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Offspring Development (offspring + development)
Selected AbstractsParent-of-origin and trans-generational germline influences on behavioral development: The interacting roles of mothers, fathers, and grandparentsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 4 2010J.P. Curley Abstract Mothers and fathers do not contribute equally to the development of their offspring. In addition to the differential investment of mothers versus fathers in the rearing of offspring, there are also a number of germline factors that are transmitted unequally from one parent or the other that contribute significantly to offspring development. This article shall review four major sources of such parent-of-origin effects. Firstly, there is increasing evidence that genes inherited on the sex chromosomes including the nonpseudoautosomal part of the Y chromosome that is only inherited from fathers to sons, contribute to brain development and behavior independently of the organizing effects of sex hormones. Secondly, recent work has demonstrated that mitochondrial DNA that is primarily inherited only from mothers may play a much greater than anticipated role in neurobehavioral development. Thirdly, there exists a class of genes known as imprinted genes that are epigenetically silenced when passed on in a parent-of-origin specific manner and have been shown to regulate brain development and a variety of behaviors. Finally, there is converging evidence from several disciplines that environmental variations experienced by mothers and fathers may lead to plasticity in the development and behavior of offspring and that this phenotypic inheritance can be solely transmitted through the germline. Mechanistically, this may be achieved through altered programming within germ cells of the epigenetic status of particular genes such as retrotransposons and imprinted genes or potentially through altered expression of RNAs within gametes. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 312,330, 2010. [source] Parental care in response to natural variation in nest predation pressure in six sunfish (Centrarchidae: Teleostei) speciesECOLOGY OF FRESHWATER FISH, Issue 4 2008S. J. Cooke Abstract,,, Parental care is an important, energetically costly component of the life history of many fishes. Despite this importance, little is known about how different species of fish vary parental care in response to natural nest predator burdens. In this study, underwater videography was used to quantify parental care activity of six species of syntopic nesting male centrarchid fishes in Lake Opinicon, Ontario, in response to natural predators. This approach was used to test the hypothesis that as offspring develop from eggs to wrigglers, parental care activity should decrease or remain static for fish guarding nests with low predator burden and increase for those with high predator burden, reflecting different external risks. Principal components analysis (PCA) was used to derive common aeration and nest defence variables. Aeration and predator defence activity of the fish varied extensively among species. Parental care behaviours indicative of defence and vigilance (e.g., turning, departures, time away from nest, displays) tended to be highest for species that had the most predation attempts, although this was not entirely consistent. There was also a positive relationship between the defence PCA metric and attempted predation. Defence did not vary with stage of offspring development, although interactions between defence and developmental stage were noted for several species. A trade-off between aeration and defence was not observed. In fact, species that provide high levels of aeration also simultaneously provide high levels of defence. Stage-specific patterns of defence in this study were less apparent than those documented by studies using responses to staged predator intrusions making it unclear as to the extent that fish were responding to the level of the risk to offspring than to the value of the brood. Therefore, combined use of observational and experimental assessments of parental care investment may be most appropriate for refining current theoretical paradigms. [source] Offspring performance and the adaptive benefits of prolonged pregnancy: experimental tests in a viviparous lizardFUNCTIONAL ECOLOGY, Issue 4 2009Geoffrey M While Summary 1Offspring locomotor performance has been shown to influence fitness related traits in a wide range of taxa. One potential mechanism by which viviparous animals can increase the performance (e.g. sprint speed) of their offspring is by prolonging pregnancy (beyond that required for complete development). However, to date studies examining this potentially important maternal effect have been largely descriptive. 2The skink Egernia whitii is an ideal candidate species to examine the consequences of delayed parturition on the performance of offspring as it routinely gives birth asynchronously despite synchronous offspring development. 3Using correlative data from a natural population and experimental manipulations of birthing asynchrony, we tested the prediction that, within litters, last born offspring have a better locomotor performance than first born offspring. 4We show that prolonged pregnancy does significantly influence average offspring locomotor performance; however, contrary to predictions, the direction of this effect is dependent on gestation length and thus offspring date of birth. Last born offspring had significantly poorer performance than first born offspring in litters early in the season with this pattern reversed late in the season. 5These results do not support the hypothesis that prolonged retention of fully formed offspring consistently increases offspring performance; however, they may help us understand the asymmetries in offspring competitive ability generated by birthing asynchrony. [source] Testosterone response to GnRH in a female songbird varies with stage of reproduction: implications for adult behaviour and maternal effectsFUNCTIONAL ECOLOGY, Issue 4 2007JODIE M. JAWOR Summary 1Despite considerable recent interest in plasma and yolk testosterone (T) in female birds, relatively little is known about environmental regulation of female T, individual variation in female T or the relationship between plasma and yolk T. 2In breeding females of a wild population of dark-eyed junco (Junco hyemalis), we assessed variation in the responsiveness of the hypothalamo-pituitary-gonadal (HPG) axis to a challenge with gonadotropin-releasing hormone (GnRH) by measuring circulating T before and 30 min after a standardized injection of GnRH. We asked whether response to challenge varied seasonally or with stage of reproduction and whether it was repeatable within individuals or related to T deposited in eggs. 3Initial and post-challenge levels of T were measured using enzyme immunoassay. In a subset of these females, luteinising hormone (LH) was measured using radioimmunoassay (RIA). In addition, eggs were collected from nests of 15 females that had received a GnRH challenge, and yolk T was measured using RIA. 4During most of the breeding season, plasma T did not increase in response to GnRH. GnRH consistently caused increases in plasma T only during the 7 days before oviposition, when females were rapidly depositing yolk in eggs but had not yet begun to lay them. Among a small subset of females we found a positive correlation between the magnitude of this increase in plasma T in response to GnRH during egg development and the amount of T deposited in the yolk of eggs collected at a later time. 5These results suggest that ovarian response to GnRH-induced increases in LH is greatest when females are actively depositing yolk into eggs. Factors that stimulate the release of GnRH during egg formation may result in higher levels of plasma T which could influence adult female behaviour. Further, because plasma T was correlated with later yolk T, factors that stimulate GnRH release may also lead to higher levels of yolk T potentially influencing offspring development or behaviour. [source] Consequences of maternal yolk testosterone for offspring development and survival: experimental test in a lizardFUNCTIONAL ECOLOGY, Issue 3 2007T. ULLER Summary 1Hormone-mediated maternal effects and developmental plasticity are important sources of phenotypic variation, with potential consequences for trait evolution. Yet our understanding of the importance of maternal hormones for offspring fitness in natural populations is very limited, particularly in non-avian species. 2We experimentally elevated yolk testosterone by injection of a physiological dose into eggs of the lizard Ctenophorus fordi Storr, to investigate its roles in offspring development, growth and survival. 3Yolk testosterone did not influence incubation period, basic hatchling morphology or survival under natural conditions. However, there was evidence for increased growth in hatchlings from testosterone-treated eggs, suggesting that maternal hormones have potential fitness consequences in natural populations. 4The positive effect of prenatal testosterone exposure on postnatal growth could represent a taxonomically widespread developmental mechanism that has evolved into an adaptive maternal effect in some taxa, but remains deleterious or selectively neutral in others. 5A broader taxonomic perspective should increase our understanding of the role of physiological constraints in the evolution of endocrine maternal effects. [source] Evidence for non-genomic transmission of ecological information via maternal behavior in female ratsGENES, BRAIN AND BEHAVIOR, Issue 1 2007J. McLeod Maternal behavior is flexible and programs offspring development. Using a novel manipulation, we demonstrate that rat maternal behavior is sensitive to ecologically relevant stimuli. Long-Evans hooded rat dams (F0) and pups were exposed to a predator condition (cat odor) or a control condition (no odor) for 1 h on the day of parturition. Predator-exposed F0 dams displayed significantly more maternal behavior (licking/grooming, arched-back nursing) relative to control-exposed dams across five subsequent observation days. Female offspring (F1) were raised to adulthood, bred and maternal behavior was observed. F1 dams reared by a predator-exposed F0 dam displayed significantly higher maternal behavior relative to F1 dams reared by a control-exposed F0 dam across 5 days of observation. Increased levels of maternal behavior in predator-reared (PR) F1 dams were evident even in F1 females that had been cross-fostered (CF) from a control-exposed F0 dam, suggesting a non-genomic transmission of increased levels of maternal behavior. Lactating PR F1 dams had significantly elevated estrogen receptor , and , mRNA in the medial preoptic area relative to control-reared (CR) F1 dams. Furthermore, among CR F1 dams, there was no significant difference between those dams that had been CF from predator-exposed F0 dams and those that had been sham CF. These results support the hypothesis that flexible rat maternal behavior can shape offspring development according to current environmental conditions. The results also suggest that estrogen signaling may be part of an epigenetic mechanism by which changes in maternal behavior are passed from F0 to F1 dams. [source] Copepod life cycle adaptations and success in response to phytoplankton spring bloom phenologyGLOBAL CHANGE BIOLOGY, Issue 6 2009HANNO SEEBENS Abstract In a seasonal environment, the timing of reproduction is usually scheduled to maximize the survival of offspring. Within deep water bodies, the phytoplankton spring bloom provides a short time window of high food quantity and quality for herbivores. The onset of algal bloom development, however, varies strongly from year to year due to interannual variability in meteorological conditions. Furthermore, the onset is predicted to change with global warming. Here, we use a long-term dataset to study (a) how a cyclopoid copepod, Cyclops vicinus, is dealing with the large variability in phytoplankton bloom phenology, and (b) if bloom phenology has an influence on offspring numbers. C. vicinus performed a two-phase dormancy, that is, the actual diapause of fourth copepodid stages at the lake bottom is followed by a delay in maturation, that is, a quiescence, within the fifth copepodid stage until the start of the spring bloom. This strategy seems to guarantee a high temporal match of the food requirements for successful offspring development, especially through the highly vulnerable naupliar stages, with the phytoplankton spring bloom. However, despite this match with food availability in all study years, offspring numbers, that is, offspring survival rates were higher in years with an early start of the phytoplankton bloom. In addition, the phenology of copepod development suggested that also within study years, early offspring seems to have lower mortality rates than late produced offspring. We suggest that this is due to a longer predator-free time period and/or reduced time stress for development. Hence, within the present climate variability, the copepod benefited from warmer spring temperatures resulting in an earlier phytoplankton spring bloom. Time will show if the copepod's strategy is flexible enough to cope with future warming. [source] Time , size tradeoffs: a phylogenetic comparative study of flowering time, plant height and seed mass in a north-temperate floraOIKOS, Issue 3 2008Kjell Bolmgren Parents face a timing problem as to when they should begin devoting resources from their own growth and survival to mating and offspring development. Seed mass and number, as well as maternal survival via plant size, are dependent on time for development. The time available in the favorable season will also affect the size of the developing juveniles and their survival through the unfavorable season. Flowering time may thus represent the outcome of such a time partitioning problem. We analyzed correlations between flowering onset time, seed mass, and plant height in a north-temperate flora, using both cross-species comparisons and phylogenetic comparative methods. Among perennial herbs, flowering onset time was negatively correlated with seed mass (i.e. plants with larger seeds started flowering earlier) while flowering onset time was positively correlated with plant height. Neither of these correlations was found among woody plants. Among annual plants, flowering onset time was positively correlated with seed mass. Cross-species and phylogenetically informed analyses largely agreed, except that flowering onset time was also positively correlated with plant height among annuals in the cross-species analysis. The different signs of the correlations between flowering onset time and seed mass (compar. gee regression coefficient=,7.8) and flowering onset time and plant height (compar. gee regression coefficient=+30.5) for perennial herbs, indicate that the duration of the growth season may underlie a tradeoff between maternal size and offspring size in perennial herbs, and we discuss how the partitioning of the season between parents and offspring may explain the association between early flowering and larger seed mass among these plants. [source] | ||||||||||