Total Number Of Offspring Research Articles

Short‐ and long‐term costs of reproduction in a migratory songbird

Costs of reproduction represent a common life‐history trade‐off. Critical to understanding these costs in migratory species is the ability to track individuals across successive stages of the annual cycle. We assessed the effects of total number of offspring fledged and date of breeding completion on pre‐migratory body condition, the schedule of moult and annual survival in a migratory songbird, the Savannah Sparrow Passerculus sandwichensis. Between 2008 and 2010, moult was delayed for individuals that finished breeding later in the breeding period and resulted in reduced lean tissue mass during the pre‐migratory period, suggesting an indirect trade‐off between the timing of breeding completion and condition just prior to migration. Lean tissue mass decreased as the number of offspring fledged increased in 2009, a particularly cool and wet year, illustrating a direct trade‐off between reproductive effort and condition just prior to migration in years when weather is poor. However, using a 17‐year dataset from the same population, we found that parents that fledged young late in the breeding period had the highest survival and that number of offspring fledged did not affect survival, suggesting that individuals do not experience long‐term trade‐offs between reproduction and survival. Taken together, our results suggest that adult Savannah Sparrows pay short‐term costs of reproduction, but that longer‐term costs are mitigated by individual quality, perhaps through individual variation in resource acquisition.

Variance Effective Population Size for Dioecious Species

ABSTRACTThe concept of effective population size (Ne) is an important measure of representativeness in many areas. In this research, we consider the statistical properties of the number of contributed gametes under practical situations by adapting Crow and Denninston's (1988) Ne formulas for dioecious species. Three sampling procedures were considered. In all circumstances, results show that as the offspring sex ratio (r) deviates from 0.5, Ne values become smaller, and the efficiency of gametic control for increasing Ne is reduced. For finite populations, where all individuals are potentially functional parents, the reduction in Ne due to an unequal sex ratio can be compensated for through female gametic control when 0.28 ≤ r ≤ 0.72. This outcome is important when r is unknown. When only a fraction of the individuals in a population is taken for reproduction, Ne is meaningful only if the size of the reference population is clearly defined. Gametic control is a compensating factor in accession regeneration when the viability of the accession is around 70 or 75%. For germplasm collection, when parents are a very small fraction of the population, maximum Ne will be approximately 47 and 57% of the total number of offspring sampled, with female gametic control, r varying between 0.3 and 0.5, and being constant over generations.

Inter-birth interval in zebras is longer following the birth of male foals than after female foals

Mammalian reproductive rates vary among individuals for physiological and environmental reasons. This study aims to determine reproductive rates from an individually monitored population of wild Plains zebras Equus quagga, and to assess the sources of variability in inter-birth intervals. The animals were monitored, where possible, every six months from 2004 to 2011. Thirty nine intervals corresponding to 65 births in 26 mares were identified, using direct observations and faecal steroid monitoring. Mean foaling rate of the population is 0.74 foal/year, and comparable with the literature. There was no significant effect of mother’s age, nor of the season of previous birth on the length of inter-birth intervals. Inter-birth interval was significantly longer when the first foal was a male. This finding indicates that additional costs of having a son may delay future reproduction and thus reduce the total number of offspring a mare can have during her lifetime. Individually-based data provide critical information on the determinants of reproductive rates, and are therefore a key to understanding the causes of variations in life-history traits.

Effects of different light intensities on growth, survival, reproductive and life span characteristics ofArtemia urmiana(Günther 1890)

Effects of light intensities on growth, survival, reproductive and life span traits of Artemia urmiana were investigated under laboratory conditions. Nauplii of A. urmiana were hatched and raised in 100 g L−1 at four illuminations including 0, 100, 2000 and 5000 lx with 14:10 (light:dark) photoperiod. Mating pairs of mature animals were randomly isolated and reared continuously under similar conditions. The mode and potential of reproduction as well as adult survival shown by each pair were determined throughout their life span. Results showed that percentages of nauplii survival were significantly (P ≤ 0.05) different at 5000 and 0 lx (76.50% compared with 26.25%) respectively. Total number of offspring was highly correlated with the light intensities showing increased numbers at higher light intensities compared with darkness or 100 lx. Reproduction mode was relatively affected by various light intensities. Significant (P ≤ 0.05) differences were found both in reproductive period and life span at different illuminations. Maximum and minimum offspring productions per reproductive day were found at 5000 and 100 lx respectively. The relative degree of oviparity increased as the illumination decreased (57.92% compared with 22.65% at 0 and 5000 lx respectively). The optimum light intensities appear to be between 2000 lx and 5000 lx in this study. These findings could probably be useful for mass culture of A. urmiana in indoor or recirculating systems as well as in outdoor systems for intensive cyst and biomass production.

Wild yellow dung fly females may not select sperm based on dung pat microclimate but could nevertheless benefit from polyandry

Molecular techniques have substantially improved our knowledge of postcopulatory sexual selection. Nevertheless, studies examining sperm utilization in natural populations of nonsocial insects are rare, support for sperm selection (biased use of stored sperm, e.g. to match offspring genotypes to prevailing environmental conditions) is elusive, and its relevance within natural populations unknown. We performed an oviposition site choice experiment in the field where female yellow dung flies Scathophaga stercoraria could deposit eggs into three different microenvironments on a dung pat (the east–west ridge, north- or south-exposed side), and genotyped the offspring and sperm remaining in storage after oviposition. Females exhibited plasticity in the number of eggs deposited according to pat age. Additionally, temperature strongly influenced egg placement: the warmer the temperature, the higher the proportion of eggs laid into the north-exposed side of dung. The number of ejaculates in storage differed amongst spermathecae, and females stored sperm from more males than fathered their offspring (2.11 sires vs. 2.84 males within sperm stores). Mean last male paternity was 83.4%, roughly matching previous laboratory estimates. Importantly, we found no evidence that females selectively lay eggs of different genotypes, by biasing paternity towards certain males, depending on offspring’s microclimate. Thus, while we show female choice over number of eggs and where these are deposited, there was no evidence for sperm selection. We further revealed positive effects of multiple mating on total number of offspring and proportion of offspring emerging from the dung. We argue that the integration of field studies and laboratory experiments is essential to promote our understanding of polyandry and cryptic female choice.

Landscape structure affects activity density, body size and fecundity of Pardosa wolf spiders (Araneae: Lycosidae) in winter oilseed rape

In large parts of Europe Pardosa spp. (Lycosidae) are among the most abundant wolf spiders in arable fields and potentially important natural control agents of pests. We studied the influence of landscape factors on activity density, adult body size and fecundity of P. agrestis in 29 winter oilseed rape fields (Brassica napus L.) in Eastern Austria using pitfall traps. Landscape data were obtained for eight circular landscape sections around each field (radii 250-2000 m). Multivariate regression models were used to analyze the data. Activity density was highest when the length of strips of grassy road-sides in the surroundings was highest and distance to the next grassy fallow lowest. Body size was negatively related to activity density and to the length of road-side strips and positively to woody areas in the vicinity of the fields. Clutch size was unrelated to any of the landscape factors tested but was positively correlated with female body size. Woody areas and grassy fallow in the close vicinity of the fields had a positive influence on number of offspring per female and total number of offspring. These results indicate that various non-crop components in the landscape surrounding oilseed rape fields can specifically influence the activity density and fitness-related traits of P. agrestis in crops. The possible role of Pardosa spp. in natural pest control is discussed.

Host Suitability and Gas Exchange Response of Grapevines to Potato Leafhopper (Hemiptera: Cicadellidae)

Although potato leafhopper, Empoasca fabae (Harris) (Hemiptera: Cicadellidae), is highly polyphagous, classic host studies do not recognize grapevines (Vitis spp.), as suitable hosts. Recently, injury has been reported and reproduction documented within grape vineyards, suggesting a host expansion for the leafhopper. To document this apparent expansion in host use, we determined whether grape plants were suitable hosts for potato leafhopper reproduction, measured the consequence of feeding injury on gas exchange rates of grape leaves, and compared the susceptibility to feeding injury among cultivars. We found that potato leafhopper adults survived equally well on grape (Vitis vinifera L.), alfalfa (Medicago sativa L.), and fava bean (Vicia faba L.). The total number of offspring was greater on fava bean but did not differ between alfalfa and grape. Injury to grapevines was assessed by measuring gas exchange responses of leaves in field cages and in greenhouse tests. We found marginally significant declines in photosynthesis and transpiration rates in the field (9.6 and 13.2%, respectively), and much stronger effects in greenhouse tests (ranging between 22 and 52%). Our results verify that Vitis is a suitable host, and that potato leafhopper is capable of injuring its gas exchange physiology. We discuss possible explanations for the host expansion, and its potential to damage commercial grapevines.

Mechanisms, functions, and fitness consequences of pre- and post-copulatory rituals of the parasitoid wasp Ooencyrtus kuvanae

Males and females of the parasitoid wasp Ooencyrtus kuvanae (Howard) (Hymenoptera: Encyrtidae) emerge en masse from gypsy moth, Lymantria dispar dispar (L.) (Lepidoptera: Noctuidae: Lymantriinae), host egg masses. Males engage females in a brief pre-copulatory ritual, mate, and then execute a post-copulatory ritual. We investigated mechanisms, functions, and fitness consequences of the pre- and post-copulatory ritual by high-speed cinematography, gas chromatographic-mass spectrometric analyses of volatile constituents on the insects’ integument, and behavioral assays. Our data indicate that the mechanisms of the pre- and post-copulatory ritual are physical interactions rather than pheromone transfer. During the pre-copulatory ritual, the males put females into a trance-like state that persists for some time after copulation. Males attained a mating with in-trance females 9.5 times faster than with females that had come out of trance. Mated females with post-copulatory ritual experience did not remate, whereas females lacking that experience did. The total number of offspring and daughters did not differ between females with or without post-copulatory ritual experience or in relation to the duration of that ritual. The post-copulatory ritual functions as a form of mate guarding in that the male accelerates awakening of the in-trance female, which then rejects mating attempts by other males, ensuring his paternity.

Hormetins, antioxidants and prooxidants: defining quercetin-, caffeic acid- and rosmarinic acid-mediated life extension in C. elegans

Quercetin, Caffeic- and Rosmarinic acid exposure extend lifespan in Caenorhabditis elegans. This comparative study uncovers basic common and contrasting underlying mechanisms: For all three compounds, life extension was characterized by hormetic dose response curves, but hsp-level expression was variable. Quercetin and Rosmarinic acid both suppressed bacterial growth; however, antibacterial properties were not the dominant reason for life extension. Exposure to Quercetin, Caffeic- and Rosmarinic acid resulted in reduced body size, altered lipid-metabolism and a tendency towards a delay in reproductive timing; however the total number of offspring was not affected. An indirect dietary restriction effect, provoked by either chemo-repulsion or diminished pharyngeal pumping was rejected. Quercetin and Caffeic acid were shown to increase the antioxidative capacity in vivo and, by means of a lipofuscin assay, reduce the oxidative damage in the nematodes. Finally, it was possible to demonstrate that the life and thermotolerance enhancing properties of Caffeic- and Rosmarinic acid both rely on osr-1, sek-1, sir-2.1 and unc-43 plus daf-16 in the case of Caffeic acid. Taken together, hormesis, in vivo antioxidative/prooxidative properties, modulation of genetic players, as well as the re-allocation of energy all contribute (to some extent and dependent on the polyphenol) to life extension.

The interactive effects of microcystin and nitrite on life-history parameters of the cladoceran Daphnia obtusa

Elevated nitrite and microcystin concentrations co-occur during degradation of Microcystis blooms and are toxic to aquatic organisms. We studied the relative and combined effects of these on Daphnia obtusa life-history. Nitrite and microcystin-LR treatments were: 0, 1, 3 mg L −1 and 0, 10, 100, 300 μg L −1, respectively. Experiments were factorial with 12 treatment combinations. Incubations were 15 d and recorded: moult number; time to first batch of eggs; time to first clutch; size at first batch of eggs; size at first clutch; number of clutches per female; number of offspring per clutch; total offspring per female. Interactive effects of the toxins occurred for time to first batch of eggs and time to first clutch. The remaining traits were negatively affected by nitrite: a significant decrease occurred in number of offspring per clutch and total number of offspring per mother (both decreased by ∼50%); total clutches per mother; number of moults; mother size at first clutch; and first appearance of eggs (primarily at the highest nitrite concentration). We support the literature, recognising nitrite is toxic, and although Microcystis is toxic to zooplankton, the main threat is not from dissolved microcystin but from degradative products such as nitrite.

Concentration–response function of nitrite on survival, molting, and reproduction of Daphnia similoides

We assessed the chronic toxicity of nitrite to Daphnia similoides and modeled the concentration–response function of nitrite on survival, molting, and reproduction. Survival time, number of molting, number of total offspring per female, number of broods per female, and number of offspring per brood decreased significantly with increasing NO2–N concentration during the 21-day experiment. The EC50s for number of total offspring per female, number of broods per female, and number of offspring per brood were 1.56, 3.99, and 1.71 mg L−1, respectively. A four-parameter logistic model was suitable for describing the concentration–response function and allows the estimation of reproduction indices of D. similoides at any given concentration of NO2–N.

Demography of greenbug, Schizaphis graminum (Rondani) (Hemiptera: Aphididae) on six barley cultivars

The greenbugs, Schizaphis graminum (Rondani) were collected from the barley fields in Isfahan region of Iran. The aphid colonies were maintained on each of six barley cultivars including Karoon, Kavir, Zarjoo, Nosrat, Afzal and Rihane. All the experiments were done on the mentioned barley varieties at 26 ± 1°C, 60 ± 5% relative humidity (RH) and at a photoperiod of 16:8 (L:D) h. The shortest and longest developmental times were obtained on Nosrat 6.35 ± 0.11 and Rihane 6.75 ± 0.07 days, respectively. The survivorship of immature stages varied from 71.95% on Nosrat to 82.14% on Zarjoo. The total number of offsprings were 71.05 and 63.22 nymphs per female on Kavir and Karoon. The highest and lowest r m values were observed on Kavir (0.336 ± 0.005) and Rihane (0.299 ± 0.008), respectively. The statistical analysis of jackknife did not show a significant influence of the tested barley varieties for the mean generation time and a similar procedure of difference for λ and r m was estimated.

Effects of an Environmentally Realistic Pesticide Mixture on Daphnia magna Exposed for Two Generations

Daphnia magna were exposed under semistatic conditions (i.e., conditions taking natural degradation into account) to a pesticide mixture consisting of a pyrethroid insecticide (cyfluthrin) and a pre-emergent herbicide (diuron) as well as pesticides individually using a full life cycle exposure (21days). Subsequently, offspring from the second reproductive brood were used to continue exposure for a second generation. Survival, time to first brood, total number of offspring produced, number of broods produced, growth rate, and population growth rate were recorded for each generation and concentration. Significant differences existed between F0 and F1 D.magna for survival, in which F1 were less sensitive to pesticide mixtures than F0. In addition, F1 D. magna were significantly smaller than F0, which resulted in longer time to first brood. There were no differences in any end point examined between D.magna exposed to the pesticide mixture and diuron alone, although differences existed in survival, total number of offspring, total number of broods, and population growth rate when F0 D.magna were exposed to cyfluthrin alone. This study illustrates the utility of a two-generation study design that may more fully reflect, and more accurately predict, population level effects of pesticide exposures to short-lived aquatic organisms.

Characterization of mitochondrial ferritin‐deficient mice

Characterization of mitochondrial ferritin‐deficient mice

OP10.06: Influence of second trimester placental volume, shell volume and intraplacental circulation on birth weight

Objectives: Nowadays Mode B ultrasound biosafety is not been currently questioned. Instead Doppler mode has not yet reached the same security fee, most probably due to the small number of studies on the topic or that the ones available are not conclusive about harmlessness. Moreover, ISUOG requires all informed patients consent, for every study that includes first trimester Doppler. To determine whether color and pulsed Doppler exposure of rat embryos at different gestational ages could modify any anatomic or clinical parameter. Methods: In a first stage 4 animals of different gestational ages (n = 42 fetuses) were exposed to Doppler during different periods of time. During a second stage two different groups of 8 rats each were used: a) 8 days of gestational age (early ultrasound or EU; n = 68 fetuses), 15 minutes during 4 consecutive days, b) 15 days of gestational age (late ultrasound or LU; n = 45 fetuses) under the same conditions. All ultrasound exposures were done by two or three operators using a Sonoace 8800 Digital Gaia (Medison ultrasound system) ultrasound machine with a 7 MHz lineal transducer. The evaluated parameters were: total number of offspring (alive and dead), gestational age, weight at 2 and 21 days of life, clinical parameters of neuronal development, reproductive capacity. Pathological studies were performed to a group of fetuses obtained by Cesarean section. Results: During the first stage no congenital abnormalities were observed related to Doppler exposure. These animals, exposed during the fetal period, did not show any alteration in their reproductive capacity. During the second stage neither congenital abnormalities nor pathological events were observed. The only statistical significant result (P < 0.001) was a reduction in weight of animals that belong to UL group and at out breeding (day 22), compared to control animals. Conclusions: These results reinforce the necessity to continue studying about the harmlessness of the method.

OP10.05: Prenatal exposure to Doppler ultrasound waves in mice: results at short and long term exposure

Nowadays Mode B ultrasound biosafety is not been currently questioned. Instead Doppler mode has not yet reached the same security fee, most probably due to the small number of studies on the topic or that the ones available are not conclusive about harmlessness. Moreover, ISUOG requires all informed patients consent, for every study that includes first trimester Doppler. To determine whether color and pulsed Doppler exposure of rat embryos at different gestational ages could modify any anatomic or clinical parameter. In a first stage 4 animals of different gestational ages (n = 42 fetuses) were exposed to Doppler during different periods of time. During a second stage two different groups of 8 rats each were used: a) 8 days of gestational age (early ultrasound or EU; n = 68 fetuses), 15 minutes during 4 consecutive days, b) 15 days of gestational age (late ultrasound or LU; n = 45 fetuses) under the same conditions. All ultrasound exposures were done by two or three operators using a Sonoace 8800 Digital Gaia (Medison ultrasound system) ultrasound machine with a 7 MHz lineal transducer. The evaluated parameters were: total number of offspring (alive and dead), gestational age, weight at 2 and 21 days of life, clinical parameters of neuronal development, reproductive capacity. Pathological studies were performed to a group of fetuses obtained by Cesarean section. During the first stage no congenital abnormalities were observed related to Doppler exposure. These animals, exposed during the fetal period, did not show any alteration in their reproductive capacity. During the second stage neither congenital abnormalities nor pathological events were observed. The only statistical significant result (P < 0.001) was a reduction in weight of animals that belong to UL group and at out breeding (day 22), compared to control animals. These results reinforce the necessity to continue studying about the harmlessness of the method.

A large population parental care game: Polymorphisms and feedback between patterns of care and the operational sex ratio

This article presents a game theoretic model of parental care which models the feedback between patterns of care and the operational sex ratio. It is assumed here that males can be in one of two states: searching for a mate or breeding (including caring for their offspring). Females can be in one of three states: receptive (searching), non-receptive or breeding. However, these sets of states can be adapted to the physiology of a particular species. The length of time that an individual remains in the breeding state depends on the level of care an individual gives. When in the searching state, individuals find partners at a rate dependent on the proportion of members of the opposite sex searching. These rates are defined to satisfy the Fisher condition that the total number of offspring of males equals the total number of offspring of females. The operational sex ratio is not defined exogenously, but can be derived from the adult sex ratio and the pattern of parental care. Pure strategy profiles and so-called single sex stable polymorphisms, in which behaviour is varied within one sex, are derived analytically. The difference between mixed evolutionarily stable strategies and stable polymorphisms within this framework is highlighted. The effects of various physiological and demographic parameters on patterns of care are considered.

ADaphniaParasite (Caullerya mesnili) Constitutes a New Member of the Ichthyosporea, a Group of Protists near the Animal–Fungi Divergence

Caullerya mesnili is a protozoan endoparasite in the gut epithelium of Daphnia, which causes regular epidemics in lakes throughout Europe. Its classification has remained unchanged for over a century, leaving it placed with the Haplosporidia, despite speculation that this position is incorrect. The difficulty in classifying C. mesnili stems from its few known morphological and ecological characteristics, as well as a lack of genetic markers. Here we sequenced the nuclear small subunit (SSU) and internal transcribed spacer rDNA regions of C. mesnili samples from 10 locations. Based on sequence similarities, we suggest the re-classification of C. mesnili to the Ichthyosporea, a class of protists near the animal-fungi divergence. We report average intragenomic variation of 0.75% and 2.27% in the SSU and internal transcribed spacer regions, respectively. From electron micrographs and light microscopy of histological sections we determined that C. mesnili spores grow within the intestinal epithelium where they establish themselves intercellularly. In addition, we confirmed previous accounts regarding the high virulence of this parasite. Caullerya mesnili reduces host lifespan, the number of clutches, and the total number of offspring. This high selection pressure placed on hosts supports the importance of C. mesnili as a model parasite for the study of host-parasite biology in permanent lakes.

Effects of Genetic Captive-Breeding Protocols on Sperm Quality and Fertility in the White-Footed Mouse1

Mice (Peromyscus leucopus noveboracensis) from a captive-breeding program were used to test the effects of three genetic breeding protocols (minimizing mean kinship [MK], random breeding, and selection for docility [DOC]) and inbreeding levels on sperm traits and fertility. Earlier, in generation 8, one DOC replicate went extinct because of poor reproductive success. By generation 10, spermatozoa from DOC mice had more acrosome and midpiece abnormalities, which were shown to be strong determinants of fertility, as well as lower sperm production and resistance to osmotic stress. In addition, determinants of fertility, including male and female components, were assessed in a comprehensive manner. Results showed that the probability (P) of siring litters is determined by sperm number, sperm viability, and midpiece and acrosome abnormalities; that the P of siring one versus two litters is determined by tail abnormalities; and that the total number of offspring is influenced by female size and proportion of normal sperm, showing the relative importance of different sperm traits on fertility. On average, males with 20% normal sperm sired one pup per litter, and males with 70% normal sperm sired eight pups per litter. Interestingly, the proportion of normal sperm was affected by docility but not by relatively low inbreeding. However, inbreeding depression in sperm motility was detected. In the MK group, inbreeding depression not only affected sperm motility but also fertility: An increase in the coefficient of inbreeding (f) of 0.03 reduced sperm motility by 30% and translated into an offspring reduction of three pups in second litters. A genetic load of 48 fecundity equivalents was calculated.

Scaling limits for simple random walks on random ordered graph trees

Consider a family of random ordered graph trees (Tn)n≥1, whereTnhasnvertices. It has previously been established that if the associated search-depth processes converge to the normalised Brownian excursion when rescaled appropriately asn→ ∞, then the simple random walks on the graph trees have the Brownian motion on the Brownian continuum random tree as their scaling limit. Here, this result is extended to demonstrate the existence of a diffusion scaling limit whenever the volume measure on the limiting real tree is nonatomic, supported on the leaves of the limiting tree, and satisfies a polynomial lower bound for the volume of balls. Furthermore, as an application of this generalisation, it is established that the simple random walks on a family of Galton-Watson trees with a critical infinite variance offspring distribution, conditioned on the total number of offspring, can be rescaled to converge to the Brownian motion on a related α-stable tree.