scholarly journals No impact of biocontrol predator on development time or size of surviving Aedes albopictus under optimal nutritional availability

2021 ◽  
Author(s):  
Marie C. Russell ◽  
Lauren J. Cator
Keyword(s):  
Aedes Albopictus ◽  
Development Time ◽  
Wing Length ◽  
Sublethal Effects ◽  
Cyclopoid Copepod ◽  
Adult Size ◽  
Fish Food ◽  
Predator Treatment ◽  
Copepod Predation ◽  
Significant Difference

AbstractBackgroundCyclopoid copepods have been applied successfully to limit populations of highly invasive Aedes albopictus mosquitoes that can vector diseases, including chikungunya, dengue, yellow fever, and Zika, to humans. However, there is concern that changes in certain vector traits, induced by exposure to copepod predation, might increase the risk of disease transmission. In this study, we tested whether cyclopoid copepod predation has sublethal effects on the development time or adult size of Ae. albopictus under the scenario of an invasion in southeast England, which lies at the northern edge of the vector’s expanding global range.MethodsThird instar Ae. albopictus larvae, hereafter referred to as “focal individuals”, were placed in individual Petri dishes, each containing four newly-hatched Ae. albopictus larvae, which were counted, removed, and replaced daily. All focal individuals were provided with fish food ad libitum, and half were exposed to Megacyclops viridis copepod predators. The day of pupation was recorded for each focal individual, and the wing length of each focal adult was also measured.ResultsExposing late instar Ae. albopictus to predation decreased their chances of surviving to adulthood. Mortality of the focal individuals was 12.9% in the predator treatment, and 2.9% in the controls. Three focal larvae that died in the predator treatment showed signs of melanization, indicative of wounding. Among surviving Ae. albopictus, no significant difference in either pupation day or wing length was observed due to copepod predation.ConclusionsWe found that M. viridis predation on smaller Ae. albopictus larvae does not significantly affect the pupation day or adult size of surrounding larger larvae that are less vulnerable to copepod attacks. This study controlled for density effects on size by maintaining a constant number of newly-hatched prey larvae surrounding each focal larva. Those working to control Ae. albopictus populations in the field should be made aware that increased adult body size can occur if copepod biocontrol agents are applied at lower than necessary levels. The absence of a significant sublethal impact from M. viridis copepod predation on surviving later-stage larvae in this analysis supports the use of M. viridis as a biocontrol agent.Graphical abstract

scholarly journals Implementation of a deep learning model for automated classification of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) in real time

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Song-Quan Ong ◽  
Hamdan Ahmad ◽  
Gomesh Nair ◽  
Pradeep Isawasan ◽  
Abdul Hafiz Ab Majid
Keyword(s):  
Deep Learning ◽  
Aedes Aegypti ◽  
Real Time ◽  
Aedes Albopictus ◽  
Automated Classification ◽  
Expert Performance ◽  
Deep Convolutional Neural Networks ◽  
Significant Difference ◽  
Set Up

AbstractClassification of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) by humans remains challenging. We proposed a highly accessible method to develop a deep learning (DL) model and implement the model for mosquito image classification by using hardware that could regulate the development process. In particular, we constructed a dataset with 4120 images of Aedes mosquitoes that were older than 12 days old and had common morphological features that disappeared, and we illustrated how to set up supervised deep convolutional neural networks (DCNNs) with hyperparameter adjustment. The model application was first conducted by deploying the model externally in real time on three different generations of mosquitoes, and the accuracy was compared with human expert performance. Our results showed that both the learning rate and epochs significantly affected the accuracy, and the best-performing hyperparameters achieved an accuracy of more than 98% at classifying mosquitoes, which showed no significant difference from human-level performance. We demonstrated the feasibility of the method to construct a model with the DCNN when deployed externally on mosquitoes in real time.

Effect of Type of Tissue on the Development of Chrysomya rufifacies (Diptera: Calliphoridae) in Sri Lanka

2021 ◽  
Author(s):  
Y T B Bambaradeniya ◽  
W A I P Karunaratne ◽  
J K Tomberlin ◽  
P A Magni
Keyword(s):  
Skeletal Muscle ◽  
Sri Lanka ◽  
Forensic Entomology ◽  
Development Time ◽  
Developmental Studies ◽  
Chrysomya Rufifacies ◽  
Significant Difference ◽  
The World ◽  
Significant Temperature ◽  
Domestic Swine

Abstract Chrysomya rufifacies (Macquart), the hairy maggot blow fly, is of great importance for the field of forensic entomology due to its habit as an early colonizer of decomposing vertebrate remains and myiasis producer. Development studies on this species have been conducted in scattered regions of the world, using types of tissue from several species of animals as a rearing medium. Despite the commonality of C. rufifacies in Sri Lanka, developmental studies have never been performed in this region. As well, the effects of diet on development have not been tested. In the current study, C. rufifacies immatures were reared on skeletal muscle, liver, and heart from domestic swine, with flies from colonies maintained at 25 and 28°C. The minimum time needed to complete each stage at 25°C on liver (224.14 h) was fastest followed by skeletal muscle (249.33 h) and heart (251.64 h) respectively, whereas at 28°C, fly development was quickest on heart muscle (178.27 h) followed by liver (178.50 h) and skeletal muscle (186.17 h) respectively. A significant difference in total development time was determined for temperature, while the rearing medium was not significant. Temperature also showed a significant effect on the length and the width of the larvae, while the type of tissue statistically impacted only the width.

DENSITY-DEPENDENT FERTILITY SELECTION IN EXPERIMENTAL POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1981 ◽  
Vol 98 (4) ◽  
pp. 849B-869
Author(s):  
Andrew G Clark ◽  
Marcus W Feldman
Keyword(s):  
Drosophila Melanogaster ◽  
Development Time ◽  
Wing Length ◽  
Larval Density ◽  
High Density ◽  
Density Dependent ◽  
Resource Limited ◽  
Adult Body ◽  
Adult Body Weight ◽  
Mutant Lines

ABSTRACT The effects of larval density on components of fertility fitness were investigated with two mutant lines of Drosophila melanogaster. The differences in adult body weight, wing length, larval survivorship and development time verified that flies reared at high density were resource limited. Experimental results indicate that: (1) relative fecundities of both sexes show density-dependent effects, (2) there is a strong density effect on male and female mating success, and (3) in general, there is a reduction in fecundity differences between genotypes at high density. These results imply that it may be important to consider fertility in models of density-dependent natural selection.

scholarly journals Effects of Plant Species, Insecticide, and Exposure Time On the Efficacy Of Barrier Treatments Against Aedes albopictus

2018 ◽  
Vol 34 (4) ◽  
pp. 281-290 ◽  
Author(s):  
Benjamin E. McMillan ◽  
Jake E. Bova ◽  
Carlyle C. Brewster ◽  
Nicola T. Gallagher ◽  
Sally L. Paulson
Keyword(s):  
Plant Species ◽  
Aedes Albopictus ◽  
Adult Mortality ◽  
Miscanthus Sinensis ◽  
Chemical Treatments ◽  
Residual Toxicity ◽  
Japanese Honeysuckle ◽  
Lambda Cyhalothrin ◽  
Significant Difference ◽  
Over Time

ABSTRACT The effect of 5 plant species (arborvitae [Thuja occidentalis], boxwood [Buxus sp., Japanese honeysuckle [Lonicera japonica], rhododendron [Rhododendron sp.], and zebra grass [Miscanthus sinensis]) and 2 rates of lambda-cyhalothrin (3.13 ml and 6.25 ml active ingredient [AI]/liter) on knockdown (1 h) and mortality (24 h) of adult female Aedes albopictus was evaluated over an 8-wk period. A significant difference in knockdown was observed between the 2 rates of lambda-cyhalothrin on the 5 plant species, with the highest proportion of knockdown observed on zebra grass and rhododendron treated at the higher rate. Although mortality was ≥60% and 85% on the 5 plant species at the low and high rates of lambda-cyhalothrin, respectively, a significant difference between the 2 rates was only observed on boxwood and Japanese honeysuckle (P < 0.0001). We also tested the residual toxicity of 3 barrier sprays (lambda-cyhalothrin, bifenthrin, and deltamethrin) and evaluated the efficacy of a short (5-min) exposure to the insecticides on knockdown and mortality of adults over time. Significantly higher knockdown was observed with lambda-cyhalothrin compared with bifenthrin and deltamethrin (P < 0.0001). Mean knockdown was ∼98%, 92%, and 20% for lambda-cyhalothrin, bifenthrin, and deltamethrin, respectively, at week 2, and ∼98%, 0%, and 44%, respectively, 8 wk after treatments were applied. Adult mortality from the 3 chemical treatments, however, remained above 90% throughout the study. Lastly, the trends in mean proportion of knockdown were similar for mosquitoes exposed for either 5 min or 24 h to the 3 chemicals. An overall decline in mean mortality over time, however, was observed for mosquitoes exposed for 5 min to the chemicals compared with mortality from the 24-h exposure. The results suggest that lambda-cyhalothrin can be an effective barrier spray treatment against Ae. albopictus adults because its efficacy is limited little by plant species, it has long residual toxicity, and it is effective following only 5 min of exposure.

Guideline Values for Minimum Nasal Cross-Sectional Area in Children

2018 ◽  
Vol 55 (8) ◽  
pp. 1043-1050
Author(s):  
Maija T. Laine-Alava ◽  
Siiri Murtolahti ◽  
Ulla K. Crouse ◽  
Donald W. Warren
Keyword(s):  
Cleft Lip ◽  
Cross Sectional Area ◽  
Adult Size ◽  
Nasal Airway ◽  
Sectional Area ◽  
Cross Sectional ◽  
Age Cohorts ◽  
Guideline Values ◽  
Significant Difference ◽  
Research Criteria

Objective: The purpose was to determine age-specific values of the minimum cross-sectional area of the nasal airway in children without cleft lip or palate and to assess whether gender differences occur with growth in order to develop guidelines for assessment in children with clefts. Participants: All schoolchildren aged 8 to 17 years who met the research criteria were studied during rest breathing using the pressure-flow technique. The children came from a rural area of 3800 inhabitants. Consecutive age cohorts were used for comparisons. Results: Nasal cross-sectional area increased in females from 0.38 cm2 in 8-year-olds to 0.58 cm2 in 17-year-olds. There was a decrease in size at ages 10 to 11 and 14 to 15 years. In males, the area increased from 0.40 to 0.68 cm2 and decreased slightly from 9 to 10 and 14 to 15 years. The annual changes were statistically significant in females between 8 and 9 and 11 to 13 years of age, and in males from 11 to 12, 13 to 14, and 15 to 17 years of age. Across gender, the only significant difference occurred at age 16. Conclusions: Our results indicate that the increase in nasal airway size is not consistent during growth. Nasal airway size showed almost equal values for both genders in young children but was systematically larger in boys from 14 years of age on. The results refer that by 17 years of age nasal airway may not have reached adult size in males.

scholarly journals Patterns of Growth in Nestling Indian Barn-Owls

The Condor ◽  
2002 ◽  
Vol 104 (4) ◽  
pp. 885-890 ◽  
Author(s):  
Rajarathinavelu Nagarajan ◽  
Krishinamoorthy Thiyagesan ◽  
Rajagopalan Natarajan ◽  
Ramalingam Kanakasabai
Keyword(s):  
Body Mass ◽  
Body Length ◽  
Wing Length ◽  
Growth Patterns ◽  
The Body ◽  
Logistic Growth ◽  
Adult Size ◽  
Tyto Alba ◽  
Tarsus Length ◽  
Bill Length

Abstract We examined nestling growth patterns of the Indian Barn-Owl (Tyto alba stertens) in Tamilnadu, Southern India, with reference to body mass, body length, bill length, bill width, wing length, wingspan, tail length, tarsus length, and middle claw length. Body mass reached an asymptote of 447.0 ± 6.8 g during week 7, which was 10% higher than the adult mass. Then it significantly declined to 437.0 ± 10.9 g at fledging. At the end of week 4, the body length, bill length, bill width, tarsus length, and middle toe length had surpassed 50% of adult sizes. The wingspan and tarsus length reached almost adult size by the time of fledging. A logistic growth curve was found to be a good fit for all the growth variables and explained between 71% (wing length) and 86% (body length) of the variance. Patrones de Crecimiento en Polluelos de Tyto alba stertens Resumen. Examinamos los patrones de crecimiento de polluelos de Tyto alba stertens en Tamilnadu, sudoeste de India, en relación al peso y el largo del cuerpo, el largo y el ancho del pico, el largo del ala y su envergadura, y el largo de la cola, los tarsos y de la garra mediana. El peso corporal alcanzó una asíntota de 447.0 ± 6.8 g durante la séptima semana, el cual fue un 10% mayor que el peso de los adultos. Posteriormente, durante el período de volantones, el peso corporal disminuyó hasta 437.0 ± 10.9 g. Al final de la cuarta semana, el largo del cuerpo, el largo y el ancho del pico, y los largos del tarso y del dedo mediano habían sobrepasado el 50% de los tamaños adultos. La envergadura del ala y el largo del tarso casi alcanzaron tamaños adultos durante el período de volantones. Se encontró que una curva de crecimiento logístico se ajustó bien a todas las variables de crecimiento y explicó un 71% (largo del ala) y un 86% (largo del cuerpo) de la varianza.

scholarly journals The behavioral response of prey fish to predators: the role of predator size

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3222 ◽  
Author(s):  
Zhong-Hua Tang ◽  
Qing Huang ◽  
Hui Wu ◽  
Lu Kuang ◽  
Shi-Jian Fu
Keyword(s):  
Relative Size ◽  
The Body ◽  
Size Difference ◽  
Prey Fish ◽  
Potential Predator ◽  
Black Carp ◽  
Predator Treatment ◽  
Predator Size ◽  
Significant Difference ◽  
Spontaneous Activities

Predation is one of the key factors governing patterns in natural systems, and adjustments of prey behaviors in response to a predator stimulus can have important ecological implications for wild fish. To investigate the effects of predators on the behavior of prey fish and to test whether the possible effects varied with predator size, black carp (Mylopharyngodon piceus) and snakehead (Channa argus) (a size-matched predator treatment with a similar body size to prey fish and a larger predator treatment with approximately 2.7 times of the body mass of prey fish) were selected to function as prey and predator, respectively. Their spontaneous activities were videorecorded in a central circular arena surrounded by a ring holding the stimulus fish. The distance between prey and predator fish was approximately 200% of the distance between two prey fish, which suggested that black carp can distinguish their conspecifics from heterospecifics and probably recognize the snakehead as a potential predator. The prey fish spent substantially less time moving and exhibited an overall shorter total distance of movement after the size-matched or large predator was introduced, which possibly occurred due to increased vigilance or efforts to reduce the possibility of detection by potential predators. However, there was no significant difference in either distance or spontaneous activities between two predator treatments. These findings suggested that (1) an anti-predator strategy in black carp might involve maintaining a safe distance, decreasing activity and possibly increased vigilance and that (2) the behaviors of prey response to predators were not influenced by their relative size difference.

scholarly journals Mercury Detection in Benthic and Pelagic Fish Collected from Western Sicily (Southern Italy)

Animals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 594
Author(s):  
Gaetano Cammilleri ◽  
Francesco Giuseppe Galluzzo ◽  
Francesco Fazio ◽  
Andrea Pulvirenti ◽  
Antonio Vella ◽  
...  
Keyword(s):  
Mercury Concentration ◽  
Southern Italy ◽  
Sparus Aurata ◽  
Polluted Water ◽  
Fish Food ◽  
Pelagic Species ◽  
Direct Mercury Analyzer ◽  
Significant Difference ◽  
Fish Samples ◽  
Hg Accumulation

In highly polluted water, fish can accumulate mercury up to a concentration of 10 mgKg−1. This has occurred on the eastern coasts of Sicily (Southern Italy), probably due to the intense industrial activity of this area. However, little is known about Hg accumulation in fish of the western Sicilian coasts. In this work, we examined the Hg accumulation of 108 fish samples belonging to 14 species collected from western Sicilian coasts using a direct mercury analyzer. The samples showed a mean mercury concentration of 0.165 ± 0.22 mg kg−1 with a maximum in Lepidopus caudatus (1.72 mgKg−1), exceeding the limits provided by EC Reg. 1881/2006. The lowest Hg levels were found in Sparus aurata samples (0.001 mgKg−1). A significant difference was found between the fish species examined (p < 0.05). The comparison between benthic and pelagic species did not show statistical differences (p < 0.05). Fish food constitutes the main route of Hg uptake for humans. Only four of the 130 samples examined reached a mercury concentration over the European limits. The comparative analysis of Hg pollution for benthic and pelagic species did not confirm a different trend in metal contamination.

Sublethal Effects of Environmental Acidification on Rainbow Trout (Salmo gairdneri)

1979 ◽  
Vol 36 (1) ◽  
pp. 84-87 ◽  
Author(s):  
C. M. Neville
Keyword(s):  
Rainbow Trout ◽  
Species Differences ◽  
Sublethal Effects ◽  
Anaerobic Respiration ◽  
Acid Group ◽  
Salmo Gairdneri ◽  
Significant Difference ◽  
Caudal Vein ◽  
Erythrocyte Concentration ◽  
Oxygen Carrying Capacity

Dorsal aorta blood samples were taken from cannulated rainbow trout (Salmo gairdneri) exposed to pH 4.0 (acid group) or pH 7.0 (controls) in normocapnic conditions at 10 °C. Over a 5-d period there was a significant gradual decrease in pH and total CO2 in the acid group but no significant difference in pO2 and lactate compared to the controls. After uncannulated rainbow trout were exposed to the same conditions for 12 d there were significant increases in hemoglobin, hematocrit, and erythrocyte levels in caudal vein samples from the acid group. The results show that rainbow trout exposed to acid without hypercapnia develop acidaemia which is not a result of anaerobic respiration. The increase in erythrocyte concentration probably offsets the effects of acidaemia upon blood oxygen carrying capacity. Differences in ambient pCO2 and/or species differences could account for varying acid-base values in acid exposed fish reported by different workers. Key words: environmental acidification, acidaemia, lactate, pH, total carbonate, fish

scholarly journals Histopathological evaluation of formalin toxicity in Arapaima gigas (Arapaimidae), the giant fish from Amazon

2018 ◽  
Vol 38 (6) ◽  
pp. 1015-1025
Author(s):  
Sanny M. Andrade-Porto ◽  
Cleverson A. Ramos ◽  
Rosemary Roque ◽  
Elizabeth G. Affonso ◽  
José F.M. Barcellos ◽  
...  
Keyword(s):  
Sublethal Effects ◽  
Clinical Signs ◽  
Lethal Concentration ◽  
Histopathological Analysis ◽  
Behavioral Alterations ◽  
Mean Values ◽  
Short Term Exposure ◽  
Arapaima Gigas ◽  
Significant Difference ◽  
Hydrodynamic Equilibrium

ABSTRACT: This study aimed to determine the lethal concentration and the structural and ultra-structural effects caused by the formalin exposure on juveniles of Arapaima gigas. Ninety fish (60.1± 2.5g and 20.2±0.9cm) were exposed to 0, 22, 44, 66, 88 and 110mg L-1 in order to determine the lethal concentration (LC50-96h) that was 36.4mg L-1 of formalin. Sublethal effects were evaluated using histopathological analysis on the gills and assessment of behavioral alterations and clinical signs. The LC50 of formalin for 24, 48 and 72h was 88.3, 64.7 and 56.8mg L-1 respectively. Clinical signs and behavioral changes were found: erratic swimming, lethargy, crowding on the water surface, loss of hydrodynamic equilibrium, spasms and agonistic confrontation, which were observed only at 88 and 110mg L-1. The histological alteration index (HAI) showed that 66, 88 and 100mg L-1 presented significant difference (p<0.05) in relation to unexposed fish, indicating that moderate damage to the gills of fish exposed to formalin had occurred. The mean values of alteration (MVA) for 22, 44, 66, 88 and 110mg L-1 were 1.14, 1.29, 1.51, 1.53 and 1.60 respectively, and differences in this index were only observed with 110 mgL-1 of formalin. It is therefore possible to conclude that sublethal concentrations of formalin (22.0mg L-1) did not compromise the health of juveniles of A. gigas. Finally, concentrations greater than to LC50-96h may be carefully used for short-term exposure, since the MVA for all concentrations tested only indicated localized lesions that did not compromise gills functionality of exposed fish.

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