Hormetic effects of thiamethoxam on Schizaphis graminum: demographics and feeding behavior.

In agroecosystems, insects contend with chemical insecticides often encountered at sublethal concentrations. Insects' exposure to these mild stresses may induce hormetic effects, which has consequences for managing insect pests. In this study, we used an electrical penetration graph (EPG) technique to investigate the feeding behavior and an age-stage, two-sex life table approach to estimate the sublethal effects of thiamethoxam on greenbug, Schizaphis graminum. The LC5 and LC10 of thiamethoxam significantly decreased longevity and fecundity of directly exposed adult aphids (F0). However, the adult longevity, fecundity, and reproductive days (RPd)-indicating the number of days in which the females produce offspring - in the progeny generation (F1) exhibited significant increase when parental aphids (F0) were treated with LC5 of the active ingredient. Subsequently, key demographic parameters such as intrinsic rate of increase (r) and net reproductive rate (R0) significantly increased at LC5 treatment. EPG recordings showed that total durations of non-probing (Np), intercellular stylet pathway (C), and salivary secretion into the sieve element (E1) were significantly increased, while mean duration of probing (Pr) and total duration of phloem sap ingestion and concurrent salivation (E2) were decreased in F0 adults exposed to LC5 and LC10. Interestingly, in the F1 generation, total duration of Np was significantly decreased while total duration of E2 was increased in LC5 treatment. Taken together, our results showed that an LC5 of thiamethoxam induces intergenerational hormetic effects on the demographic parameters and feeding behavior of F1 individuals of S. graminum. These findings have important implications on chemical control against S. graminum and highlight the need for a deeper understanding of the ecological consequences of such exposures within pest management strategies across the agricultural landscapes.

Assessment of Lethal, Sublethal, Transgenerational, and Biochemical Effects of Isaria fumosorosea on Mythimna separata.

Mythimna separata is a destructive polyphagous pest of field crops. Insecticides are generally applied for its control which not only negatively affect natural enemies and the environment and cause resistance in the insect pests. There is a need for the friendly method which is safe for the environment and life. Currently, entomopathogenic fungi are being used as biological control agents for different insects. The influence of Isaria fumosorosea on survival, life table parameters, and enzymatic activities of M. separata were assessed. On the seventh day post-treatment, the highest concentration 3 × 108 spores/mL-1 caused the 92.5% larval mortality. The effect of LC15 and LC50 of I. fumosorosea were recorded on parental generation (F0) and first filial generation (F1) of M. separata. The life table parameters of F1 showed a decreasing trend in the intrinsic rate (r), net reproductive rate (Ro), mean generational time (T), total larval duration, and fecundity ratio in treated groups. In LC15 and LC50, groups the average fecundity ratio was 319.2 and 191.18 eggs/female, respectively. The activities of detoxifying enzymes were concentration-dependent and highest activities were recorded on the third day. I. fumosorosea negatively affected the growth parameters of M. separata and can be included in M. separata management program.

Socio-demographic parameters and non-cardiac comorbidity related to self-perceived quality of life in young adults after neonatal arterial switch operation for transposition of the great arteries.

Evaluating the relation of non-cardiac comorbidity and socio-demographic factors to physical and mental health-related quality of life (QOL) which has been partially found at elevated risk in young adults after neonatal arterial switch operation (ASO) for transposition of the great arteries (TGA). In a prospective reassessment study, results of 92 unselected young adults (22.8 ± 2.6 years) having undergone evaluation of QOL (SF-36) were related to non-cardiac comorbidity with special respect to neurologic and psychiatric comorbidity and to socio-demographic parameters. Neurologic (14%) contrary to psychiatric comorbidities (6.5%) were more frequent than in the general population. The educational level was higher, the rate of unemployment was double as high compared to the average German population. Significant inverse relations (p = 0.006 to 0.033) existed between physical health domains (physical functioning and general health perception) and non-cardiac, neurologic, and psychiatric comorbidity, as well as correlations between the latter domains and socio-economic status, educational level, and worse employment status (Spearman 0.22-0.41, p < 0.0001 to 0.036). Mental health domains (vitality, social functioning, psychical health) were significantly inversely related with neurologic and psychiatric comorbidity (p = 0.002 to 0.048) and correlated with higher educational level (Spearman 0.25, p = 0.019). Neurologic and psychiatric comorbidities and socio-demographic parameters are significant risk factors for a reduced QOL concerning physical and mental health in young adults with TGA after ASO. Standardized QOL measurement should be part of routine screening programs to detect subclinical physical, neurodevelopmental, and psychosocial comorbidity.

Productive and reproductive performances of smallholder West African shorthorn Lagune cattle herds under village conditions in Southern Benin.

The West African shorthorn Lagune cattle has long been incriminated as of low productivity and subjected to gradual replacement or indiscriminate crossbreeding with zebu breeds. But there are still insufficient studies reporting the productive and reproductive performances of this breed under village conditions. This study aimed to evaluate the productive and reproductive performances of the Lagune cattle herds kept under village conditions in two agroecological zones in Southern Benin. Sixteen herds (seven in the Oueme Valley zone and nine in the Pobe zone), chosen from a previous retrospective survey, were regularly visited on a bi-monthly basis between January 2018 and February 2019. At the first visit to each selected herd, all animals present were identified, their ages determined through their dentition, and their breeding history recorded. At each subsequent visit, information on calving, birth weights, herd entries and exits, disease incidence, and changes in the physiological status of the animals were recorded. In addition, all suckling calves from birth to 6 months of age were weighted and measured. The average age at first calving was 37.2 ± 3.5 months and varied from 3 to 4 years. With no significant variations between agroecological zones, the parturition rate, fertility rate, fecundity rate, and abortion rate were, respectively, 74.3% ± 10.7, 77.0% ± 12.0, 68.9% ± 9.1, and 2.7% ± 1.4. The overall annual mortality rate and perinatal mortality rate were 8.4% ± 3.1 and 7.3% ± 2.7, respectively. The annual offtake rate was 12.9% ± 4.3 and varied significantly (P ≤ 0.05) between zones. The average birth weight varied significantly (P ≤ 0.05) between sex and was 10.2 ± 0.7 kg and 10.8 ± 0.9 kg for female and male, respectively. The average daily body weight gain of calves, calculated over the period from birth to 6 months of age, was 160.5 ± 8.5 g/day. In addition to environmental conditions, individual farmers' management practices varied significantly among herds and probably influenced the recorded reproductive and productive performances. The estimates of reproductive parameters obtained in this study suggest a good reproductive ability of the Lagune breed which could be improved with better management conditions.

The influence of tolfenpyrad on fitness, development, and reproduction in parents and offspring of Coccinella septempunctata.

Coccinella septempunctata (ladybird) is one of the foremost natural predators that feed on aphids. Thus, C. septempunctata serves as an effective biological control agent in integrated pest management (IPM) programs. To supplement the activity of biological control agents, IPM programs often incorporate chemical pesticides to bolster crop protection. To evaluate the effects of a potent insecticide, tolfenpyrad, on C. septempunctata, we tested the sublethal effects of tolfenpyrad on all developmental stages of the life cycle of C. septempunctata and its effects on the next generation. For sublethal testing of the parent generation, the LR50 of tolfenpyrad for C. septempunctata was determined to range from 1.04 to 8.43 g a.i. /hm2 within a set exposure period, while the hazard quotient (HQ) values were above our threshold value of 2 during the entire observation period. These data indicated a potential toxicity risk from tolfenpyrad exposure. The no observed effect application rates (NOERs) of tolfenpyrad on parents (F0) were determined for survival (0.485 g a.i. /hm2), developmental time of pupation (0.242 g a.i. /hm2), and fecundity (0.485 g a.i. /hm2). Application of sublethal doses to unexposed progeny (F1) of exposed parents, prolonged the L1 (1st instar of larvae) and L2 (2nd instar of larvae) stage, while the total longevity, intrinsic rate of increase (r), finite rate of increase (γ), net reproductive rate (R0), and mean generation time (T) were significantly reduced. These results demonstrated the negative influence of sublethal concentrations of tolfenpyrad on C. septempunctata and its persistent effects on subsequent generations.

Performance of Tetranychus urticae (Acari: Tetranychidae) on three hop cultivars (Humulus lupulus).

Tetranychus urticae Koch (Acari: Tetranychidae) is a major pest species in numerous crops including hop (Humulus lupulus L.). Substantial T. urticae infestation was observed to occur in this recently introduced crop in Brazil. The adoption of less suitable cultivars to the pest species is highly desirable for integrated pest management. We used free-choice trials and two-sex life table analysis to determine the preference and population growth of T. urticae under laboratory conditions using three of hop cultivars currently expanding in Brazil (Mantiqueira, Victoria, and Yakima Gold). We also estimated the density of non-glandular trichomes and lupulin glands found on the abaxial leaf surface of these cultivars and correlated them with performance parameters of T. urticae. Mantiqueira appeared to be the least preferred by adult females for attractiveness and oviposition suggesting existence of antixenosis on this cultivar. Female immature stages developed slower on Yakima Gold and Mantiqueira, but no difference was observed between the latter and Victoria. Fecundity and longevity were significantly lower on Mantiqueira than on Victoria and Yakima Gold. No significant differences were observed among cultivars for intrinsic rate of increase (r), finite rate of increase (λ), and net rate of reproduction (R0), suggesting the absence of antibiosis. Although, lupilin gland densities were higher on Mantiqueira and Yakima Gold than on Victoria, no significant correlations were observed between these defensive traits and performance parameters of T. urticae. However, 30-day population simulations of T. urticae suggest that Yakima Gold is the least susceptible, Mantiqueira is moderately susceptible, and Victoria is highly susceptible.

Sex-specific actuarial and reproductive senescence in zoo-housed tiger (Panthera tigris): The importance of sub-species for conservation.

A fifth of all known species are currently classified as threatened in the wild: the rate of biodiversity loss is rapid, continuous, and mostly due to anthropogenic activities. To slow down this decline, the accurate estimation of demographic parameters for threatened species is critical. With this aim, zoo institutions play an important role, giving access to data on zoo-housed animals, which aids researchers working on species life-history traits and intrinsic factors influencing the fitness of both sexes, such as age. While tigers (Panthera tigris) are particularly threatened in their natural environment, few of their demographic parameters have been determined because of their solitary and elusive nature as well as low population density. Using individual-based information for more than 9200 tigers (from 1938 to 2018) recorded in the International Tiger Studbook 2018, we aimed to determine sub-species and sex-specific variability of survival and reproductive parameters with age. No significant sex-difference in actuarial senescence (i.e., decline of survival probabilities with age) was observed but males tended to have a higher juvenile mortality and a faster senescence than females. Reproductive senescence (i.e., decline of reproductive parameters with age) was more pronounced in females than males. Moreover, we observed sub-species-specific variation in mortality and reproductive patterns, pointing out the necessity to consider them independently for conservation goals. Our findings can provide meaningful improvements to the husbandry of zoo-housed tigers, emphasizing the importance of adult breeding females of 7-9 years-old to control zoo-housed population size, but also providing accurate demographic estimates, crucial to set up effective conservation plans.

Sublethal effects of a juvenile hormone analog, Pyriproxyfen on demographic parameters of non-target predator, Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae).

Insect predators, in general, play an important role in regulating pest populations in agricultural systems, but may be negatively affected by pesticides used in pest management. Convergent lady beetle, Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae) is known as an important biological control agent of soft-bodied insect pests. The development of Integrated Pest Management (IPM) program against insect pests requires an assessment of the side effect of insecticides on biological control agents. In the present work, we assessed the sublethal effects of an insect growth regulator, Pyriproxyfen (juvenile hormone mimic) on a common aphidophagous beetle, H. convergens by computing its demographic parameters through age-stage, two-sex life table theory. Present results showed that sublethal (LC10 and LC30) concentrations of tested insecticide prolonged the pre-adult developmental duration while adult longevity, fecundity and fertility were reduced following treatment compared with control. However, total pre-ovipositional period (TPOP) was declined with the increasing trend of insecticide concentration. In additions, population growth parameters such as intrinsic rate of increase r, finite rate of increase λ and net reproductive rate R0 were dramatically reduced in H. convergens population when they treated with sublethal concentrations pyriproxyfen. Therefore, the results obtained through this study reflected that pyriproxyfen impairs the population growth parameters and could reduce the biological services provided by H. convergens. Thus, more attention should be paid to the use of this insecticide in IPM program.

Effect of photoperiods on development and acaricide susceptibility in the two-spotted spider mite, Tetranychus urticae.

Demographic analysis of Tetranychus urticae under photoperiods of 12L:12D, 14L:10D and 18L:6D at 75% relative humidity and 25 °C showed that the developmental time and oviposition per female declined with increasing light period. The nymph, oviposition and adult stages were significantly shortened, resulting in shorter generation duration and faster population decline, but there was no effect on egg and larval stages of T. urticae. Kaplan-Meier survival analysis followed by a log-rank test indicated that the mean and median survival times were 40.4 (12:12), 39.1 (14:10), and 38.1 (18:6) days, and 42.0, 40.0, 39.0 days, respectively-this difference among photoperiods was significant. The total number of eggs per female under the three photoperiods was 69.63 (12:12), 77.44 (14:10) and 42.17 (18:6), respectively, and the sex ratios were 70.0, 81.6 and 71.6% female offspring. Under 14 h light, T. urticae experienced its highest net reproductive rate (R0 = 83.0577), intrinsic rate of increase (rm = 0.2740), finite rate of increase (λ = 1.3153), lowest mean generation time (T = 16.1277 days) and population doubling time (Dt = 2.5294 days). All demographic parameters displayed a decreasing relationship with the light phase under the three photoperiods. No significant difference in susceptibilities to the acaricides diafenthiuron and propargite was shown among the three photoperiods. The results of this study indicated that the 14L:10D photoperiod was optimal for the development and reproduction of T. urticae, and the 18L:6D period was disadvantageous for spider mite development.

Size-abundance rules? Evolution changes scaling relationships between size, metabolism and demography.

Body size often strongly covaries with demography across species. Metabolism has long been invoked as the driver of these patterns, but tests of causal links between size, metabolism and demography within a species are exceedingly rare. We used 400 generations of artificial selection to evolve a 2427% size difference in the microalga Dunaliella tertiolecta. We repeatedly measured size, energy fluxes and demography across the evolved lineages. Then, we used standard metabolic theory to generate predictions of how size and demography should covary based on the scaling of energy fluxes that we measured. The size dependency of energy remained relatively consistent in time, but metabolic theory failed to predict demographic rates, which varied unpredictably in strength and even sign across generations. Classic theory holds that size affects demography via metabolism - our results suggest that both metabolism and size act separately to drive demography and that among-species patterns may not predict within-species processes.

A comparison of sexual competitiveness and demographic traits of Anastrepha obliqua (Macquart) (Diptera: Tephritidae) among fruit-associated populations.

The control of Anastrepha obliqua includes the sterilization of mass-reared insects grown in isolation in a constantly controlled environment. Through time, laboratory mass-reared colonies may produce flies with lower field performance. To recover the genetic variation and aptitude of mass-reared populations, wild insects are introduced into mass-reared colonies. Our aim in this study was to determine whether the host species from two localities influence the life history traits of A. obliqua. We collected flies as larvae from infested fruits of Spondias purpurea, S. mombin, Mangifera indica cv. 'piña', and M. indica cv. 'coche' from two localities in Chiapas, Mexico. There were significant differences in the mating competitiveness of males collected from mango cv. 'coche' compared with mass-reared males. There were no differences in the mating propensity between flies from the two localities, even in the number of matings, when weight was considered as a covariable. The mass-reared strain showed the earliest age at first oviposition. The locality affected the longevity and oviposition period, and these influenced the birth rate, intrinsic rate of increase, finite rate of population increase, mean generation time, and doubling time. According to the demographic parameters, the population of S. mombin would allow artificial colonization in less time, considering that it has a high reproduction rate starting at an early age. Even in the propensity test, it had the highest number of matings. However, males with greater sexual competitiveness and longevity for colonization corresponded to those collected from S. purpurea.

Biological and demographic parameters of Tegolophus brunneus (Acari: Eriophyidae) in citrus.

The brown citrus rust mite, Tegolophus brunneus Flechtmann (Acari: Eriophyidae), causes citrus rust, as does Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae). As the citrus rust damage has intensified in recent years and T. brunneus has been reported in high population levels in several regions of Brazil, this mite has caused concern to growers and technicians. Because T. brunneus has been little studied and its bioecological characteristics are unknown, this study investigated the biological and demographic parameters of T. brunneus on citrus fruits under laboratory conditions. Our results showed that the egg incubation period and viability were 3.0 and 94.5%, respectively. The larval and nymphal stage durations were 1.1 and 2.8 days, respectively. The development time of the immature stage was 6.9 days, with 92.3% survival. When females and males were maintained together, the sex ratio of offspring was 0.7; virgin females produced only males. The pre-oviposition (from adult emergence to the first egg) and total pre-oviposition (egg-to-egg) periods were 1.6 and 8.5 days, respectively. Fecundity was 8.5 eggs, and female and male longevities were 13.2 and 11.4 days, respectively. The estimate of demographic parameters indicated that the Ro and T of T. brunneus were 6.45 offspring and 13.0 days, and r and λ were 0.142 and 1.153 day-1, respectively. These results suggest that T. brunneus has high growth potential on citrus trees. Therefore, management strategies may be required to reduce the population levels and damage caused by T. brunneus in citrus groves.

Peanut cultivars display susceptibility by triggering outbreaks of Tetranychus ogmophallos (Acari: Tetranychidae).

The peanut red spider mite, Tetranychus ogmophallos Ferreira and Flechtmann (Acari: Tetranychidae), is an important pest of peanut in Brazil and is considered a quarantine pest in other countries. This study investigates the development, reproduction, survival and life table parameters of T. ogmophallos on five peanut cultivars-three with high levels of oleic acid [high oleic] and recently released: Granoleico, IAC OL 3 and IAC 503; and two regular and previously used by farmers: Runner IAC 886, IAC Tatu ST 3-and two breeding lines (L. 8008 and L. 322) in the growth chamber. There were differences between the developmental times of all immature stages, the oviposition period, fecundity and adult longevity of T. ogmophallos reared on the peanut cultivars and breeding lines. The longest duration of the immature stage and lowest fecundity occurred on cultivars Granoleico and Runner IAC 886, and breeding line L. 322, which also displayed the lowest intrinsic rate of increase (r), finite rate of increase (λ) and net reproductive rate (R0) and the shortest mean generation time (T). The highest fitness occurred on the IAC Tatu ST, IAC OL 3, IAC 503 and L. 8008. Our study shows that peanut cultivars belonging to the group with high oleic trait and recently released (IAC OL 3 and IAC 503) are susceptible to T. ogmophallos, except Granoleico, which is resistant. The regular and previously used cultivar Runner IAC 886 and breeding line L. 322 are resistant to the peanut red spider mite.

Relationships between vital rates and ecological traits in an avian community.

Comparative studies about the relationships between vital rates and ecological traits at the community level are conspicuously lacking for most taxa because estimating vital rates requires detailed demographic data. Identifying relationships between vital rates and ecological traits could help to better understand ecological and evolutionary demographic mechanisms that lead to interspecific differences in vital rates. We use novel dynamic N-mixture models for counts to achieve this for a whole avian community comprising 53 passerine species, while simultaneously accounting for density dependence and environmental stochasticity in recruitment and survival and, importantly, correcting our inferences for imperfect detection. Demographic stochasticity is taken into account in the form of the binomial and Poisson distributions describing survival events and number of recruits. We then explore relationships between estimated demographic parameters (i.e., vital rates) and ecological traits related to migration patterns, diet, habitat and nesting location of each species. The relative importance of recruitment and adult survival as contributors to population growth varied greatly among species, and interspecific differences in vital rates partly reflected differences in ecological traits. Migratory mode was associated with interspecific differences in population growth and density dependence. Resident species had higher population growth rates than long- and short-distance migrants. We found no relationships between diet and population growth rate. Habitat differences were associated with different growth rates: alpine, wetland and farmland species had lower population growth rates than forest species. Differences in population growth rates among nesting locations showed that breeding habitat is essential for population dynamics. Our study reveals relationships between ecological traits and contributions of vital rates to population growth and suggests ways in which patterns of population growth fluctuations in a community might be determined by life history.

Quality of life of immigrant and non-immigrant infertile patients in a publicly funded in vitro fertilisation program: a cross-sectional study.

OBJECTIVE: To investigate whether there are differences in fertility quality of life (FertiQoL) and socio-demographic characteristics between immigrants and non-immigrant patients attending a government-funded fertility program. DESIGN: Cross-sectional study. SETTING: McGill University Reproductive Center in Montreal, Canada, at a time when governmental funding for in vitro fertilisation (IVF) was provided to all residents. POPULATION: All infertile patients, males and females, attending the center between March and July 2015. METHODS: Patients were invited to complete anonymous questionnaires which included socio-demographic items and the validated FertiQoL questionnaire. MAIN OUTCOME MEASURES: Socio-demographic characteristics (age, gender, marital state, infertility type & duration, previous IVF attempts; education, employment, income, ethnicity, spoken languages) and FertiQoL scores. RESULTS: In all, 1020 patients completed the questionnaires; of these, 752 (77.7%) non-immigrant Canadian citizens and 215 (22.3%) resident immigrants were included in the analysis. Median duration in Canada for immigrants was 4 years. Immigrants were more likely to have university/graduate degrees (75% versus 64%), to be unemployed (37% versus 13.1%) and to have lower annual household incomes (72.8% versus 39.5%, all P < 0.05). They also reported poorer QoL and achieved significantly lower scores in the emotional, mind/body, social, treatment and total FertiQoL domains. Multivariate analysis showed male gender, lower education level and Caucasian/European ethnicity to be significantly associated with higher QoL. CONCLUSIONS: Despite governmental funding of IVF, immigrants experience reduced fertility QoL, implying cost is not the only barrier to IVF use. The reduced QoL may stem from cross-cultural differences in infertility perception. This population may be at greater risk for depression and anxiety and should be flagged accordingly. TWEETABLE ABSTRACT: Immigrants' fertility QoL is lower despite publicly funded IVF implying cost is not the only barrier to IVF use.

An Introduction to Modelling Abundance and Life History Parameters in Shark Populations.

Elasmobranchs play critically important ecological roles throughout the world's oceans, yet in many cases, their slow life histories and interactions with fisheries makes them particularly susceptible to exploitation. Management for these species requires robust scientific input, and mathematical models are the backbone of science-based management. In this chapter, we provide an introductory overview of the use of mathematical models to estimate shark abundance. First, we discuss life history models that are used to understand the basic biology of elasmobranchs. Second, we cover population dynamics models, which are used to make inferences regarding population trend, size, and risk of extinction. Finally, we provide examples of applied models used to assess the status of elasmobranchs in the Northeast Pacific Ocean to guide management for these species. This chapter is not a comprehensive review of quantitative methods, but rather introduces various mathematical tools in fisheries management, with a focus on shark management in the Northeast Pacific Ocean.

Lysophosphatidic acid plasma concentrations in healthy subjects: circadian rhythm and associations with demographic, anthropometric and biochemical parameters.

BACKGROUND: Lysophosphatidic acid (LPA) is a bioactive lipid with a wide biological activity. Previous studies have shown its potential usefulness as a diagnostic marker for ovarian cancer. The aim of the study was to investigate which factors may influence plasma LPA concentrations in healthy subjects and to propose reference values. METHODS: The study group consisted of 100 healthy subjects. From all of them the blood samples were taken at 7 a.m. (fasting state). From 40 volunteers additional blood samples were taken at 2 p.m., at 8 p.m. and at 2 a.m. next morning. Concentrations of LPA were measured in plasma samples using enzyme-linked immunosorbent assay. RESULTS: Analysis of samples from 100 healthy volunteers showed significant influence of sex and age on plasma LPA. The reference range for the plasma LPA concentration corrected for age and sex, determined at 2.5-97.5 percentile interval is 0.14-1.64 µM. LPA correlates positively with BMI, serum total cholesterol, triacylglycerols, uric acid and negatively with estimated glomerular filtration rate and serum albumin. Concentration of LPA at 2 a.m. was lower than at 2 p.m. There were not any significant differences between plasma LPA at 7 a.m. and any other time of the day. CONCLUSIONS: Plasma LPA is associated with demographic, anthropometric and biochemical parameters. It seems that LPA concentrations have no specific circadian rhythm and the time of donation and fasting state have marginal effect on plasma LPA. These findings may be helpful in future incorporation of LPA as a diagnostic marker.

The Dynamics of the Defense Strategy of Pea Induced by Exogenous Nitric Oxide in Response to Aphid Infestation.

The aim of this study was to investigate the effect of exogenous nitric oxide (NO), i.e., S-nitrosoglutathione (GSNO) and sodium nitroprusside (SNP), on the metabolic status of Pisum sativum L. cv. Cysterski leaves infested by Acyrthosiphon pisum Harris, population demographic parameters and A. pisum feeding activity. A reduction in the level of semiquinone radicals in pea seedling leaves pretreated with exogenous NO occurred 24 h after A. pisum infestation, which was earlier than in non-pretreated leaves. A decrease in the level of O2•- was observed in leaves pretreated with GSNO and infested by aphids at 48 and 72 h post-infestation (hpi). Directly after the pretreatment with GSNO, an increase in the level of metal ions was recorded. NO considerably induced the relative mRNA levels for phenylalanine ammonia-lyase in 24-h leaves pretreated with NO donors, both non-infested and infested. NO stimulated the accumulation of pisatin in leaves until 24 h. The Electrical Penetration Graph revealed a reduction in the feeding activity of the pea aphid on leaves pretreated with NO. The present study showed that foliar application of NO donors induced sequentially defense reactions of pea against A. pisum and had a deterrent effect on aphid feeding and limited the population growth rate.

Effect of photoperiod on development and demographic parameters of Neoseiulus barkeri (Acari: Phytoseiidae) fed on Tyrophagus putrescentiae (Acari: Acaridae).

Effects of five photoperiods (Light:Dark = 4:20, 8:16; 12:12, 16:8, 20:4) on the development, survival and reproduction of Neoseiulus barkeri Hughes fed on storage mite Tyrophagus putrescentiae (Schrank) were examined under laboratory conditions at 85 % relative humidity and 24 °C. Development time of almost all immature stages in N. barkeri was the shortest (5.43 ± 0.12 days) under 12 h of daylight. Total duration of immature stages was as high as 8.55 ± 0.16 days during the longest photoperiod. Photoperiod had no effect on hatching rate, but did affect survival of larvae, protonymphs and deutonymphs. Total survivorship ranged from 20 (4:20) to 60 % (12:12). Under 12 h daylight, female adults had the shortest pre- and post-oviposition period, longest oviposition period and longevity, largest total number of eggs (15.95) and and highest daily egg production (1.43) per female. Under 12 h light, N. barkeri experienced its highest net reproductive rate (R 0  = 11.791), intrinsic rate of increase (r m  = 0.180), and finite rate of increase (λ = 1.197), and lowest mean generation time (t = 13.71 days) and population doubling time (DT = 3.86 days). All demographic parameters displayed a parabolic relationship with photoperiod. The results of the present study indicated that the photoperiod of 12:12 is optimal for the development and reproduction of N. barkeri fed on T. putrescentiae, and that N. barkeri may serve most efficiently as a biological control agent under this regime.

Using biological variables and reproductive strategy of the undulate ray Raja undulata to evaluate productivity and susceptibility to exploitation.

The present work provides a detailed analysis of the reproductive strategy of the undulate ray Raja undulata in Portuguese mainland waters. The species was found mostly between 30 and 40 m deep on sandy bottoms. Egg-laying sites were observed in the north, centre and south-west regions, mainly at depths below 30 m. The peak of the reproductive season occurred from December to May. Asynchrony between reproductively active females and males appeared to occur, although most adult males were capable of reproducing throughout the year. The estimated length at 50% maturity was 86·2 cm (8·7 years) and 76·8 cm (7·6 years) total length for females and males, respectively. The maximum potential fecundity was estimated to be 69·8 follicles per female per reproductive season, which are released in 4·7 batches of 15 follicles. The life-history and demographic parameters of R. undulata are similar to those of other skate species, while the potential rate of population increase (0·49) is above the published values for other elasmobranch species. With these new findings, this study makes an important contribution to the understanding of the life history of R. undulata, and provides a first evaluation of the productivity and susceptibility of the species to exploitation.