Maximum Number Of Larvae Research Articles

Study of Population Dynamics of Syrphid Fly (Order- Diptera, Family- Syrphidae) in ITM University Gwalior, India

An intriguing ecological interaction can exist between aphids and Syrphid flies, particularly in the setting of millet crops. Aphids (Order Hemiptera: Family Aphididae) are a problem variety of crops, including all types of millets. Syrphid flies (Order Diptera: Family Syrphidae) naturally prey on aphids when they are in their larval stage. Syrphid fly larvae are referred to as "aphid lions" or "hoverfly larvae." Aphids are the main source of food for these larvae, and they manage the aphid population in millet crops. Therefore, Syrphids are used as natural enemies and biological control agents and syrphid flies are advantageous insects in agriculture. The present study was conducted in the month of August 2021 to March 2022 (summer and winter season) to find out the population dynamic of syrphid flies in agricultural farms and the campus of ITM University. The target crops like maize, sorghum, pearl millets, okra, mustard crop, cabbage cauliflower, marigold and brinjal were tagged and marked and Syrphid fly larvae and pupa were counted four times in a month. The larvae and pupa were also collected and kept for adult emergence. The maximum number of larvae were collected from the Turari campus and were as a minimum found in CRC 2. The other predator like lady bird beetles were also observed but their population was very minor. The population of syrphid flies and larvae depends on the climatic conditions and the availability of foods and their prey.

Evaluations on Bioecology of Contarinia pruniflorum Coutin & Rambier, 1955 (Diptera: Cecidomyiidae)

Apricot flower midge (Contarinia pruniflorum Coutin & Rambier Diptera: Cecidomyiidae) was first detected in Prunus species in the 1950s and did not become a significant pest for a long time. However, towards the 2000s, the pest caused damage to apricot and plum especially in Mediterranean countries and its distribution continued to increase. The population density of the pest is closely related to the climate of the agricultural area. In recent years, the fluctuation in climatic data causes the population fluctuations. The study was carried out in the Kale and the Yeşilyurt district of Malatya province (Turkey) in 2017-2018. Some biological stages of apricot flower midge were determined in Malatya province and these data were interpreted together with climatic data. It was determined that the pest overwinters as a pupa in the soil. In February, the adult emerges from the pupa with the warming of the air and soil temperatures. It was determined that the adult emerged from the pupa when the soil temperature was 13-14 °C and the air temperature was 7-15 °C. At the beginning of the pink-bud stage of apricot, the pests lay eggs into flower buds. The larval development is approximately 25-28 days. The average number of larvae in the damaged buds was 14, the maximum number of larvae in a bud was 26, and the pest gave an offspring annually and the ratio of male to female was 0.08.

Analysis of the Potential of GIS Technologies in the Assessment of Environmental Factors of Malariogenicity in the Territories of the Volgograd Region

In the southern regions of Russia, high risks of the spread of malaria remain. The situation is aggravated by the increase in average annual temperatures in the long-term distribution and the growth of eutrophicated small water bodies, which are favorable for the completion of the life cycle of the disease vectors mosquitoes of the genus Anopheles. In order to establish the relationship between climatic factors and the status of populations of insect vectors of the causative agent of malaria, an analysis of the amount of surface water was carried out using GIS technologies. For the calculation, the MNDWI index was chosen, based on the use of images in the Green and SWIR bands of the Landsat 8 satellite. The indicators of the average and maximum number of larvae and adults of mosquitoes were analyzed on the basis of information presented in the annual reports of the Office of the Federal Service for Supervision of Consumer Rights Protection and human well-being in the Volgograd region. There are three malariogenic zones in the region: northern (Kamyshinsky), central (Volgograd) and southern (Kotelnikovskaya). The overall dynamics of MNDWI for the Kamyshin zone tended to increase the water index from -0.176 to -0.171 in a two-year range. Similar MNDWI indicators for the Volgograd and Kotelnikovsky malariogenic foci also had a positive trend in the period from 2018 to 2020. The modified normalized water index for them increased from -0.152 to -0.126 and from -0.215 to -0.158, respectively. Calculation of the Pearson correlation coefficient for the study area revealed the presence of a high closeness of a direct relationship between the MNDWI index and the maximum number of larvae/adults in the Kamyshin region (0.994/0.833). For Volgograd, the strength of the correlation was in the region of average (noticeable) values, except for the average value for adults, where the relationship was strong (0.904). In Kotelnikovo, the relationship between periods of drought and the number of larvae was inversely proportional, with the exception of the maximum number of adults (0.943), which can be explained by the small value of the sample of the final emergence of insects and the measurement error due to the logic of the methodology for studying the number of larval forms in natural water bodies. The results obtained can be used to improve the system for monitoring the dynamics of malariogenicity by supervisory authorities in the field of population welfare. Further research prospects are associated with a change in approaches to assessing the average values of the number of malaria vector insects, as well as with our own field work on the study of the composition of the mosquito entemofauna of the river. Anopheles for the purpose of calibrating data reported by government agencies.

Larval development and habitat usage of stream-breeding Fire salamanders in an urban environment

Urbanisation adversely affects the abiotic and biotic characteristics of watercourses, including freshwater streams that support the development of stream-breeding salamanders. We conducted a study over four years on an isolated fire salamander population inhabiting a stream valley northwest of Budapest, Hungary. Our aim was to understand aspects of larval development and habitat usage within this population. The maximum number of larvae was observed in April and the first weeks of May. Due to drifting caused by heavy rainfall, there was a mean decrease of 63.3% in the number of larvae. The abundance of larval salamanders within 16 stream segments showed strong temporal and spatial variation, and there was a strong relationship between larval abundance and the % cover of fine gravel substrate. Some of the larvae could escape drift by entering pools with slower water flow and shelter. Larvae were predominantly solitary in smaller pools but occasionally aggregated in high numbers in some segments. The first larvae with yellow spots (indicative of metamorphosis) appeared in June, and by early September, all larvae were metamorphosing. Our results show that in this urbanised environment, larval development through to metamorphosis is occurring, but increasing urbanisation and alterations to stream flow threaten the persistence of the local population.

Breeding Enhancement of Musca domestica L. 1758: Egg Load as a Measure of Optimal Larval Density.

Simple SummaryThe amount of waste produced by the population creates general health problems in terms of public health and hygiene. In recent years the common housefly (Musca domestica L. 1758) has been widely used in the treatment of organic wastes. This study aims to assess the effect of egg loading of the common housefly on maggot development and waste reduction. To do this, several housefly egg loads were incubated on three different substrates. This study indicated that larval biomass, larval number, the survival rate from egg hatching until the last larval instar and substrate rate reduction of Musca domestica are affected by the egg load, substrate type and their interaction. It was found that under the same nutritional conditions, the yield of housefly larvae, the number of larvae and the reduction of substrates increased with increasing egg load.The amount of waste produced by the population creates general health problems in terms of public health and hygiene. In recent years the common housefly (Musca domestica L. 1758; Dipteran: Muscidae) has been widely used in the treatment of organic wastes. This study aims to assess the effect of egg loading of the common housefly on maggot development and waste reduction. Housefly larvae were reared at four egg loads (1.25, 2.5, 5, 10 mg) under three different diets (wheat bran, millet bran, cow dung). Two-factor ANOVA (α = 0.05) was used to test the effect of two fixed factors (egg load and substrate) on larval biomass, the survival rate from egg hatching until the last larval instar, number of larvae and substrate reduction rate. The comparison of means based on Duncan’s test was performed to compare the means of the different variables measured. Principal component analysis (PCA) was used to determine the relationship between the measured variables (larval biomass, the survival rate from egg hatching until the last larval instar, number of larvae, and substrate reduction rate) on the discrimination of the egg load factor. The results showed that under the same nutritional conditions, the yield of housefly larvae, the number of larvae and the reduction of substrates increased with increasing egg load. Indeed, at each of three substrates, the rearing egg load of 10 mg resulted in the maximum larval yield, maximum number of larvae, and maximum substrate reduction rate. At this optimum load, wheat bran generated greater biomass, greater number of larvae and greater reduction of substrate compared to millet bran and cow dung. The egg load as a whole had no effect on the survival rate from egg hatching until the last larval instar, unlike substrate type. The high egg load for the survival rate (from egg hatching until the last larval instar) for millet bran was 1.25 while there was no difference for the other two substrates. These results can help to make the waste treatment process efficient with the subsequent production of a large larval biomass that can serve as added value in animal feed. The egg load of 10 mg and the wheat bran were superior respectively to the other egg load and substrates type for all parameters tested excepted for the survival rate (from egg hatching until the last larval instar). Ours study indicated that larval biomass, larval number, egg viability and substrate rate reduction of Musca domestica are affected by the egg load, substrate type and their interaction.

Modeling and simulation of the spatial population dynamics of the Aedes aegypti mosquito with an insecticide application

BackgroundThe Aedes aegypti mosquito is the primary vector for several diseases. Its control requires a better understanding of the mosquitoes’ live cycle, including the spatial dynamics. Several models address this issue. However, they rely on many hard to measure parameters. This work presents a model describing the spatial population dynamics of Aedes aegypti mosquitoes using partial differential equations (PDEs) relying on a few parameters.MethodsWe show how to estimate model parameter values from the experimental data found in the literature using concepts from dynamical systems, genetic algorithm optimization and partial differential equations. We show that our model reproduces some analytical formulas relating the carrying capacity coefficient to experimentally measurable quantities as the maximum number of mobile female mosquitoes, the maximum number of eggs, or the maximum number of larvae. As an application of the presented methodology, we replicate one field experiment numerically and investigate the effect of different frequencies in the insecticide application in the urban environment.ResultsThe numerical results suggest that the insecticide application has a limited impact on the mosquitoes population and that the optimal application frequency is close to one week.ConclusionsModels based on partial differential equations provide an efficient tool for simulating mosquitoes’ spatial population dynamics. The reduced model can reproduce such dynamics on a sufficiently large scale.

Ultrasonography: a method used for pregnancy imaging of the fire salamander (Salamandra salamandra).

Ultrasound imaging has more frequently been used in veterinary medicine of amphibians and reptiles. In this study, we have verified the usefulness of ultrasound imaging in pregnancy determination of the fire salamander Salamandra salamandra. We have also undertaken to estimate the number of larvae and their developmental stage directly in the oviducts. Three gravid females from Lower Silesia (southern Poland) were examined. Due to the small size of the scanned animals, and the particular arrangement of embryos in the oviducts and ultrasound beams dispersal, the method proved to be inaccurate. Therefore, the minimum number of well-visualized larvae was determined. The maximum number of larvae was established on the basis of the visible fragments of embryos. After birth, we found that the number of larvae born was included in the "min-max" range in only one case. In the remaining two salamanders the number of larvae was higher than estimated in 3 to 7 individuals. The results showed that ultrasound imaging allows the minimum number of larvae in salamander; oviducts to be specified. However, total length measurements were possible only for single and clearly visible embryos.

Can leaf-mining flies generate damage with significant impact on the submerged weed Lagarosiphon major?

Effective biological control of a weed cannot be achieved unless agents can inflict sufficient damage for the plant’s growth and reproduction to be significantly depressed. The leaf-mining fly Hydrellia lagarosiphon is being considered for release in Ireland and New Zealand as a biocontrol agent for the invasive African macrophyte Lagarosiphon major. However no leaf-mining biological control agent has achieved successful control of any submerged macrophyte to date. Pre-release efficacy experiments help predict the likelihood of the biocontrol agents impact provided trials take into account expected agent densities and field conditions. Sustained damage induced by consecutive generations of the leaf-mining fly was capable of halting plant growth and undamaged shoot fragments produced 100 % more shoot biomass in just 70 days when compared with those exposed to larval damage. The number of larvae required to induce this level of damage was less than the maximum number of larvae a plant can sustain under both laboratory and natural field conditions and was between three and four larvae per shoot tip. Larval damage to L. major also had a significant effect on the subsequent establishment of detached apical shoots under field conditions. All control shoots displayed 100 % establishment whereas medium (three larvae per shoot) and high larval density plants (five larvae per shoot) had 85 and 25 % establishment, respectively. Pre-release trials indicate that relatively low larval abundances of H. lagarosiphon can contribute to the suppression of plant growth and reduce the establishment of shoot fragments, making this species a potentially effective biocontrol agent.

Bio-efficacy of Eco-friendly Insecticides against Cabbage Butterfly, <i>Pieris brassicae</i> (L.) on Cabbage in the Mid Altitudes Hills of Meghalaya, North East India

In this study nine eco-friendly insecticides viz., Annonin, Azadirachtin (oil base 300 ppm), Neem Seed Kernel Extract 300 ppm, Garlic Extract (1%), Karanjin, Bacillus thuringiensis (Bt), Beauveria bassiana , Spinosad 45 SC and Endosulfan 35 EC were tested for their bio-efficacy against Pieris brassicae (L.) on cabbage. After fifteen (15) days of spray it was found that endosulfan, annonin and spinosad killed maximum number of larvae with 98.65%, 98.47% and 97.84% mortality respectively. Among the botanicals, annonin was found to be the most effective whereas for microbial, spinosad was found to give maximum control.

ASSOCIATION OF <i>ESCHERICHIA COLI</i> WITH THE PREVALENCE OF FLIES POPULATION

Mass releases of house fly Musca domestica (L) and stable fly Stomoxys calcitrans (L). Produced by manure piles accumulated nearby horse stables and dairy farm village in Abu-Graib provide continuous threat to inhabitants west of Baghdad. Timing of fly’s mass release in association with the presence of Escherichia coli in manure piles was examined at these locations. Experimental result indicated that flies survived during cold period of December and January in form of larvae deep in manure piles where temperature was around 15-17°C. Once the population of fly’s larvae started to increase by the second week of February, the concentration of E. coli was up to 80×106 CFU mL-1 in manure suspension. Later when larval population reached to a maximum number by the last week of April, the concentration of E. coli in manure sample dropped down to 38×102 CFU mL-1. Similar trend was observed with the proportion of E. coli to general bacteria present in manure samples where the percent decreased from 89% in early season to 1.5% when maximum number of larvae was recorded. The correlation coefficient (R) between the number of larvae and coli form bacteria was = -0.73657. These results suggest the association of larval development with the consumption of E. coli. Thus manipulation of bacterial community in manure piles may lead to possible eradication of fly’s seasonal release.

Intensity of attack caused by Mediterranean fruit fly Ceratitis capitata Wiedem. (Diptera, Tephritidae) on mandarin along the Montenegrin seacoast

Along the Montenegrin seacoast, all cultivated citrus species (mandarin, orange, lemon, grapefruit), fig, loquat and ziziphus were detected as host plants of the Ceratitis capitata Wiedem. Among those found, in economic sense, the most important host plant is mandarin Unsiu. Intensity of the attack were monitored on mandarin in 2003 and 2004 in localities Baosici, Lastva Grbaljska and Bar, and was determined as higher in 2003. The first symptoms of attack were detected, depending on locality, from middle of September until beginning of October, one to two months earlier then in 2004. The maximum number of larvae per fruit were detected in October and November (average from 13.44?0.16 to 22.82?0.13). Time of the first symptoms appearence on mandarin in September and October 2003 and in November 2004, indicate on crucial importance of alternative host plants (figs and loquat) for reproduction and increasing of C. capitata population, because later during a season its intensity of attack on mandarin, depend largely on their presence.

Reproductive biology of the endemic Iranian cichlid, Iranocichla hormuzensis Coad, 1982 from Mehran River, southern Iran

We studied the reproductive biology of the endemic Iranian cichlid Iranocichla hormuzensis, a maternal mouthbrooder, in the Mehran River. Overall sex ratio was 1.44 M: 1F indicating a significant male bias. Monthly sex ratios did not differ from unity except in May and June when the sex ratios were strongly biased in favor of males. Four different reproductive indices and the high frequency of large oocytes, all suggest that the Iranian cichlid spawns at the end of winter and the beginning of spring. Mircoscopic gonadal maturation stages for both males and females were correlated to the gonadosomatic indices. The maximum number of larvae in the mouth of a female was 153.

Predatory behaviour of Podisus nigrispinus (Heteroptera: Pentatomidae) on different densities of Anticarsia gemmatalis (Lepidoptera: Noctuidae) larvae

The functional response of the predatory bug Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) feeding on its prey, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), was studied in a greenhouse compartment. Each cage enclosed three soybean plants plus two, four, six, eight, 10, 12 or 14 prey larvae. One adult predator was released and kept inside the cages for 24h. The predation rate of adult male P. nigrispinus was highest at densities of eight or more A. gemmatalis larvae with a handling time of 5.76h and an attack rate of 0.68h−1. Adult females had higher predation rates on plants with 10 or more A. gemmatalis larvae, with a handling time of 3.84h and an attack rate of 0.65h−1. The maximum number of larvae consumed by males and females of this predator were 4.1 and 6.0 per day, respectively, in groups of three plants. The results suggest that P. nigrispinus may be used in biological control programmes against A. gemmatalis in soybean fields.

Density and Time Effects on Distribution and Survival of Lightbrown Apple Moth (Lepidoptera: Tortricidae) Larvae on Granny Smith Apples

Distribution and survival of Epiphyas postvittana (Walker) larvae on 'Granny Smith' apples (Malus domestica Bork.) were examined in a laboratory study after a range of inoculation densities and establishment periods. First instars displayed a general trend of occurrence in the following order: off fruit > calyx > stem > cheek. Their survival was poor compared with 3rd and 5th instars and declined with time. The chance of survival was greatest when 1st instars occupied the cavity beneath the sepals of the calyx or assumed an internal position inside a tunnel. No 1st instars were found in the core after the longest establishment period (14 d). Distribution of 3rd and 5th instars was strongly influenced by inoculation density. At low densities the greatest proportion of 3rd instars occupied the calyx and stem cavities, but at high densities proportions were greatest off fruit and on the cheek. Typically, once 1-2 larvae had occupied the calyx cavity beneath the sepals and the stem cavity, the remainder moved elsewhere. Although 5th instars showed a similar change in location preference with increasing inoculation density to 3rd instars, the maximum number of larvae per apple was lower, reflecting more intense interference and competition. Although 3rd and 5th instars strongly favored the apple surface over internal positions, both instars were present in the core after a 7-d establishment period.

Strongyloides stercoralis infection in IgA-deficient dogs.

Two litters of eight-week-old, IgA-deficient pups, each including one normal littermate control, were infected with 5,000 infective third-stage Strongyloides stercoralis larvae per pup. No significant differences between the dogs deficient in serum and mucosal IgA and the normal control dogs were observed in any of the parasitologic parameters measured during the course of infection. The time required to reach patency, the maximum number of larvae shed in the feces, the number of days postinfection at which larval shedding was at its maximum, and the time required to eliminate shedding were similar in the two groups. Once larval shedding ceased, there was no recrudescence, even though serum and fecal IgA were absent or low throughout the seven-month course of the investigation. All dogs remained asymptomatic, with complete blood counts and clinical chemistries within normal ranges. In addition, serum IgM and IgG levels were within the normal range for both groups of infected dogs. All dogs from which necropsy samples were obtained harbored low numbers of adult female worms, some of which were barren. An IgA deficiency apparently does not affect the course or severity of S. stercoralis infection in the dog.

Experimental studies on the hatching rhythm and larval release in Palaemonid and Atyid prawns

The hatching behaviour and larval release ofMacrobrachium lanchesteri (de Man) (Palaemonidae) andCaridina weberi (de Man) (Atyidae) are described in relation to natural (LD nat) and altered laboratory (LL, DD and DL) illumination cycles. A clear nocturnal hatching rhythm is observed in femaleMacrobrachium lanchesteri, which releases the larvae in batches on successive nights till all the eggs held in the brood are hatched. Maximum number of larvae are released between 24 and 3 h. InCaridina weberi such a precise rhythm is loosely operative.

EFFECT OF SPACING AND CLUMPING OF CORN PLANTS ON DENSITY OF CORN-ROOTWORM LARVAE (COLEOPTERA: CHRYSOMELIDAE) PER ROOT SYSTEM

AbstractThe relative density of corn-rootworm larvae was estimated in two field plots with 4 different plant spacings and with up to 4 plants clumped per location. In both fields the relationship between plant spacing and the number of corn rootworms per sample was similar with the maximum number of larvae occurring when plants were 46 or 50 cm apart. The number of plants clumped per location affected the numbers of corn rootworm in only one field. The relationship between clumping of plants and number of corn rootworms was curvilinear in this field with the most corn rootworms occurring at 3 plants per location.

Studies on the comparative migration patterns of Ascaris suum larvae between primary and re-infected mice

In the present study, the effect of primary infection to reinfection with Ascaris suum larvae was experimented in mouse model. Mice were challenged with l,000 infective stage eggs of Ascaris suum. The embryonated eggs were directly introduced into stomach of mice. Reinfection was performed at 50 days after the primary infection with same method as primary infection. Mice were sacrificed 3, 5, 7, 10, 15 and 20 days after infection in both groups respectively. Larvae collected from livers and lungs with Baermann's apparatus were enumerated and measured after sacrifice. Sera of mice were also collected at same time. The results of the experiment were as follows: With antigen prepared from coelomic fluid of adult Ascaris suum and sera collected from mice before reinfection, the production of antibody in experimental mice was confirmed by the gel-diffusion technique. In the livers of reinfected mice, the larvae were recovered up to 10 days after challenge, otherwhile in the primary infected mice, the larvae were observed up to 7 days. The maximum number of larvae were observed in the lungs of primary infected mice on 10 days after inoculation. In the lungs of reinfected mice, maximum number of larvae were recovered on 7 days after, only few larvae were recovered on 10 days after reinfection. As regards the growth of the larvae, the third stage larvae, over 500 micrometer in length, appeared in livers at 5 days after reinfection, but it couldn't be found on 7 days and 10 days after challenge. The third stage larvae continuously developed were observed in lungs of mice from 5 days after reinfection. In conclusion, it was found that development of larvae in livers of immune mice were probably repressed by the immune mechanisms being rised in livers and defence mechanism is also acting by interfering with the process of larval penetration into the lung from the liver.

Comparative Penetration and Development of Meloidogyne Naasi in Wheat and Oat Roots

Direct observations of root penetration by Meloidogyne naasi larvae into 'Pawnee' wheat and 'Wintok' oats were made using micro-observation chambers. Effects of inoculum density, exposure time, and temperature on larval penetration and nematode development were investigated in wheat and oats. The maximum number of larvae penetrated the wheat and oat roots at the 2000 level of inoculum density, but the maximum percent penetration was at the 500 level for wheat and at the 200 level for oats. In both wheat and oats an ascending trend in larval penetration was more discernible during the first 96 hours than during 96 to 192 hours. Maximum penetration occurred at 25°C in both wheat and oat roots. Cell necrosis in association with larvae was common in oats. Three times as many larvae matured and laid eggs in wheat as in oat roots. Analysis of hostparasite relationships suggests that 'Pawnee' wheat is highly susceptible, and 'Wintok' oats tolerant or moderately resistant to M. naasi.

Effect of cortisone upon Ancylostoma caninum infection in albino mice

The administration of cortisone in daily doses of 75 mg. per kg. subcutaneously to albino mice increased susceptibility to A. caninum infection, perhaps by suppression of immunity. Pre-infection treatment with cortisone did not influence susceptibility to infection more than treatment started on the day of infection. The average percentage of larvae recovered from the cortisone-treated mice was significantly greater than that of untreated control mice after 5 days of infection. Of all organs examined, the maximum numbers of larvae were obtained from lungs of both the test and control groups of mice for a noticeable period, the former group showing considerably higher recovery than the latter from the 3rd day till 10 days after infection. The mice, after cortisone treatment, did not provide a satisfactory medium to A. caninum larvae for further development even at 14 days after infection, indicating a poor host-parasite adaptation.