Time Of Oviposition Research Articles

Life history and temperature-dependence of cassava-colonising populations of Bemisia tabaci

The whiteflies belonging to the species group Bemisia tabaci transmit viruses that are the greatest constraint to the production of cassava, Africa’s most important food security crop. We studied the life history of an endemic African population of B. tabaci SSA-ESA at six constant temperatures (16, 20, 24, 28, 32, 36 °C) in controlled environment chambers, and for 10 generations in the field. Oviposition occurred between 20 and 28 °C, with highest fecundity (114.5 ± 88.2) eggs per female at 20 °C. Similarly, B. tabaci adult females average survival time was longest (19.7 days) at 24 °C, and shortest (8.5 days) at 36 °C. Immature development time decreased with increasing temperature from 59.3 days at 16 °C to 16.3 days at 28 °C, and increased above 28 °C. A constant temperature of 36 °C was lethal to eggs and first instars and no immature stage developed further to adults at this temperature. Several temperature-driven models were fitted for describing the species development, survival and reproduction using Insect Life Cycle Modelling (ILCYM®) software. Median temperature-dependent development rates in individual immature life stages were statistically described by Taylor, Briere 1 and Tb (Logan) models. Temperature-dependent mortality and senescence rates in immature stages were described by using parabolic nonlinear models. The longevity of adult females and oviposition time was best described by the Weibull distribution. Maximum population growth was predicted between 26 and 28 °C. These results will be useful for spatio-temporal analysis of climate change impacts on the distribution and abundance of this pest.

Are the effects of hunger stage-specific? A case study in an aphidophagous ladybird beetle.

Food availability is a fundamental factor determining an animal's potential fitness. Carry-over effects of food limitation from development to adulthood are known to influence reproduction, ageing, and tolerance to stress. We have examined the effect of stage-specific variation (before adult emergence or pre-emergence, post-emergence and post-mating) in food availability in Propylea dissecta (Mulsant). Larvae were reared separately on two different pre-emergence food regimes (abundant or restricted) until pupation. Newly emerged adults were further split into two groups and placed on abundant or restricted post-emergence regimes. After mating, females were split and reared on any one of two post-mating regimes. The results revealed that: (i) time to commence mating declined with increased food availability in pre- and post-emergence stages, (ii) mating duration increased with food availability post-emergence, (iii) highest reproduction output was observed in individuals who had abundant food pre- and post-emergence. However, food availability at the time of oviposition also had a strong influence on fecundity. Solo bouts of scarcity, regardless of which stage suffered them, were effectively managed in at least two of the three stages (pre-emergence, post-emergence, post-mating) had abundant food.

Reproductive Behavior of Copitarsia uncilata (Lepidoptera: Noctuidae).

Copitarsia sp. (Hampson) (Lepidoptera: Noctuidae: Cuculliinae) is a quarantine pest in different countries and affects diverse crops of economic importance in South America. The development of ethological control strategies is an important issue that requires knowing the reproductive behavior of the species involved. Therefore, the aim of this study was to establish the reproductive behavior of Copitarsia uncilata (Burgos & Leiva) and to evaluate the attractiveness of synthetic pheromone compounds under laboratory conditions. Observations of nocturnal reproductive behavior of males and females were performed for 7days in order to register the courtship, mating, and oviposition time. Once the period of the highest reproductive activity was identified, flight behavior and attraction of virgin males were evaluated in a wind tunnel towards synthetic compounds previously reported as commercial pheromones for Copitarsia species, namely (Z)-tetradec-9-enyl acetate (Z9-14Ac), (Z)-tetradec-9-enol (Z9-14OH), and their mixture (Z9-14Ac + Z9-14OH at 4:1 ratio), in comparison with virgin females and clean air flow. We observed that reproductive behavior occurs during the first third of the scotophase and begins on the second day after adult emergence. Highest proportion of courtship and mating occurs on days 2 and 3 after emergence, and oviposition starts the night immediately after the first mating. Wind tunnel assessments showed that males were highly attracted to calling females compared with the blend of synthetic pheromone compounds, with 89% and 12% of males landing at the source, respectively. Moreover, males also showed a low response to the isolated compounds (Z9-14Ac 14% and Z9-14OH 4%).

Effects of Genotype and Oviposition Time on Egg Quality Traits of Commercial Laying Birds

This study aimed at investigating the effects of strain of layers and oviposition time on external and internal egg quality traits. The strains of layers used for this study are Isa Brown (IB), Bovan Nera (BN) and Dominant Black (DB). The time of oviposition investigated are 8-10am, 10-12noon, 12-2pm and 2-4pm. Freshly laid eggs were collected from the different strains during the aforementioned periods, and were taken to the laboratory for both external and internal egg quality analysis. Analyzed results showed that egg weight was not significantly (P>0.05) affected by strain. The three strains recorded similar mean values. Similar results were reported for other traits except egg length and shell thickness where significant differences were reported among the strains. BN and IB were superior to DB in terms of shell thickness. With regard to internal egg quality traits, significant (P<0.01) differences among strains were reported only for yolk weight and albumen width. Pertaining to oviposition effect, almost all the traits were significantly influenced by oviposition time. Both external and internal egg quality traits had superior (P<0.01) and higher mean values during morning than afternoon or evening collection. This might be due to very low temperature prevailing in the former and which encouraged the birds to eat more resulting to bigger egg size and higher egg compositions. Haugh unit in this study was not significantly affected by strain and oviposition time. It is suggested than management practices in laying farm such as lighting and feeding pattern be focussed on having more eggs laid in the morning session than afternoon or evening session.

Evaluation of prey stage preference of the predatory mite Neoseiulus longispinosus (Evans) on the spider mite pest Tetranychus neocaledonicus (André) (Acari: Phytoseiidae, Tetranychidae)

Tetranychus neocaledonicus, the commonly called vegetable spider mite is a highly polyphagous pest, infesting over 500 species of economic plants. The species has been categorized as a major pest, inducing considerable feeding damage on vegetables, fruit crops, medicinal plants, ornamentals, plantation crops etc. The present study was concentrated to assess the predatory potential of a phytoseiid predator, Neoseiulus longispinosus on the different life stages (egg, larva, nymphs and adults) of T. neocaledonicus under laboratory conditions. Separate experimental set ups were prepared with leaf arena of mulberry plants and known numbers of different life stages of the pest mite were maintained on individual leaf arena. For evaluating the predatory potential, adult females of N. longispinosus were introduced on to the individual leaf discs in the arenas and observations were made under a stereomicroscope to record the response of the predator to the individual life stage of the pest mite. The number of prey stages consumed by the predator on individual leaf arena was recorded for a time interval of 24 hrs and the rate of consumption on individual prey instar was calculated. Except at the time of oviposition, the adult predator was found to make active prey searching movement randomly, in and around the prey patches. By sensing the prey through successive contacts with the first pair of legs and pedipalps, the predator initiated feeding actively, and sucked out the entire fluid content with its mouth parts. The adult predator showed a specific preference to feed on the egg stage of the prey mite while the predator nymph exhibited preference to the nymphal stages of the prey. A decreasing sequence in the order egg > larva > nymphs> adult was recorded in the feeding preference of the adult predator towards life stages of the prey mite and the per cent consumption on egg, larva, nymphs and adult female stages was 48.4, 29.9, 26.6 and 9.3 %, respectively. However, the feeding preference of the nymphal stage of the predator showed a slight deviation in the order nymph > larva > adult > egg and the mean rates of consumption were 31.3, 22, 11.2 and 10.3 %, respectively. Data gathered on consumption rates of the predator upon statistical analysis revealed a significant variation towards different stages of T. neocaledonicus, thereby establishing a specific preference to prey eggs by the predator.

In ovo metabolism of estradiol to estrone sulfate in chicken eggs: Implications for how yolk estradiol influences embryonic development

The steroid 17β-estradiol (herein “estradiol”) is a potent regulator of sexual differentiation that exerts wide-ranging effects on the developing brain and other tissues. The developing gonads are an important source of estradiol but most, if not all, vertebrate embryos are also exposed to maternally derived estradiol during development. In birds, this maternally derived estradiol is present in the egg at the time of oviposition but very little is known about how this source of estradiol influences development. A critical aspect of understanding yolk estradiol effects is deciphering how steroid metabolism may regulate embryonic exposure to yolk estradiol. In this study, we examine the metabolic fate of estradiol during the first five days of incubation in chicken (Gallus gallus) eggs. Using tritiated estradiol to trace the movement and metabolism of estradiol, we demonstrate that estradiol is metabolized to estrone, which is subsequently conjugated to estrone sulfate as the primary metabolite. Estrone sulfate then accumulates in the albumen by day five of incubation. Overall, these findings have important implications for how yolk estradiol may influence development and alter offspring phenotype. Mechanisms through which estradiol, as well as estrone sulfate, might elicit effects are discussed.

Influence of crate size, oviposition time, number of adults and cannibalism on the reproduction ofTenebrio molitor

In an industrialised mealworm farm it is important to maximise the production and to know the number of mealworms in each container as early as possible in a fast and reliable way. Two experiments were performed. The first experiment assessed the influence of the number of beetles, crate surface area and oviposition time on the number produced mealworms. A full factorial design was used with 11 beetle densities (between 2.3-300 mg beetles/cm2), 5 oviposition times (from 1-14 days) and 4 different crate sizes (between 250-2,000 cm2). In the second experiment, the influence of cannibalism on the number of produced mealworms was assessed via an alternative oviposition method that prohibited cannibalism. Multiple linear regression was used to model the results. The results indicate that the number of beetles, oviposition time and surface area could predict the number of produced mealworms well. An increase in one of the three parameters increased the number of produced mealworms without reaching an optimum. Furthermore, the number of beetles and the oviposition time can be combined in one parameter, beetledays with minimal loss of predictive power of the model. Nevertheless, the number of produced mealworms per female did decline rapidly with increasing oviposition time and density. The latter is, at least in part, due to cannibalism, as the second experiment indicates that the density effect is almost eliminated when the beetles are unable to reach their eggs. In conclusion, this study indicates that it is possible to construct a formula that can be used toa priori determine the final number of produced mealworms based on the number of beetles, surface area and oviposition time and that cannibalism can greatly reduce the number of produced mealworms. Reducing cannibalism can greatly increase the efficiency and therefore production of a mealworm farm.

The Embryos of Turtles Can Influence Their Own Sexual Destinies

Sessile organisms with thermally sensitive developmental trajectories are at high risk from climate change. For example, oviparous reptiles with temperature-dependent sex determination (TSD) may experience strong (potentially disastrous) shifts in offspring sex ratio if reproducing females are unable to predict incubation conditions at the time of oviposition. How then have TSD reptile taxa persisted over previous periods of extreme climatic conditions? An ability of embryos to move within the egg to select optimal thermal regimes could buffer ambient extremes, but the feasibility of behavioral thermoregulation by embryos has come under strong challenge. To test this idea, we measured thermal gradients within eggs in semi-natural nests of a freshwater turtle species with TSD, manipulated embryonic thermoregulatory ability, and modeled the effects of embryonic thermoregulation on offspring sex ratios. Behavioral thermoregulation by embryos accelerated development and influenced offspring sex ratio, expanding the range of ambient conditions under which nests produce equal numbers of male and female offspring. Model projections suggest that sex ratio shifts induced by global warming will be buffered by the ability of embryos to influence their sexual destiny via behavioral thermoregulation.

Relationship between cyclic follicle recruitment and ovulation in the hen ovary

Determining whether follicle recruitment in the domestic hen is functionally linked to ovulation would inform investigations on the exact time of cyclic recruitment and subsequently, the earliest cellular event mediating recruitment. The objective of the present studies was to determine if the absence of ovulation results in the failure of cyclic recruitment. 3 groups of Hy-Line W-36 hens were studied: no-ovulation, first-ovulation, or late-ovulation within the sequence. Time and occurrence of oviposition and ovulation were documented by video recording and cloacal palpation. To determine the presence of a recently recruited follicle, ovaries were collected during the last hour of photoperiod, and follicles weighing 280 to 900mg, with yellow yolk incorporated, and diameter of 9 to 12mm, were considered recently recruited. To compare the amount of yolk uptake in recruited follicles, hens were fed Sudan IV dye 6h before ovary collection. Percent dyed yolk was quantified from cross-sections of the recruited follicles. To confirm follicle viability, granulosa cell (GC) mitotic activity was assessed via flow cytometry. Initial results indicated the presence of a recently recruited follicle in 10 of 11, 7 of 10, and 9 of 10, no-ovulation, first-ovulation, and late-ovulation ovaries, respectively, with no significant differences in weight (543 ± 62mg, 456 ± 71mg, 620 ± 75mg, respectively). There were no significant differences in yolk incorporation among the most recently recruited follicles with 19.0 ± 2.0%, 18.0 ± 3.7%, and 19.8 ± 3.2% dyed yolk in no-ovulation, first-ovulation, and late-ovulation ovaries, respectively. Finally, there were no significant differences in % GC in the S/G2-M phase of mitosis among recruited follicles (19.0 ± 5.0%, 22.0 ± 4.2%, 15.67 ± 1.0%, in no-ovulation, first-ovulation, and late-ovulation ovaries, respectively), confirming viability of all recruited follicles. We conclude that cyclic recruitment occurs independently of ovulation and propose that the order and timing of cyclic recruitment is predetermined at an earlier stage of follicle development.

Effect of Hen Oviposition Time on some Egg Characteristics

Ovulation in chicken is the process of emergence the egg yolk by controlling the steroid hormones, which is followed by oviposition that influence by several factors. Egg yolk is a huge oocyte contains fat in water emulsion with about 50% dry weight, its rounded and centrally located. The experiment was carried out to investigate the effect of oviposition time on egg external traits (egg weight, egg length, egg breadth), yolk characteristics (yolk weight, yolk high, yolk diameter, yolk index, and the proportion of yolk weight to egg whole weight), and investigate the correlations between these characteristics by using Ross 308 hybrid.When the flock was 30 weeks age, 150 fertilizes egg was used, which collected in three times, Period (1) = 9:30 am, Period (2) = 11:30 am, and Period (3) = 1:30 pm, which supplied from KOSAR company.The results reveal significant differences between the times of collection for all the yolk characteristics and egg external traits.It does conclude the yolk characteristics were differs significantly between the oviposition times and the yolk weight was highly correlated with yolk diameter, egg breadth, and proportion of yolk weight to the whole egg weight.

In-hive variation of the gut microbial composition of honey bee larvae and pupae from the same oviposition time

BackgroundKnowledge of microbiota composition, persistence, and transmission as well as the overall function of the bacterial community is important and may be linked to honey bee health. This study aimed to investigate the inter-individual variation in the gut microbiota in honey bee larvae and pupae.ResultsIndividual larvae differed in the composition of major bacterial groups. In the majority of 5th instar bees, Firmicutes showed predominance (70%); however, after larval defecation and during pupation, the abundance decreased to 40%, in favour of Gammaproteobacteria. The 5th instar larvae hosted significantly more (P < 0.001) Firmicutes than black pupae. Power calculations revealed that 11 and 18 replicate-individuals, respectively, were required for the detection of significant differences (P < 0.05) in the Bacteroidetes and Firmicutes abundance between stages, while higher numbers of replicates were required for Actinobacteria (478 replicates) and Gammaproteobacteria (111 replicates).ConclusionsAlthough sample processing and extraction protocols may have had a significant influence, sampling is very important for studying the bee microbiome, and the importance of the number of individuals pooled in samples used for microbiome studies should not be underestimated.

Do Local Environmental Factors and Lunar Cycle Influence Timing and Synchrony of Oviposition of a Turtle with Strict Nocturnal Nesting?

Timing of nesting affects fitness of oviparous animals living in seasonal environments, and females may cue on environmental factors for their nesting behavior, but these relationships are understudied in tropical turtles. Here, the timing and synchrony of egg-laying relative to environmental factors were examined in the South American freshwater turtle Podocnemis unifilis on 11 nesting beaches during three nesting seasons. Daily measurements included number of nests laid, rainfall, river level, air temperature, and the phase of the lunar cycle (full moon, last quarter, new moon and first quarter). Results confirmed that P. unifilis nested at night and revealed that females in our population nest in groups from 2 to 17 females at a time. Nesting was not correlated with rainfall, but a significant relationship was found with river level, such that nesting started at the onset of the dry season when river levels dropped and nesting grounds emerged. Importantly, we found that (1) nesting events concentrated on days with intermediate daily maximum air temperature (although maxima changed annually), and that (2) larger groups of females nested around full moon, suggesting the reliance on visual cues to initiate nesting activities (consistent with social facilitation behavior). Altogether, the timing of nesting in P. unifilis may be shaped by a combination of environmental factors, moon phase and social facilitation, where visual cues play an important role.

Modeling mountain pine beetle (Dendroctonus ponderosae) oviposition

AbstractMountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae), is a significant forest disturbance agent with a widespread distribution in western North America. Population success is influenced by temperatures that drive phenology and ultimately the adult emergence synchrony required to mass attack and kill host trees during outbreaks. In addition to lifestage‐specific developmental rates and thresholds, oviposition timing can be a source of variance in adult emergence synchrony, and is a critical aspect of mountain pine beetle phenology. Adaptation to local climates has resulted in longer generation times in southern compared to northern populations in common gardens, and the role of oviposition rate in these differences is unclear. Oviposition rates and fecundity in a northern population have been described, although data are lacking for southern populations. We assessed southern mountain pine beetle oviposition rates and fecundity in a range of temperatures using a non‐destructive technique that included frequent X‐ray imaging. We found that oviposition rate and fecundity vary independently such that a female with high oviposition rate did not necessarily have high fecundity and vice versa. Observed fecundity within the 30‐day experimental period was lowest at the lowest temperature, although estimated potential fecundity did not differ among temperatures. Females at varying temperatures have the potential to lay similar numbers of eggs, although it will take longer at lower temperatures. Southern mountain pine beetle reared in Pinus strobiformis Engelm. (Pinaceae) had a higher upper threshold for oviposition, a similar lower threshold, and slightly greater potential fecundity compared to a northern population reared in Pinus contorta Douglas. A comparison of modeled oviposition rates between the two populations, which could be influenced by host tree, suggests that differences in oviposition rate do not explain observed differences in total generation time. Our oviposition model will facilitate development of a phenology model for southern mountain pine beetle populations.

Serum prolactin and testosterone levels in captive and wild brown kiwi (Apteryx mantelli) during the prebreeding, breeding, and incubation periods.

In brown kiwi (Apteryx mantelli), the male is the primary incubator, a trait that is relatively rare among birds. The maintenance of avian incubation behavior is controlled by the protein hormone prolactin (PRL). Although steroid hormone concentrations in both wild and captive kiwi have previously been reported, this study is the first to report levels of PRL in captive and wild male and female kiwi through the prebreeding and breeding seasons, and to directly compare testosterone (T) concentrations between captive and wild males during the breeding and incubation periods. Female PRL concentrations increased at the time of oviposition, whereas male PRL concentrations rose gradually between the prebreeding and incubation periods. Although males are considered the main incubator, an increase in PRL levels could help females maintain behaviors such as nest guarding, or to take over incubation the event of mate loss. A gradual increase in PRL allows the male to be ready for incubation during the long breeding season. Interestingly, T concentrations in captive males did not decrease during incubation and was significantly higher than in wild males. Continual elevated T could have an impact on sperm production through negative feedback, thereby contributing to the low egg fertility seen in captive kiwi. Therefore, determining the underlying reason for the differences in hormone levels could be significant, if not vital, for improving the success of captive kiwi breeding programs.

Frequent double ovipositions in two flocks of laying hens

Laying hens have been selected over generations for maximal reproductive efficiency. As a result, the incidences of abnormal eggs and abnormal laying patterns are relatively low for these strains. While double ovulations, resulting in the production of double-yolked eggs, does occur on occasion in young birds just entering reproductive maturity, these double ovulations almost never result in 2 fully formed eggs, and are rare in hens that have reached peak reproductive productivity. However, there appears to be an increasing number of anecdotal accounts of backyard hens that lay more than 1 egg per day (hereafter called double oviposition). We hypothesized that double ovipositions in modern strains of laying hens are more common than previously thought. To test this, we observed a flock of Hy-Line W36 hens for 2 consecutive weeks, recording the time of oviposition for each hen on each day. We found that 13% of hens produced a double oviposition at least once during this 2-wk observation period, often producing a second egg within 2.5h of the first. One hen produced double ovipositions on 3 d during this short period. We then monitored a second flock of hens for 6 wk, collecting eggs that were part of a double oviposition and, on one day, all eggs that were part of double ovipositions. Eggs that were part of double ovipositions showed no external shell abnormalities, and were similar in size, weight, and specific gravity to single ovipositions, suggesting that laying hens can, and do, produce 2 fully formed eggs within hours of one another. We suggest that this may represent selection for maximal reproductive performance in a modern strain of laying hens.

SNP Typing Using Multiplex Real-Time PCR Assay for Species Identification of Forensically Important Blowflies and Fleshflies Collected in South Korea (Diptera: Calliphoridae and Sarcophagidae).

Medicolegal entomology—a subfield of forensic entomology—is mainly used in medicolegal investigations to estimate the postmortem interval (PMI). The minimum PMI of a corpse invaded by necrophagous immature insects can be estimated because the PMI is near to or earlier than the oviposition time of the larvae that hatched and fed on the corpse. As the growth speeds of larvae differ depending on temperature and species, species-specific growth data are used to estimate the minimum PMI. While morphological identification of adult necrophagous flies can be done by a well-trained entomologist, identification of larvae is relatively difficult. Larvae can only be identified up to the family level and developmental stage by observing the posterior spiracles. For these reasons, the molecular biology method of DNA barcoding has been developed. DNA barcoding that targets the mitochondrial cytochrome c oxidase subunit I (COI) gene is commonly used. COI sequences are currently acquired using polymerase chain reaction (PCR) and Sanger sequencing, which are too time-consuming and complex for practical use in medicolegal investigations. To compensate for these limitations and facilitate the use of entomology for medicolegal investigation, we designed a multiplex real-time PCR system to identify nineteen forensically important species of Calliphoridae and Sarcophagidae flies collected in South Korea. In contrast to the Sanger nucleotide sequencing process, this technology only requires a one-step real-time PCR with melt curve analysis of amplicons generated by primers targeting species-specific single nucleotide polymorphisms (SNPs). Multiplex real-time PCR was performed for twelve species of Calliphoridae (four reactions) and for seven species of Sarcophagidae (three reactions). This assay is expected to make it easier and faster for investigating authorities to identify major species of necrophagous flies at beginning of investigation and to increase the utilization of entomological evidence in forensic investigations.

Obyek Kesukaan Untuk Penempelan Telur (Oviposisi) Ektoparasit Argulus japonicus &lt;br&gt;&lt;i&gt;[ Preference Of Oviposition Object Of Ectoparasite Argulus japonicus]&lt;i&gt;

Abstract A. japonicus is ectoparasite that attack only freshwater fish. The fish that was attacked by A. japonicus look skinny, always rub their body and appear some red spot that will manifest for second infection. Prevent and controll of A. japonicus, were used drug or chemical materials like insecticide. This compound can damage the environment and destroy surround ecosystem. Precisely metode to controll A. japonicus was focused for egg stage. The female habits of A. japonicus always lay her eggs (oviposition) on the surface object that surround on they habitat. The research using completely randomized design (CRD). The treatment on this research use 4 oviposition object like rock, wood, plants and PVC pipe. A rock that representative a hard and rough surface. Wood that representative rather solid state and irregular surface, plants with hard surface and representative a life organism (using Echinodorus palaefolius with wide and hard surface leaf), also PVC object that representative a hard and smooth surface. For comparator treatment, all oviposition object was collected in one treatment. All treatment were replicated at four times. Object was placed on bottom aquarium for use as oviposition object, to know preference of oviposition object by oviposition periode and totally eggs produced. ANOVA (analysis of variance) and Tukey-HSD range test were used to analyze data. Results showed that significant effect (p &lt;0,05) on oviposition time and total eggs. The longest oviposition time and the higest eggs total was made by rock and pipe. The fastest oviposition time and the lowest eggs total was made by plants. Water quality during the study in optimum condition for A. japonicus and goldfish , temperature ranges from 26-28 0C, pH 7 and dissolved oxygen (DO) ranged at 5 mg/L.

Anticipatory parental effects in a subtropical lizard in response to experimental warming

Parental effects may produce adaptive or maladaptive plasticity that either facilitates persistence or increases the extinction risk of species and populations in a changing climate. However, empirical evidence of transgenerational adaptive plastic responses to climate change is still scarce. Here we conducted thermal manipulation experiments with a factorial design in a Chinese lacertid lizard (Takydromus septentrionalis) to identify the fitness consequences of parental effects in response to climate warming. Compared to present climate conditions, a simulated warming climate significantly advanced the timing of oviposition, depressed the immune capability of post-partum females, and decreased the hatching success of embryos, but did not affect female reproductive output (clutch size and egg mass). These results indicate that maternal warming negatively affects female health, and embryonic hatchability. More interestingly, we found that offspring from parents exposed to warming environments survived well under a simulated warming climate, but not under a present climate scenario. Accordingly, our study demonstrates anticipatory parental effects in response to a warming climate in an ectothermic vertebrate. However, the fitness consequences of this parental effect will depend on future climate change scenarios.

Effects of different diets on biological parameters of the predatory mite Amblyseius swirskii (Acari: Phytoseiidae)

ABSTRACTThe predatory mite, Amblyseius swirskii Athias-Henriot is one of the natural enemies of agricultural pests such as the spider mite, Tetranychus urticae (Koch). Pollen, as a food supplement or alternative food source, has a considerable impact on the efficiency of the predatory mite in the biological control programme. In this study, the effect of six distinct diets (one consisting solely of the eggs of T. urticae and the others being pollen of apricot, soybean, sesame, walnut, and date, each mixed with the eggs of T. urticae) on the biological parameters of A. Swirskii was studied. Development from egg to adult, oviposition day, and daily mortality were investigated in 65 replications for each type of food. The results demonstrated that A. swirskii was able to adapt to each of the six tested diets and growth development was considerable with each. Comparisons of the biological parameters among these diets showed that the average generation length, from egg to adult, had significant differences at the 5% level. The fertility life table parameters showed no significant differences between treatments for rm (the rate at which a population increases in size in the absence of density-dependent forces impacting the population)‚ λ (sustained increase in population in one day compared to the previous day), and R0 (number of progeny of the substituted females per person in one generation). The results showed that the oviposition and survival times of A. swirskii were greatly enhanced by the pollen diets so that a much greater efficiency of this predatory mite in biological control programmes was achieved.

Reproduction and development of Spodoptera exigua from cadmium and control strains under differentiated cadmium stress

The growth and development of living organisms is programmed in genes, but exogenous factors (e.g. cadmium) may modulate endogenous information. Heavy metals may disturb physiological functions and accumulate in the tissues. The insects under prolonged heavy metal stress show some modifications in their metabolism management.The aim of this study was to compare the reproduction and development between individuals of S. exigua from the strain, exposed over 130 generations to sublethal concentration of cadmium (44 mg Cd/kg dry weight of larval diet), and the individuals from the control strain, both additionally exposed to different concentration of cadmium (22-704 mg Cd/kg dry weight of larval diet).The exposure to various cadmium concentrations in the diet revealed survival difference between the cadmium and the control animals at the larvae stage. The differences between adults were not evident. The telomere length (responsible for the duration of a lifespan) in the cadmium strain was shorter in the females than in the males and the individuals from the control strain. TERF1 gene expression (indirectly responsible for the telomere length) was higher in the individuals from the cadmium strain 24 hrs after eclosion.The significant reduction in the larvae body mass was observed in both strains, when the metal concentration was equal to or higher than 264 mg/kg dry weight of larval diet. The EC50 values (defined as of body mass loss), calculated 48 hours after cadmium exposure of individuals from control and cadmium strains, were respectively 632 and 725 mg Cd/kg dry weight of diet.However, some difference in reproduction (the total number of eggs laid and the oviposition time) between the strains appeared only in the groups fed on the uncontaminated diet. The control females laid almost two times more eggs than those from the cadmium strain, and the control ones had more than two times longer oviposition time than the females from the cadmium strain.The fluctuation was also noted in the size of eggs and the hatching success on the following days when both strains were compared, while the hatching success was higher for the insects from the cadmium strain.In conclusion, the insects from the cadmium strain are more resistant to cadmium contamination, as it is evidenced by the EC50 parameter. However, the females from the cadmium strain start laying eggs statistically later, have shorter telomeres and slightly reduced TERF1 gene expression, but hutching success in the strain is significantly higher when compared with the control individuals.