Total Developmental Duration Research Articles

Comparison of life cycle traits of a Helopeltis theivora Waterhouse (Heteroptera: Miridae) population infesting organic and conventional tea plantations, with emphasis on deltamethrin resistance

The tea mosquito bug, Helopeltis theivora (Waterhouse), is an important economic pest of tea in India. The development of resistance in H. theivora populations obtained from a conventional plantation as compared with a strain from an organic plantation was studied in the laboratory for five generations, and associated changes in life cycle traits were assessed. Selection using sublethal concentrations of deltamethrin resulted in a 5.19-fold increase in insecticide resistance ratio from the F1 to the F5 generation in the H. theivora population from the conventional plantation. By the F5 generation, nymphal duration and total developmental duration and adult longevity were higher and fecundity was lower in the deltamethrin-selected strain than in the non-selected strain from a conventional plantation and the susceptible strain from an organic plantation. These findings have practical implications for insecticide resistance management of this important sucking pest of tea.

Temperature-Dependent Development, Life Table Parameters and Predation Rate of Euseius scutalis (A.- H.) Fed on the Two-Spotted Spider Mite

Biological aspects, thermal requirement, predation rate and life table parameters of the phytoseiid predatory mite Euseius scutalis (A.– H.) fed on nymphs of Tetranychus urticae Koch was determined at four temperature degrees, 15, 20, 25 and 30 °C. The total developmental durations of female was correlated negatively with increasing temperature. Minimum developmental thresholds (To) of egg, larva, protonymph, deutonymph, total immature stages and life cycle of E. scutalis female averaged, 4.26, 10.98, 6.90, 1.20, 2.49 and 2.89; respectively. On the other hand E. scutalis female required 208.33 DD to reach adulthood. The net rate of natural increase (rm) was 0.008, 0.126, 0.166 and 0.193, whereas the finite rate of increase (erm) averaged 1.092, 1.134, 1.181 and 1.213 at 15, 20, 25 and 30 o C; respectively.

Thermal requirements and biological life table parameters of the predatory mite Amblyseiella denmarki (Zaher and El-Borolossy) (Acari: Phytoseiidae)

The biological aspects, thermal requirements and life table parameters of the phytoseiid predatory mite Amblyseiella denmarki fed on Aceria dioscoridis was determined at four temperatures, i.e. 15, 20, 28 and 35°C. The total developmental durations for both females and males were correlated negatively with increasing temperature. The minimum developmental thresholds (T 0) of egg, larva, protonymph, deutonymph stages and life cycle of A. denmarki females averaged 13.15, 4.56, 11.22, 12.72 and 11.80, respectively, while those of males were 12.40, 3.01, 9.82, 10.88 and 10.04. On the other hand, females and males required 89.28 and 93.45 degree days (DD), respectively, to reach adulthood. The male life span averaged 63.32, 49.25, 25.39 and 18.26 days while that of female was 90.51, 64.44, 29.51 and 19.99 days when the predator was reared at 15, 20, 28 and 35°C, respectively. The mean generation time (T) averaged 38.84, 24.87, 9.24 and 8.56 days, and the net reproductive rate (R 0) values were 3.79, 10.042, 26.488 and 7.172 when the predator was kept at 15, 20, 28 and 35°C, respectively. The net rate of natural increase (r m) was 0.032, 0.092, 0.354 and 0.230, whereas the finite rate of increase (e rm) averaged 1.032, 1.097, 1.425 and 1.258 at 15, 20, 28 and 35°C, respectively.

Effect of temperature on the development of the mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

An invasive mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) has attacked cotton (Gossypium hirsutum L.) seriously in Pakistan and India, and caused great loss in the production of cotton in recent years. This kind of pests can probably spread rapidly and would threaten cotton and other crops in many infested and non-infested countries. P. solenopsis has first been reported to severely damage Chinese hibiscus (Hibiscus rosa-sinensis) in Guangzhou, in December, 2008. In order to understand the effects of temperature on the development of P.solenopsis, the developmental threshold temperature (Ct) and effective accumulated temperature (K) were calculated for each developmental stage. A total of 30 P. solenopsis individuals were divided into 6 groups and reared at six constant temperatures (18, 21, 24, 27, 30, and 33°C). Total developmental duration ranged from 81.3 days at 18°C to 24.06 days at 30°C for female mealybug, and from 44.21 days at 18°C to 12.95 days at 30°C for male mealybug. Degree-day values for each developmental stage for both male and female mealybugs were determined. Total degree-day values required for full development for female and males were 414.9 and 218 degree-days respectively. Estimated threshold temperatures for different life stages ranged from 12.8°C (pre-oviposition) to11.7°C (3rd instar) for female mealybugs, and 16.5°C (prepupa) to 11.5°C (2nd instar) for male mealybugs. Key words: Mealybug, Phenacoccus solenopsis, development, temperature.

Effect of Larval Density and Host Species on Preimaginal Development of Bactrocera tau (Diptera: Tephritidae)

The fruit fly, Bactrocera tau (Walker) (Diptera: Tephritidae), is an important pest of fruit and vegetable crops. In this study, host preference of B. tau females and the effects of host species and larval density on larval survival, pupal weight, adult emergence, and developmental duration were investigated on cucumber (Cucumis sativus L.), sponge gourd (Luffa cylindrical L. (Roem)), bitter gourd [Momordica charantia (Cucurbitaceae) L.], guava [Psidium guajava (Myrtaceae) L.], and tangerine [Citrus reticulata (Rutaceae) (Blanco)]. The results showed that females preferred to cucumber over other host species. Larval feeding experience affected subsequent host oviposition preference of adult females. Host species and initial larval density affected certain aspects of the biology of B. tau. Larval density negatively affected insect performance. Survival rates at low densities were significantly higher than that at high densities. Total developmental duration reduced at high larval densities. Cucumber was more suitable to larval growth. Larvae on cucumber grew faster and the puparia were heavier than that on other host species. Larval survival, pupation rate and adult emergence were higher on cucumber compared with those in other host species. Oviposition preference of adult females was correlated with performance of their offspring.

Temperature influence on biology, thermal requirement and life table of the predatory mites Agistemus exsertus Gonzalez and Phytoseius plumifer (Can. & Fanz.) reared on Tetranychus urticae Koch

The effect of temperature on the biology, thermal requirement and life table of Agistemus exsertus Gonzalez and Phytoseius plumifer (Can. & Fanz.) feeding on immatures of Tetranychus urticae Koch, was determined at four temperature degrees, i.e. 20, 25, 30 and 35°C. The total developmental durations of either predatory mite correlated negatively with increasing temperature. Minimum developmental thresholds (T o) of egg, larva, protonymph, deutonymph stages and life cycle of A. exsertus females averaged 0.95, 9.25, 7.80, 1.03 and 5.29 respectively, while those of P. plumifer females were 6.83, 9.35, 15.39, 15.40 and 13.22. On the other hand, A. exsertus and P. plumifer female required 416.66 and 126.58 DD, respectively, to reach adulthood. A. exsertus and P. plumifer net reproductive rate (R 0) averaged 16.13 and 8.23 then increased to 29.67 and 13.67 then sharply declined reaching 12.10 and 7.93 when the predator was kept at 20, 25 and 35°C, respectively. r m values of A. exsertus reached 0.06, 0.11, 0.12 and 0.13 reared at 20, 25, 30 and 35°C, respectively, while those of P. plumifer averaged 0.04, 0.11, 0.12 and 0.16. The doubling time (DT) of A. exsertus was 10.98, 6.10, 5.82 and 5.25, while that of P. plumifer averaged 15.93, 6.18, 5.70 and 4.35 at 20, 25, 30 and 35°C, respectively. Also, gross reproductive rate (GRR) of A. exsertus was 22.05, 51.70, 29.01 and 22.18, while that of P. plumifer averaged 12.67, 18.20, 18.40 and 11.82 at the same temperatures. The finite rate of increase in e rm values of either predator increased positively with increasing temperature degree.

Model selection and averaging in the estimation of population parameters of Bemisia tabaci (Gennadius) from stage frequency data in sweet pepper plants

Bemisia tabaci is a significant pest for many crops, but there are few population studies of this insect on sweet pepper (Capsicum annuum). In this study, stage frequency data were generated with B. tabaci in sweet pepper plants in various situations, and the Bellows and Birley method was used to obtain population parameters from the data. The Akaike Information Criterion (AIC) was used to select the best option of the Bellows and Birley method and, in some cases, to estimate the parameters of the population using model averaging. The ratios estimated/observed for each population parameter were calculated to assess bias and were used to correct the estimations if the ratios were different from 1. The effects of different factors on the estimations of population parameters were analysed. The total duration of development was affected by the experimental conditions (laboratory vs. greenhouse) and temperature, but it had the highest precision. The final survival rate was affected by temperature, and the estimation of individuals entering each stage was affected only by the options included in the Bellows and Birley method. AIC helped to detect differences in the daily survival rate among the different experiments between N1 (first instar) (range 0.842–0.923), and the egg (range 0.989–1.0) and N4 (fourth instar) (0.990). The methodology used can be employed in field population studies. For example, the final survival rate in the greenhouse experiments varied between 0.624 and 0.097, depending on if the parasitoids were present or not, and the total development varied between 420.6 and 440.7 degree days.

Notes on Diagnosis and Biology of Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae), a Parasitoid of the Invasive Mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Sternorrhyncha: Pseudococcidae)

Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae), is a specific, solitary endoparasitoid of Phenacoccus solenopsis Tinsley, a major invasive pest on cotton in all the cotton growing states in India. This paper provides a short diagnostic description of A. bambawalei with illustrations to facilitate easy identification and notes on the biology of A. bambawalei on P. solenopsis in the laboratory. The mean duration of development of A. bambawalei from egg laying to pupation was 8.85±0.21 days and pupation to adult emergence took 7.35±0.15 days in males and 7.00±0.16 in females. The mean total duration of development of A. bambawalei from egg laying to adult emergence was 16.10±0.25 days (range 14-18 days). The adults survived for 2-4 days on water, but the mean longevity was considerably enhanced on 50% honey (70.95±2.30 days in females and 49.00±2.35 days in males). Unmated females produced 100% male progeny. Four hyperparasitoids of A. bambawalei were recorded on field collected samples namely, Prochiloneurus pulchellus Silvestri, P. albifuniculus (Hayat et al.), and P. aegyptiacus (Mercet) (Hymenoptera: Encyrtidae) and Promuscidea unfasciativentris Girault (Hymenoptera: Aphelinidae).

Biological characteristics of Orius similis Zheng (Heteroptera, Anthocoridae) by feeding on different aphid species as prey

The predatory flower bug Orius similis Zheng (Heteroptera, Anthocoridae) which originated in China is a polyphagous predator that feeds on a wide range of arthropod pests such as aphids, thrips and spider mites. However, sufficient information about the biological parameters of O. similis with different aphid species as prey is still lacking in the literature. Therefore, in the present work, development, mortality, longevity and reproduction of O. similis were studied in the laboratory with Aphis fabae (Scopoli), Aphis gossypii (Glover), Acyrthosiphon pisum (Harris), Myzus persicae (Sulzer) and Aphis pomi (De Geer) as prey. Prey species, their (prey’s) host plants and the age of the females had influenced the duration of embryonic development of O. similis. Nymphal developmental duration varied significantly according to prey species and (prey’s) host plant. The mean total nymphal developmental duration of both sexes was significantly shorter when feeding on A pomi [14.0 (♀♀) and 14.4 (♂♂) days] than with other aphid species as prey. Total mortality during the development was also affected by prey and plant species. O. similis was able to develop with different aphid species as prey and reach the adult stage. The different aphid species as prey and the sex of the predator had significantly influenced longevity, which was the longest in unmated females with A gossypii as prey. Pre-oviposition and oviposition period varied also significantly depending on prey species. Adult females started oviposition 4–6 days after emergence, and the mean total fecundity was significantly the highest with A pisum as prey with a mean of 161.3 eggs/♀. The ability of this predator to oviposit and develop with different aphid species as prey is discussed in relation to its practical use for biological control of aphids in protected cultivation.

Codeine accumulation and elimination in larvae, pupae, and imago of the blowfly Lucilia sericata and effects on its development

The aim of this study was to evaluate the reliability of insect larvae as samples for toxicological investigations. For this purpose, larvae of Lucilia sericata were reared on samples of minced pig liver treated with different concentrations of codeine: therapeutic, toxic, and potentially lethal doses. Codeine was detected in all tested larvae, confirming the reliability of these specimens for qualitative toxicology analysis. Furthermore, concentrations measured in larvae were correlated with levels in liver tissue. These observations bring new elements regarding the potential use of opiates concentrations in larvae for estimation of drug levels in human tissues. Morphine and norcodeine, two codeine metabolites, have been also detected at different concentrations depending on the concentration of codeine in pig liver and depending on the substance itself. The effects of codeine on the development of L. sericata were also investigated. Results showed that a 29-h interval bias on the evaluation of the larval stage duration calculated from the larvae weight has to be considered if codeine was present in the larvae substrate. Similarly, a 21-h interval bias on the total duration of development, from egg to imago, has to be considered if codeine was present in the larvae substrate.

Natural Survivorship of Immature Stages of Culex vishnui (Diptera: Culicidae) Complex, Vectors of Japanese Encephalitis Virus, in Rice Fields in Southern India

Abstract The development and survival of immatures of Culex vishnui (Diptera: Culicidae) complex, vectors of Japanese encephalitis virus, were studied in transplanted rice, Oryza savita L., fields during three crop growing seasons. The total duration of development from the first instar to adult emergence varied from 6 to 8 d. Survival rate estimates ranged from 0.003 to 0.524, but they generally were <0.1. Unusually high survival rates (0.192–0.524) were observed in summer and long-term monsoon crop seasons during 1993. A multiple regression method using backward elimination was used to analyze the factors responsible for these variations. The model identified nine parameters related with survival rates that explained 99% of the variance. Area of water surface and hardness were negatively related, whereas green algae, notonectid adults, anisopterans, dytiscids, salinity, water depth, and dissolved oxygen were positively associated with immature survival.

Natural Survivorship of Immature Stages of <I>Culex vishnui</I> (Diptera: Culicidae) Complex, Vectors of Japanese Encephalitis Virus, in Rice Fields in Southern India

The development and survival of immatures of Culex vishnui (Diptera: Culicidae) complex, vectors of Japanese encephalitis virus, were studied in transplanted rice, Oryza savita L., fields during three crop growing seasons. The total duration of development from the first instar to adult emergence varied from 6 to 8 d. Survival rate estimates ranged from 0.003 to 0.524, but they generally were <0.1. Unusually high survival rates (0.192-0.524) were observed in summer and long-term monsoon crop seasons during 1993. A multiple regression method using backward elimination was used to analyze the factors responsible for these variations. The model identified nine parameters related with survival rates that explained 99% of the variance. Area of water surface and hardness were negatively related, whereas green algae, notonectid adults, anisopterans, dytiscids, salinity, water depth, and dissolved oxygen were positively associated with immature survival.

A field study of larval development in a dragonfly assemblage in African desert ponds (Odonata)

Aquatic animals distributed along a 'habitat-permanence' gradient (HPG), differ in life history (Wellborn et al., 1996. Annual Revue of Ecology and Systematics 27: 337--363). Dragonflies that occur in hot arid regions often occur in temporary waters and consequently perform direct and rapid development. Dragonfly species of the Namibian desert do differ in their selection of habitats along the HPG and therefore may also differ in life cycle. Here, we attempt to monitor colonisation, larval growth and emergence in a temporary pond of known history. We studied the development of dragonfly species that laid eggs in artificial ponds constructed by us in March 2001. The assemblage consisted of species that originate from different habitats along the HPG. To obtain data on larval development we took samples from the ponds at 10-day intervals. Most species showed rapid development. By regressing the maximum sizes attained by larvae on each sampling date against time we estimated growth rates for five species and were thereby able to estimate that total duration of development from oviposition to emergence ranged between 38 and 70 days. Observation of first oviposition and first emergence for three of these species corroborated our estimates based on growth rate. Of few species, which laid eggs in the ponds no larvae or adults were found. For some this may have been the result of predation whereas others may not have grown fast enough to emerge before the ponds dried up. Our results indicate that dragonflies cannot recognise whether a pond will retain water long enough for full larval development and oviposit in waters that will not allow larval development.

Influence of host plant species of Bemisia tabaci (Genn.) (Hom., Aleyrodidae) on some of the biological and ecological characteristics of the entomophagous Serangium parcesetosum Sicard (Col., Coccinellidae)

The entomophagous Serangium parcesetosum Sicard (Col., Coccinellidae) is an effective predator of some whitefly species. However, information on the influence of the prey’s host plant species on its biological and ecological characteristics is still lacking in the literature. Therefore, the current study focuses on the possible influence of three greenhouse and two field host plant species of Bemisia tabaci (Genn.) (Hom., Aleyrodidae) on the number of eggs laid by S. parcesetosum. In addition, because of the economic importance and widespread planting of cucumber in greenhouses and cotton in the field, these plants were selected for further investigation into the development, mortality, longevity and reproduction of S. parcesetosum at a high temperature in the laboratory. Results showed that S. parcesetosum was able to lay eggs on all five host plant species of B. tabaci, whether greenhouse or field plants. However, among the three greenhouse plant species studied, S. parcesetosum females laid the highest number of eggs on cucumber followed by tomato and then sweet pepper. Of the two field plant species, significantly higher numbers of eggs were laid on tobacco than on cotton. S. parcesetosum could develop either on cucumber or on cotton as preferable host plant species for B. tabaci. There were significant differences in mean developmental duration of larval instars of the same sex between both host plant species; the duration was significantly shorter on cucumber than on cotton. There were no significant differences for mean total developmental duration from egg to adult emergence between both host plant species within the same sex; females showed a mean of 15.9 days and males of 15.1 days on cucumber, while on cotton the means were 17.2 days for females and 16.2 days for males. Total mortality percentage of S. parcesetosum during development from egg to adult stage was lower on cucumber than on cotton, 20.6 and 23.8%, respectively. Longevity of S. parcesetosum varied according to host plant species and sex with a mean of 63.4 days for females and 50.3 days for males on cucumber, and 92.4 days for females and 52.5 days for males on cotton. On cucumber, mean period of oviposition of S. parcesetosum was significantly longer than on cotton. Mean total fecundity was significantly higher on cucumber than on cotton, with means of 97.7 and 31.0 eggs/female, respectively.

Influence of Helicoverpa Armigera (Hübner) Diet on Its Parasitoid Campoletis Chlorideae Uchida

A study was undertaken to test the hypothesis that the quality of host plant parts determines the nutritional quality of herbivorous insects feeding on it to their parasitoids. A Gossypium hirsutum-Helicoverpa armigera-Campoletis chlorideae tritrophic system was evaluated. The superior nutritional quality of bolls and young leaves of Gossypium hirsutum (MCU-5 variety) contributes to more efficient feeding, growth and reproduction of the bollworm, Helicoverpa armigera (Hubner) and better survival of its larval parasitoid, Campoletis chlorideae Uchida. Longer total developmental duration and decrease in adult longevity were observed in H. armigera reared on senescent leaves than in those reared on bolls. Consumption, growth rate and efficiency measures were significantly lower in parasitised H. armigera larvae than in unparasitised larvae. Percentage parasitism was highest (84.1%) in H. armigera fed on bolls. The parasitoid C. chlorideae displayed shorter developmental duration and improved survival on H. armigera fed on bolls.

Morphology and development ofTetrastichussp. (Hymenoptera: Eulophidae), parasitizing fallwebworm pupae,Hyphantria cuneaDrury (Lepidoptera: Arctiidae)

The life history and development of Tetrastichus sp. parasitizing fallwebworm pupa in Korea were studied. The mean lifetime fecundity was 94.7 with a maximum of 125, and the portion of female progeny averaged 90.3%. A male and a female lived for an average of 19.8±4.5 and 21.7±4.2 days, respectively. The duration of development for each stage was as follows: egg, 2 d; the 1st instar larva, 2±1 d; the 2nd instar larva, 2±1 d; the 3rd instar larva, 3±1 d; the 4th instar larva, 6±2 d; and pupa, 8±2 d. Total developmental duration from hatching of the larva to adult emergence required 21.1±3.7 d, and females took 1–2 days more than males in the incubator (28°C, 70% RH, and 16:8 LD).

Biology of the Yellowmargined Leaf Beetle (Coleoptera: Chrysomelidae) on Crucifers

Multi-generation survivorship, developmental biology, fecundity, and adult longevity of the yellowmargined leaf beetle, Microtheca ochroloma Stål, were studied in the laboratory on cabbage, Brassica oleracea var. capitata L., collard, B. oleracea var. acephala L., mustard, B. juncea Cosson, turnip, B. rapa L., and radish, Raphanus sativus L. Host plant significantly affected multi-generation survivorship; survivorship was 0% on cabbage but &amp;gt;70% on the other hosts when tests were terminated in the fourth generation. Duration of development of life stages and total duration of development from oviposition to adult emergence did not vary significantly with host at 20°C. The latter averaged 27 d among hosts. Development averaged 7.8 d for eggs, 10 d for the four larval instars, 3 d for prepupae, and 5.6 d for pupae. Fecundity and adult longevity were significantly affected by host plant. Egg numbers per female were significantly higher on turnip than on collard but did not differ significantly among cabbage, mustard and radish. Sex did not affect longevity, but beetles lived significantly longer on radish than cabbage, collard, mustard, or turnip.

Incubation and Fledging Durations of Woodpeckers

The relatively long fledging duration of cavity-nesting birds has been related to the relative safety of their nesting sites (Lack 1968). We compared the relationships between body and egg masses and incubation (I) and fledging (F) times of 39 species of woodpeckers and wrynecks (Picidae) to those of altricial birds in general. We found that Picidae have shorter incubation and longer fledging periods in the comparable range of altricial birds' body and egg masses. However, the total development duration (I + F) is similar to that of other altricial birds. The representative F/I ratios of altricial birds within the size range of Picidae are 1.21-1.26, while for 32 picid species they are 2.09 + 0.09 SE. Similar trends appear to exist in other cavity-nesters. We suggest that the short incubation of Picidae is an adaptation to the apparently poor gas exchange around the eggs under the incubating parent in the nest chamber, where oxygen and carbon dioxide levels may be low and high, respectively, and early transition to pulmonary respiration associated with an increase in nest ventilation is of advantage. The relatively short incubation may indicate a relatively immature state of hatching that requires compensation by a prolonged hatching to fledging duration.

Cob Borer Mussidia Nigrivenella (Lepidoptera; Pyralidae) Of Maize in Ivory Coast. I — Morphological and Biological Data

Mussidia nigrivenella Ragonot is the main cob borer of maize in Ivory Coast. An accurate description of male and female genitalia is given. Rearing in the laboratory has permitted determination of the number and duration of the pre-imaginal instars, fecundity of adults and fertility of eggs as also the sex-ratio. An artificial diet has been elaborated which provides conditions of similar development to those observed in the field: The insect has 5 to 6 larval instars and the total duration of development from the egg-laying to the adult emergence is 46 days for the male and 49 days for the female.

Effect of temperature on the development of prepupa and pupa of the rat flea, Xenopsylla cheopis Rothschild.

Experiments employing a total of 4680 cocoons were carried out on the development of prepupae and pupae of the common rat flea, Xenopsylla cheopis Roth., at 7°, 10° 15°, and 27°C and at a constant RH of 80%. Fourteen stages of the pupa are described on the basis of morphology and degree of pigmentation. The distribution of these stages under varying experimental conditions was used as an index of development. Under the conditions of temperature and relative humidity of the experiments, complete arrest of development did not occur. However, the total duration of development was prolonged if pupae were incubated at 10°C or 15°C.