Total Number Of Offspring Research Articles

Bracon wasps for ecological pest control-a laboratory experiment.

Biological control of pest insects by natural enemies may be an effective, cheap and environmentally friendly alternative to synthetic pesticides. The cosmopolitan parasitoid wasp species Bracon brevicornis Wesmael and B. hebetor Say (Hymenoptera: Braconidae) use lepidopteran species as hosts, including insect pests like Ephestia kuehniella or Ostrinia nubilalis. Here, we compare the reproductive success of both Bracon species on E. kuehniella in a laboratory experiment. We asked (1) how the reproductive success on a single host larva changes with temperature, (2) how it changes with temperature when more host larvae are present and (3) how temperature and availability of host larvae influence the efficacy of Bracon species as biological control agents. In general, differences between B. brevicornis and B. hebetor have been small. For rearing both Bracon species in the laboratory on one host larva, a temperature between 20–27 °C seems appropriate to obtain the highest number of offspring with a female-biased sex ratio. Rearing the braconid wasps on more than one host larva revealed a higher number of total offspring but less offspring per host larva on average. Again, highest numbers of offspring hatched at 27 °C and the sex ratio was independent from temperature. Although no parasitoids hatched at 12 °C and only few at 36 °C, host larvae were still paralyzed. The efficacy of B. brevicornis was higher than 80% at all numbers of host larvae presented at all temperatures while the efficacy of B. hebetor was less than 80% at 12 °C and 27 °C at low numbers of host larvae presented. In conclusion, practitioners can use either B. brevicornis or B. hebetor at low and high temperatures and at varying host densities to achieve high pest control efficacy.

Warmer April Temperatures on Breeding Grounds Promote Earlier Nesting in a Long-Distance Migratory Bird, the Prothonotary Warbler

Global climate change and warming are altering hemispheric and local weather patterns. Altered weather patterns have great potential to affect the phenology of life history events, such as the initiation of breeding in organisms that reproduce seasonally. Long-distance migratory birds may be particularly challenged by changes in local weather on breeding grounds because they arrive from distant locations and must commence breeding when conditions are appropriate. Here we explore the effects of local temperature on first egg dates and annual productivity in a long-distance Neotropical migratory songbird, the prothonotary warblerProtonotaria citrea. We present results from a 20-year (1994 to 2013) study documenting the detailed nesting activities of a color-marked population (average of 155 individual females each year) of warblers in southern Illinois, United States. The warblers typically arrive in April and start breeding in late April and May in our study system. We tested for an effect of local average April daily temperature and female age on first egg dates, total number of offspring produced per female, and the probability of fledging two broods. We found that warmer April temperatures promoted earlier first egg dates and higher average annual productivity in the warblers. On average, older females had earlier first egg dates than 1-year-old females, but both age groups responded similarly to local April temperatures. The reproductive gains associated with earlier first egg dates in warmer years stemmed from an increased probability of successfully fledging two broods, suggesting that earlier first egg dates do not currently create a mismatch with food (insect) resources. Earliest arrival dates of warblers to the region of our study system were not affected by local April temperatures, suggesting that females vary their first egg date based on conditions they experience/assess after their arrival. Whereas these birds currently adjust the timing of their breeding and actually produce more offspring in warmer years, continued global warming may eventually upset the current balance between arrival dates, food resources, and the commencement of nesting.

Reproductive Traits of Ontsira mellipes (Hymenoptera: Braconidae), a North American Parasitoid, as a Novel Biological Control Agent for Exotic Anoplophora glabripennis (Coleoptera: Cerambycidae).

Ontsira mellipes Ashmead is a gregarious larval ectoparasitoid of woodboring cerambycids that is native to North America but can readily attack the exotic Asian longhorned beetle, Anoplophora glabripennis (Motschulsky). To evaluate the potential of the parasitoid as a novel association control agent for the pest beetle, this study investigated some key reproductive traits of the parasitoid, including egg maturation dynamics, and host size preference and suitability in association with the beetle. Results showed that female wasps emerged with a substantial portion (38%) of their lifetime complement of mature eggs and matured eggs rapidly, reaching a peak 4-6 d post-eclosion. The number of mature eggs was positively related to the female wasp's body size. Oviposition prompted production of more mature eggs by young female wasps. The parasitoid did not show a significant preference for large over small hosts in a choice test. Host size did not affect the parasitoid's offspring survival, developmental time, or sex ratio. However, clutch size increased with increasing host size. Female wasps that developed from large hosts had larger body size and consequently a higher mature egg load than those reared from small hosts. Neither longevity nor the total number of parasitized hosts over a female's lifetime was affected by the female's size, but the total number of offspring produced per female increased with the female's size. These results have important implications for improving rearing and field-release strategies as well as understanding the ecological mechanisms underlying host size selection in gregarious parasitoids.

How does individual variation in sociality influence fitness in prairie voles?

Comparative studies aid in our understanding of specific conditions favouring the initial evolution of different types of social behaviours, yet there is much unexplained intraspecific variation in the expression of social behaviour that comparative studies have not yet addressed. The proximate causes of this individual variation in social behaviour within a species have been examined in some species but its fitness consequences have been less frequently investigated. In this study, we quantified the fitness consequences of variation in the sociality of prairie voles, Microtus ochrogaster. We characterized sociality of voles in seminatural enclosures using an automated behavioural tracking system paired with social network analyses to quantify the degree of spatial and temporal co-occurrence of different voles. We then assessed the relationship between sociality and both mating success (number of different conspecifics with which an individual produced offspring) and reproductive success (total number of offspring surviving to first capture). We measured the number of social connections each individual had with all voles and with only opposite-sex voles (unweighted degree) through social network analyses. Both female and male voles varied in the number of social connections they had with all conspecifics and with opposite-sex conspecifics. In both analyses, females and males with an intermediate number of social connections had higher mating success overall and, for the analysis with all connections, produced more offspring. Males with many or few social connections also had the lowest average body mass. Overall, our results suggest some limit on the fitness benefits of sociality. Although there was substantial individual variation in our measure of vole social behaviour, intermediate levels of social connections may be most favourable.

Microcystis aeruginosa affects the inducible anti-predator responses of Ceriodaphnia cornuta

Cyanobacterial blooms are an increasing problem in a more eutrophic world. It is still a challenge to fully understand the influence of cyanobacteria on the interactions between predator and prey at higher trophic levels. The present study was mainly undertaken to understand the inducible anti-predator responses of cladocerans while using cyanobacteria as part of food. Specifically speaking, we focused on the anti-predator strategies of Ceriodaphnia cornuta in response to different predators (fish and Chaoborus larvae) under food with different proportions of Microcystis aeruginosa. The morphological (i.e., body size and the induction of horns) and life history traits (e.g., time to first reproduction, offspring number, and survival time) responses were measured under different proportions of M. aeruginosa (i.e., 0%, 20%, 40%, 60%, 80%, and 100%). Our results showed that both the life history and the inducible anti-predator responses of C. cornuta were significantly affected by different concentrations of M. aeruginosa. Specifically, lower concentrations of Microcystis (20%–60%) can significantly promote the horns induction under Chaoborus predation risks, and higher Microcystis concentrations (60%–100%) tend to enhance reproduction in response to fish predation risks, such as larger body size, decreased time to first reproduction, and increased total offspring number. Additionally, an increasing concentration of M. aeruginosa decreased the ability of C. cornuta to reverse horns when predation risks removed. Our findings indicated that cyanobacteria affecting life history traits and the subsequent indirect effects on anti-predator responses in cladocerans could impact the interactions between predator and prey at higher trophic levels and may consequently contribute to shaping the structure of the community in a cyanobacteria bloom area.

The effects of 1-hexyl-3-methylimidazolium bromide on embryonic development and reproduction in Daphnia magna.

Ionic liquids (ILs) are acknowledged as green chemicals and favorable substitutes for volatile organic solvents, which are currently used. However, previous studies have shown that these compounds had toxicological impacts on aquatic organisms. To investigate the effects of 1-hexyl-3- methylimidazolium bromide ionic liquid ([C6mim]Br) on embryonic development and reproduction in water flea (Daphnia magna), a series of exposure experiments were conducted, including acute toxicity, maternal exposure, and chronic exposure tests. In acute toxicity experiment, D. magna neonates exhibited developmental abnormalities in the shell spine and the second antennae in a concentration-dependent manner after exposure to [C6mim]Br. The results in maternal exposure test also revealed a certain embryo-toxicity in response to [C6mim]Br in D. magna. However, the toxicity was lower than that conveyed by direct acute exposure, this indicated that the IL could act directly on organism. During the 21 days chronic exposure, the 1.6mg/L exposure caused marked drop in the survival, molts and the number of the first brood of D. magna. Meanwhile, the total number of offspring was significantly declined in 1.6mg/L concentration treatment groups, whereas increased in 0.2mg/L groups. Generally, abnormalities in the offspring were significantly increased across all of the treatment groups in contrast to the control. No effect on sex differentiation was found during the experiments. These findings suggested that [C6mim]Br could affect embryonic development and reproduction in D. magna, and provided references for further study on the mechanisms underlying toxicological effects of ILs and the assessment of their potential environmental risks.

Acute and Chronic Toxicity to Daphnia magna of Diuron and Capsaicin Used in Antifouling Paints

Diuron is a biocidal active substance commonly and typically used in antifouling paints, and capsaicin is a new-type of natural products used for antifouling paints. To evaluate acute and chronic toxicity of diuron and capsaicin on aquatic organism, Daphnia magna was selected as a model test organism. Based on the toxicity effects on fatality, time of the first reproduction, number of brood per female, body length, number of total offspring in acute and chronic test, a dose-response relationship was established and the most sensitive biological indices were proposed. The acute toxicity test showed that the 48 h-EC50 of diuron to Daphnia magna was 17.1 mg·L-1, the 48 h-EC50 of capsaicin to Daphnia magna was 12.4 mg·L-1. The chronic toxicity test showed that there were signifi-cant effects on all observed biological indices. The sensitive biological indices for diuron from strong to weak were number of total offspring > time of the first reproduction > body length > number of brood per female, and the sensitive biological indices for capsaicin from strong to weak were number of total offspring > body length > number of brood per female > time of the first reproduction. Based on the number of total offspring, the 21 d-EC10 of diuron was calculated to be 0.830 mg·L-1, the 21d-EC10 of capsaicin was 1.63 mg·L-1. Capsaicin was readily biodegradable and its EC10 of reproduction to Daphnia magna was greater than 1 mg·L-1. According to the Rules for Classification and Labeling of Chemicals-Part 28:Hazardous to the Aquatic Environment (GB 30000.28-2013), capsaicin can be considered to have low chronic risk for aquatic environment and an environment-friendly potential.

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.

Influence of graft size, histocompatibility,and cryopreservation on reproductive outcome following ovary transplantation in mice

PurposeTransplantation of ovarian tissue is a valuable method to rescue mouse strains with fertility problems and to revitalize archived strains. The purpose of this study was to investigate the effect of (i) different sizes of transplanted ovary pieces on reproductive outcome, (ii) use of immunodeficient recipients to overcome the limitation of histocompatibility, and (iii) to compare different protocols for cryopreservation of ovarian tissue.MethodsHalves, quarters, and eights of mouse ovaries were transplanted. Half ovaries from B6 donors were transferred into immunodeficient mice. Halves of ovaries were frozen according to four different protocols, thawed and transferred.ResultsPregnancy rate after transplantation of ovarian tissue was high (90–100%) independent of the transplant size. Although, the average litter size was significantly lower for recipients of quarters and eights (4.4 and 4.6 vs. 6.5), the total number of offspring produced per donor ovary was higher compared with recipients of halves. Pregnancy rate of immunodeficient recipients was 40% (mean 4.7 offspring per litter). All four cryopreservation protocols used were able to preserve functionality of the ovarian tissue.ConclusionsTransplantation of ovarian tissue smaller than halves resulted in reduced litter sizes. The distribution of ovarian tissue of one donor female to 4 or 8 recipients will therefore yield in a higher total number of offspring in a certain time period. The use of immunodeficient recipients is an option for non-histocompatible donors. Cryopreservation of ovarian tissue is generally feasible but the function of frozen-thawed ovary halves after transplantation differs depending on the freezing protocol used.

Anti-plant Defense Response Strategies Mediated by the Secondary Symbiont Hamiltonella defensa in the Wheat Aphid Sitobion miscanthi.

Bacterial symbionts are omnipresent in insects, particularly aphids, and often exert important effects on the host ecology; however, examples of symbionts that mediate herbivore-plant interactions remain limited. Here, three clones with identical genetic backgrounds were established: a Hamiltonella defensa-free clone, H. defensa-infected clone and H. defensa-cured clone. H. defensa infection was found to increase the fitness of Sitobion miscanthi by increasing the total number of offspring and decreasing the age of first reproduction. Furthermore, gene expression studies and phytohormone measurement showed that feeding by the Hamiltonella-infected clone suppressed the salicylic acid (SA)- and jasmonic acid (JA)-related defense pathways and SA/JA accumulation in wheat plants relative to feeding by the other two clones. Additionally, after feeding by the Hamiltonella-infected clone, the activity levels of the defense-related enzymes polyphenol oxidase (PPO) and peroxidase (POD) in wheat plants were significantly decreased compared with the levels observed after feeding by the other two clones. Taken together, these data reveal for the first time the potential role of H. defensa of S. miscanthi in mediating the anti-plant defense responses of aphids.

Association between maternal age and outcomes in Kawasaki disease patients

BackgroundThe etiology of Kawasaki disease (KD) is still unknown; perinatal factors may have role with few studies. This study was aim to survey the perinatal factors and clinical outcome of KD, including coronary artery lesion (CAL) formation and intravenous immunoglobulin (IVIG) treatment response.MethodsWe enrolled a total of 185 KD patient–caregiver dyads in this study using questionnaires. The questionnaire included two categories: children’s characteristics, which consisted of age at disease onset, gender, gestational age at delivery, birth body weight, delivery methods, and breastfeeding status, and caregivers’ characteristics, which consisted of parents or not, education levels, maternal age at giving birth, total number of offspring, and family income. We analyzed the association of these factors with CAL formation and IVIG treatment response of KD.ResultsKD patients with CAL formation had a higher maternal age than non-CAL patients (32.49 ± 3.42 vs. 31.01 ± 3.92 years, p = 0.016). We also found that maternal age ≥ 32 years group had a higher rate of having KD patients with CAL (39/81 vs. 24/74, odds ratio 1.935, 95% confidence interval [1.007, 3.718], p = 0.047). The maternal age ≥ 35 years group had a higher rate of having KD patients with IVIG resistance (6/31 vs. 6/116, odds ratio 4.400, 95% confidence interval [1.309, 14.786], p = 0.01). There was no significant difference in either CAL formation or IVIG resistance in KD with regard to patient’s age at disease onset, gestational age, birth body weight, delivery methods, breastfeeding, caregiver type, caregivers’ education level, total number of offspring, or family income (p > 0.05).ConclusionsThis study is the first to report that maternal age is significantly associated with CAL formation and IVIG resistance in KD. We hypothesize that a maternal age less than 32 years would benefit KD offspring.

Female asthma and atopy - impact on fertility: a systematic review.

Background and objectiveAsthma is one of the most common chronic diseases among women of reproductive age, and previous studies have suggested a link between female asthma and infertility. The aim of the present review is to provide an update on current knowledge of the association between female asthma and/or atopy and a reduction in fertility, ie, number of offspring, time to pregnancy (TTP) and need for fertility treatment.MethodsSystematic review performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-guidelines.ResultsA total of 14 studies fulfilled the predefined criteria for inclusion in the present review. Six studies investigated the association between female asthma and/or atopy and number of offspring, of which one reported a positive, two a negative, and three no association. Three studies addressed the association between asthma and TTP and found that TTP was significantly prolonged in asthmatic women compared to non-asthmatic women. Five studies investigated subfertility and the need for fertility treatments of which two studies found a higher prevalence of infertility among women prescribed anti-asthma medication. One study found no difference in the number of fertility treatments of asthmatic women compared to non-asthmatic women, whereas three studies reported that female asthma was associated with significantly more fertility treatment compared to non-asthmatic women.ConclusionAlthough the available evidence is conflicting, there is a clear trend toward an association between female asthma and a reduction in fertility, and by that a larger proportion requiring fertility treatment, even though female asthma might not negatively affect total number of offspring.

Interspecific effects of the cladoceran- (Moina macrocopa) and the rotifer- (Brachionus calyciflorus) conditioned medium on main life history variables in relation to temperature and algal density

Current research on the effects of cladoceran allelochemicals on rotifers has been inconclusive and the allelopathic effects of rotifers on cladocerans are unknown. We sought to fill this knowledge gap with life table demography experiments assessing the interspecific effects ofMoina macrocopa-conditioned mediums (MCM) andBrachionus calyciflorus-conditioned mediums (CCM) on the main life history variables under different temperatures and algal densities. Our results demonstrate that, when compared to the allelopathic effects ofM. macrocopaonB. calyciflorus,M. macrocopahad higher sensitivity to the allelochemicals fromB. calyciflorus. When compared to the controls, the chemically-mediated effects ofM. macrocopaon the net reproductive rate (R0), intrinsic rate of population growth (rm) and total number of offspring (NO) ofB. calycifloruswere non-significant in many cases while in a few the impacts were stimulatory or inhibitory under different concentrations of MCM, temperatures, and food densities. However, when compared to the controls, the allelopathic effects ofB. calycifloruson theR0,rmand NO ofM. macrocopawere stimulatory in many cases; some impacts were inhibitory or non-significant under different concentrations of CCM, temperatures, and food densities. In addition, life expectancy at birth (e0), generation time (T), and average lifespan (LS) ofB. calyciflorusandM. macrocopacultured in the conditioned medium nearly did not differ significantly from the controls. Our results suggest that the interspecific allelopathic effects ofB. calyciflorusandM. macrocopaare dependent on the origin and concentration of the allelochemical, life history variable, temperature, and food (algal) density. Additionally, the underlying mechanisms should be further investigated.

High concentration of Phaeocystis globosa reduces the sensitivity of rotifer Brachionus plicatilis to cadmium: Based on an exponential approach fitting the changes in some key life-history traits

Most coastal waters are at risk of heavy metal pollution, and the biomass of primary producer phytoplankton always fluctuates, which usually causes zooplankton to be exposed in different concentrations of food and heavy metal. Phytoplankton abundance and heavy metal may interact on zooplankton. Therefore, to assess the definite interactive way, in this study we investigated the combined effects of different cadmium (Cd) levels and Phaeocystis globosa concentrations on some key life-history traits of the rotifer Brachionus plicatilis. Results showed that the Cd level and P. globosa concentration had a significant interaction on the key life-history parameters of the rotifer. Mid-level algal concentrations (5–36 × 104 cells mL−1) had an apparent effect on brood production and the number of rotifers producing offspring at high Cd level. The time to first reproduction exponentially decreased with increasing P. globosa concentrations under any Cd levels and then subsequently reached a constant value. With increasing P. globosa concentration, the total number of offspring exponentially increased and then reached the asymptotic value; the survival time under any Cd levels exponentially decreased with the increasing P. globosa concentration and subsequently tended to be a constant value. Without Cd, the low P. globosa concentration only decreased the reproduction of rotifers. However, the extreme low P. globosa concentration (1–3 × 104 cells mL−1) under higher Cd level (0.0354 mM) completely inhibited the reproduction and also shorten the survival time. Higher Cd level decreased the asymptotic total offspring per rotifer and survival time. High concentration of P. globosa can reduce the sensitivity of rotifer to heavy metal. However, the negative effects could not be eliminated completely by the increasing P. globosa concentration. The findings indicated that ecotoxicological studies on the toxicity of heavy metal need to consider the effects of food concentrations, which contributes to understanding the diverse tolerance of zooplankton to heavy metals.

73 Artificial incubation of resplendent quetzal (Pharomachrus mocinno mocinno) eggs

The scientific literature lacks information regarding the incubation conditions and hatching success of the resplendent quetzal (Pharomachrus mocinno mocinno). Jesús Estudillo López, founder of the El Nido aviary, was the first to succeed with quetzal reproduction in captivity. Quetzals do not typically reproduce in captivity and the aim of this study was to increase fecundity through artificial incubation. Over a 3-year period (Yr1, Yr2, and Yr3), data about quetzal eggs, artificial incubation, and diet were recorded for 3 quetzal pairs (ranging from ~4-12 years old, with females ~4-8 years old). Eggs were manually collected from artificial nests and egg substitution was utilised. Quetzals can continue laying eggs up to 8 times with egg substitution. Eggs were weighed and placed into an 80W incubator (INCA 200®, DMP Engineering, Tel Aviv, Israel) with an automatic egg turner. The eggs were incubated for 17 to 18 days at 37.2 to 37.6°C with a relative humidity of 20 to 40%. Fisher’s exact test (2-tailed, α=0.05) was used for statistical analyses comparing the numbers of eggs hatched, infertile eggs, and eggs experiencing embryonic death for the study period. Eggs were candled on Day 3 to determine fertility by the presence of a darker area with vasculogenesis. Hatchability (%) was determined by dividing the total number of offspring hatched by the total number of eggs deemed fertile after candling. All of the eggs that did not hatch were opened at the end of the incubation period to detect early embryo death. A total of 27 quetzal eggs [mean weight (g)=17.3, s.d.=1.2] were incubated over 3 years, of which 10 (~37%) hatched, with 3 (30%) fledging and surviving to adulthood. Six of the eggs (~22%) suffered embryonic mortality during incubation, whereas 11 eggs were infertile (~41%). Hatchability over the study period was 62.5% (10/16). During Yr1 and Yr2 two eggs hatched each year, and compared with the 6 eggs that hatched in Yr3, a noteworthy but not significant difference was observed (Yr1v. Yr2, P=1; Yr1v. Yr3, P=0.188; Yr2v. Yr3, P=0.170). Embryonic death of the eggs was also not significantly different between the years (Yr1v. Yr2, P=1; Yr1v. Yr3, P=0.314; Yr2v. Yr3, P=0.303). However, the number of infertile eggs was significantly different between Yr1v. Yr3 (P=0.007) and Yr2v. Yr3 (P=0.003), but not Yr1v. Yr2 (P=1). During Yr1 and Yr2 the diet consisted of fruit (aguacatillo, banana, and papaya) and a mouse pup once a week. In Yr3 the diet was modified to include blueberry and a commercial food for Tucans (Mazuri®; https://www.mazuri.com/) and a new quetzal pair was added. The modified diet will continue to be used given that there were fewer infertile eggs. However, future research will need to be conducted to elucidate which variables specifically contribute to better hatching results. The results of this study demonstrate an assisted reproductive technique for quetzals that can benefit conservation efforts for this species.

Life-history consequences of bidirectional selection for male morph in a male-dimorphic bulb mite

Intralocus sexual conflict (IASC) arises when males and females have different trait optima. Some males pursue different alternative reproductive tactics (ARTs) with different trait optima, resulting in different strengths of IASC. Consequently, for instance daughter fitness is differentially affected by her sire’s morph. We tested if—and which—other life-history traits correlatively change in bidirectional, artificial selection experiments for ARTs. We used the male-dimorphic bulb mite Rhizoglyphus robini, the males of which are high-fitness ‘fighters’ or low-fitness ‘scramblers’. Twice in each of the five generations of selection, we assessed clutch composition (number of mites of the various life stages present) and size (total number of offspring). Furthermore, we tracked offspring from egg to adulthood in the first and final generation to detect differences between selection lines in the size and duration of stages, and in maturation time. We found that selection for male morph increased the frequency of that morph. Furthermore, compared to fighter lines, scrambler lines produced more females, which laid larger eggs (in the final generations), and maintained a higher egg-laying rate for longer. Otherwise, our results showed no consistent differences between the selection lines in clutch size and composition, life stage size or duration, or maturation time. Though we found few correlated life-history trait changes in response to selection on male morph, the differences in egg laying rate and egg size suggest that IASC between fighters is costlier to females than IASC with scramblers. We hypothesize that these differences in reproductive traits allow fighter-offspring to perform better in small, declining populations but scrambler-offspring to perform better in large, growing populations.

Developmental and reproductive effects of tamoxifen on Daphnia magna.

Although medicines are less toxic than other toxicants, increased production and usage of pharmaceuticals have led to many concerns regarding their toxic effects on human and non-target organisms. Additionally, reproductive toxicity after long-term exposure is difficult to anticipate. Tamoxifen (TAM), a selective estrogen receptor modulator, has been widely used as an anticancer drug for mammalian breast and endometrial cancers. With increased TAM usage, it has frequently been reported that TAM is a potential endocrine disruptor capable of interfering with reproduction in non-target organisms. However, the mode of action of TAM in the endocrine system is unknown. In this study, we performed a 21-day chronic toxicity test using the crustacean Daphnia magna and investigated the transcriptional modulation of major genes related to the endocrine system, molting, development, and reproduction (i.e., Dm-vtg2, vmo1, cyp314, usp, and ecrb) after TAM exposure for 3, 6, 12, and 24h. Our results showed a concentration-dependent decrease in the total number of offspring per individual, except for the concentration 25μg/L; additionally, the expression of oogenesis-related genes was induced early but was later inhibited by TAM exposure. Additionally, molting-related genes were also downregulated in a time-dependent manner. Our findings suggested that TAM regulates reproduction by interfering with the molecular mechanisms involved in oogenesis and molting. This study supports the hypothesis that D. magna are a useful model to rapidly evaluate the reproductive effects of pharmaceuticals.

Steady state and intermittency in the critical branching random walk with arbitrary total number of offspring

ABSTRACTFor the critical branching random walk on the lattice , in the case of an arbitrary total number of produced offspring spreading on the lattice from the parental particle, the existence of a limit distribution (which corresponds to a steady state (or statistical equilibrium)) of the population is proved. If the second factorial moment of the total number of offspring is much larger than the square of the first factorial moment, then the limit particle field displays strong deviations from the uniformity: this is intermittency.

Effects of experimental light at night on extra-pair paternity in a songbird.

Light pollution is increasing worldwide and significantly affects animal behavior. In birds, these effects include advancement of morning activity and onset of dawn song, which may affect extra-pair paternity. Advanced dawn song of males may stimulate females to engage in extra-pair copulations, and the earlier activity onset may affect the males' mate guarding behavior. Earlier work showed an effect of light at night on extra-pair behavior, but this was in an area with other anthropogenic disturbances. Here, we present a two-year experimental study on effects of light at night on extra-pair paternity of great tits (Parus major). Previously dark natural areas were illuminated with white, red, and green LED lamps and compared to a dark control. In 2014, the proportion of extra-pair young in broods increased with distance to the red and white lamps (i.e., at lower light intensities), but decreased with distance to the poles in the dark control. In 2013, we found no effects on the proportion of extra-pair young. The total number of offspring sired by a male was unaffected by artificial light at night in both years, suggesting that potential changes in female fidelity in pairs breeding close to white and red light did not translate into fitness benefits for the males of these pairs. Artificial light at night might disrupt the natural patterns of extra-pair paternity, possibly negates potential benefits of extra-pair copulations and thus could alter sexual selection processes in wild birds.

Biology and performance of two indigenous larval parasitoids on Tuta absoluta (Lepidoptera: Gelechiidae) in Sudan

ABSTRACTTuta absoluta is an alien invasive pest in Sudan. Since it was detected in the country, the pest continues to cause major tomato losses. Alarmed by its devastating nature and the speed of spread, tomato growers resorted to the indiscriminate use of broad-spectrum insecticides. Promising indigenous parasitoid(s) may contribute to suppression of this pest. The biology and performance of the native parasitoids, Bracon nigricans Szépligeti (Braconidae) and Dolichogenidea appellator (Telenga) (Braconidae), was therefore evaluated against different immature stages of T. absoluta under laboratory conditions. A significantly higher number of fourth instar larvae was accepted for oviposition by B. nigricans. Similarly, fourth instar larvae yielded a considerably higher number of parasitoid offspring compared to third instar larvae. The male ratio of B. nigricans offspring which emerged from both larval instars was high, 0.96 and 0.66 for third and fourth instar larvae of T. absoluta, respectively. There was, however, no significant difference in the number of males and females that emerged from fourth instar larvae. Conversely, the number of hosts killed by stinging behaviour or host feeding was significantly higher on third instar larvae. B. nigricans potential fecundity varied with the age of the wasp with the lowest fecundity on the day of eclosion. The performance of D. appellator in terms of the total number of offspring produced and female progeny was similar for second and third instar larvae of T. absoluta. The preimaginal developmental time for both parasitoid species did not vary with either host stage or sex of the parasitoid. B. nigricans adult longevity was similar for both sexes, while that of D. appellator significantly varied with females living longer than males. Prospects for conservative biological control of T. absoluta are discussed in the light of the results of this study.