scholarly journals Culex quinquefasciatus larvae development arrested when fed on Neochloris aquatica

2021 ◽  
Vol 15 (12) ◽  
pp. e0009988
Author(s):  
M. Florencia Gil ◽  
Marisol Fassolari ◽  
Marina E. Battaglia ◽  
Corina M. Berón
Keyword(s):  
Culex Quinquefasciatus ◽  
Biological Control Agent ◽  
The Other ◽  
Organic Load ◽  
Site Preference ◽  
Mosquito Larvae ◽  
Fish Food ◽  
Breeding Sites ◽  
Artificial Breeding ◽  
Gravid Females

Culex quinquefasciatus is a cosmopolitan species widely distributed in the tropical and subtropical areas of the world. Due to its long history of close association with humans, the transmission of arboviruses and parasites have an important role in veterinary and public health. Adult females feed mainly on birds although they can also feed on humans and other mammals. On the other hand, larvae are able to feed on a great diversity of microorganisms, including microalgae, present in natural or artificial breeding sites with a high organic load. These two particularities, mentioned above, are some of the reasons why this mosquito is so successful in the environment. In this work, we report the identification of a microalga found during field sampling in artificial breeding sites, in a group of discarded tires with accumulated rainwater. Surprisingly, only one of them had a bright green culture without mosquito larvae while the other surrounding tires contained a large number of mosquito larvae. We isolated and identified this microorganism as Neochloris aquatica, and it was evaluated as a potential biological control agent against Cx. quinquefasciatus. The oviposition site preference in the presence of the alga by gravid females, and the effects on larval development were analyzed. Additionally, microalga effect on Cx. quinquefasciatus wild type, naturally infected with the endosymbiotic bacterium Wolbachia (w+) and Wolbachia free (w−) laboratory lines was explored. According to our results, even though it is chosen by gravid females to lay their eggs, the microalga had a negative effect on the development of larvae from both populations. Additionally, when the larvae were fed with a culture of alga supplemented with balanced fish food used as control diet, they were not able to reverse its effect, and were unable to complete development until adulthood. Here, N. aquatica is described as a biological agent, and as a potential source of bioactive compounds for the control of mosquito populations important in veterinary and human health.

A field trial of the synthetic oviposition pheromone with Culex quinquefasciatus say (Diptera: Culicidae) in Kenya

1988 ◽  
Vol 78 (3) ◽  
pp. 463-470 ◽  
Author(s):  
W. A. Otieno ◽  
T. O. Onyango ◽  
M. M. Pile ◽  
B. R. Laurence ◽  
G. W. Dawson ◽  
...  
Keyword(s):  
Growth Regulator ◽  
Culex Quinquefasciatus ◽  
Pupal Stage ◽  
Insect Growth Regulator ◽  
Breeding Sites ◽  
Insect Growth ◽  
Gravid Females ◽  
A Site ◽  
Effervescent Tablet ◽  
First Time

AbstractThe synthetic attractant pheromone 6-acetoxy-5-hexadecanolide in a formulation of 20 mg containing 5 mg of the active (−)-(5R,6S)-isomer in an effervescent tablet produced a high, positive overall response by gravid females of Culex quinquefasciatus Say when the mosquitoes were exposed to the pheromone in established breeding sites in western Kenya. Significantly more females (82%) oviposited around the pheromone source compared to a control. The activity of the pheromone persisted in the established breeding place for four days after application. The addition of the insect growth regulator S-31183 (2-[1-methyl-2-(4-phenoxyphenoxy)ethoxy]pyridine) to the formulation did not affect the activity of the pheromone. Newly-made breeding sites exposed domestically were not attractive initially for oviposition by gravid females but, after 18 days, they became more attractive. Trays treated with synthetic pheromone diverted females from similar unbaited trays exposed within 10 m. A sample of larvae taken from a site treated with pheromone and insect growth regulator showed 100% mortality by the pupal stage. Thus, the efficacy of the pheromone has been demonstrated for the first time in the field and the possibility of using this material in combination with a ‘safe’ insecticide confirmed.

Utilization of Vinasse Effluents from an Anaerobic Reactor

1986 ◽  
Vol 18 (12) ◽  
pp. 135-141 ◽  
Author(s):  
F J. C. B. Costa ◽  
B B. M. Rocha ◽  
C. E. Viana ◽  
A. C. Toledo
Keyword(s):  
Post Treatment ◽  
Organic Load ◽  
Secondary Treatment ◽  
Fish Food ◽  
Anaerobic Reactor ◽  
Streams And Rivers ◽  
Alcohol Industry ◽  
Treated Effluent ◽  
Very High

An anaerobic reactor was developed to biodigest alcohol distillery wastes. A further post-treatment of the effluent reduced the level of pollution to the point of eventually discharging into streams and rivers. The present work also analyses the use of biodigested vinasse as a source of food for fish. Very high efficiencies were obtained during primary and secondary treatment of vinasse effluent, as demonstrated by the greatly reduced organic load. The utilization of the treated effluent as a source of fish food presents an excellent alternative for the Brazilian alcohol industry.

scholarly journals Entomological Surveillance in Former Malaria-endemic Areas of Southern Italy

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1521
Author(s):  
Donato Antonio Raele ◽  
Francesco Severini ◽  
Daniela Boccolini ◽  
Michela Menegon ◽  
Luciano Toma ◽  
...  
Keyword(s):  
Malaria Vectors ◽  
Public Health Issue ◽  
Entomological Surveillance ◽  
Widespread Species ◽  
Animal Shelters ◽  
Breeding Sites ◽  
Artificial Breeding ◽  
Anopheles Vectors ◽  
Gargano Promontory ◽  
Anopheles Algeriensis

Malaria still represents a potential public health issue in Italy, and the presence of former Anopheles vectors and cases imported annually merit continuous surveillance. In areas no longer endemic, the concurrent presence of gametocyte carriers and competent vectors makes re-emergence of local transmission possible, as recently reported in Greece. In October 2017, due to the occurrence of four suspected introduced malaria cases in the province of Taranto (Apulia region), entomological investigations were performed to verify the involvement of local anopheline species. In 2019–2020 entomological surveys were extended to other areas historically prone to malaria between the provinces of Taranto and Matera and the province of Foggia (Gargano Promontory). Resting mosquitoes were collected in animal shelters and human dwellings, larvae were sampled in natural and artificial breeding sites, and specimens were both morphologically and molecularly identified. A total of 2228 mosquitoes were collected, 54.3% of which were anophelines. In all the investigated areas, Anopheles labranchiae was the most widespread species, while Anopheles algeriensis was predominant at the Gargano sites, and Anopheles superpictus and Anopheles plumbeus were recorded in the province of Matera. Our findings showed a potentially high receptivity in the surveyed areas, where the abundance of the two former malaria vectors, An. labranchiae and An. superpictus, is related to environmental and climatic parameters and to anthropic activities.

scholarly journals Larvicidal effect of some natural products on mosquito and some aquatic predators in Gezira State, Sudan: Field assessment

2021 ◽  
Vol 3 (2) ◽  
pp. 078-082
Author(s):  
Abdelmonem Eltiyab Houmida Ali ◽  
Mutaman Ali A. Kehail
Keyword(s):  
Natural Products ◽  
Mosquito Control ◽  
Mosquito Larvae ◽  
Biological Control Agents ◽  
Stagnant Water ◽  
Source Reduction ◽  
Breeding Sites ◽  
Field Assessment ◽  
Neem Leaves ◽  
Aquatic Predators

There are many methods used for mosquito control. Depending on the situation, source reduction (removing stagnant water), bio-control (importing natural predators), trapping, and insecticides to kill larvae or adults may be used. Some aquatic predators were reputed as biological control agents for mosquito larvae. Hence they have to be considered when experimenting on the lethal effects of any material on mosquito larvae. The objectives of this study were to study the effects of neem leaves and usher latex against Anopheles and Culex larvae and some of their aquatic predators (hemipteran boatman (HB), tadpole (T), swimming beetle larvae (SBL) and adult (SBA) and mayfly naiad (MF)) in some breeding sites around Wad Medani Town. Gezira State, Sudan. Two villages were selected for conducting this study. The count of the mosquito larvae and the aquatic predators continued for four days from applying natural products. The results showed that, mosquito’s larvae were affected more than the aquatic by Neem leaves and Ushar latex. The study of the microclimates in the breeding sites will help to correlate toxicity to any level of any environmental factor.

Geographic variation in the underwater vocalizations of Weddell seals (Leptonychotes weddelli) from Palmer Peninsula and McMurdo Sound, Antarctica

1983 ◽  
Vol 61 (10) ◽  
pp. 2203-2212 ◽  
Author(s):  
Jeànette A. Thomas ◽  
Ian Stirling
Keyword(s):  
Mating System ◽  
Weddell Seal ◽  
Mirror Image ◽  
The Other ◽  
Mcmurdo Sound ◽  
Breeding Sites ◽  
Weddell Seals ◽  
Antarctic Seals ◽  
Geographic Differences ◽  
Polygynous Mating System

The Weddell seal (Leptonychotes weddelli) is one of the most vocal pinnipeds. The repertoires of subice vocalizations of Weddell seals recorded at Palmer Peninsula and at McMurdo Sound, Antarctica, are different. Although seals at both sites give some of the same vocalizations, there are subtle spectral and temporal differences. In addition each population has unique vocalizations which are not heard at the other site. At Palmer Peninsula, there are several usage characteristics not exhibited at McMurdo Sound, such as mirror-image vocalization pairs and vocalization trios. Weddell seals in McMurdo Sound make extensive use of nine auxiliary sounds, while the Peninsula repertoire has none. Factors which appear to have been important in the development of these geographic differences appear to include strong fidelity to breeding sites, a polygynous mating system, and learning. Geographically different vocal repertoires have potential for identifying discrete breeding stocks of Antarctic seals.

scholarly journals Large males have a mating advantage in a species of darter with smaller, allopaternal males Etheostoma olmstedi

2010 ◽  
Vol 56 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Kelly A. Stiver ◽  
Suzanne H. Alonzo
Keyword(s):  
Mating Success ◽  
Breeding Population ◽  
Male Mating ◽  
Breeding Sites ◽  
Spawning Site ◽  
Egg Deposition ◽  
Artificial Breeding ◽  
Mean Size ◽  
Natural Breeding ◽  
To Receive

Abstract Theory suggests that males that are larger than their competitors may have increased mating success, due to both greater competitive ability and increased attractiveness to females. We examined how male mating success varies with male size in the tessellated darter Etheostoma olmstedi. Previous work has shown that large males tend to move around and breed in vacant breeding sites, and consequently provide less care for their eggs, while smaller individuals can be allopaternal, caring for the eggs of other males as well as for their own. We studied female egg deposition in a natural breeding population using artificial breeding sites and in the laboratory, where female choice of spawning site was restricted to two breeding sites tended by two males of different sizes. In both the field and the laboratory, nests tended by larger males were more likely to receive new eggs. Additionally, the mean size of males associated with a nest was positively correlated with both the maximum coverage of eggs at the nest and the number of times new eggs were deposited. We discuss how the increased mating success of larger males, despite their decreased parental care, may help explain allopaternal care in this species.

scholarly journals Effects of ivermectin on Culex quinquefasciatus larvae

1996 ◽  
Vol 38 (4) ◽  
pp. 293-298 ◽  
Author(s):  
Ricardo Miguel Costa de Freitas ◽  
Mágda de Abreu Faria ◽  
Stênio Nunes Alves ◽  
Alan Lane de Melo
Keyword(s):  
High Mortality ◽  
Culex Quinquefasciatus ◽  
Chloride Channel ◽  
Cell Membranes ◽  
Toxic Effects ◽  
Parasitic Diseases ◽  
Mosquito Larvae ◽  
Channel Activation ◽  
Synthetic Drug

The effects of ivermectin, a semi-synthetic drug widely used for treatment of livestock parasitic diseases, were observed on Culex quinquefasciatus larvae. Toxic effects and mortality evaluation were carried out after 5, 15, 30 and 60 minutes of exposure to 1, 5 or 10 ppm of ivermectin solutions. Observations were made 24 and 48 hours after the beginning of the experiment, and loss of mobility, progressive paralysis and high mortality of larvae were recorded. The observed effects of ivermectin on the mosquito larvae is probably correlated with chloride channel activation on cell membranes.

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