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1.
Indian J Med Res ; 148(3): 334-340, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30425225

RESUMEN

BACKGROUND & OBJECTIVES: In sterile insect technology (SIT), mating competitiveness is a pre-condition for the reduction of target pest populations and a crucial parameter for judging efficacy. Still, current SIT trials are being hindered by decreased effectiveness due to reduced sexual performance of released males. Here, we explored the possible role of a herbal aphrodisiac in boosting the mating activity of Aedes aegypti. METHODS: Males were fed one of two diets in this study: experimental extract of Eurycoma longifolia (MSAs) and sugar only (MSOs). Differences in life span, courtship latency, copulation activity and mating success were examined between the two groups. RESULTS: No deaths occurred among MSA and MSO males. Life span of MSOs was similar to that of MSAs. The courtship latency of MSAs was shorter than that of MSOs (P<0.01). MSAs had greater copulation success than MSOs (P<0.001). In all female treatments, MSAs mated more than MSOs, but the differences in rate were significant only in the highest female density (P<0.05). In MSAs, mating success varied significantly with female density (P<0.01), with the 20-female group (P<0.01) having the lowest rate. Single MSA had better mating success at the two lowest female densities. In MSOs, there were no significant differences in mating success rate between the different female densities. INTERPRETATION & CONCLUSIONS: Our results suggested that the herbal aphrodisiac, E. longifolia, stimulated the sexual activity of Ae. aegypti and may be useful for improving the mating competitiveness of sterile males, thus improving SIT programmes.


Asunto(s)
Afrodisíacos/farmacología , Eurycoma , Mosquitos Vectores , Control Biológico de Vectores/métodos , Aedes/efectos de los fármacos , Aedes/fisiología , Animales , Copulación/efectos de los fármacos , Insectos , Insecticidas/farmacología , Inseminación/efectos de los fármacos , Control de Mosquitos , Mosquitos Vectores/efectos de los fármacos , Mosquitos Vectores/fisiología
2.
J Insect Sci ; 152015.
Artículo en Inglés | MEDLINE | ID: mdl-26386041

RESUMEN

Viable biocontrol agents for mosquito control are quite rare, therefore improving the efficacy of existing biological agents is an important study. We need to have a better understanding of the predation-risk behavioral responses toward prey. This research examined prey choices by Toxorhynchites splendens by monitoring the behavioral responses of Aedes aegypti, Aedes albopictus, and Anopheles sinensis larvae when exposed to the predator. The results show that Tx. splendens prefers to consume Ae. aegypti larvae. The larvae exhibited different behavioral responses when Tx. splendens was present which suggest vulnerability in the presence of predators. "Thrashing" and "browsing" activities were greater in Ae. aegypti larvae. Such active and risky movements could cause vulnerability for the Ae. aegypti larvae due to increasing of water disturbance. In contrast, Ae. albopictus and An. sinensis larvae exhibited passive, low-risk behaviors, spending most of the time on the "wall" position near the edges of the container. We postulated that Ae. aegypti has less ability to perceive cues from predation and could not successfully alter its behavior to reduce risk of predation risk compared with Ae. albopictus and An. sinensis. Our results suggest that Tx. splendens is a suitable biocontrol agent in controlling dengue hemorrhagic vector, Ae. aegypti.


Asunto(s)
Aedes/fisiología , Anopheles/fisiología , Culicidae/fisiología , Conducta Predatoria , Aedes/crecimiento & desarrollo , Animales , Anopheles/crecimiento & desarrollo , Conducta Animal , Culicidae/crecimiento & desarrollo , Larva/fisiología , Control de Mosquitos , Control Biológico de Vectores
3.
J Insect Sci ; 14: 180, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25368088

RESUMEN

Natural insecticides from plant origin against mosquito vectors have been the main concern for research due to their high level of eco-safety. Control of mosquitoes in their larval stages are an ideal method since Aedes larvae are aquatic, thus it is easier to deal with them in this habitat. The present study was specifically conducted to explore the larvicidal efficacy of different plant parts of Ipomoea cairica (L.) or railway creeper crude extract obtained using two different solvents; methanol and acetone against late third-stage larvae of Aedes albopictus (Skuse) and Aedes aegypti (L.) (Diptera: Culicidae). Plant materials of I. cairica leaf, flower, and stem were segregated, airdried, powdered, and extracted using Soxhlet apparatus. Larvicidal bioassays were performed by using World Health Organization standard larval susceptibility test method for each species which were conducted separately for different concentration ranging from 10 to 450 ppm. Both acetone and methanol extracts showed 100% mortality at highest concentration tested (450 ppm) after 24 h of exposure. Results from factorial ANOVA indicated that there were significant differences in larvicidal effects between mosquito species, solvent used and plant parts (F=5.71, df=2, P<0.05). The acetone extract of I. cairica leaf showed the most effective larvicidal action in Ae. aegypti with LC50 of 101.94 ppm followed by Ae. albopictus with LC50 of 105.59 ppm compared with other fractions of I. cairica extract obtained from flower, stem, and when methanol are used as solvent. The larvae of Ae. aegypti appeared to be more susceptible to I. cairica extract with lower LC50 value compared with Ae. albopictus (F=8.83, df=1, P<0.05). Therefore, this study suggests that the acetone extract of I. cairica leaf can be considered as plant-derived insecticide for the control of Aedes mosquitoes. This study quantified the larvicidal property of I. cairica extract, providing information on lethal concentration that may have potential for a more eco-friendly Aedes mosquito control program.


Asunto(s)
Aedes , Insectos Vectores , Insecticidas/análisis , Ipomoea/química , Animales , Dengue/transmisión , Larva , Componentes Aéreos de las Plantas , Extractos Vegetales/química , Pruebas de Toxicidad
4.
J Am Mosq Control Assoc ; 27(3): 263-71, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22017091

RESUMEN

Discarded cigarette butts (DCB) waste occurs worldwide, pollutes landscapes, is unsightly, and results in added debris removal costs. There is, therefore, a great deal of current interest in making use of DCBs in beneficial ways. Despite evidence that DCBs are harmful to water fleas (Daphnia magna), which breed in aquatic environments as do mosquito larvae, their impact on dengue vectors is unknown. We examined whether Aedes albopictus alters its ovipositional responses, larval eclosion, and development in response to presence of DCBs in its habitats. We found oviposition activity in DCB-treated water similar to that of control water and that ovipositional activity in DCB solutions steadily increased over time as those solutions aged to 10 days. Larval eclosion was initially suppressed on day 1 in DCB solution, but increased thereafter to levels similar to control larval eclosion rates. The DCB-water solutions produced significantly higher mortality in both 1st and 2nd instars over control larvae for several days after initial exposure. Mortality rates decreased sharply 3 to 5 days postexposure as DCBs continued to decompose. We found increased survival rates during late development, but daily input of fresh DCBs prevented most young larvae from completing development. Taken together, these observations suggest that decomposing did not deter gravid Ae. albopictus females from ovipositing in treated containers and that DCB solutions had larvicidal effects on early instars. Our results are discussed in the context of DCB use to control container-breeding Ae. albopictus, a competent dengue vector in Asia and other parts of the world.


Asunto(s)
Aedes , Control de Mosquitos/métodos , Animales , Dengue/prevención & control , Femenino , Concentración de Iones de Hidrógeno , Insectos Vectores , Larva , Oviposición , Fumar , Nicotiana
5.
Sci Rep ; 11(1): 5180, 2021 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-33664425

RESUMEN

The usage of insecticide rendered the successful vector control program with the high usage of the pyrethroid. However, the intensive and extensive use of pyrethroid, causing resistance in Aedes aegypti and hampered the control program. Knockdown resistance (kdr) resulting from the Voltage-Gated Sodium Channel (VGSC) is one of the mechanisms of resistance in pyrethroid group insecticide. Investigating the phenotypic status of Ae. aegypti mosquitoes is a lead in knowing the current resistance status and as an indicator of the genotypic resistance. In this study, we investigate the resistance in phenotypic and genotypic of Ae. aegypti with a new kdr mutation point A1007G was detected. Using the adult bioassay, we tested the phenotypic resistance from the Selangor state against 0.75% permethrin, 0.05% deltamethrin with and without the addition of PBO synergist. Permethrin-resistant and deltamethrin-resistant, including susceptible samples, were subjected to genotyping analysis on mutation point in domain II and domain III of Voltage-Gated Sodium Channel (VGSC). Adult bioassay revealed that the Ae. aegypti was highly resistance toward 0.75% permethrin and 0.05% deltamethrin. The bioassay with the presence of PBO synergist showed an increment of mortality rate, but Ae. aegypti status is still resistance towards both insecticides. Genotyping result showed that three common kdr mutations (S989P, V1016G, and F1534C) have existed in the Ae. aegypti population. A new novel mutation on A1007G was also detected in this population, which is the first time reported. This study has brought a piece of information on the current resistance status in Ae. aegypti in Malaysia. The detection of new mutation point of A1007G has added the knowledge on the resistance in mosquitoes. Thus, this study will aid with the decision making in the usage of insecticides in the vector control program; before this invaluable insecticide rendered ineffective in killing mosquitoes.


Asunto(s)
Aedes/efectos de los fármacos , Resistencia a los Insecticidas/genética , Insecticidas/efectos adversos , Canales de Sodio Activados por Voltaje/genética , Aedes/genética , Alelos , Animales , Genotipo , Humanos , Resistencia a los Insecticidas/efectos de los fármacos , Insecticidas/farmacología , Mosquitos Vectores/efectos de los fármacos , Mosquitos Vectores/genética , Mutación/genética , Piretrinas/efectos adversos , Piretrinas/farmacología
6.
Plant Signal Behav ; 16(10): 1935605, 2021 10 03.
Artículo en Inglés | MEDLINE | ID: mdl-34151732

RESUMEN

Bee orchids have long been an excellent example of how dishonest signal works in plant-animal interaction. Many studies compared the flower structures that resemble female bees, leading toward pseudo-copulation of the male bees on the flower. Using Machine Learning, we tested whether nature is capable of besting artificial intelligence. A total of 2000 images of related bees, wasps, and Ophrys sp. were collected from the Google Image Repository. Unsuitable images were later filtered out manually, leaving a total of 995 images in the final selection. 80% of these images were used to build a supervised model using Logistic Regression, while the model accuracy was tested using 20% of the remaining images. Based on our results using Wolfram Mathematica, the Ophrys is not capable of fooling artificial intelligence. The accuracy, accuracy baseline, mean cross-entropy, Area Under ROC (receiver operating characteristic curve) curve (AUC) and the confusion matrix gave excellent image classification. However, we can now show the key points and highlights of the images and how the structures closely resemble actual bees using the SURF method. Rather than just a descriptive method, ML learning has enabled a more quantitative approach. Since this is a simple test, we encourage other scientists to adopt our approach using a larger dataset and better database samples.


Asunto(s)
Inteligencia Artificial , Abejas , Mimetismo Biológico , Flores , Orchidaceae , Animales , Abejas/anatomía & histología , Abejas/clasificación , Femenino , Flores/anatomía & histología , Procesamiento de Imagen Asistido por Computador , Masculino , Orchidaceae/anatomía & histología , Orchidaceae/clasificación , Polinización
7.
Insects ; 12(12)2021 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-34940185

RESUMEN

Flowers and their spatial clustering are important parameters that mediate the foraging behavior and visitation rate of pollinating insects. Visual stimuli are crucial for triggering behavioral changes in the house fly, Musca domestica, which regularly visits plants for feeding and reproduction. The success of bait technology, which is the principal means of combatting flies, is adversely affected by reduced attractiveness and ineffective application techniques. Despite evidence that house flies have color vision capacity, respond to flowers, and exhibit color and pattern preference, the potential of artificial flowers as attractive factors has not been explored. The present study was performed to investigate whether artificial floral designs can lure and kill house flies. Starved wild house flies were presented with equal opportunities to acquire sugar meals, to which boric acid had been added as a toxin, from one flower arrangement (blue-dominated design, BDD; yellow-dominated design, YDD; or pink-dominated design, PDD), and a non-toxic white design (WDD). We also allowed house flies to forage within an enclosure containing two non-toxic floral designs (WDDs). The differences in mortality between the two environments with and without toxicant were examined. The survival rate of Musca domestica was extremely high when WDDs containing non-toxic sugar sources were the only feeding sites available. When given an option to forage in an environment containing a BDD and a WDD, house flies showed a high mortality rate (76%) compared to their counterparts maintained in the WDD environment (2%). When kept in an enclosure containing one YDD and a WDD, flies showed a mortality rate of 88%; however, no mortality occurred among flies confined to a compound with a WDD pair. When provided an even chance of foraging in an enclosure containing a mixed pair of floral arrangements (PDD and WDD) and another with two WDDs, flies showed a higher mortality rate (78%) in the first environment. However, the maximum survival rate (100%) was seen in the WDD environment. Exposure to YDD tended to result in a greater mortality rate than with the two other floral designs. Mortality gradually increased with time among flies exposed to tested artificial floral designs. The results presented here clearly indicated that artificial flower arrangements with a toxic sugar reward were strikingly attractive for house flies when their preferred color (white) was present. These observations offer novel possibilities for future development of flower mimic-based house fly control.

8.
PLoS Negl Trop Dis ; 14(3): e0008075, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32218580

RESUMEN

The massive flood in Malaysia's east coast in December 2014 has placed Kelantan in a possible dengue outbreak risk. At this point, community awareness is essential in preventing disease spread. However, no data on knowledge, attitude, and practice (KAP) of dengue in Kelantan have existed in relevance to flood disaster, although such information is necessary for the vector control programs. The purpose of this study is to assess the KAP regarding dengue among school children from flooded and unflooded areas and to evaluate the effectiveness of the dengue health education program in improving their KAP level. A school-based pre- and post-tests design was utilized in this study whereby a booklet on dengue was distributed during the interphase of the tests. The information collected was on the socio-demographic, KAP and the source of dengue information. We statistically compared the KAP between the two study sites and the pre- and post-test scores to evaluate the health education program. A total of 203 students participated in the survey, and 51.7% of them were flood victims. When comparing the baseline KAP, the respondents from the unflooded area had higher knowledge scores compared to those from the flooded area (P<0.05), while non-significant differences were observed in the attitude and practice between the two study areas (P>0.05). The health education program significantly improved knowledge and practice in the flooded area and knowledge only in the unflooded area (P<0.05). The multinomial regression analysis suggests that age and dengue history are the primary determinants that influence the high practice level in both areas. We suggest the need to increase routine dengue health education programs to all age groups targeting both high and low dengue risk areas, and the necessity to ensure the translation of positive knowledge and attitude changes into real dengue preventive practices.


Asunto(s)
Control de Enfermedades Transmisibles/métodos , Infecciones Comunitarias Adquiridas/prevención & control , Dengue/prevención & control , Educación en Salud/organización & administración , Conocimientos, Actitudes y Práctica en Salud , Estudiantes/psicología , Adolescente , Infecciones Comunitarias Adquiridas/epidemiología , Estudios Transversales , Femenino , Humanos , Malasia , Masculino , Instituciones Académicas , Encuestas y Cuestionarios
9.
Acta Trop ; 185: 230-238, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29856985

RESUMEN

Food location by mosquitoes is mediated by resource-derived olfactory and visual signals. Smell sensation is intermittent and dependent on the environment, whereas visual signals are continual and precede olfactory cues. Success of mosquito bait technology, where olfactory cues are used for attraction, is being impeded by reduced attractiveness. Despite proof that mosquitoes respond to colored objects, including those mimicking floral shape, and that they can discriminate among flowers, the impacts of artificial flowers on foraging remain unexplored. Using artificial flowers with sugar rewards, we examined the foraging responses of Aedes aegypti to various colors in equal choice bioassays. Starved adults were exposed to single flowers with petals of a given color (Single Blue Flowers [SBFs]; Single Red Flowers [SRFs]; Single Yellow Flowers [SYFs]; Single Pink Flowers [SPIFs]; and Single Purple Flowers [SPFs]) and two others with white petals (SWFs). Discrepancies in response time, visitation, feeding, and resting of both sexes were compared between colored flowers and SWFs. Ae. aegypti exhibited shorter response times to colored flowers compared to SWFs, but this behavior was mostly seen for SBFs or SYFs in females, and SRFs, SYFs, SPIFs, or SPFs in males. When provided an option to land on colored flowers and SWFs, female visitation occurred at high rates on SBFs, SRFs, SYFs, SPIFs, and SPFs; for males, this preference for colored flowers was seen to a lesser degree on SBF and SPIFs. Both sexes exhibited preference for colored flowers as sugar sources, but with different patterns: SPIFs, SRFs, SYFs, and SPFs for females; SYFs, SPFs, SPIFs and SRFs for males. Females preferentially rested on colored flowers when in competition with SWFs, but this preference was more pronounced for SPFs, SRFs, and SBFs. Males exhibited an increased preference for SRFs, SPFs, and SYFs as resting sites. Our results indicated the attraction of Ae. aegypti to rewarding artificial flowers, in some cases in ways similar to live flowering plants. The discovery that both male and female Ae. aegypti can feed on nectar mimics held by artificial flowers opens new avenues for improving sugar bait technology and for developing new attract-and-kill devices.


Asunto(s)
Aedes/fisiología , Conducta Alimentaria , Flores , Mosquitos Vectores/fisiología , Animales , Femenino , Masculino , Néctar de las Plantas , Olfato , Azúcares
10.
Environ Sci Pollut Res Int ; 25(14): 13833-13843, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29512008

RESUMEN

Nectar is the staple diet of adult mosquitoes in the wild, but its availability is inconsistent and can be affected by rainfall. In urban centers, Aedes vectors commonly use man-made containers as their major habitat; however, they can colonize any items replenished by rainfall. Garbage output has increased significantly in recent years, at a time when collection frequency is reducing. Such garbage usually includes organic components, some of which are sweet and can be fed upon by other animals or become can containers for rainwater. Despite evidence that Aedes larvae can thrive in containers comprised of organic waste material, which can be produced by rodents gnawing on fruits or vegetables, and that adults can survive on sweet waste fluids, the capacity of organic waste materials to accumulate rainwater and act as egg deposition sites has not been examined. It is also unknown for how long sweet extracts can sustain the life of adult vectors. Here, we investigated the abundance of sweet leftovers at garbage sites and the rainwater retention capacity of some organic materials through a field survey and laboratory bioassays. We also examined whether sweet waste fluids impact egg hatching success and longevity of Aedes aegypti. The results of this study indicated that sweet products with leftovers are highly prevalent in garbage. When exposed to rain, food items (BAFrc, banana fruit resembling container; and BSPrc, boiled sweet potato resembling container) and the packaging of sweet foods (SMIc, sweetened condensed milk can) retained water. When provided an opportunity to oviposit in cups containing BAF extract (BAFex), BSP extract (BSPex), and SMI extract (SMIex), eggs were deposited in all media. Egg maturation in the BAFex environment resulted in similar larval eclosion success to that resulting from embryo development in a water milieu. Adults maintained on sweet waste extracts had long lifespans, although shorter than that of their sugar solution (SUS)-fed counterparts. Taken together, these results indicated that sweet waste materials are useful to dengue mosquitoes, acting both as oviposition sites and energy sources.


Asunto(s)
Aedes/fisiología , Oviposición , Lluvia , Instalaciones de Eliminación de Residuos , Aedes/crecimiento & desarrollo , Animales , Conducta Alimentaria , Residuos de Alimentos , Larva/crecimiento & desarrollo , Larva/fisiología , Longevidad , Reproducción
11.
Rev Inst Med Trop Sao Paulo ; 59: e4, 2017 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-28380115

RESUMEN

Paederus fuscipes, a vector of Paederus dermatitis in most tropical and subtropical countries of the world have a high prevalence in human dwellings due to their positively phototaxic behaviour which has caused a tremendous impact on human health. In this paper, P. fuscipes dispersal flights were studied for two seasons of the rice cultivation phases in residential premises built close to rice field areas (≈32-60 m and 164 m) in mainland Penang, Malaysia. We examined the effects of different light illuminance, building floor level and their association with rice stages as a focal cause of P. fuscipes dispersion from the rice fields towards human dwellings. The present study showed a significant interaction between different light illuminances and rice cultivation phases in attracting P. fuscipes to disperse and invade human dwellings. The highest number of P. fuscipes was captured near the bright light. P. fuscipes flights increased in line with each floor level, and the highest captures took place at higher building floor levels (levels 2 and 3) compared to lower building floor levels (ground floor and level 1) of a three storey apartment in both rice seasons. This finding not only conveys a better understanding on P. fuscipes dispersal pattern, but also draws public attention on the occurrence of dermatitis linearis caused by the Paederus beetles.


Asunto(s)
Conducta Animal/fisiología , Escarabajos/fisiología , Dermatitis por Contacto/parasitología , Distribución Animal , Animales , Humanos , Luz , Malasia , Oryza , Densidad de Población , Estaciones del Año
12.
Environ Sci Pollut Res Int ; 24(17): 14782-14794, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28470499

RESUMEN

In dengue mosquitoes, successful embryonic development and long lifespan are key determinants for the persistence of both virus and vector. Therefore, targeting the egg stage and vector lifespan would be expected to have greater impacts than larvicides or adulticides, both strategies that have lost effectiveness due to the development of resistance. Therefore, there is now a pressing need to find novel chemical means of vector control. Coffee contains many chemicals, and its waste, which has become a growing environmental concern, is as rich in toxicants as the green coffee beans; these chemicals do not have a history of resistance in insects, but some are lost in the roasting process. We examined whether exposure to coffee during embryonic development could alter larval eclosion and lifespan of dengue vectors. A series of bioassays with different coffee forms and their residues indicated that larval eclosion responses of Aedes albopictus and Ae. aegypti were appreciably lower when embryonic maturation occurred in environments containing coffee, especially roasted coffee crude extract (RCC). In addition, the lifespan of adults derived from eggs that hatched successfully in a coffee milieu was reduced, but this effect was less pronounced with roasted and green coffee extracts (RCU and GCU, respectively). Taken together, these findings suggested that coffee and its residues have embryocidal activities with impacts that are carried over onto the adult lifespan of dengue vectors. These effects may significantly reduce the vectorial capacity of these insects. Reutilizing coffee waste in vector control may also represent a realistic solution to the issues associated with its pollution.


Asunto(s)
Aedes , Café , Dengue/transmisión , Control de Insectos , Insectos Vectores , Animales , Bioensayo , Larva
13.
Environ Sci Pollut Res Int ; 24(26): 21375-21385, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28744676

RESUMEN

Yearly, huge amounts of sock refuse are discarded into the environment. Socks contain many molecules, and worn ones, which are rich in smell-causing bacteria, have a strong influence on animals' behaviors. But the impacts of sock odor on the oviposition behavior of dengue vectors are unknown. We assessed whether Aedes albopictus changes its oviposition activity in response to the presence of used socks extract (USEx) in potential breeding grounds, using choice and no-choice bioassays (NCB). When furnished even chances to oviposit in two sites holding USEx and two others containing water (control), Ae. albopictus deposited significantly less eggs in USEx than in water sites. A similar pattern of oviposition preference was also observed when there were more oviposition options in water. When there were greater oviposition opportunities in USEx sites, Ae. albopictus oviposited preferentially in water. Females laid significantly more eggs during the NCB involving water than USEx. Also, significantly more mature eggs were retained by females in the NCB with USEx than in that with water. These observations strongly suggest the presence of molecules with either repellent or deterrent activities against Ae. albopictus females and provide an impetus to advocate the integration of used socks in dengue control programs. Such applications could be a realistic end-of-life recourse to reroute this waste from landfills.


Asunto(s)
Aedes/efectos de los fármacos , Virus del Dengue , Control de Insectos/métodos , Repelentes de Insectos/farmacología , Mosquitos Vectores/efectos de los fármacos , Oviposición/efectos de los fármacos , Aedes/anatomía & histología , Aedes/virología , Animales , Conducta Animal/efectos de los fármacos , Vestuario , Dengue/prevención & control , Femenino , Repelentes de Insectos/química , Masculino , Modelos Teóricos , Mosquitos Vectores/anatomía & histología , Mosquitos Vectores/virología
14.
Acta Trop ; 169: 84-92, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28174057

RESUMEN

In nature, adult mosquitoes typically utilize nectar as their main energy source, but they can switch to other as yet unidentified sugary fluids. Contemporary lifestyles, with their associated unwillingness to consume leftovers and improper disposal of waste, have resulted in the disposal of huge amounts of waste into the environment. Such refuse often contains unfinished food items, many of which contain sugar and some of which can collect water from rain and generate juices. Despite evidence that mosquitoes can feed on sugar-rich suspensions, semi-liquids, and decaying fruits, which can be abundant in garbage sites, the impacts of sweet waste fluids on dengue vectors are unknown. Here, we investigated the effects of extracts from some familiar sweet home waste items on key components of vectorial capacity of Aedes aegypti. Adult mosquitoes were fed one of five diets in this study: water (WAT); sucrose (SUG); bakery product (remnant of chocolate cake, BAK); dairy product (yogurt, YOG); and fruit (banana (BAN). Differences in survival, response time to host, and egg production were examined between groups. For both males and females, maintenance on BAK extract resulted in marked survival levels that were similar to those seen with SUG. Sweet waste extracts provided better substrates for survival compared to water, but this superiority was mostly seen with BAK. Females maintained on BAK, YOG, and BAN exhibited shorter response times to a host compared to their counterparts maintained on SUG. The levels of egg production were equivalent in waste extract- and SUG-fed females. The findings presented here illustrate the potential of sweet waste-derived fluids to contribute to the vectorial capacity of dengue vectors and suggest the necessity of readdressing the issue of waste disposal, especially that of unfinished sweet foods. Such approaches can be particularly relevant in dengue endemic areas where rainfall is frequent and waste collection infrequent.


Asunto(s)
Aedes/fisiología , Fertilidad/efectos de los fármacos , Mortalidad , Mosquitos Vectores/fisiología , Edulcorantes/farmacología , Animales , Dengue/transmisión , Dieta , Ambiente , Femenino , Masculino , Edulcorantes/administración & dosificación
15.
Acta Trop ; 176: 446-454, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28865898

RESUMEN

In dengue vector control, attempts to minimize or replace the use of pesticides have mostly involved use of predators, but success has been severely impeded by difficulties associated with financial and environmental costs, predator mass production, and persistence in target habitats. Visual deterrents have been used successfully to control animal pests, in some cases in an effort to replace pesticide use. Despite evidence that visual signals are crucial in site choice for egg deposition by dengue vectors, and that female mosquitoes respond to artificial predation, the role of predator intimidation as it affects the oviposition behavior of dengue vectors remains largely unexplored. Here, we examined the oviposition responses of Aedes aegypti exposed to various mosquito predator pictures. Gravid females were presented with equal opportunities to oviposit in two cups with predator images [Toxorhynchites splendens-TXI, Goldfish (Carassius auratus)-small (SFI) and large (LFI) and Tx. splendens+Goldfish-TXFI] and two others without pictures. Differences in egg deposition were examined between sites with and without these images. When given a chance to oviposit in cups with and without TXI, Ae. aegypti females were similarly attracted to both sites. When provided an opportunity to oviposit in cups displaying pictures of fish (SFI or LFI) and blank cups, egg deposition rates were much lower in the fish picture sites. Females showed a preference for blank cups over TXFI for egg deposition. They also equally avoided cups with pictures of fish, regardless of the size of the picture. Our results indicate that the presence of images of goldfish and their association with Tx. larvae significantly reduced egg deposition by Ae. aegypti, and this was not the case with the predatory larvae alone. The observations that the images of natural predators can repel gravid females of a dengue vector provide novel possibilities to develop effective and inexpensive alternative tools to harmful insecticides.


Asunto(s)
Aedes/fisiología , Dengue/prevención & control , Mosquitos Vectores/fisiología , Oviposición , Percepción Visual , Animales , Conducta Animal , Cruzamiento , Dengue/transmisión , Ecosistema , Femenino , Carpa Dorada , Larva , Estimulación Luminosa
16.
Plant Signal Behav ; 11(7): e1197466, 2016 07 02.
Artículo en Inglés | MEDLINE | ID: mdl-27315145

RESUMEN

Macaranga bancana is considered as a successful pioneer plant species. Usually found in disturbed and open areas, most of the current research focused on its relations with ants. One of the unique feature of the plants is that the seedling leaves are red, resembling and almost matching the background. Using a portable spectrometer, we measured the color reflectance of M. bancana seedlings (less than 20 cm in height). We also measured the leaf litter reflectance, adult M. bancana leaves and also seedlings of several other species found in the vicinity of M. bancana seedlings. The reflectances of M. bancana seedlings are very similar to that of the leaf litter background. We suggest that this cryptic coloration is crucial during the early stages of the plant when it still cannot rely on the protection of ants.


Asunto(s)
Euphorbiaceae/metabolismo , Plantones/metabolismo , Euphorbiaceae/fisiología , Pigmentación/fisiología , Hojas de la Planta/metabolismo , Hojas de la Planta/fisiología , Plantones/fisiología
17.
Trop Life Sci Res ; 27(supp1): 95-101, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27965746

RESUMEN

Paederus fuscipes Curtis is a nocturnal insect. The attractiveness of artificial light sources from residential premises eventually causes the risk of severe dermatitis effect, once Paederus is in contact with human skin. The objective of this study is to investigate whether the light and height factors of residential buildings and its' association to rice cultivation phases are primary reasons for P. fuscipes's mass dispersal into human residential areas. The study site was located in residential premises that were built adjacent to rice field areas (≈ 32-60 m and 164 m) north of the rice field located in Teluk Air Tawar, mainland of Pulau Pinang. Overall, both light sources and rice cultivation phases caused a significant effect for P. fuscipes beetles dispersal flight to invade human settlements. More P. fuscipes were captured near the bright light source with the highest number of beetles found during harvesting stage. Whereas, significantly higher number of P. fuscipes were captured at level 2 and 3 compared to ground and level 1 of the apartment building and P. fuscipes was also found significantly affected by the rice cultivation phases at different elevation levels. This indicates that bright light sources and higher elevation levels are the main factors in attracting P. fuscipes beetles to disperse and causes infestations in residential areas. This finding could create awareness among the public on P. fuscipes dispersal pattern.

18.
Trop Life Sci Res ; 27(2): 91-102, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27688853

RESUMEN

The interaction between plants and insects is dynamic, and may favour either the plant or the insect. Plant chemicals are deeply implicated in this relationship and influence insect behaviour. Here, we investigated the oviposition behaviour response of Culex quinquefasciatus mosquitoes based on the colour cues produced by Ipomoea cairica leaves extract. In this study, two sets of oviposition choice experiments were conducted: (1) single solution in a cage; and (2) multiple concentration solutions in a cage. In the single solution experiment, only 1 available oviposition site was offered to 5 gravid females and in the multiple concentration tests, 4 available oviposition sites were offered to 20 gravid females. The tested concentrations were set up at 100 mL of: (1) control (distilled water only); (2) 50 ppm; (3) 150 ppm; and (4) 300 ppm of I. cairica plant extracts. The highest concentration of 300 ppm appeared to show the highest intensity with the darkest colour followed by 150 ppm and 50 ppm concentrations. More gravid females were found drowned in the highest concentration, 300 ppm of acethonilic leaves extract, compared to 150 ppm and 50 ppm of the tested extract. No eggs were found in all tested solutions. The studied extract was found to effectively attract gravid Cx. quinquefasciatus females and subsequently cause mortality and inhibit egg deposition. The interference caused by the acethonilic extract of I. cairica on the oviposition activity of Cx. quinquefasciatus can result in better control of the vector insect.

19.
Artículo en Inglés | MEDLINE | ID: mdl-27253746

RESUMEN

Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity) and eggs hatchability (fertility) in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors.


Asunto(s)
Aedes/efectos de los fármacos , Insectos Vectores/efectos de los fármacos , Ipomoea/química , Oviposición/efectos de los fármacos , Animales , Dengue/transmisión , Femenino , Fertilidad/efectos de los fármacos , Larva/efectos de los fármacos , Dosificación Letal Mediana , Masculino , Extractos Vegetales/farmacología
20.
Trop Life Sci Res ; 27(supp1): 117-122, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27965749

RESUMEN

To understand the effects of fish predator's kairomones on Aedes mosquitoes' oviposition, we established an experiment using gravid Aedes females. Kairomones concentrations were established using Hampala macrolepidota. One individual fish was placed inside containers with varying water levels (1 L, 5 L, and 10 L of water). The fish were kept in the containers for 24 hours and were removed immediately at the start of each trial in order to have the kairomones remnants. Twenty gravid adult females of Aedes aegypti and Aedes albopictus were allowed to lay eggs on oviposition site with various treatments: (1) control without any kairomones; (2) kairomone remnant in 1 L of water; (3) kairomone remnant in 5 L of water; and (4) kairomone remnant in 10 L of water. There are significant differences between the numbers of eggs laid by both Aedes species for each different treatment (F = 9.131, df = 16, p<0.001). However, fewer eggs were laid by Ae. albopictus compared to Ae. aegypti in the presence of kairomone remnants. This suggested that Ae. albopictus are significantly affected by the kairomones itself and have ability to detect the residual kairomone presence from H. macrolepidota.

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