, Cryptocercus kyebangensis. In the field-caught subsocial woodroaches of C. kyebangensis, offspring with both parents were greater in both head width and body weight than those with single parents. Manipulation experiments showed that offspring separated from their parents could survive independently without parents, but they grew more rapidly when they remained with their parents. In particular, the effects of parental care on offspring growth were found to be stronger in groups with both parents than those with single parents. These results suggest that the prolonged parental care evolved in Cryptocercus has a significant impact on offspring growth. Electronic Publication     

Chemotherapy versus supportive care alone in pediatric palliative care for cancer: comparing the preferences of parents and health care professionals

Background:

The choice between palliative chemotherapy (defined as the use of cytotoxic medications delivered intravenously for the purpose of our study) and supportive care alone is one of the most difficult decisions in pediatric oncology, yet little is known about the preferences of parents and health care professionals. We compared the strength of these preferences by considering children’s quality of life and survival time as key attributes. In addition, we identified factors associated with the reported preferences.

Methods:

We included parents of children whose cancer had no reasonable chance of being cured and health care professionals in pediatric oncology as participants in our study. We administered separate interviews to parents and to health care professionals. Visual analogue scales were shown to respondents to illustrate the anticipated level of the child’s quality of life, the expected duration of survival and the probability of cure (shown only to health care professionals). Respondents were then asked which treatment option they would favour given these baseline attributes. In addition, respondents reported what factors might affect such a decision and ranked all factors identified in order of importance. The primary measure was the desirability score for supportive care alone relative to palliative chemotherapy, as obtained using the threshold technique.

Results:

A total of 77 parents and 128 health care professionals participated in our study. Important factors influencing the decision between therapeutic options were child quality-of-life and survival time among both parents and health care professionals. Hope was particularly important to parents. Parents significantly favoured chemotherapy (42/77, 54.5%) compared with health care professionals (20/128, 15.6%; p < 0.0001). The opinions of the physician and child significantly influenced the parents’ desire for supportive care; for health care professionals, the opinions of parents and children were significant factors influencing this decision.

Interpretation:

Compared with health care professionals, parents more strongly favour aggressive treatment in the palliative phase and rank hope as a more important factor for making decisions about treatment. Understanding the differences between parents and health care professionals in the relative desirability of supportive care alone may aid in communication and improve end-of-life care for children with cancer.Despite the substantial improvements in rates of cure among children with cancer, some children will have progressive or recurrent disease and will die.¹ Cancer remains the second most common cause of death for North American children between 5 and 14 years of age.^2–4 When cure becomes unlikely, parents and health care professionals are often faced with the decision to continue further aggressive treatments or to provide relief from symptoms alone.¹The choice between palliative chemotherapy and supportive care alone is one of the most important and difficult decisions for parents of children whose disease cannot be cured.⁵ At this point, the goals of therapy are usually to maximize the child’s quality and length of life and to ensure respect for the family’s and child’s preferences.⁶Given the difficult nature of this decision, it is worthwhile to compare and contrast the perspectives of parents and health care professionals. Discordance in these perspectives could heighten the anxiety felt by patients and parents and might lead to their dissatisfaction with the care received. One qualitative study that interviewed parents of children with recurrent cancer found that “fearing disagreement with staff” was an important negative factor in decision-making.⁷ However, little is known as to whether the attitudes of parents and health care professionals toward therapeutic options are congruent.The goal of this study was to compare the strength of preference between parents and health care professionals for supportive care alone versus palliative chemotherapy for children whose cancer has no reasonable chance of being cured, and to determine how specific factors affect these preferences.     

Stepparental Behavior as Mating Effort in Birds and Other Animals

In many animal species, widowed or divorced parents may remate before young of the prior union are independent. In such circumstances, stepparents may kill their predecessors' offspring, may tolerate them without providing care, or may invest in them more or less as genetic parents do. Rohwer proposed that all three of these responses may be understood as mating tactics, adapted to different social and ecological circumstances. We discuss the selection pressures that would favor each of these alternatives and review relevant evidence on nonhuman stepparenting, especially in birds. Stepparental tolerance and (partial or full) care, which are the predominant human responses, are common in nonhuman animals too, and in many cases there is evidence supporting their interpretation as stepparental mating effort adaptations. In general, however, this interpretation is not as well established for tolerance and care as it is for stepparental infanticide. Because tolerance and care are not distinct modes of behavior peculiar to stepparents, the hypothesis that they are nonadaptive by-products of parental psychology often remains tenable. We discuss the kinds of evidence needed to choose between by-product and stepparental adaptation hypotheses.     

Should young ever be better off with one parent than with two?

We analyze models of parental care, providing the first systematiccomparison of the care given to young by one parent versus bytwo parents. In the Houston-Davies model of care, young alwaysdo better with two parents rather than with one parent. Whenone parent decides about its level of care before the other,then the young may do better with one parent when the costsof care for the parents are asymmetric. When the level of parentaleffort is reached by negotiation, there are cases in which youngdo better with one parent, even when costs are symmetric. Theanalysis suggests empirical ways to differentiate between differentresponse rules.     

Do honest signalling models of offspring solicitation apply to insects?

Honest signalling models predict that the intensity of solicitation by offspring influences the level of provisioning provided by parents and reflects offspring need. The empirical evidence supporting these predictions primarily comes from studies of birds or mammals. Thus, although parental care of altricial offspring is taxonomically widespread, the generality of these models is not well known. To investigate whether honest signalling models apply to insects, we manipulated parent and offspring behaviour in the burying beetle Nicrophorus orbicollis, a species with advanced parental care. First, within biparental care, we manipulated the brood size to alter the parents'' perception of offspring need. We measured the care giving behaviour of male and female parents to examine whether either adjusts its level of care according to offspring need. In the second experiment, because two parents together provision the brood more often than single parents, we manipulated the number of care givers (uniparental and biparental care) and measured offspring solicitation to assess whether offspring change their behaviour in response to need. Our results show that parent behaviour is broadly consistent with the first prediction of the models; both sexes provisioned larger broods more often than smaller broods. Larval solicitation was also consistent with the second prediction; larvae that were provisioned less often begged more. Our results provide evidence that honest signalling models can be applied to insects as well as vertebrates, although there are also subtle differences in care giving behaviour that may be important.     

Intergenerational effects of inbreeding in Nicrophorus vespilloides: offspring suffer fitness costs when either they or their parents are inbred

Inbreeding depression is the reduction in fitness caused by mating between related individuals. Inbreeding is expected to cause a reduction in offspring fitness when the offspring themselves are inbred, but outbred individuals may also suffer a reduction in fitness when they depend on care from inbred parents. At present, little is known about the significance of such intergenerational effects of inbreeding. Here, we report two experiments on the burying beetle Nicrophorus vespilloides, an insect with elaborate parental care, in which we investigated inbreeding depression in offspring when either the offspring themselves or their parents were inbred. We found substantial inbreeding depression when offspring were inbred, including reductions in hatching success of inbred eggs and survival of inbred offspring. We also found substantial inbreeding depression when parents were inbred, including reductions in hatching success of eggs produced by inbred parents and survival of outbred offspring that received care from inbred parents. Our results suggest that intergenerational effects of inbreeding can have substantial fitness costs to offspring, and that future studies need to incorporate such costs to obtain accurate estimates of inbreeding depression.     

Extraordinary Care for Extraordinary Conditions: Constructing Parental Care for Serious Mental Illness in Japan

This article presents an account of how Japanese parents in a family support group for mental illness constructed understandings of care for adult children with serious mental illness, primarily schizophrenia. I build from Janis H. Jenkins’s research on the “extraordinary condition” of schizophrenia to discuss “extraordinary care,” which parents practiced as a way to refute cultural and clinical beliefs about pathogenic families and degenerative diseases. Parents’ accounts of extraordinary care revealed a reliance on biomedical knowledge to treat the symptoms of mental illness coupled with an ongoing determination to improve children’s lives beyond what psychiatry could offer. Extraordinary care thus points to the therapeutic limits of biomedical psychiatry while also reinforcing the significance of social relations as families work toward recovery.     

Nest Attendance does not Predict Offspring Desertion by Eurasian Penduline Tit Parents

Parental care is costly, and in many organisms, the male or the female parent benefits from reducing its own care which may be compensated for by its mate. One of the parents may even face all costs of parental care if its mate deserts and leaves him/her to care for the offspring alone. Theoretical models have generated contrasting predictions as to how parents negotiate a resolution of this sexual conflict over care, although empirical tests are largely lacking. We investigated pre‐desertion behaviour (nest attendance) of a highly polygamous passerine, the Eurasian penduline tit ( Remiz pendulinus) that exhibits intense sexual conflict over care culminating in clutch desertion by the male, by the female or by both parents. We conjectured that nest attendance of parents should predict desertion, so that the lack of care provided by the deserting parent may be compensated for. By analysing over 200 000 video frames (2.50 ± 1.36 d per pair, 302 ± 170 min/d) of 20 pairs, we show that nest desertion is not a gradual process and cannot be predicted by nest attendance. These results are consistent with the argument that the predictable desertion may not be evolutionarily stable, and suggest that male and female penduline tits do not negotiate clutch desertion.     

Postfledging parental care in Savannah sparrows: sex, size and survival

We investigated postfledging parental care in a philopatric population of Savannah sparrows,Passerculus sandwichensis , breeding on Kent Island, New Brunswick, Canada in an effort to understand the factors influencing adult birds' decisions about parental investment in offspring. Brood division was not based on offspring sex: male and female parents were equally likely to care for sons or daughters. The total duration of parental care, from hatching to independence, was similar for sons and daughters (median=23 days), regardless of the sex of the care-giving parent. The duration of parental care also corresponded closely to the time required for juveniles to acquire basic foraging skills. Despite high levels of extrapair paternity, male Savannah sparrows invested as much in postfledging care and were as effective as females in caring for fledglings, based on recruitment of fledglings into the breeding population the following year. Male parents were more likely to care for smaller fledglings and for offspring from early broods (presumably to enable females to dedicate their efforts towards second clutches). Caring for fledglings was costly for parents: survivorship decreased as a function of the duration of postfledging parental care and the number of fledglings cared for. Parental survivorship, however, was not affected by the sex of the fledglings cared for. This study suggests that sex-biased provisioning may be unlikely except in species with strongly sexually dimorphic offspring, biased offspring sex ratios and sex-biased natal dispersal. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.      

Step-parents and infanticide: new data contradict evolutionary predictions

Evolutionary psychologists have hypothesized, inspired by evolutionary biology, that parents should care less for children with whom they are not genetically related since these young do not contribute to the genetic fitness of the parents. Based on this, evolutionary psychologists have predicted that there will be an overrepresentation of step-parents as offenders in family-related killings of children. Data on child homicide, particularly from Canada, have supported this prediction in that the frequency of children killed was relatively high in families where one of the two parents was a step-parent. Here we present a survey of all child homicide that occurred in Sweden between 1975 and 1995. In contrast to the Canadian data, children in Sweden living in families with a step-parent were not at an increased risk compared with children living together with two parents to whom they were genetically related. In addition, there were no other indications that step-parents are overrepresented as offenders.     

Parents like me: biosociality and lay expertise in self-help groups of parents of screen-positive newborns

This study focuses on patterns of communication and interaction for peer support, which develop among parents of screen-positive children in the socio-medical space created by the diagnostic uncertainty of newborn screening, the limitations of established patient support groups and the daily challenges of screen-positive care management. Based on semi-structured interviews conducted in 2015–2017 with 34 Israeli parents whose child is screen positive, we describe and analyze the spontaneous grouping of parents using the WhatsApp instant messaging service for smartphones. These self-help groups did not reflect an attempt to forge an alternative movement of de-medicalization but rather to provide satisfactory answers to shared problems of care management under diagnostic uncertainty. These self-help groups are further discussed as a form of biosociality and lay expertise where elements of communication such as simplicity, reciprocity, and deliberative democracy serve as a complementary mirror-image of the asymmetrical patient–doctor communication.     

Childhood malignancies and decision making.

Failure to obtain "adequate" medical care for a child constitutes child neglect, which may be used as the basis for prosecution of parents, removal of the child from the home, or court-ordered medical treatment. "Adequate" care is usually construed as that which is given by a licensed physician, but, in case of dispute, courts almost never engage in choosing one medical approach over another. The principle that parents may not refuse medical care, however, is made very difficult when children have malignancies--the long-term nature of the treatment means that, if the child is left at home, court order or not, the parents may flee with their child. Removing the child from the home, however, adds that trauma to the ill child's burdens. Questions should be asked before making a request to a court to order a therapy which will prolong but not save a child's life if the parents would prefer to spare their child the side effects. Parents, however, may always refuse to permit their child to participate in research studies, no matter how promising. Adolescents are increasingly believed to be capable of medical decision making; most courts, however, would not allow an adolescent to refuse life-saving treatment.     

Costs of parental care on hunting behaviour of Helobdella papillornata (Euhirudinea: Glossiphoniidae)

Helobdella papillornata, an Australian freshwater leech, feeds primarily on snails and has a high level of parental care involving brooding eggs and young, with direct feeding of young. Parental costs and offspring benefits from these behaviours are poorly understood. A potential cost of parental care may be a change in the time taken to hunt prey. To test this hypothesis, the hunting behaviour of adults without progeny, parents with eggs, and parents with young were compared. We found that parents brooding eggs had a significantly (P = 0.029) longer lag time to begin hunting than parents brooding young, and spent significantly (P = 0.018) less time actively hunting than non-brooding adults. These costs, which may represent lost potential for the parent’s future reproductive success, should be outweighed by the fitness benefits of improved growth and survival of offspring, if parental care is favoured by selection. The hunting costs of care in Helobdella and other benthic, dorsoventrally flattened leeches in the family Glossiphoniidae may be smaller than the costs of brood tending that would be imposed on other freshwater leeches, and this difference may help explain the restriction of care to a single clade of the Euhirudinea.