Offspring Mortality Rates Research Articles

A demographic assessment of the Lansing Effect in duckweed ( Lemna turionifera Landolt)

The Lansing Effect is the propensity for offspring of older parents to have shorter lifespans than offspring of younger parents. A recent review identified two demographic patterns that can produce the Lansing Effect: (i) a greater offspring mortality rate at all offspring ages in offspring of older versus younger parents (greater initial mortality parameter); and (ii) an offspring mortality rate that increases more rapidly with offspring age in offspring of older versus younger parents (greater mortality rate parameter). Here, we report on a longitudinal study designed to investigate these patterns, using the duckweed Lemna turionifera . We tracked asexually produced offspring that detached from parents that were comparatively young versus old (first versus fifth offspring, respectively). Offspring of older parents lived 15% shorter, on average, than offspring of younger parents, providing evidence of the Lansing Effect. A model-selection approach revealed that the difference between survival curves of first versus fifth offspring was mainly attributable to greater initial mortality in fifth compared to first offspring, though alternative models also received some support. Our study provides a demographic explanation for the Lansing Effect in L. turionifera in particular and provides a method for assessing the survival patterns underpinning the Lansing Effect in general.

Post-fledging survival of Tengmalm’s owl offspring in boreal forests: Interactive effects of varying dynamics of main prey and habitat composition

The knowledge about the mortality rate of offspring is crucial for estimating bird population dynamics and conserving species with declining populations. Parents of predatory birds provide food for their offspring during the post-fledging dependency period, which is frequently described as essential due to inexpert flying skills. Using radio telemetry, we studied fledglings’ probability of dying by starvation and predation in Tengmalms’ owls (Aegolius funereus). Nestlings (21 and 39) from 10 and 14 broods in 2019 and 2021, respectively, were equipped with leg-mounted tags and monitored throughout the post-fledging dependency period in west-central Finland. In total, 28 out of 60 fledglings did not survive the post-fledging dependency period (12 died due to starvation, and 16 were predated). The fledglings’ probability of dying by starvation and predation was 3.7 and 2.4 times higher, respectively, in the decreasing (2019) than during the increasing (2021) abundance of main foods (voles), showing that prey availability is essential for survival during the post-fledging dependency period. The probability of starvation increased with augmenting agricultural lands in the home range and increasing precipitation after fledging, which indicated that parent owls avoided hunting in open areas and during rainy nights. The predation rate during the post-fledging dependency period increased with augmenting cover of old-growth forests in the home range. This result suggested that coverage of old-growth forests is nowadays so small in the study area that they act as ecological traps for newly-fledged owlets. The reason is that the main avian enemies of Tengmalm’s owls’ (goshawks and Ural owls) also prefer old-growth forests for breeding and hunting.

Effect of Entomopathogenic Fungi, Beauveria bassiana (Cordycipitaceae), on the Bark Beetle, Ips typographus (L.), under Field Conditions.

Simple SummaryThe effect of B. bassiana fungal treatment on spruce bark beetle, Ips typographus (L.), was tested under field conditions. Altogether, it was detected that the effect of B. bassiana preparations on bark beetle infestations in terms of possible environmental effects is minimal compared to the severe damage and hence yield loss caused by this insect species worldwide. Even if the relatively low effects on I. typographus stages, including adults, larvae, pupae and even next-generation young adults, were reported, it remains clear that the present novel approach using a natural biological control agent rather than toxic synthetic insecticides is timely and may be potentially beneficial to the forestry industry as a rational control approach to combat this pest.The spruce bark beetle, Ips typographus (L.), attack progression (adult and larval galleries) and parental and offspring mortality rate were assessed in managed forests of the Poiana Ruscă and Bihor Mountains, along with Western Romanian Carpathians using fungal (Beauveria bassiana) treatments. The results show that the effect of B. bassiana on adult (maternal) gallery length was similar to the untreated variant and was less effective than the synthetic insecticide lambda-cyhalothrin applied at a dose of 50 g/L. Additionally, its effect on the mean larval gallery number per maternal gallery was low. B. bassiana did not have a significant influence on the attack progression. Significant correlations between log diameter and I. typographus attack progression were detected; such differences were higher than the effect of any treatment. Altogether, abiotic (low humidity, high temperature) and biotic factors (log diameter) influenced the bark beetles’ attack progression and reduced the entomopathogenic fungal effects. Considering the efficacy of the B. bassiana treatment on logs infested with I. typographus, the results showed that parents and offspring were infected, but even if the fungal treatment was applied in high concentrations, the mortality rate remained relatively low. Further research is necessary to test if different B. bassiana strains and their commercially recommended concentrations might be more effective under dry and warm climate conditions, respectively.

Risk of Pregnancy Complications and Low Birth Weight Offsprings in Korean Women With Rheumatic Diseases: A Nationwide Population-Based Study.

BackgroundTo determine the risk of pregnancy complications and adverse offspring outcomes in Korean women with rheumatic diseases (RDs).MethodsWomen aged 20–44 years with pregnancies ending in delivery were identified from the National Health Insurance Service-National Health Information Database (2009–2016). Women with RD including systemic lupus erythematosus (SLE), seropositive rheumatoid arthritis (SPRA), and ankylosing spondylitis (AS) (n = 4,284) were age-matched with controls (n = 26,023). Outcome variables included threatened abortion (TA), preterm birth (PB), preeclampsia/eclampsia (PE/E), intrauterine growth retardation (IGR), urinary tract infection, low birth weight (LBW) offsprings, and offspring death within 1 year of birth.ResultsWomen with RDs had increased risks for cesarean section delivery (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.4–1.6), TA (OR, 1.4; 95% CI, 1.2–1.5), PB (OR, 2.4; 95% CI, 1.9–3.2), PE/E (OR, 4.4; 95% CI, 3.3–5.9), and IGR (OR, 2.4; 95% CI, 2.0–3.1) than the controls. The risk of pregnancy complications was increased in SLE and SPRA pregnancies but not in AS pregnancies. Offsprings of women with RDs had an increased risk of LBW (OR, 4.0; 95% CI, 3.2–4.9). The offspring mortality rate within 1 year of birth was higher in women with RDs (6.2/10,000 persons) than in the controls (4.9/10,000 persons).ConclusionWomen with RDs are at a risk of developing pregnancy complications, and the risk of LBW offsprings and offspring death within 1 year of birth is increased in these women. Therefore, this population requires special attention during their childbearing years.

Establishment and validation of a guinea pig model for human congenital toxoplasmosis

BackgroundToxoplasma gondii is an obligate intracellular parasite with a worldwide distribution. Congenital infection in humans and animals may lead to severe symptoms in the offspring, especially in the brain. A suitable animal model for human congenital toxoplasmosis is currently lacking. The aim of this study is to establish and validate the guinea pig as a model for human congenital toxoplasmosis by investigating the impact of the T. gondii infection dose, the duration of infection and the gestational stage at infection on the seroconversion, survival rate of dams, fate of the offspring, T. gondii DNA loads in various offspring tissues and organs and the integrity of the offspring brain.MethodsPregnant guinea pigs were infected with three different doses (10, 100, 500 oocysts) of T. gondii strain ME49 at three different time points during gestation (15, 30, 48 days post-conception). Serum of dams was tested for the presence of T. gondii antibodies using immunoblotting. T. gondii DNA levels in the dam and offspring were determined by qPCR. Offspring brains were examined histologically.ResultsWe found the survival rate of dams and fate of the offspring to be highly dependent on the T. gondii infection dose with an inoculation of 500 oocysts ending lethally for all respective offspring. Moreover, both parameters differ depending on the gestational stage at infection with infection in the first and third trimester of gestation resulting in a high offspring mortality rate. The duration of infection was found to substantially impact the seroconversion rate of dams with the probability of seroconversion exceeding 50% after day 20 post-infection. Furthermore, the infection duration of dams influenced the T. gondii DNA loads in the offspring and the integrity of offspring brain. Highest DNA levels were found in the offspring brain of dams infected for ≥ 34 days.ConclusionThis study contributes to establishing the guinea pig as a suitable model for human congenital toxoplasmosis and thus lays the foundation for using the guinea pig as a suitable animal model to study scientific questions of high topicality and clinical significance, which address the pathogenesis, diagnosis, therapy and prognosis of congenital toxoplasmosis.Graphical abstract

Early Neurodevelopmental Anomalies in Young Rats from Adult female Treated with Valproic Acid

Background: the influence of VPA on murine fertility, and on offspring is well documented: VPA decreases the fertility rate (by 25%) and the number of fÅ“tus. Furthermore, VPA causes behavioral alterations in rodents similar to the symptoms observed in autism.Objective: in this study we investigated the effects of exposure of non-pregnant adult rats to VPA in the offspring of these animals.Material and methods: non-pregnant adult rats were divided into 3 groups; (1) distilled water group, (2) VPA 200 mg / kg group and (3) VPA 400 mg/kg group. The products were administered orally daily for 30 days. At the end of treatments, all rats were put into monogamous mating with breeding males. The zootechnical characteristics (gestation period, litter size, mortality rate) were then noted. The young rats were then subjected to a battery of behavioral tests (reversal and anti-gravity reflexes, cliff avoidance, suspension, motor coordination and eye opening), carried out at different stages of life to assess sensorimotor development. Morphological abnormalities were also sought, as well as the mortality rate on the 28th day of life.Results: An increase in the mortality rate and a decrease in the mean lifespan were found in female rats exposed to VPA. Young rats from female rats exposed to VPA showed decreased success rates and performance in behavioral testing. Morphodevelopmental abnormalities such as adictalia or stump necrosis were found in the VPA groups. The offspring mortality rate of female rats exposed to VPA 200 mg/kg was 100%.Conclusion: VPA administered to non-pregnant adult rats causes developmental abnormalities, decreased success rates for performance testing, deformities and increased mortality in young rats from the treated rats by VPA. Â

Effects of maternal age on reproductive performance of the southern medicinal leech, Hirudo verbana Carena, 1820

Medicinal leeches can be used to address important needs in medicine and veterinary medicine, as well as pharmaceutical and cosmetic industries. These leeches, however, are among the endangered species. The reproductive processes of the medicinal leeches are not well-known. The aim of the present study was to elucidate effects of maternal age on reproductive performance of medicinal leeches (Hirudo sp.). This study was conducted on Hirudo verbana which were 1, 2 and 3 years of age. The results from the study indicate the youngest maternal leeches have greater reproductive performance. Cocoon production was 4.30 ± 0.72, 3.00 ± 0.71 and 2.80 ± 0.65 cocoons/leech at 1-, 2- and 3-years of age, respectively. Offspring production was greater in younger leeches with there being 11.16 ± 0.63, 10.60 ± 0.96 and 7.14 ± 1.20 offspring produced per cocoon when the cocoon was produced by leeches that were 1, 2, and 3 years of age, respectively. With increasing age of leeches producing the cocoon, the number of cocoons from which there are no offspring produced and the rate of abnormalities of cocoons and morphological abnormalities of offspring increased. The mortality rate of offspring was 10% and 40% in offspring from cocoons produced by 1- and 3-year-old leeches, respectively, being greater when from cocoons produced by 3-year old leeches. Consistent with these findings, younger maternal leeches during their first reproductive phase after hatching from a cocoon have the greatest reproductive performance and should be utilized in leech aquaculture enterprises.

Investigating ovine placentome blood perfusion using power flow Doppler ultrasonography

Abstract Increasing ovine placentome blood perfusion improves placental efficiency while increasing the likelihood of healthier birth weights and lower mortality rates in offspring. Invasive surgical techniques have been used to examine uteroplacental blood flow; however, non-invasive Doppler ultrasonography has recently been observed as a reliable alternative method. Even so, smaller tissues, such as placentomes, do not permit reliable measurements of vessel diameter and subsequently blood flow calculations. Objectives were to validate Doppler ultrasonography techniques for examining placentome blood perfusion in ewes administered vasoactive compounds. Ewes (n = 28) were bred to a single ram, with pregnancy being confirmed prior to experimentation. For experiment 1, placentome blood perfusion was determined pre-infusion (PRE1; n = 8) and 3–5 minutes post i.v. infusion with sodium nitroprusside at 5 μg/kg of body weight (SN5; n = 4) or 10 ug/kg of body weight (SN10; n = 4). Immediately after ultrasonography all ewes were administered N(G)-Nitro- l -arginine methyl ester (L-NAME) at 12.5 mg/kg of body weight (n = 8) and imaged for placentome perfusion 30 min post i.v. infusion. For experiment 2, ewes (n = 15) were first imaged for placentome perfusion prior to the administration of antioxidants (min 0; PRE2) and then 30 min following i.v. infusion of melatonin (MEL; 100 ug/kg of body weight), ascorbate (ASC; 10 mg/kg of body weight), or vehicle (VEH; 50% ethanol solution). Data for experiment 1 and 2 were analyzed separately by ANOVA with least significant difference test. For experiment 1, the percent area of placentome perfusion was not different (P > 0.05) between SNP and l -NAME infusions. However, the summation and average integrated pixel density of placentomes were increased (P l -NAME. For experiment 2, the percent area of placentome perfusion was increased (P

Analysis of Drosophila melanogaster reproduction and preadult mortality after the influence of microwave radiation

A new type of anthropogenic impact – low-intensity electromagnetic radiation of extremely high frequencies (EHF EMR) demonstrates various genetic effects. The questions of the organism adaptive response formation to short-term exposure of EMR that depends on the individual’s genotype are of particular interest. The objective of this study was to analyze the reproductive ability and preadult mortality in Drosophila melanogaster with whiteapticot mutation after the influence of microwave radiation. We used D. melanogaster stocks that carry whiteapticot mutation, but differ in the genetic background on which this mutation is located: wa(C-S), wa(Or) and wa. Virgin flies were irradiated. The parameters of the external influence were power flux density W=10 μW/cm2, frequency F=65 GHz, exposure time t=5 minutes. The stages of embryo death, number of adult offspring, and mortality rate at the pupal stage were analyzed. The results of the study showed that the effect of electromagnetic radiation on virgin imagoes of Drosophila with an impaired tryptophan metabolism modifies the survival rate of the offspring at the preimaginal stages of ontogenesis. In the offspring of young flies (at the age of 3–8 days) the frequency of embryonic mortality decreases during the 0–5.5 hours period (initial stages of cleavage and blastoderm formation) and 5.5–17 hours period (stage of gastrulation and embryo segmentation, histogenesis) of embryogenesis. The total number of offspring at the adult stage does not differ from the control values; the mortality rate at the pupal stage also does not change in the offspring of young parents after exposure to EMR. An increase in the age of parental couples that were exposed to short-term EMR on the first day after eclosion from pupae (20–25 days aged) leads to a decrease in the embryonic mortality rate of offspring during the 17–22 hours of embryogenesis (organogenesis stage and larval exit from chorion). The total embryonic mortality rate is determined solely by the age of the parents. The strength of this factor for the stocks is h2wa=69.7 %, h2wa(C-S)=52.2 % and h2wa(Or)=64.9 % respectively. The impact of EMR affects the embryonic mortality rate only for the wa(Or) (h2EMR=18.3 %). External exposure does not change the number of imago offspring in individuals aged 0–5 days; the number of adult offspring increased by 1,2 times in individuals aged 20–25 days in the stock wa(C-S). A decrease in the number of dead individuals at the pupal stage in the descendants of 20–25-day-old parents after exposure to EMR EHF on average by three times was shown.

Evaluation of adult and offspring thiamine deficiency in salmonine species from Lake Ontario

Thiamine Deficiency Complex (TDC) is an ongoing problem impacting salmonine health in various waterbodies, including Lake Ontario. The prevalence of TDC has been variable and explanations for differences are limited. In the current study, thiamine concentrations were measured in eggs, liver tissue, and muscle tissue sampled from brown trout (Salmo trutta), Chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), lake trout (Salvelinus namaycush), and steelhead trout (O. mykiss) that were collected from Lake Ontario and its surrounding tributaries. The occurrence of TDC was measured for each species based on TDC-induced offspring mortality rates under laboratory conditions. TDC-induced offspring mortality was observed for all species except brown trout. For affected species, egg free thiamine (Th) was consistently low compared to lake trout collected from Lake Superior that are considered thiamine replete. In addition, species with the lowest percentages of Th in their eggs were the most susceptible to TDC, suggesting that limited thiamine reserves in the form of Th may cause TDC-induced offspring mortality. Lastly, our results show that egg thiamine concentrations have yearly variation and increased for all species throughout the study. Reasons for such variation are undetermined; but, if egg thiamine concentrations continue to increase, the impacts of TDC on these salmonine species may lessen. Future monitoring is needed for determining if thiamine concentrations are increasing and the potential impacts that may have on the entire Lake Ontario fishery.

Küçükbaş Hayvancılıkta Yavru Ölümlerinin Azaltılmasına Yönelik Barındırma ve Yetiştirme Uygulamaları

Küçükbaş hayvancılık işletmelerinin yıl boyunca yaptığı her türlü yatırım, doğum dönemindeki yatırımlar kadar etkili değildir. Koyun-keçi işletmelerinin ekonomik başarısı, büyük ölçüde hayvan başına sütten kesimdeki yavru sayısının arttırılması ve üretim giderlerinin azaltılmasına bağlıdır. Karlı ve sürdürülebilir küçükbaş hayvan yetiştiriciliği için öncelikle büyütme döneminde ortaya çıkan yavru ölümleri azaltmalıdır. Yavru ölümleri, işletmelerde uygulanan üretim sistemi ve barındırma yöntemine bağlı olarak da değişiklik göstermektedir. Bu ölümler, daha çok doğumu izleyen ilk on gün içinde gerçekleşmektedir. Belirtilen dönemde alınacak bazı önlemler yavruların yaşama gücüne önemli katkı sağlayacaktır. Bu nedenle entansif yetiştiricilik yapan küçükbaş hayvancılık işletmelerinde karlı bir üretim için yeni doğan yavruların barındırma, besleme ve sağlık koruma gibi uygulamalarının doğru yapılması gerekmektedir. Aksi taktirde küçükbaş hayvansal üretimin sürdürülebilir olması mümkün olmayacaktır. Bu makalede, entansif küçükbaş hayvancılık işletmelerinde yavru büyütme döneminde olması gereken yapısal ve teknik uygulamalar incelenerek, yavru ölümlerinin azaltılmasına yönelik öneriler sunulmuştur.

The Cavity-Nesting Bee Guild (Apoidea) in a Neotropical Sandy Coastal Plain

Some solitary bees establish their nests in preexisting cavities. Such nesting behavior facilitates the investigation of their life history, as well as the monitoring of their populations in natural, semi-natural and cropped habitats. This study aimed to evaluate the acceptance of artificial substrates by cavity-nesting bees in a heterogeneous landscape. We investigated the percentage of occupation of the different trap-nests, the monthly fluctuations in the nesting activity, offspring sex ratio, mortality and parasitism, in two phytophysiognomies: herbaceous-shrub restinga (site 1) and arboreal restinga (site 2). We used as trap-nests, bamboo canes, large and small straws of cardboard inserted into solid wooden blocks. Five bee species established 193 nests, from which 386 adults emerged. Centris tarsata Smith was the most abundant species. Large straws were signifi cantly more occupied than small straws (χ² = 19.951; df = 1; p < 0.0001). Offspring mortality rate for unknown reasons was signifi cant diff erent between sites, 11% (site 1) and 20% (site 2) (χ² = 4.203; df = 1; p = 0.04). The cavity-nesting bee guild had similar composition in both phytophysiognomies, there was a similar rate of occupation of trap-nests in both sites, as well as dominance of C. tarsata nests. Offspring mortality and parasites attack rates seem to be the more distinctive aspects between the herbaceous shrub and arboreal restinga sampled. Our study indicated that remnant fragments of coastal native habitats may be important nesting sites for the maintenance of bee populations, some of which have been indicated as candidates for management as pollinators of cultivated plants in Brazil.

RESISTÊNCIA À VERMINOSE E SUPLEMENTAÇÃO PROTEICA NO PERIPARTO: EFEITO NO PARASITISMO E NO DESEMPENHO REPRODUTIVO DE OVELHAS DO GRUPAMENTO RACIAL PANTANEIRO

Resumo Os objetivos do trabalho foram avaliar o efeito do grau de resistência à verminose e da suplementação proteica nos índices reprodutivos e no parasitismo em ovelhas do grupamento racial Pantaneiro. As ovelhas foram classificadas pelo número de ovos de nematodas por grama de fezes (OPG) como resistentes (RR), sensíveis (SS) e intermediárias (RS), e submetidas (SUPL) ou não (NSUPL) à suplementação durante o terço final da gestação e na lactação. Em dois ciclos reprodutivos, a cada 28 dias, as ovelhas foram pesadas e tratadas com anti-helmínticos quando o OPG apresentava-se ≥ 4000. O peso das ovelhas não foi influenciado pelo grau de resistência aos nematódeos e a suplementação teve efeito no peso somente no período em que foi ofertada. As taxas de natalidade e de desmame não foram influenciadas pelo grau de resistência e pela suplementação. A taxa de mortalidade de crias foi menor no grupo SUPL. A taxa de mortalidade de ovelhas foi três vezes mais elevada no grupo SS em relação ao grupo RR e o peso das crias foi menor no grupo SS em relação aos grupos RR e RS. Os três grupos mostraram picos no OPG durante o terço final da gestação, mas as médias foram sempre menores no grupo RR que, no geral, necessitaram 2,5 vezes menos tratamentos anti-helmínticos que as SS. A suplementação não apresentou correlação com o OPG e com o número de tratamentos anti-helmínticos. A classificação de ovelhas pelo OPG em resistentes aos nematodas proporcionou menor número de tratamentos anti-helmínticos, menor taxa de mortalidade de ovelhas e peso maior das crias ao nascimento.

Within- and trans-generational effects of herbivores and detritivores on plant performance and reproduction.

Mutualistic and antagonistic above-ground and below-ground species have the potential to be involved in strong interactions that can either weaken or strengthen their individual impacts on plants. Their impacts can also have delayed effects on a plant's progeny by altering offspring traits and survival. Few studies have explored the effect of herbivore and detritivore interactions with parent plants on offspring vital life-cycle processes, such as seedling emergence rate, seedling establishment and offspring survival. In the field, I experimentally studied the combined effects of floral herbivores (FH), root herbivores (RH) and detritivores on plant growth and reproduction of Moricandia moricandioides (Brassicaceae). In particular, I analysed the trans-generational effects of herbivores and detritivores on seed and juvenile production as well as on vital life-cycle processes (i.e. seedling emergence rates, survival). Floral herbivores strongly reduced the number of flowers, fruits, seeds and juveniles. Detritivores had an impact on plant success by increasing seed quality (% N and N : C ratio), although the effect was altered by the presence of floral and RH. I found maternal effects (trans-generational effects) of FH, RH and detritivores. Floral herbivores reduced seedling emergence and establishment. Floral and RH in combination reduced seedling emergence timing, but the effect was counteracted by detritivores. Detritivores also reduced the negative effect of FH on offspring mortality rate. This study shows that the impact of above-ground and below-ground organisms on M. moricandioides plants go beyond seed production and were evident in the probability of establishment and survival of the following generation. Trans-generational effects were induced by all three groups of interacting organisms and the net consequences for plant offspring depended on the organisms interacting with the plant.

Intra- and trans-generational effects of larval diet on susceptibility to an entomopathogenic fungus, Beauveria bassiana, in the greater wax moth, Galleria mellonella.

In addition to nutritional conditions experienced by individuals themselves, those experienced by their parents can affect their immune function. Here, we studied the intra- and trans-generational effects of larval diet on susceptibility to an entomopathogenic fungus, Beauveria bassiana, in the greater wax moth, Galleria mellonella. In the first part of the study, a split-brood design was used to compare the susceptibility of full sibs raised either on low- or on high-nutrition larval diet. In the second part of the study, a similar experimental design was employed to investigate the effects of maternal and paternal diet as well as their interaction on offspring's susceptibility. In the first part of the study, we found that individuals fed with high-nutrition diet had higher mortality from infection than individuals fed with low-nutrition diet. However, diet did not affect post-infection survival time. Conversely, in the second part of the study, maternal diet was found to have no significant effect on final mortality rate of offspring, but it affected survival time: larvae with high-nutrition maternal diet survived fewer days after infection than larvae with low-nutrition maternal diet. Paternal diet had no significant effect on offspring's susceptibility to the fungus, indicating that paternal effects are not as important as maternal effects in influencing immune function in this species. Our findings provide further indication that maternal nutrition affects immune function in insects, and suggest that the direct effects of nutrition on immunity may be different, yet parallel, to those caused by parental nutrition.

Impact of maternal death from female cancers on child mortality.

6591 Background: Cervical and breast cancers are the most common causes of cancer mortality in women of childbearing age. The impact of maternal mortality on child mortality remains an under-investigated area. Elevated mortality rates in offspring are significantly associated with maternal death in both Bangladeshi and Scandinavian cohorts (Ronsmans 2010, Li 2014). This effect is contextual: when a mother dies, a child in Bangladesh is 10 times more likely to die before 10, versus 1.5 times more for a Scandinavian child. By ignoring this impact disease mortality rates underrepresent life lost, and this underestimation affects appropriate resource allocation. We propose a country-specific model to allow for estimates of offspring death rates attributable to breast and cervical cancers in women of childbearing age. Methods: A Monte Carlo simulation model (TreeAge) analyzed a sample population of 1 million 15yo fertile girls of a specific nationality and at risk of dying from cervical and breast cancer. Info...

Effects of Subcutaneous LPS Injection on Gestational Length and Intrauterine and Neonatal Mortality in Mice

Background: Infection during pregnancy can predispose offspring to develop various psychiatric disorders such as depression in later life. In order to investigate the potential mechanisms underlying these associations, animal models of maternal infection have been employed. As such, lipopolysaccharide (LPS) has been commonly used to mimic a bacterial infection in pregnant mice. Objective: The original aim of our study was to investigate the effects of different doses of subcutaneous LPS administration on affective behavior in adult mouse offspring. In the present paper, however, we report that subcutaneous LPS administration has a profound impact on gestational length, litter size, and perinatal mortality in the offspring, even at a relatively low dose. Methods: Pregnant mice were randomly divided into 3 groups, receiving either a high (2 mg/kg) or a low (0.5 mg/kg) dose of LPS or phosphate-buffered saline by means of subcutaneous injection. Subsequently, the effects on gestational length, litter size, and perinatal mortality in the offspring were assessed. Results: After subcutaneous injection with a high dose of LPS, we observed a significant decrease in gestational length and an increase in neonatal mortality. When the low dose was administered, a tendency towards a reduced litter size was observed, most likely reflecting increased intrauterine mortality in response to prenatal maternal LPS exposure. Conclusions: We showed that subcutaneous administration of 2 mg/kg LPS to pregnant mice in the last phase of gestation should be avoided because of high offspring mortality rates, whereas subcutaneous injection of 0.5 mg/kg LPS seems to result in reabsorption of the fetuses.

Pregnancy during breast cancer: does a mother’s parity status modify an offspring’s mortality risk?

To assess whether children born to primiparous women around the time of a breast cancer diagnosis have an increased mortality risk. From the merged Swedish Multi-Generation and Cancer Registers, we identified 49,750 eligible children whose mother was diagnosed with breast cancer between 1958 and 2010. Mortality rates in offspring were compared to the background population using standardized mortality ratios (SMR), adjusted for calendar year of birth, attained age, and sex, and calculated for each category of timing of delivery (before, around, or after mother's diagnosis) and mother's parity status. Hazard ratios were assessed using a Cox proportional hazards model and adjusted for socioeconomic status, year of birth and mother's age at birth. Children born to a primiparous woman around a breast cancer diagnosis had a mortality rate five times greater than the background population (SMR 5.26, 95 % CI 1.93-11.5), whereas children born to a multiparous woman had a twofold increase (SMR 2.40, 95 % CI 1.10-4.55). Children of primiparous women born around diagnosis had an adjusted hazard ratio fourfold to that of children of primiparous women born before their mother's diagnosis (HR 4.29, 95 % CI 1.68-8.91), whereas hazard ratios for children of primiparous or multiparous women born at other times were not statistically significant. Children born to primiparous women around a breast cancer diagnosis have an increased relative mortality risk. Although relative risk is increased, in absolute terms children born from a cancer complicated pregnancy do relatively well. Additional investigations are needed to elucidate the reason(s) underlying this observation before the information can be used to inform patient counseling and clinical care.

A Conceptual Framework for Clutch-Size Evolution in Songbirds

Causes of evolved differences in clutch size among songbird species remain debated. I propose a new conceptual framework that integrates aspects of traditional life-history theory while including novel elements to explain evolution of clutch size among songbirds. I review evidence that selection by nest predation on length of time that offspring develop in the nest creates a gradient in offspring characteristics at nest leaving (fledging), including flight mobility, spatial dispersion, and self-feeding rate. I postulate that this gradient has consequences for offspring mortality rates and parental energy expenditure per offspring. These consequences then determine how reproductive effort is partitioned among offspring, while reproductive effort evolves from age-specific mortality effects. Using data from a long-term site in Arizona, as well as from the literature, I provide support for hypothesized relationships. Nestling development period consistently explains fledgling mortality, energy expenditure per offspring, and clutch size while accounting for reproductive effort (i.e., total energy expenditure) to thereby support the framework. Tests in this article are not definitive, but they document previously unrecognized relationships and address diverse traits (developmental strategies, parental care strategies, energy requirements per offspring, evolution of reproductive effort, clutch size) that justify further investigations of hypotheses proposed here.

Contrasting predation rates on planktotrophic and lecithotrophic propagules by marine benthic invertebrates

When modeling life-history evolution of marine benthic invertebrates, it has been common to assume constant mortality rate of offspring during the pre-settlement phase and greater propagule vulnerability in the pelagic than in the benthic habitat. However, recent findings have challenged these assumptions, emphasizing the need for further empirical tests. Here we present the results of a multifactorial experimental investigation of predation rates on propagules of various taxa by benthic invertebrates. Planktotrophic and lecithotrophic propagules of echinoderms, cnidarians and annelids (i.e. sea cucumbers, sea stars, sea urchins, corals, sea anemones, jellyfishes, and polychaetes) were tested at various stages of development to examine the effects of ontogeny, size and behavior on predation rates by common filter feeders (mussels, tunicates) and suspension feeders (sea anemones). Overall, propagule survival was positively correlated with their size, although on closer inspection this was essentially due to the size difference between developmental modes (larger lecithotrophic propagules being less vulnerable). A slight inverse relationship between survival and age was detected in both lecithotrophic and planktotrophic propagules; however ingestion rates were not systematically higher on more advanced life stages within prey species due to predator-specific responses to ontogenetic changes. Filter feeders were generally more effective predators than suspension feeders. Tunicates expressed greater selectivity based on size and age of propagules than on their behavior, while the inverse occurred in the two other predators. A combination of factors, i.e. size, buoyancy and chemical defenses, presumably underlie overall higher survival rates in lecithotrophic than in planktotrophic propagules, supporting the hypothesis that the former but not the latter may have evolved due to increased epibenthic predation.