Offspring Life History Research Articles

Controlling resource acquisition to reveal a life history trade‐off: egg mass and clutch size in an iteroparous seed predator, Prostephanus truncatus

1. A trade‐off constraining egg production was investigated and the consequences of egg mass for the offspring life history in Prostephanus truncatus investigated. Fresh egg mass was found to vary between 0.065 and 0.109 mg (about 20% of fresh body mass at emergence) and was correlated both with dry egg mass (r = 0.8) and with the mass of first‐instar larvae (r = 0.8).2. There was a negative correlation between egg mass and clutch size: doubling clutch size from eight to sixteen eggs resulted in a reduction in egg mass from 0.09 to 0.07 mg. Resource allocation per clutch was not constant but increased with clutch size. After allowing for the relationship between egg mass and clutch size, heavier females were found to oviposit both heavier eggs and more eggs in a clutch.3. By placing eggs in prepared seeds that minimized variation in resource acquisition, it was discovered that development period of females, but not of males, was negatively correlated with egg mass. Egg size was not correlated with body size at emergence in either sex.4. The results are interpreted as revealing a resource‐allocation trade‐off in egg production.

Off-Timedness as a Contributor to Subjective Burdens for Parents of Offspring with Severe Mental Illness

Life course theory posits the existence of an age-graded timetable that marks when the movement into and out of expected stages should occur (Hagestad & Neugarten, 1985; Marini, 1984; Neugarten & Peterson, 1957). An individual's achievement of events, such as leaving home or bearing children, is evaluated as being on-time if the transition takes place at the culturally determined age, or off-time if one fails to sequence into the next stage at the expected time (Hagestad, 1990; Neugarten, Moore, & Lowe, 1965). The off-time individual may be thought of as lagging behind same-age peers and his or her behavior often is labeled by others as immature or age inappropriate (Lawrence, 1988; Neugarten, 1976; Urdy, 1982). Timing expectations are shared among family members, with parents imparting information to their children as to when transitions should occur (Cohler, 1983; Hagestad & Neugarten, 1985; Plath, 1980). Studies in this area have found that parents have high aspirations for their offsprings' achievement of expected stages, and anticipate their children's successful progression through the life course (Greene & Boxer, 1982; Hagestad, 1986; Howell & Freeze, 1982). Moreover, parents often feel responsible for their children's failures (Pillemer & Suitor, 1991) and express feelings of distress and disappointment when their offspring do not attain normative goals (Ward & Spitze, 1992). This article examines the subjective burdens experienced by parents when their offspring fail to achieve expected life-span goals. Specifically, we explore how the non-normative experience of severe mental illness (Marsh, 1992) may result in an adult child being perceived as off-time and may contribute to parental feelings of emotional distress. In so doing, we discuss the theoretical and empirical relationships between severe mental illness, off-timedness, and subjective burden, and also describe the effect of offspring illness and life history characteristics on these relationships. REVIEW OF THE LITERATURE Severe Mental Illness and Off-timedness The cyclical nature of severe mental illness limits the individual's ability to meet expected life course transitions, causing the ill person to become off. time (Lefley, 1987; Marsh, 1992). Repeated psychiatric hospitalizations, and dealing with symptoms such as paranoia, depression, and hallucinations, make it difficult for the ill individual to finish college, live independently, and have intimate relationships with others: the illness hinders the successful completion of expected life tasks mastered by same-age peers. Parents may experience feelings of grief and frustration as they watch their ill adult child struggle -- and often fail -- to achieve normative life-span goals (Pickett, Cook, & Solomon, in press). In addition, given that the symptoms of severe mental illness usually do not appear until late adolescence or early adulthood, many ill individuals have been able to accomplish some expected tasks (Marsh, 1992). Parents may continue to hold normative expectations for adult offspring, who, prior to the onset of their psychiatric illness, may have been employed or married. Parental perceptions of off-timedness may reflect the difference between parental expectations for their ill child and the child's actual achievement of life-span goals (Pickett, Cook, & Cohler, 1994). Off-timedness and parental burden. Severe mental illness also necessitates the need for familial support and assistance, and numerous studies have documented the consequences of care-giving for parents of psychiatrically disabled adult children (Cook, Lefley, Pickett, & Cohler, 1994; Cook & Pickett, 1988; Greenberg, Greenley, McKee, Brown, & Griffen-Francell, 1993; Hatfield, 1978; Hatfield & Lefley, 1987; Thompson & Doll, 1982). Regarding is. sues of off-timedness, research has focused on parental anxieties related to normative goals (Hatfield, 1992) and changes in the parents' life course as a result of their offspring's illness (Cohler, Pickett, & Cook, 1991; Cook & Cohler, 1986; Marsh, 1992). …

Parental Host Plant Affects Offspring Life Histories in a Seed Beetle

Non—genetic effects of maternal environment often have large influences on offspring phenotypes. Some maternal effects may be adaptive in heterogeneous environments, whereby mothers can program a developmental switch in their offspring in response to a predictive environmental cue. For herbivorous insets, maternal rearing hosts (i.e., maternal environment) may have large effects on offspring, including adaptive effects on patterns of host suitability. For example, if maternal rearing host is predictive of local host availability, then it is advantageous for mothers reared on one host to produce offspring that are physiologically 'acclimated' to that host. Previous research has demonstrated that seed beetles, Stator limbatus, collected from Cercidium floridum survived better and developed faster on this host than beetles collected from Acacia greggii or C. microphyllum at either the same site or from a different locality. These results indicate either within— and among—population host—associated genetic differentiation or a non—genetic maternal host effect, in which offspring survive better and develop faster on the host their mother was reared on. We examine the influence of maternal and paternal rearing hosts on the survivorship, development time, and body size in offspring in S. limbatus. We find no evidence that beetles are acclimated to perform better on the host their mother was reared on via non—genetic maternal effects. However, maternal rearing host did affect offspring in other ways; mothers reared on C. floridum produced larger offspring that developed faster than offspring of mothers reared on A. greggii, due to a non—genetic maternal effect (paternal rearing host had no effect). In addition, both maternal and paternal host had a large effect on offspring survivorship; offspring of parents reared on C. floridum survived better than those of parents reared on A. greggii. The symmetry between the maternal and paternal host effects on survivorship suggests that they represent a response to intense selection during the experiment, and suggest the potential for rapid adaptation to this host. Alternatively, non—genetic effects of both maternal and paternal rearing host may simultaneously influence survivorship of S. limbatus offspring. Although paternal effects are generally disregarded as an important source of environmental variation, they are potentially important for S. limbatus; non—genetic paternal effects were detected in this experiment for development time of offspring: fathers reared on C. floridum produced offspring that developed slower on C. floridum, and offspring that developed faster on A. greggii, than fathers reared on A. greggii.

The influence of maternal age and mating frequency on egg size and offspring performance in Callosobruchus maculatus (Coleoptera: Bruchidae).

Maternal age influences offspring quality of many species of insects. This observed maternal age influence on offspring performance may be mediated through maternal age effects on egg size, which in turn may be directly influenced by the female's nutritional state. Thus, behaviors that influence a female's nutritional status will indirectly influence egg size, and possibly offspring life histories. Because males provide nutrients to females in their ejaculate, female mating frequency is one behavior which may influence her nutritional status, and thus the size of her eggs and the performance of her offspring. In this paper, I first quantify the influences of maternal age on egg size and offspring performance of the bruchid beetle, Callosobruchus maculatus. I then examine whether nutrients transferred during copulation reduce the magnitude of maternal age effects on egg size and larval performance when mothers are nutrient-stressed. Egg size and egg hatchability decreased, and development time increased, with increasing maternal age. Multiple mating and adult feeding by females both resulted in increased egg size. This increase in egg size of females mated multiply did not translate into reduced development time or increased body size and egg hatchability, but did correlate with improved survivorship of offspring produced by old mothers. Thus, it appears that because the influence of mating frequency on egg size is small relative to the influence of maternal age, the influence of nutrients derived from multiple mating on offspring life history is almost undetectable (detected only as a small influence on survivorship). For C. maculatus, female multiple mating has been demonstrated to increase adult female survivorship (Fox 1993a), egg production (Credland and Wright 1989; Fox 1993a), egg size, and larval survivorship, but, contrary to the suggestion of Wasserman and Asami (1985), multiple mating had no detectable influence on offspring development time or body size.

Initiation of maternal effects in Lymantria dispar: Genetic and ecological components of egg provisioning

AbstractResources supplied by mothers to offspring through the egg are known to significantly influence offspring life history traits in the gypsy moth, Lymantria dispar. The purpose of this research was to determine the relative contribution of genetics (based on familial contribution) and the nutritional environment of the parents to the mean and variance of resources supplied to the eggs. Vitellogin, the dominant egg storage protein in the gypsy moth, was selected as the focus of the study. The amount of vitellogin in individual eggs from 48 mothers reared on one of four host species, quaking aspen, chestnut oak, red oak, or pitch pine was quantified with an immunoassay. Results of a nested analysis of variance show that both genetics and parental nutritional experience make significant contributions to egg vitellogin levels. When parents were reared on quaking aspen, vitellogin levels were highest and the expression of familial variation was greatest. This study shows that polyphagy can amplify phenotypic variance in reproductive traits through the interaction between genotype and nutritional environment. To the extent that egg resources influence offspring vigor, the fitness of offspring can include a time‐lagged component which arises from the interaction between the parental genotype and the parental environment. The time‐lagged expression of such a maternal trait is capable of influencing the rate and direction of character evolution and the stability of local population dynamics.

Differences in the effects of parental age on offspring life history between tropical and temperate populations of milkweed bugs (Oncopeltus spp.)

We compare the effects of parental age on several offspring life history traits in two milkweed bug populations: a typically univoltine population ofOncopeltus fasciatus from the Sacramento Valley of California and a typically multivoltine population ofO. cingulifer from Monteverde, Costa Rica. Reared under identical conditions (27°C, 12 h light: 12 h dark photoperiod), these bugs exhibit significant differences in the effects of parental age on offspring life history. As they age,O. fasciatus females from Sacramento lay clutches of eggs of decreasing average weight and a decreasing proportion of their eggs produce offspring that survive to adulthood. Those offspring which do survive have a significantly faster developmental rate and females have a larger body size at adult eclosion. AsO. cingulifer from Monteverde age, they also produce lighter eggs, but there is no significant change in the offspring developmental rate, survival or female adult body size. We suggest that these results are largely explicable as the consequence of different parental investment strategies associated with the predictable relationship between parental age and time of season inO. fasciatus but not inO. cingulifer. AsO. fasciatus from Sacramento age, they may be increasing their investment per developing offspring so as to increase the probability that nymphs hatching late in the season will reach a prereproductive adult diapause before the first killing frost.

Maternal Effects Generate Variation in Life History: Consequences of Egg Weight Plasticity in the Gypsy Moth

Features of an individual's life history are the product of its genotypic background and environmental experience. For the gypsy moth, Lymantria dispar L., the earliest environmental experience comes via maternal nutrients supplied to the egg. To estimate the importance of maternal provisions to the expression of offspring life history in the gypsy moth, egg weights of siblings were measured 1 week before hatch in each of 18 families. Siblings representing the range of egg weights produced by each mother were reared individually under homogeneous conditions and monitored for time until hatch, larval development time and pupal weight. There was significant variation among families in each life-history trait for both sexes suggesting the presence of genetic variation. Life-history expression also had a strong maternal effect component. Based on partial correlation coefficients which control for familial differences in life-history expression, the following relationships were seen: when individuals came from larger eggs, they hatched earlier (both sexes), daughters finished the larval period faster, and became heavier pupae. Maternal effects generate phenotypic variation within a family. This may represent a bet-hedging strategy in response to the environment typically encountered by this species: an unpredictable one. Key-words: Bet-hedging, egg provisions, gypsy moth, Lyman tria dispar, life-history traits, maternal effects, plant-herbivore interactions

An Optimal Life-History Strategy in which Reproductive Effort Decreases with Age

Previous articleNext article No AccessLetters to the EditorsAn Optimal Life-History Strategy in which Reproductive Effort Decreases with AgeRobert M. FagenRobert M. Fagen Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 106, Number 948Mar. - Apr., 1972 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/282766 Views: 4Total views on this site Citations: 17Citations are reported from Crossref Copyright 1972 The University of Chicago.PDF download Crossref reports the following articles citing this article:Reuven Dukas Animal expertise: mechanisms, ecology and evolution, Animal Behaviour 147 (Jan 2019): 199–210.https://doi.org/10.1016/j.anbehav.2018.05.010Reuven Dukas Life history of learning: performance curves of honeybees in settings that minimize the role of learning, Animal Behaviour 75, no.33 (Mar 2008): 1125–1130.https://doi.org/10.1016/j.anbehav.2007.08.029SÉBASTIEN DESCAMPS, STAN BOUTIN, DOMINIQUE BERTEAUX, JEAN-MICHEL GAILLARD Female red squirrels fit Williams’ hypothesis of increasing reproductive effort with increasing age, Journal of Animal Ecology 76, no.66 (Nov 2007): 1192–1201.https://doi.org/10.1111/j.1365-2656.2007.01301.x Lock Rogers and Robert Craig Sargent A Dynamic Model of Size‐Dependent Reproductive Effort in a Sequential Hermaphrodite: A Counterexample to Williams's Conjecture. L. Rogers and R. C. Sargent, The American Naturalist 158, no.55 (Jul 2015): 543–552.https://doi.org/10.1086/323119JOSEPH APALOO FREQUENCY INDEPENDENT EVOLUTIONARY MODELS, Journal of Biological Systems 07, no.0101 (Mar 1999): 1–9.https://doi.org/10.1142/S0218339099000024P. A. Langley, T. H. Clutton-Brock Does reproductive investment change with age in tsetse flies, Glossina morsitans morsitans (Diptera: Glossinidae)?, Functional Ecology 12, no.66 (Mar 2002): 866–870.https://doi.org/10.1046/j.1365-2435.1998.00262.xJohn P. Phelan, Peter C. Frumhoff Differences in the effects of parental age on offspring life history between tropical and temperate populations of milkweed bugs (Oncopeltus spp.), Evolutionary Ecology 5, no.22 (Apr 1991): 160–172.https://doi.org/10.1007/BF02270832James T. Giesel Life-history strategies, (Jan 1988): 153–161.https://doi.org/10.1007/978-1-4899-2683-8_12Ismo J. Holopainen, Ilkka Hanski Life history variation in Pisidium (Bivalvia: Pisidiidae), Ecography 9, no.22 (May 1986): 85–98.https://doi.org/10.1111/j.1600-0587.1986.tb01195.xTakashi Kohyama Studies on theAbies population of Mt. Shimagare II. Reproductive and life history traits, The Botanical Magazine Tokyo 95, no.22 (Jun 1982): 167–181.https://doi.org/10.1007/BF02488583Richard Shine ?Costs? of reproduction in reptiles, Oecologia 46, no.11 (Jul 1980): 92–100.https://doi.org/10.1007/BF00346972 Nancy Burley Clutch Overlap and Clutch Size: Alternative and Complementary Reproductive Tactics, The American Naturalist 115, no.22 (Oct 2015): 223–246.https://doi.org/10.1086/283556Nils Chr. Stenseth Demographic strategies in fluctuating populations of small rodents, Oecologia 33, no.22 (Jan 1978): 149–172.https://doi.org/10.1007/BF00344845John Michael Dearn Variable life history characteristics along an altitudinal gradient in three species of Australian grasshopper, Oecologia 28, no.11 (Mar 1977): 67–85.https://doi.org/10.1007/BF00346837Jesús Alberto León Life histories as adaptive strategies, Journal of Theoretical Biology 60, no.22 (Aug 1976): 301–335.https://doi.org/10.1016/0022-5193(76)90062-X Brian Charlesworth , and Jesus Alberto Leon The Relation of Reproductive Effort to Age, The American Naturalist 110, no.973973 (Oct 2015): 449–459.https://doi.org/10.1086/283079 Eric R. Pianka , and William S. Parker Age-Specific Reproductive Tactics, The American Naturalist 109, no.968968 (Oct 2015): 453–464.https://doi.org/10.1086/283013