Showing 17 results for Fecundity
Mohammad Sadegh Alavi-Yeganeh, Bahram Falahatkar,
Volume 2, Issue 3 (12-2013)
Abstract
Length-weight relationship, age range and fecundity of 40 specimens of the Russian sturgeon, Acipenser gueldenstaedtii, collected from two fishing stations in the southeastern Caspian Sea, were determined. Average length (TL) and weight were 129.5 cm and 12.7 kg for males and 145.8 cm and 22.15 kg for females, respectively. Absolute fecundity was 184000 in average and condition factor calculated 0/58 and 0/7 for male and females, respectively. Average age for males and females was 12.7 and 14.6 years, respectively. All these factors were lower than previous records from the Volga river estuary. Length-weight relationships results demonstrated isometric growth pattern with average slope of 2.978 and 2.822 for males and females respectively. These values were not statistically different between sexes (p> 0.05), but using this relationships for each sex separately will be useful for more reliable results especially in broodstock studies.
Volume 2, Issue 4 (12-2013)
Abstract
The effect of host diet on developmental time, fecundity and life-table parameters of Bracon hebetor (Say) (Hymenoptera: Braconidae) against the Mediterranean flour moth Ephestia kuehniella (Zeller) was studied in the laboratory condition at 26 ± 1 °C, 65 ± 5% relative humidity and a photoperiod of 16L:8D h. The diets used were rice, barley, corn and wheat flours. The developmental time (egg to adult) of the first and second generations ranged from 9.00 to 14.00 days on barley flour and wheat flour, respectively. The survival of immature generations 1 and 2 ranged from 27 to 63%. The sex ratio of wasp progeny (females/total) ranged from 36.72 to 57.83% on wheat flour and rice flour, respectively. In the first and second generations, the fecundity of B. hebetor reared on barley and rice flours was greatest. Life table parameters varied significantly with host diets. In generation 2, B. hebetor-parasitized larvae reared on rice flour showed the highest net reproduction rate (R0 = 106.13) and the highest intrinsic rate of increase (rm = 0.269) of parasitoids. Based on the life-table analyses, rice flour was found to be the best diet for rearing the parasitoid. The results of this study can be used to improve mass-rearing programs of B. hebetor.
Volume 2, Issue 4 (12-2013)
Abstract
Cotton bollworm, Helicoverpa armigera (Hübner) is one of the most destructive insect pests on many crops in the world that has been found to develop resistance against conventional insecticides. Using insecticides with different modes of action may result in appropriate control of the pest and delay insecticide resistance development. In this study, lethal and sublethal effects of emamectin benzoate and cypermethrin insecticides were investigated on third instar larvae of H. armigera by residue contact methods at 26 ± 1 oC, 70 ± 5% RH and a photoperiod of 16:8h (L: D) under laboratory conditions. LC50 values, on larval stage of the pest, of emamectin benzoate and cypermethrin were 1.75 and 127.74 µg a.i./ml, respectively. According to the findings, the larvae that were exposed to the LC30 of emamectin benzoate and cypermethrin exhibited lower pupal weight and increased larval and pupal developmental times compared with control. The longevity and fecundity of adults were significantly affected by the insecticides. Emamectin benzoate and cypermethrin reduced fecundity by 53.1% and 50.5%, respectively compared to control. The LC30 values of emamectin benzoate and cypermethrin reduced egg hatching by 62.06% and 37.9%, respectively. It is predicted that these insecticides, especially emamectin benzoate, may induce significant effects on population of H. armigera.
Mohammad Alavi-Yeganeh, Bahram Falahatkar,
Volume 3, Issue 1 (6-2014)
Abstract
Length-weight relationships and fecundity of 93 individual female Acipenser persicus broodstocks were investigated. The specimens were caught during 2001-2005 from Golestan, Mazandaran and Guilan provinces along the southern coast of the Caspian Sea. Total length and weight of each fish was measured to the nearest 1cm and 100 g, respectively. Age determination was carried out by using transects of the first ray of pectoral fin. The absolute fecundity was assessed by egg count per weight unit of all eggs existed in the body. The specimens were from 13 to 20 years old, of which the 16 years old had the highest proportion with 23.7%. Range of total length and weight were 132.5 to 211 cm and 14 to 42 kg, respectively. Mean absolute fecundity was estimated 267810 ± 92570. Total length, weight and absolute fecundity of fish increased with age in all cases, showed a significant positive correlation (p <0.01). The slope of the length-weight relationship (b) was equal to 2.745 and isometric growth pattern was determined in this species.
Volume 3, Issue 3 (9-2014)
Abstract
No doubt, damage and losses inflicted by Callosobruchus maculatus to stored products in general and chickpea in particular can be significant. The objective of this work was to evaluate the effect of the Verbascum sinuatum powder on C. maculatus oviposition behavior in chickpea under laboratory conditions (30 °C, 60% relative humidity). Powder of Mullein plant (V. sinuatum) caused reduction in fecundity, fertility, adult emergence from seeds and chickpea weight loss depending on treatment concentration (0.1, 0.05 and 0.025 g/ ml). It reduced the number of eggs laid by the weevil at first concentration to 136 eggs, the egg hatching rate at 52.22% and adult emergence to 34.03%. The percentage of seed weight loss was reduced at all studied concentrations but not significantly different at second and third concentrations compared to control. The lowest weight loss of seeds was registered at first concentration (4.7%). V. sinuatum, according to this study, showed a significant potential to reduce the egg deposition and chickpea seed weight loss due to the chickpea beetle.
Volume 4, Issue 1 (3-2015)
Abstract
It has been hypothesized that the survival, development, fecundity and population of insects are affected significantly by high temperatures. The diamondback moth, Plutella xylostell (L.) (Lepidoptera: Plutellidae), is a serious and economically important pest of cruciferous crops throughout the word. In this research, the adult longevity and fecundity of P. xylostella were studied in laboratory conditions. After applying heat shock stress, (30, 35 and 40 °C) for 2, 4, 6 and 8h, the experiments were conducted at 25 ± 1 °C, 65 ± 5% RH, and a photoperiod of 16:8 (L: D)h on Brassica napus. The developmental time of immature stages were significantly affected by heat shock temperatures (30 to 40 °C) compared to the 25 °C (control), but the developmental time of larvae did not differ significantly at 40 °C. The pupal development time differed significantly at heat shock temperatures, which was longest (6.13 ± 0.05 days) at 30 °C for 2h. Heat shock temperature also had significant impact on adult longevity and fecundity of diamondback moth. The longest adult longevity for females and males was determined to be 14.47 ± 1.04 and 11.04±0.95 days respectively at 35 °C for 2h. The fecundity of females fluctuated significantly with increasing temperature stress. Our findings provide useful information on the potential of this insect in response to environmental temperature changes.
Volume 4, Issue 1 (3-2015)
Abstract
The prey suitability for generalist predators is an important feature for efficient mass rearing and IPM. The green lacewing, Chrysoperla carnea (Stephens) is a polyphagous predator attacking several pests on various crops. This experiment was conducted under laboratory conditions at 25 ± 2 °C, 60 ± 5% R. H. and a photoperiod of 16L: 8D h. The effects of different prey species were investigated on the pre-imaginal development, survival, adult longevity and fecundity of the green lacewing. The results indicated that duration of each pre-imaginal stage development and total development time in C. carnea were significantly affected by species of prey tested. The total developmental period was 19.63 ± 0.125, 20.63 ± 0.180, 22.06 ± 0.183, 22.35 ± 0.120, and 23.81 ± 0.356 days on Aphis gossypii (Glover), Myzus persicae (Sulzer), Aphis punicae (Passerini), Aphis fabae (Scopoli) and Aphis craccivora (Koch),respectively. The maximum mean fecundity per female of C. carnea was 478.50 ± 8.38 eggs recorded when fed as larvae on M. persicae followed by 409.33 ± 8.16 eggs on A. gossypii, whereas, the minimum of 242.78 ± 7.37 eggs was recorded when fed on A. craccivora nymphs. The longest female longevity was recorded for C. carnea fed on M. persicae. There was significant difference in adult longevity due to feeding on different preys. However, nymphs of M. persicae and A. gossypii were the best of the prey species tested, in that when fed on these species the pre-imaginal developmental period of C. carnea was shorter and its adult longevity, fecundity and percentage survival was greater than those fed on the other preys. These findings could be useful in defining more optimum conditions for the mass rearing of C. carnea in IPM programs.
Volume 5, Issue 2 (6-2016)
Abstract
Glyphodes pyloalis Walker is a serious pest of mulberry trees in Iran. In this study, lethal (LC50 = 19 ppm) and sublethal effects (LC10 = 3.74 andLC30 = 9.77 ppm) of lufenuron were evaluated against 4th instar larvae of G. pyloalis. After treating the larvae at LC30 and LC50 level, most of them died during the molting process and only a few individuals developed to the 5th larval instar. The highest rate of mortality wasobserved in 5th larval (68.42%) and pre-pupal (59.57%) stages at LC50 concentration. Also, lufenuron caused an increase in larval, pre-pupal and pupal developmental periods. The successful pupation decreased to 53.64% at the LC30. Also, no prepupa molted to pupation after treatment of larvae at the LC50. Larval weight was significantly reduced at 48, 72 and 96 h after treatment, compared to the control. Adult emergence and female longevity were also reduced at LC30. The LC30 of lufenuron negatively affected reproduction of G. pyloalis. Larval content of carbohydrate and protein were decreased significantly 48 and 72 h after treatment, however, lipid and glycogen content were decreased significantly only 72 h after treatment at LC10, LC30 or LC50. Findings indicated adverse effects on some biological and biochemical parameters at lethal and sublethal concentrations of lufenuron which necessitate further investigations for its application in an integrated management of G. pyloalis.
Volume 5, Issue 2 (6-2016)
Abstract
Angoumois grain moth, Sitotroga cerealella (Olivier) is one of the most important pests of stored products and known as factitious host for mass rearing of insect natural enemies. Effect of four commercial barely varieties including Fajr 30, Behrokh, Nik and Yousef on life table parameters of S. cerealella was determined at 26 ± 2 °C, 65 ± 5% RH and a photoperiod of 12:12 h (L: D). Data were analyzed based on the age-stage, two-sex life table theory. The results revealed that there were significant differences among various barely varieties regarding the developmental times, adult longevity and fecundity of S. cerealella. The longest developmental time (56.72 ± 0.29 days) was observed on Yousef. The longest and shortest male longevity were obtained on Behrokh (6.77 ± 0.27 days) and Yousef (5.79 ± 0.16 days). Moreover, female longevity ranged from 6.20 ± 0.18 to 7.23 ± 0.24 days on Yousef and Behrokh, respectively. The highest values of intrinsic rate of increase (r) were estimated 0.0719 ± 0.004 and 0.0717 ± 0.003 day-1 on Fajr 30 and Behrokh, respectively and the lowest values were 0.0539 ± 0.004 and 0.0542 ± 0.003 day-1 on Nik and Yousef, respectively. The longest generation time (T) was observed on Yousef. Furthermore, peaks of reproductive value occurred at ages of 45, 49, 48 and 53 days when reared on Fajr 30, Behrokh, Nik and Yousef, respectively. It can be concluded that Fajr 30 and Behrokh can be used for mass rearing programs of S. cerealella as an alternative host for natural enemies.
Y. Keivany, S.s. Mortazavi , O. Farhadian ,
Volume 7, Issue 2 (6-2018)
Abstract
Aims: King Nase fish (Chondrostoma regium) is a benthopelagic species that lives in stagnant and current water with a temperature range of 3-21°C and in the middle and upper parts of the river. The aim of this study was to evaluate the reproductive characteristics of King Nase fish.
Materials and Methods: In this experimental study, 335 fish were randomly caught and transferred to the laboratory after anesthetization and fixation for biometric measurements and dissections. The data were analyzed by one-way analysis of variance (ANOVA), Duncan's multiple range test (MRT), and unpaired T-test and SPSS 19 software.
Findings: The fork length and weight changes in male and female fish in all age groups, except for 1 and 2 year in females, showed a significant difference. There was a significant correlation between fork length, weight, and age of fish with its fecundity (r2=0.6922; r2=0.6852; r2=0.7284). Age groups of the males and females were 1 to 5 and 1 to 6 years, respectively. The sex ratio of male to female was 1:1.3. The oocyte diameter significantly increased from April to June and decreased in July and August. Changes in oocyte diameter corresponded to gonadosomatic index. The highest gonadosomatic index in males and females was in April and June, respectively, and varied with other months (p<0.05). The mean of this index was significantly higher in females than in males. The hepatosomatic index showed a significant difference during the months of the year (p<0.05). The spawning season was from late March to June.
Conclusion: The spawning season of King Nase fish is from late March to June and has a group simultaneous spawning pattern.
Volume 8, Issue 1 (1-2019)
Abstract
The nematotoxic potential of water extracts and green manures prepared from three plant species, daikon Raphanus sativus var. longipinnatus L., purslane Portulaca oleracea L. and chinaberry Melia azedarach L., on Globodera rostochiensis was examined in vitro and in microplots. Significant alteration in J2 (second stage juvenile) activity and their hatching from eggs was observed with different exposure times by all plant species; more than 99% of the J2s were inactivated after 72h and the same degree of inhibition in hatching of the eggs occurred after exposure to the plant extracts. In microplots, the numbers of newly formed cysts and final nematode multiplication rates were reduced in unsterilized soil at 1, 3 and 5% (w:w) rates of amendment with fresh plant materials, and the infestation rates of potato plants did not differ significantly from those in soil treated with metham sodium 37%. The rate of emergence of J2 from cyst inocula declined by 36% in soil treated with chinaberry and purslane and by 71% in soil treated with daikon. The reduced availability of J2 in soil must be one of the reasons for decrease in nematode multiplication rates of 65% and 86% where soil was amended with chinaberry/purslane and daikon, respectively. In terms of plant growth improvement and nematode control, daikon amendment outperformed other treatments, including metham sodium.
Volume 8, Issue 3 (6-2019)
Abstract
In the present study, the toxicity of three oxygenated monoterpenes, viz., (R)-carvone, (R)-camphor and (1R, 2S, 5R)-menthol was evaluated against the adults of the peach fruit fly, Bactrocera zonata (Saunders). Effects of these monoterpenes on oviposition, adult longevity and ovarian development have also been studied. The tested compounds revealed strong toxic effect against the adults of B. zonata. Nevertheless, (-)-carvone showed higher insecticidal activity than (1R, 2S, 5R)-menthol and (R)-camphor. Moreover, the tested monoterpenes induced significant reduction in female longevity at 20 and 50 mg/kg compared with control, with (-)-carvone being the most effective monoterpene. In addition, egg deposition was completely inhibited when the adults were treated with (-)-carvone at 20 and 50 mg/kg, and (1R, 2S, 5R)-menthol and (R)-camphor at 50 mg/kg. Histological studies indicated that monoterpenes induced delay in the development of ovarioles of females that fed on artificial diet treated with 20 and 50 mg/kg of compounds. Changes, such as empty egg chambers; constricted germarium, vacant spaces between ovarioles and failure of oocyte formation were observed.
Volume 9, Issue 1 (12-2020)
Abstract
The Mediterranean flour moth, Ephestia kuehniella (Zeller) (Lep.: Pyralidae) is not only known as stored products pest, but also used as a potential factitious host for mass rearing of biological agents. The aim of this study was to evaluate the effect of five different cereal cultivars (Wheat: Homma, Mihan and Zareh; Corn: 704 and Barley: Makui) on feeding performance and life table parameters of E. kuehniella, which was estimated by Carey life table producer. The results showed that preadult period ranged from 46.91 to 59.00 days on Corn and Zareh, respectively. The highest and lowest net reproductive rates (R0) were obtained on Homma (128.76) and Zareh (61.77) offspring/female, respectively. The highest values of the intrinsic rate of increase (r) and finite rate of increase (λ) were on Corn and Homma and the lowest was on Zareh (r: 0.079 day-1, λ: 1.08 day−1). Based on the life history and demographic parameters results, Corn and Homma were the most suitable hosts for E. kuehniella. These findings may provide helpful information in integrated pest management programs including rearing of E. kuehniella as the alternative host, which could be used in the mass production of natural enemies.
Volume 12, Issue 2 (4-2010)
Abstract
The biology of Chrysocharis pentheus (Walker) (Hymenoptera: Eulophidae), the most abundant endoparasitoid of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) in Ehime prefecture, Japan, was studied under laboratory and field conditions. The mean immature developmental time and adult longevity at different temperatures (22 to 31°C) under 50-70% RH decreased as the temperature increased, and females survived longer than males. The developmental threshold of male and female was 8.9°C and 11.9°C, respectively. The effective accumulative temperature (thermal constant) for males and females from egg to adult was 181.8 and 238.1 degree-days, respectively. C. pentheus appeared to be a synovigenic species. The offspring sex ratio from females provided with males was 73.8% males and 26.2% females. Presumably, mated females began oviposition 1-2 days after emergence and continued for up to 40 days. Females laid a mean of 118.2±10.10 eggs each, and their longevity reached 32.3±0.30 days at 27±1°C, 50-70% RH. The intrinsic rate of natural increase (rm) was 0.144. Host feeding or stinging without oviposition killed 65.7±8.65 P. citrella larvae per female. Oviposition in the field was highest (62.7%) on the third instar larva of P. citrella, with the rest on the prepupal stage (37.3%), showing a significant preference for third instars. The sex ratio (M:F) of C. pentheus reared from the third instar larvae of host and pupae was 3.3:1.0 and 1.0:3.0 respectively.
Volume 20, Issue 5 (7-2018)
Abstract
The two-spotted spider mite, Tetranychus urticae Koch, causes major yield loss in numerous plants. The control of this mite is achieved mainly with synthetic acaricides; other strategies are the use of predatory mites or plant natural products. This study evaluated the effects of Lavandula latifolia Medik. (Lamiaceae) essential oil on the survival rate and fecundity of T. urticae by slide-dip and leaf-disk bioassays. Acute contact toxicity was provoked by different spike lavender oil concentrations although 95-100% mortality was observed when emulsions contained at least 0.20% (v/v). In the residual toxicity experiments, lavender oil (0.15-0.25%) reduced mite survival and affected its fecundity; laid eggs and emerging larvae were lowered as the oil concentration increased. Incubation temperature determined egg viability; 12ºC did not allow larval development, while the highest percentage of hatched eggs was counted at 30ºC. Our results confirmed the possibility of using spike lavender oil as an alternative to conventional pesticides.
Volume 20, Issue 5 (7-2018)
Abstract
The effects of different fertilizers including ‘Cow manure’, ‘Vermicompost’, ‘NPK’ (20-20-20 NPK), ‘NPKBN’ (NPK+Azotobacter vinelandii), ‘NPKBP’ (NPK+Pantoea agglomerans+Pseudomonas putida), and ‘NPKBNBP’ (NPK+Azotobacter vinelandii+Pantoea agglomerans+Pseudomonas putida) were compared with the control treatment. Comparisons included not only the nutrient and chlorophyll content of cucumber leaves, but also the demographic parameters and body size of Aphis gossypii Glover. The highest nitrogen content (2.45%) was observed in ‘NPKBN’ and the highest phosphorus, along with potassium content (0.58 and 12.17%, respectively) was observed in ‘cow manure’ treatment. The highest chlorophyll content (37.51 SPAD units) was measured in ‘NPKBNBP’ treatment. Results showed that the intrinsic rate of increase (r) varied from 0.409 (in ‘Cow manure’) to 0.480 d-1 (in ‘NPKBP’) under application of different fertilizers. Net Reproductive rate (R0) varied from 71.65 to 79.25 nymphs/individual in ‘Vermicompost’ and ‘NPKBP’ treatments, respectively. The largest (1.28 mm) and smallest (1.00 mm) body length of the aphids was measured on ‘Vermicompost’ and ‘Control’, respectively. Results revealed that ‘NPKBP’ was the most suitable fertilizer for population growth of A. gossypii, compared with the other treatments, and the aphid’s longevity and fecundity was relatively low under ‘Vermicompost’ application.
Volume 20, Issue 6 (11-2018)
Abstract
Safflower (Carthamus tinctorius L.) is an important oilseed crop in Iran and many other countries around the world. Safflower fly, Acanthiophilus helianthi Rossi is one of the main limiting agents to expand the production area of the crop in different countries and the most major pests of safflower in Iran. In this research, the influence of 10 safflower genotypes on biology and population parameters of A. helianthi was evaluated under the laboratory conditions at 25±1°C, 65±5% relative humidity, and a photoperiod of 16:8 (L: D) hours. The shortest and longest total developmental time were recorded in Mexico 37 (16.85±0.31) and Goldasht (21.76±0.59), respectively. The intrinsic rate of natural increase (r) ranged from 0.129 to 0.186 (day-1), which was lowest on Goldasht and highest in Mexico 37. The net reproductive rate (R0) ranged from 50.809 to 125.846 offspring on different genotypes. The values of finite rate of increase (λ) and mean generation time (T) on different safflower genotypes ranged from 1.138 to 1.205 day-1 and 25.778 to 30.421 days, respectively. The results demonstrated that Goldasht, Line 411, and KW2 genotypes were less suitable host plants, suggesting that they are more resistant to A. helianthi than the other genotypes, have high yield, and could have the potential for using in Integrated Pest Management program (IPM) of A. helianthi in safflower fields.
