Female Progeny Research Articles

Effect of honeybee products, as food supplements, on the biological activities of three Trichogramma species (Hymenoptera: Trichogrammatidae)

Egg parasitoids play a significant role in biological control for lepidopteran insects, where they kill the eggs (the first stage of the developmental cycle). Trichogramma species are the very important ones of these egg parasitoids. Under natural conditions, adult Trichogramma species are known to feed upon nectar, pollen, and honeydew. Here, the effects of four honey bee products; honey, pollen grains, royal jelly, propolis, their mixtures, and sugar solution, as food supplements, on longevity, fecundity, emergence rate, and sex ratio on different Trichogramma species were evaluated. Three species, Trichogramma evanescens, T. bourarachae, and T. cacoeciae, differed in their responses to the tested diets. In general, all diets containing honey improved longevity and fecundity. Honey + royal jelly and honey + propolis were the most diets improved the longevity of T. evanescens. Honey + royal jelly + propolis and honey alone resulted in the longest lifetime for T. bourarachae. While the best diets that prolonged the longevity of T. cacoeciae were honey + royal jelly and honey alone. The highest fecundity was obtained by honey + royal jelly + propolis, honey + royal jelly, honey alone and honey + pollen grains + royal jelly for T. evanescens, honey + royal jelly + propolis, honey + pollen grains + propolis, and honey + pollen grains + royal jelly + propolis for T. bourarachae, and by honey + royal jelly, and honey alone in case of T. cacoeciae. The emergence rate had not affected by most of the treatments for three Trichogramma species. Food supplements caused an indirect effect on sex ratio of T. evanescens and T. bourarachae, whereas long-lived females were male-biased progeny. Except when T. evanescens females were fed on honey + royal jelly and T. bourarachae on honey + royal jelly, and honey + pollen grains + royal jelly, they lived for a long time but that did not decrease the female progeny percentage. Thus, providing a suitable diet may help to enhance the biological activities for the rearing parasitoids.

Sex-Ratio Meiotic Drive Shapes the Evolution of the Y Chromosome in Drosophila simulans.

The recent emergence and spread of X-linked segregation distorters-called "Paris" system-in the worldwide species Drosophila simulans has elicited the selection of drive-resistant Y chromosomes. Here, we investigate the evolutionary history of 386 Y chromosomes originating from 29 population samples collected over a period of 20 years, showing a wide continuum of phenotypes when tested against the Paris distorters, from high sensitivity to complete resistance (males sire ∼95% to ∼40% female progeny). Analyzing around 13 kb of Y-linked gene sequences in a representative subset of nine Y chromosomes, we identified only three polymorphic sites resulting in three haplotypes. Remarkably, one of the haplotypes is associated with resistance. This haplotype is fixed in all samples from Sub-Saharan Africa, the region of origin of the drivers. Exceptionally, with the spread of the drivers in Egypt and Morocco, we were able to record the replacement of the sensitive lineage by the resistant haplotype in real time, within only a few years. In addition, we performed in situ hybridization, using satellite DNA probes, on a subset of 21 Y chromosomes from six locations. In contrast to the low molecular polymorphism, this revealed extensive structural variation suggestive of rapid evolution, either neutral or adaptive. Moreover, our results show that intragenomic conflicts can drive astonishingly rapid replacement of Y chromosomes and suggest that the emergence of Paris segregation distorters in East Africa occurred less than half a century ago.

Preconception maternal cocaine self-administration increases the reinforcing efficacy of cocaine in male offspring.

Although the influence of gestational cocaine exposure on offspring has been the focus of a sustained research effort, the effect of preconception cocaine self-administration by dams on progeny has received far less attention. In the current study, adult female rats were allowed to self-administer cocaine 2h a day for 60days and then after a 10-day wash out period, bred to naïve males. Maternal behavior was measured in dams until weaning. When male and female progeny reached adulthood, anxiety-like behavior, memory, and cocaine self-administration were assessed in separate cohorts of rats. Despite a total of at least 30days of cocaine abstinence, the quality of maternal behaviors was negatively affected by previous cocaine exposure as reflected by less time spent with pups as well as an excess of other maladaptive maternal behaviors. Measures of anxiety-like behavior and memory were not affected by maternal cocaine intake in either male or female offspring. In contrast, male, but not female, the progeny of dams exposed to cocaine showed increased reinforcing efficacy of cocaine as measured by cocaine self-administration under a progressive ratio schedule. The fact that cocaine self-administration was influenced only in the male offspring of cocaine-exposed dams argues against this phenotype being linked to altered maternal behavior, although this possibility cannot be ruled out completely. Collectively, these results indicate that preconception cocaine self-administration by dams results in the relatively selective enhancement of cocaine addiction-like behavior in male offspring.

Validation of Gender Specific CAPS Marker in Turkish Fig (Ficus carica L.) Collection and F1 Progenies

In most dioecious plants, distinguishing male and female progenies is not possible until flowering or fruiting stage. The fig (Ficus carica L.) is such a plant where distinguishing male and female plants at the seedling stage can accelerate fig-breeding programs. An orthologue of RAN1 loci was reported to be associated with sex determination in fig (Mori et al., 2017). The objective of this study is to validate this locus on Turkish fig germplasm collection and F1 population obtained from a cross between female genotypes ‘Bursa Siyahi’ and male genotype ‘Ak Ilek’. A total of 144 genotypes from germplasm collection and 115 F1 individuals were tested with CAPS (cleaved amplified polymorphic sequences) marker following the Mori et al. (2017). The loci produced a 315bp amplification product from all genotypes. PciI digestion of PCR products resulted in 100% concordance between phenotypes and molecular tests. On the other hand, HpyCH4IV enzyme digestion of 8 female genotypes resulted in false negatives among the tested materials. Therefore, despite overall results show that the locus is suitable for gender selection of plants at the seedling stage in the breeding programs, care should be taken when HpyCH4IV enzyme is to be employed for CAPS assay.
 
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 In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue.
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Cigarette smoke during lactation in rat female progeny: Late effects on endocannabinoid and dopaminergic systems

AimsMaternal smoking is considered a risk factor for childhood obesity. In a rat model of tobacco exposure during breastfeeding, we previously reported hyperphagia, overweight, increased visceral fat and hyperleptinemia in adult female offspring. Obesity and eating disorders are associated with impairment in the endocannabinoid (EC) and dopaminergic (DA) systems. Considering that women are prone to eating disorders, we hypothesize that adult female Wistar rats that were exposed to cigarette smoke (CS) during the suckling period would develop EC and DA systems deregulation, possibly explaining the eating disorder in this model. Material and methodsTo mimic maternal smoking, from postnatal day 3 to 21, dams and offspring were exposed to a smoking machine, 4×/day/1 h (CS group). Control animals were exposed to ambient air. Offspring were evaluated at 26 weeks of age. Key findingsConcerning the EC system, the CS group had increased expression of diacylglycerol lipase (DAGL) in the lateral hypothalamus (LH) and decreased in the liver. In the visceral adipose tissue, the EC receptor (CB1r) was decreased. Regarding the DA system, the CS group showed higher dopamine transporter (DAT) protein expression in the prefrontal cortex (PFC) and lower DA receptor (D2r) in the arcuate nucleus (ARC). We also assessed the hypothalamic leptin signaling, which was shown to be unchanged. CS offspring showed decreased plasma 17β-estradiol. SignificanceNeonatal CS exposure induces changes in some biomarkers of the EC and DA systems, which can partially explain the hyperphagia observed in female rats.

Exclusion of two microsatellite markers in the sex-linkage study of Nile tilapia (Oreochromis niloticus L.)

Monosex Nile tilapia (Oreochromis niloticus) is highly preferred in semi-intensive and intensive culture systems to prevent uncontrolled reproduction and to obtain fast growing male. Production of all male tilapia is being practiced by the hatcheries of Bangladesh mainly by administering androgen hormones (particularly 17-α-methyl-testosterone) with feed in a mixture of undifferentiated fry for about a month. The direct application of hormone to such food chain often arises question in respect to public health and safety. The alternative to this is the production of putative supermales, a rather safe but longer procedure to obtain all male progeny. However, sex determination system in tilapia is fairly complex. Recent developments have resulted in a linkage map and genetic markers that can be used to analyze the sex determination system. For genetic analysis of different genotypes of fish, microsatellite DNA marker ARO120 and ARO121 were used for studying the inheritance pattern for possible sex linkage using Polyacrylamide gel electrophoresis. In case of ARO120, it was observed that the Dam XX was heterozygous; 11 out of 22 female progeny and 10 out of 22 male progeny were found to be heterozygous. In case of ARO121, it was observed that the Dam XX was heterozygous; 16 out of 22 female progeny and 20 out of 22 male progeny were found to be heterozygous. Though the marker polymorphisms were observed in this study, these were excluded from the sexlinkage study due to limited extent of information as sex-linked markers in Nile tilapia BFRI strain. This study provides a baseline for further research using other suitable polymorphic markers for assisting marker-assisted selection.
 Res. Agric., Livest. Fish.6(1): 143-151, April 2019

The frequency of thelytokous parthenogenesis in European-derived Apis mellifera virgin queens

Thelytokous parthenogenesis is the asexual production of female progeny. In the honey bee, Apis mellifera, thelytoky is unknown from mated queens, but can occur in virgin queens that have been induced to lay. We used microsatellite markers to quantify theltyoky in virgin A. mellifera queens of European origin that were sham inseminated with saline and/or narcotised with carbon dioxide. Of 20 queens, 17 (85%) produced at least one daughter thelytokously during an 8-week period. One exceptional queen produced 19% thelytokous progeny, though few total offspring (20 daughters in 107 pupae). The average proportion of thelytokous progeny among the remaining queens was 0.9% (range 0–3.5%), with the balance being males. These results are consistent with observations from the pre-molecular biology era that virgin honey bee queens of non-African subspecies regularly produce thelytokous offspring at low frequency and indicate that there is significant natural variation in the capacity for thelytoky among these queens.

Specific Interactions Between Autosome and X Chromosomes Cause Hybrid Male Sterility in Caenorhabditis Species.

Hybrid male progeny from interspecies crosses are more prone to sterility or inviability than hybrid female progeny, and the male sterility and inviability often demonstrate parent-of-origin asymmetry. However, the underlying genetic mechanism of asymmetric sterility or inviability remains elusive. We previously established a genome-wide hybrid incompatibility (HI) landscape between Caenorhabditis briggsae and C. nigoni by phenotyping a large collection of C. nigoni strains each carrying a C. briggsae introgression. In this study, we systematically dissect the genetic mechanism of asymmetric sterility and inviability in both hybrid male and female progeny between the two species. Specifically, we performed reciprocal crosses between C. briggsae and different C. nigoni strains that each carry a GFP-labeled C. briggsae genomic fragment referred to as introgression, and scored the HI phenotypes in the F1 progeny. The aggregated introgressions cover 94.6% of the C. briggsae genome, including 100% of the X chromosome. Surprisingly, we observed that two C. briggsaeX fragments that produce C. nigoni male sterility as an introgression rescued hybrid F1 sterility in males fathered by C. briggsae Subsequent backcrossing analyses indicated that a specific interaction between the X-linked interaction and one autosome introgression is required to rescue the hybrid male sterility. In addition, we identified another two C. briggsae genomic intervals on chromosomes II and IV that can rescue the inviability, but not the sterility, of hybrid F1 males fathered by C. nigoni, suggesting the involvement of differential epistatic interactions in the asymmetric hybrid male fertility and inviability. Importantly, backcrossing of the rescued sterile males with C. nigoni led to the isolation of a 1.1-Mb genomic interval that specifically interacts with an X-linked introgression, which is essential for hybrid male fertility. We further identified three C. briggsae genomic intervals on chromosome I, II, and III that produced inviability in all F1 progeny, dependent on or independent of the parent-of-origin. Taken together, we identified multiple independent interacting loci that are responsible for asymmetric hybrid male and female sterility, and inviability, which lays a foundation for their molecular characterization.

Characterization of a non-sexual population of Strongyloides stercoralis with hybrid 18S rDNA haplotypes in Guangxi, Southern China.

Strongyloidiasis is a much-neglected but sometimes fatal soil born helminthiasis. The causing agent, the small intestinal parasitic nematode Strongyloides stercoralis can reproduce sexually through the indirect/heterogonic life cycle, or asexually through the auto-infective or the direct/homogonic life cycles. Usually, among the progeny of the parasitic females both, parthenogenetic parasitic (females only) and sexual free-living (females and males) individuals, are present simultaneously. We isolated S. stercoralis from people living in a village with a high incidence of parasitic helminths, in particular liver flukes (Clonorchis sinensis) and hookworms, in the southern Chinese province Guangxi. We determined nuclear and mitochondrial DNA sequences of individual S. stercoralis isolated from this village and from close by hospitals and we compared these S. stercoralis among themselves and with selected published S. stercoralis from other geographic locations. For comparison, we also analyzed the hookworms present in the same location. We found that, compared to earlier studies of S. stercoralis populations in South East Asia, all S. stercoralis sampled in our study area were very closely related, suggesting a recent common source of infection for all patients. In contrast, the hookworms from the same location, while all belonging to the species Necator americanus, showed rather extensive genetic diversity even within host individuals. Different from earlier studies conducted in other geographic locations, almost all S. stercoralis in this study appeared heterozygous for different sequence variants of the 18S rDNA hypervariable regions (HVR) I and IV. In contrast to earlier investigations, except for three males, all S. stercoralis we isolated in this study were infective larvae, suggesting that the sampled population reproduces predominantly, if not exclusively through the clonal life cycles. Consistently, whole genome sequencing of individual worms revealed higher heterozygosity than reported earlier for likely sexual populations of S. stercoralis. Elevated heterozygosity is frequently associated with asexual clonal reproduction.

Reproduction and Offspring Sex Ratios Differ Markedly among Closely Related Hyperparasitoids Living in the Same Microhabitats

Closely related species in nature usually exhibit very similar phylogenetically conserved traits, such as reproduction, behavior and development. Here, we compared fecundity schedules, lifetime reproductive success and offspring sex ratios in three congeneric facultative hyperparasitoid wasps that exhibit several overlapping traits and which co-occur in the same small-scale habitats. Gelis agilis, G. proximus and G. hortensis are abundant in meadows and forest edge habitats in the Netherlands. Gelis agilis is asexual (all female), whereas the other two species reproduce sexually. Here they developed on cocoons of the primary parasitoid Cotesia glomerata. When provided with unlimited hosts, lifetime reproductive success was three times higher in G. proximus than in G. agilis with G. hortensis producing intermediate numbers of offspring. All three species depleted their teneral reserves during their lives. Females of G. proximus and G. hortensis lived significantly longer than females of G. agilis. Offspring sex ratios in young G. proximus mothers were female-biased and marginally male-biased in G. hortensis. As mothers aged, however, the ratio of male:female progeny produced rapidly increased until no daughters emerged later in life. Our results reveal significant differences in reproductive traits among the three species despite them co-occurring in the same microhabitats, being very closely related and morphologically similar. The increase in the production of male progeny by Gelis mothers over time suggests a depletion in sperm number or viability with age. This is especially interesting, given that Gelis species are among the least fecund parasitoids thus far studied. It is likely that in the field most Gelis mothers are probably only able to parasitize a few hosts and to maintain the production of female offspring.

Molecular evidence for recent divergence of X- and Y-linked gene pairs in Spinacia oleracea L.

Dioecy has evolved recently and independently from cosexual populations in many angiosperm lineages, providing opportunities to understand the evolutionary process underlying this transition. Spinach (Spinacia oleracea) is a dioecious plant with homomorphic sex chromosomes (XY). Although most of the spinach Y chromosome recombines with the X chromosome, a region around the male-determining locus on Y does not recombine with its X counterpart, suggesting that this region might be related to the evolution of dioecy in the species. To identify genes located in the non-recombining region (MSY, male-specific region of Y), RNA-seq analysis of male and female progeny plants (eight each) from a sib-cross of a dioecious line was performed. We discovered only 354 sex-chromosomal SNPs in 219 transcript sequences (genes). We randomly selected 39 sex-chromosomal genes to examine the reproducibility of the RNA-seq results and observed tight linkage to the male-determining locus in a spinach segregating population (140 individuals). Further analysis using a large-scale population (>1400) and over 100 spinach germplasm accessions and cultivars showed that SNPs in at least 12 genes are fully linked to the male-determining locus, suggesting that the genes reside in the spinach MSY. Synonymous substitution rates of the MSY genes and X homologues predict a recent divergence (0.40 ± 0.08 Mya). Furthermore, synonymous divergence between spinach and its wild relative (S. tetrandra), whose sex chromosomes (XY) originated from a common ancestral chromosome, predicted that the species diverged around 5.7 Mya. Assuming that dioecy in Spinacia evolved before speciation within the genus and has a monophyletic origin, our data suggest that recombination around the spinach sex-determining locus might have stopped significantly later than the evolution of dioecy in Spinacia.

Regional variation in life history traits and plastic responses to temperature of the major malaria vector Nyssorhynchus darlingi in Brazil

The primary Brazilian malaria vector, Nyssorhynchus darlingi (formerly Anopheles darlingi), ranges from 0°S–23°S across three biomes (Amazonia, Cerrado, Mata Atlântica). Rising temperatures will increase mosquito developmental rates, and models predict future malaria transmission by Ny. darlingi in Brazil will shift southward. We reared F1Ny. darlingi (progeny of field-collected females from 4 state populations across Brazil) at three temperatures (20, 24, 28 °C) and measured key life-history traits. Our results reveal geographic variation due to both genetic differences among localities and plastic responses to temperature differences. Temperature significantly altered all traits: faster larval development, shorter adult life and overall lifespan, and smaller body sizes were seen at 28 °C versus 20 °C. Low-latitude Amazonia mosquitoes had the fastest larval development at all temperatures, but at 28 °C, average development rate of high-latitude Mata Atlântica mosquitoes was accelerated and equivalent to low-latitude Amazonia. Body size of adult mosquitoes from the Mata Atlântica remained larger at all temperatures. We detected genetic variation in the plastic responses among mosquitoes from different localities, with implications for malaria transmission under climate change. Faster development combined with larger body size, without a tradeoff in adult longevity, suggests vectorial capacities of some Mata Atlântica populations may significantly increase under warming climates.

Different Oxytocin Responses to Acute Methamphetamine Treatment in Juvenile Female Rats Perinatally Exposed to Stress and/or Methamphetamine Administration.

Methamphetamine (MA) is an addictive psychostimulant, often abused by drug-addicted women during pregnancy. The offspring of drug-addicted mothers are often exposed to perinatal stressors. The present study examines the effect of perinatal stressors and drug exposure on plasma oxytocin (OXY) levels in female progeny. Rat mothers were divided into three groups according to drug treatment during pregnancy: intact controls (C); saline (SA, s.c., 1 ml/kg); and MA (s.c., 5 mg/kg). Litters were divided into four groups according to postnatal stressors lasting from PD1 to 21: non-stressed controls (N); maternal separation (S); maternal cold-water stress (W); and maternal separation plus cold-water stress (SW). On postnatal day 30, acute MA or SA was administrated 1 h before the rats were sacrificed. Trunk blood was collected and plasma OXY was measured by specific ELISA after extraction. Our results showed that acute MA administration significantly increases plasma OXY levels in juvenile female rats; this effect was observed in prenatally intact rats only. Prenatal exposure of rats to mild stressor of daily SA injection prevented both acute MA-induced OXY stimulation and also stress-induced OXY inhibition. Although postnatal MA and stress exposure exert opposite effects on OXY release in juvenile rats, our data point out the modulatory role of prenatal mild stress in OXY response to postnatal stressors or MA treatment.

Development and reproduction of Brevipalpus yothersi on orange fruits infected with Citrus leprosis virus C

ABSTRACTPlant-pathogenic viruses cause physiological and biochemical changes in the host plant as well as direct and indirect effects on the biology and behaviour of the vector. Brevipalpus yothersi Baker is considered the main vector of Citrus leprosis virus C (CiLV-C). Under laboratory conditions, we studied the effect of feeding on CiLV-C-infected oranges compared with virus-free oranges, on the duration of the life cycle of B. yothersi and the longevity and fecundity of adult female progeny. Life table parameters were estimated and compared between both populations. No virus was detected in virus-free treatments, while the virus was always detected in mites feeding on virus-infected fruit; this was confirmed by RT-PCR analysis. The duration of the developmental stages of B. yothersi was similar between both mite populations, and no differences in the longevity and fecundity of adult female progeny was observed. In the life table analysis R0 (net reproductive rate), DT (doubling time), λ (finite rate of increase) and Rm (intrinsic rate of increase) had lower values for mites feeding on virus-infected oranges than for mites feeding on uninfected oranges. In contrast, no differences were found in the mean generation time (MGT). Our results suggest an overall reduction in reproductive potential for mite’s feeding on virus-infected oranges.

Effects of photoperiod and light intensity on wing dimorphism and development in the parasitoid Sclerodermus pupariae (Hymenoptera: Bethylidae)

Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae), a newly described ectoparasitoid, has been used as a biocontrol agent against several buprestid and cerambycid pests in China. Both winged and wingless female morphs of S. pupariae can find and parasitize hosts; however, winged parasitoids can disperse faster and further to new habitats and thus are more adapted to spatial and temporal changes in host densities than wingless morphs. In the present study, we determined the effects of photoperiod and associated light intensity on the parasitoid development time from egg to adult, the proportion of winged females, fecundity, and progeny sex ratio. Significantly more winged female parasitoid progeny were produced with long-day photoperiods and high light intensity compared to short day-photoperiods and low light intensity treatments. Photoperiod alone (regardless of light intensity) has significant impact on developmental time of parasitoid progeny. Light intensity, interacted with photoperiod, significantly affected the degree of phenotypic partitioning and development time, but light intensity and photoperiod did not significantly influence the parasitoid fecundity and sex ratio. These results are relevant to laboratory rearing of S. pupariae when the optimal light conditions are needed to produce winged female parasitoids.

Wolbachia induce cytoplasmic incompatibility and affect mate preference in Habrobracon hebetor to increase the chance of its transmission to the next generation.

Wolbachia are common intracellular bacteria that are generally found in arthropods, including a high proportion of insects and also some nematodes. This intracellular symbiont can affect sex ratio with a variety of reproductive anomalies in the host, including cytoplasmic incompatibility (CI) in haplodiploids. In this study, we questioned if the parasitoid wasp, Habrobracon hebetor (Hym.: Braconidae), an important biological control agent of many lepidopteran larvae, is infected with Wolbachia. To test this, DNA was extracted from adult insects and subjected to PCR using specific primers to Wolbachia target genes. The results showed a high rate of Wolbachia infection in this parasitoid wasp. To determine the biological function of Wolbachia in H. hebetor, we removed this bacterium from the wasps using antibiotic treatment (cured wasps). Results of crossing experiments revealed that Wolbachia induced CI in H. hebetor in which cured females crossed with infected males produced only males, while both male and female progeny were observed for other crosses. Also, we showed that the presence of Wolbachia in females increased fecundity and female offspring of this parasitoid wasp. The presence of Wolbachia in the males had no significant effect on fecundity and female production, but might have incurred costs. We also investigated the effect of Wolbachia on mate choice and found that Wolbachia affects mating behavior of H. hebetor. Together, we showed that Wolbachia induces CI in H. hebetor and affects host mating behavior in favor of its transmission. Wolbachia utilize these strategies to increase the frequency of infected females in the host population.

Effects of sublethal fumigation with phosphine on the reproductive capacity of Liposcelis entomophila (End.) (Psocoptera: Liposcelididae)

The goal of our study was to determine if phosphine exposure changed the fecundity of the surviving Liposcelis entomophila, and the fitness of resulting offspring. Two strains of L. entomophila, were tested. One (F0) that had not been exposed to phosphine in the laboratory, and a second (F4) that had been exposed to the LC50 dose of phosphine for 4 successive generations. The daily egg production, rate of growth, hatching rate, sex ratio, and adult emergence rate were measured after exposures to phosphine at the LC20 and LC50 doses. LC20 fumigation did not affect peak oviposition and fumigation at LC50 dose delayed peak oviposition peak in F0. Females fumigated at LC20 dose had higher fecundity in the first oviposition peaks from 3rd day. The accumulated egg production of F4 fumigated at LC20 and LC50 was significantly higher than that of F0 in the first and second weeks. All the results indicated that long term fumigation with sublethal LC20 could stimulate the surviving females to lay more eggs. Fumigation at LC50 dose could inhibit female fecundity and progeny population growth. The results suggested that long-term fumigation with LC20 could induce strong population growth and lead to L. entomophila infestations.

Prenatal stress decreases sperm quality, mature follicles and fertility in rats

ABSTRACTPrenatal stress disrupts reproductive function in females and males. These alterations have primarily been related to maternal corticosteroid fetal programming due to the stress response, affecting the fetus and causing long-lasting effects. The aim of this study was to investigate the influence of prenatal stress on male and female fertility. Dams were exposed to stress by immersion in cold water twice a day for the last week of gestation (days 15–21). In the adulthood, sperm quality, mature follicles, sexual hormones and fertility were assessed in female and male progeny. The results in prenatally stressed females showed lower body weight, longer estrous cycles, lower estradiol and progesterone, and lower number of pups. In prenatally stressed males, lower body weight, increased testicular cell death, as well as decreased testosterone levels, sperm quality, and fertility were observed. Aside from these effects, corticosterone levels in prenatally stressed males and females increased. These results show that prenatal stress can markedly influence infertility in adult female and male progeny.Abbreviations: 3β-HSD: 3β hydroxysteroid dehydrogenase; CRH: corticotropin releasing hormone; DEX: dexamethasone; ERα: estrogen receptor alpha; H-E: hematoxylin-eosine; HPA: hypothalamus-pituitary-adrenal; KISS: Kisspeptin; ORW: ovarian relative weight; PBS: phosphates; PS: prenatally stressed; PRW: prostatic relative weight; ROS: reactive oxygen species; SRW: seminal relative weight; TdT: terminal deoxynucleotidyl transferase; TUNEL: terminal deoxynucleotidyl transferase dUTP Nick-end labelling; TRW: testicular relative weight; URW: uterine relative weight

Transgenerational Effects of Periconception Heavy Metal Administration on Adipose Weight and Glucose Homeostasis in Mice at Maturity.

We previously demonstrated that periconception maternal administration (2 mg/kg body weight each) of cadmium chloride (CdCl2) plus methylmercury (II) chloride (CH3HgCl) impaired glucose homeostasis and increased body weights and abdominal adipose tissue weight of male offspring in the F1 generation. However, transgenerational effects of this exposure have not been studied. Therefore, the effects of periconception Cd+Hg administration on indices of chronic diseases at adulthood in F2-F4 generations were examined. Male and female progeny of Cd+Hg periconceptionally treated females, and offspring of vehicle control females were bred with naïve CD1 mice to obtain F2 offspring, with additional crosses as above to the F4 generation (F1-F4 animals were not administered Cd+Hg). Birth weights and litter size were similar in all generations. Indices of impaired glucose homeostasis were observed in matrilineally descended F2 male offspring, including reduced glucose tolerance, along with increased basal phosphorylation of insulin receptor substrate 1 (IRS1) at serine 307 suggesting altered insulin signaling. Reduced glucose tolerance was also seen in F4 males. Increased body weight and/or abdominal adiposity were observed through the F4 generation in males descended matrilineally from the treated female progenitors. Patrilineally derived F2 females displayed reduced glucose tolerance. Females (F2) patrilineally and matrilineally derived displayed significant kidney enlargement. Periconception administration of cadmium and mercury caused persistent transgenerational effects in offspring through the F4 generation in the absence of continued toxicant exposure, with persistent transgenerational effects inherited specifically through the matrilineal germline.

Mate choice in the parasitoid Lysiphlebus fabarum is conditioned by host species and influences progeny fitness

We used the aphid parasitoid wasp, Lysiphlebus fabarum (Hymenoptera: Braconidae) reared on host aphids Aphis fabae (Hemiptera: Aphididae) and Aphis gossypii to examine whether or not mating preference can be conditioned by the host species on which the wasps were reared. The effect of the parental hosts on the fitness of the progeny was also examined. The results revealed that male and female wasps reared on one host species preferred each other as mates than those individuals reared on a different species. This was demonstrated by counting the number of mating successes and the olfactory response of males to the odor of females that developed in Aphis fabae or A. gossypii. The results also revealed that conditional mate choice mediated by a host species increased the fitness of the female progeny (i.e. larger bodies, shorter developmental time and higher egg load with larger eggs), and led to a higher female sex ratio. Because the particular host species confers fitness on the developed wasps, the fitness traits appear in the progeny when both parents are reared on one host species, but not in the progeny of two parents reared on different host species.