Larvivorous Fish Research Articles

Effect of Agricultural Pesticide, Cypermethrin on Changes in Behavioural and Protein profile of larvivorous fish Aplocheilus lineatus

Cypermethrin is a synthetic pesticide that is widely used in agricultural fields and domestic areas to control pests and insect vectors. Cypermethrin considered to be a synthetic pyrethroid is extremely lethal on insects, and fishes and has a low impact on mammals and Aves. The present study aimed to investigate the acute toxicity of cypermethrin on the larvivorous fish Aplocheilus lineatus, which is the most common fish seen in pools, ponds, streams, paddy fields, and similar wetlands. The fish is highly significant in controlling vector-borne diseases prevailing in tropical countries. The LC50 value was determined to be 1.8 µg/L after 96 hrs of exposure to cypermethrin and the lethal value was 4 µg/L. The fish showed various behavioral changes during the experiment, including convulsions, vigorous gasping for air, erratically swimming, and loss of equilibrium. The results showed that even low concentrations of cypermethrin can exert acute effects on the biochemical constituents and behavioral aspects of A. lineatus. Total protein, structural protein, and soluble protein decreased from 1.33 ± 0.003 to 0.746 ± 0.015 mg/g, 0.967 ± 0.024 to 0.476 ± 0.0272 mg/g, and 0.444 ± 0.09 to 0.360 ± 0.018 mg/g, respectively, at 96 hours of exposure to 1 µg/L of cypermethrin. At the same time, glycogen levels also decreased from 1.11 ± 0.054 to 0.51 ± 0.019 mg/g. These variations in the behavioral and biochemical content of the fish after exposure indicate the toxic effect of cypermethrin. Hence the present study suggests monitoring and regulatory use of this pesticide.

Native Larvivorous Fishes vs Alien Fishes: A Comparative Study of Biological Control of Mosquito Larvae

Native Larvivorous Fishes vs Alien Fishes: A Comparative Study of Biological Control of Mosquito Larvae

Fish microbiota repel ovipositing mosquitoes.

The mere presence of predators causes prey organisms to display predation-avoidance strategies. Predator presence is often communicated through predator-released chemical signals. Ovipositing female mosquitoes of several species are repelled by unknown signals released from larvivorous fish. It was previously suggested that in many cases, a predator's microbiota plays an important role in the release of these signals; however, this mechanism is still poorly understood. In this study, we looked into the effects of the microbiota originating from the larvivorous Gambusia affinis (Baird and Girard) on the oviposition behaviour of gravid female mosquitoes. We used fish with altered microbiota and bacterial isolates in a set of outdoor mesocosm experiments to address this aim. We show that interference with the fish microbiota significantly reduces fish's repellent effect. We further show that the bacterium Pantoea pleuroti, isolated from the skin of the fish, repels oviposition of Culex laticinctus Edwards and Culiseta longiareolata Macquart mosquitoes similarly to the way in which live fish repel them. Our results highlight the importance of bacteria in the interspecies interactions of their hosts. Furthermore, this finding may lead to the development of an ecologically friendly mosquito repellent, that may reduce the use of larvivorous fish for mosquito control.

Short Communication: Aplocheilus panchax Hamilton, 1822 Found at Acidic Waters of Abandoned Ex-tin Mining Ponds as Insectivorous Fish and Its Role for Water Quality Improvement

Kepala timah fish or blue panchax is one of the species found at acidic waters of abandoned ex-tin mining pond. Kepala timah fish belongs to the extremophile fishes which can survive in extreme aquatic environments caused by pressure from environmental factors. This study aimed to confirm the kepala timah fish as a species of Aplocheilus panchax and to analyze its natural food habits. Molecular analysis through DNA barcoding was carried out by analyzing the COI gene and confirming the sequence of kepala timah fish in the gene bank on the NCBI website and constructing a phylogenetic tree for kepala timah fish to other A. panchax populations. Analysis of food habits was carried out by identifying the contents of the digestive tract of kepala timah fish which were observed microscopically. The results showed that kepala timah fish found at acidic waters of abandoned ex-tin mining pond was confirmed as Aplocheilus panchax Hamilton, 1822. Some morphological characters confirmed the similarity between kepala timah fish and A. panchax such as a silvery white spot on its head, terminal type of the mouth position, body shape was sagittiform, small dorsal fin on posterior body, and the shape of the caudal fin was rounded or rhomboid. Analysis of the contents of digestive tract showed the food habits of A. panchax found at acidic waters of ex-tin mining pond was insects. The food habits explained that A. panchax was classified as larvivorous or insectivorous fishes. The presence of A. panchax and its metabolic activity at abandoned ex-tin mining ponds can contributed to increasing organic matter in the waters so that it can be beneficial for improving water quality.

The Use of Larvivorous Fish Species to Control Malaria Transmission in Africa: A Review

The Use of Larvivorous Fish Species to Control Malaria Transmission in Africa: A Review

Effect of predators on Anopheles arabiensis and Anopheles funestus larval survivorship in Homa Bay County Western Kenya

BackgroundThe rise of insecticide resistance against malaria vectors in sub-Saharan Africa has resulted in the need to consider other methods of vector control. The potential use of biological methods, including larvivorous fish, Bacillus thuringiensis israelensis (Bti) and plant shading, is sustainable and environmentally friendly options. This study examined the survivorship of Anopheles arabiensis and Anopheles funestus larvae and habitat productivity in four permanent habitat types in Homa Bay county, western Kenya.MethodsPredator densities were studied in a laboratory setup while habitat productivity and larval survivorship was studied in field setup.ResultsFish were observed as the most efficient predator (75.8% larval reduction rate) followed by water boatman (69%), and dragonfly nymph (69.5%) in predation rates. Lower predation rates were observed in backswimmers (31%), water beetles (14.9%), water spiders (12.2%), mayflies (7.3%), and tadpoles (6.9%). Increase in predator density in the field setup resulted in decreased Culex larval density. Larval and pupa age–specific distribution was determined and their survivorship curves constructed. Combined larvae (Stage I–IV) to pupa mortality was over 97% for An. arabiensis and 100% for An. funestus. The highest larval stage survival rate was from larval stages I to II and the lowest from larval stage IV to pupa. Stage-specific life tables indicated high mortality rates at every developmental stage, especially at the larval stage II and III.ConclusionDetermination of the efficiency of various larval predators and habitat productivity will help with the correct identification of productive habitats and selection of complementary vector control methods through environmental management and/or predator introduction (for instance fish) in the habitats.

Predatory Efficiency of Larvivorous Fish against Mosquito Larvae in Different Water Temperature Levels: Implication in Control Measure of Dengue Vector.

Reduction of the Aedes aegypti population is the priority effort to control dengue virus transmission including the use of larvivorous fish. Biologically, the predatory efficiency of fish will slow down when the water acidity and temperature change from normal conditions. This study aimed to determine the predatory efficiency of three species of larvivorous fish against the Ae. aegypti larvae in different water temperatures. Three well-known species of larvivorous fish namely Poecilia reticulata, Betta splendens, and Aplocheilus panchax were placed into 12 cm diameter jars with three water temperature ranges namely 20-21 °C, 27-28 °C, and 34-35 °C, and allowed to three days acclimatization. As many as one hundred 4th-instars larvae of Ae. aegypti were gradually entered into each jar, and a longitudinal observation was made at 5, 10, 30, 60, 120, 240, 360, 480, 600, and 720 minutes. The predated larvae were recorded. In normal temperature ranges, the predatory efficiency of the larvivorous fish was 75%, 72.3%, and 32.8% for B. splendens. Aplocheilus panchax, and P. reticulata, respectively. The predation abilities decreased due to temperature changes. Betta splendens and A. panchax indicated the best predatory efficiency against Ae. aegypti larvae in different temperature conditions. Betta splendens is the best larvivorous fish in the lower to normal, but A. panchax is the best in the normal to higher temperature ranges. This finding should be considered by public health workers in selecting larvivorous fish to control the Dengue vectors.

Study on prey preference of two indigenous larvivorous fish Trichogaster fasciata and Puntius sophore

The most effective way to control mosquito populations is through biological control methods, among them, fishes are the top contenders as natural agents to manage mosquito larvae. Fishes not only consume mosquito larvae efficiently but also readily adapt to new environmental conditions, reproduce rapidly and effectively control mosquito breeding in a self-sustaining manner. In present study two easily available indigenous fishes Trichogaster fasciata and Puntius sophore were considered to evaluate the feeding preference and the effect of alternative prey on larval feeding efficacy. For food preference test, mosquito larvae, mosquito pupae, chironomid larvae, daphnia and artificial fish food were considered. The live foods were gathered from the possible water lodging areas and artificial foods from aquarium shops. Experiments were conducted by providing equal number of different food items - mosquito larvae, mosquito pupae, chironomid larvae, daphnia and artificial fish food in the same container. Both the fish prefer maximum consumption of live and wriggly food than artificial stationery food. All length sizes of Puntius sophore consumed a maximum number of chironomid larvae, while Trichogaster fasciata prefer to consume mosquito larvae as the top choice. In both fish, as increasing length size, consumption rate of food increases significantly. Tested prey consumption data of both fishes were statistically represented by Mean±SD and significance differences of means was analysed by ANOVA. The food preferences of both fish directly depend on their feeding habits.

Assessment of the impact of the biological larvicide VectoMax G: Combination of Bacillus thuringiensis and Lysinibacillus sphaericus on non-target aquatic organisms in Yaoundé-Cameroon

There has been a renewed interest for larviciding during the recent decade. Although biological larvicides are considered not to be harmful to non-target organisms, there is still not sufficient data on the effect of new long-lasting larvicide formulations such as VectoMax G combining Bacillus thuringiensis israelensis and Lysinibacullus sphaericus on the environment especially on non-target organisms. The present study aimed to assess the possible influence of VectoMax G on the diversity and abundance of the aquatic fauna cohabiting with mosquito larvae in breeding habitats during a larviciding trial in the city of Yaoundé.Twelve districts of the city of Yaoundé divided into 6 intervention and 6 control sites were chosen for the study. In each district 4 semi-permanent or permanent aquatic habitats were followed. VectoMax G application was done once every two weeks during 6 months and aquatic organisms were collected 48 h after each treatment. All collected organisms were brought to the laboratory for identification. Physico-chemical parameters were recorded as well.A high diversity of the zooplankton was recorded in the intervention areas with 28 species collected against 14 species in the control areas. Cladocerans were the most represented group in both sites while Ostracods were found only in control sites. A total of 19 macro-invertebrates species were recorded in the control areas vs 16 species in the intervention areas. Gasteropods were the most represented groups of macro-invertebrates. Vertebrates such as larvivorous fishes and amphibians larvae were also found in approximately similar densities in both sites.The study indicated no significant influence of larviciding with VectoMax G on the diversity and abundance of the non-target aquatic fauna in the city of Yaoundé.

KOMUNIKASI SINGKAT: KEBIASAAN MAKAN IKAN KEPALA TIMAH (Aplocheilus panchax, Hamilton 1822) DI PERAIRAN EKSTREM ASAM PASCATAMBANG TIMAH TERABAIKAN

Kepala Timah (Aplocheilus panchax, Hamilton 1822) is one of the fish that has the survival abilities to live in a wide variety of quality waters. The ability of A. panchax to survive in acidic waters has begun to be widely studied as extremophile fish to study ecosystems in aquatic habitats that have acidic characteristics. This study aimed to determine the food habits of A. panchax as natural food in acid water of abandoned ex-tin mining activity. The results showed that the natural food for A. panchax was insects larvae or insects that fall on the surface of the waters. The food habits and terminal mouth type confirmed that A. panchax was surface feeder fish, carnivorous fish, larvivorous or insectivorous fish. The sagittiform body type was used A. panchax to did the strategy of feeding behavior by pursue or ambush their prey and it indicated that A. panchax as ambush predator.

Laveran and the eradication of malaria in Corsica

The observation of miasmas and fevers was attested in the region of Biguglia, South of Bastia, in 1499, confirmed during the 17th century. Drainage works on the eastern coast were started in 1770, abandoned during the revolutionary period, restarted under the Second Empire, with few results on the endemic. Thus in 1875, 80% of the inhabitants of the eastern plain were considered on their appearance to suffer malaria. The rural population was miserable, the mortality high. However, it was not possible to distinguish the responsibility of malaria among the other fevers.In 1899 and following years, A. Laveran was in Corsica. He confirmed the presence of Anopheles in the localities where malaria was present. He encouraged the creation in Bastia in 1902 of the Corsican League against Malaria and he chaired it. The actions of this League were based on the fight against the larvae by chemical destruction, on the use of mosquito nets and on massive and free preventive "quininisation". A sanitation and development law for Corsica was passed in 1911. Initial results were observed, confirmed by Léger and Arlo (1913) [6]. After WW1, the activities started again, in particular by Sergent and Sergent. An antimalarial application station, subsidized by the Rockefeller Foundation, was created in Bastia in 1925, supported by the laboratory of parasitology of the Faculty of Medicine of Paris. Plasmodium falciparum was predominant, transmitted essentially by Anopheles labranchiae of the maculipennis complex, up to an altitude of 500 m. The role of population displacements, linked to pastoral practices, the absence of stables and therefore of zoonotic deviation of anopheles were underlined.The liberation of Corsica in October 1943 allowed the installation by the American army of numerous airfields on the eastern plain. An intense local mosquito control by DDT was then carried out, impressing the population. However, malaria prospered on the island with an acme of indices in 1947. From 1948, campaigns of spraying insecticide against adults, chemical control of larvae or use of larvivorous fish, treatment of patients in dispensaries led to very good results. Since 1953, malaria transmission is interrupted in Corsica excepted 30 indigenous cases in 1970-71. Currently, the situation in Corsica of an anophelism without malaria is considered to be under control with a low risk of resumption of a localized transmission.

Potential biological control agents for the control of vector mosquitoes: A review

Mosquitoes are a major cause of lethal vector-borne diseases like dengue, malaria, filariasis, chikungunya, and Japanese encephalitis, among other diseases. In a developing country like India, mosquito-borne diseases are significant threats to familiar people as in certain places, there remains low sanitation. Larval and pupal life stages of mosquitoes are mostly confined to tropical and temperate waterbodies and often form a significant proportion of biomass waterbodies. Due to rebound vectorial capacity, resistance to chemical insecticides, and harmful environmental effects, the vector control program has shifted to using biological control agents. These methods are target-specific, eco-friendly, cost-effective, and can be easily deployed. So, the present review is focused on collating and updating the information on the use of aquatic predators, bacterial strains such as Bacillus sp. and actinobacterial, algae, and fungi, which are widely used for control of adult mosquitoes in their variety of natural habitats. This review also covers the predation of larvivorous fish and botanical insecticides.

Encapsulation of silver nano crystals using Salvinia molesta against the Anopheles stephensi and oxidative stress enzyme activity of larvivorous fish

Anopheles mosquitoes, which are the main carriers of the disease throughout India, Asia, and the Middle East, are the ones that cause malaria. The role of water predators in mosquito aquatic stage regulation is still recognized. With the use of synthetic insecticides, the environment became contaminated and insects developed high resistance to chemical pesticides. Based on our outline, we anticipated an innovative technique of bioencapsulated silver nanoparticles (AgNPs) using Salvinia molesta, which would perform as a reducing and stabilizing agent. Bioencapsulated-AgNPs existed and were classified using a variety of physiochemical techniques. In bioassays, the LC50 values of S. molesta aqueous extract against Anopheles stephensi range from 240.247 (1st instar larvae) - 428.851 ppm (pupae), LC50 of S. molesta-encapsulated AgNPs ranges from 20.010 (1st instar larvae) to 35.676 ppm (pupae). An experiment with S. molesta extract and encapsulated AgNPs was conducted in the open environment, and the larval reduction of mosquitoes was 100% after 72 h. In the ovicidal activity of An. stephensi, hatched eggs were reduced by 100% when treated with 40 ppm of encapsulated AgNPs and 500 ppm of S. molesta extract and encapsulated AgNPs, which significantly reduced the life span of malarial mosquito adults. Furthermore, we investigated the predatory ability of the larvivorous fish Aplocheilus blockii against third and fourth instar larvae of An. stephensi in laboratory conditions using ultra-low doses of bioencapsulated-AgNPs. Regarding non-target impact, in a conventional laboratory environment, the predation efficacy of the larvivorous fish A. blockii, was 58.58% and 54.78% against the 3rd and 4th instar larvae of An. stephensi, respectively. In bioencapsulated AgNPs-contaminated circumstances, fish predation was amplified to 78.18% and 75.54%, respectively. A. blockii was exposed to sublethal concentrations of AgNPs, namely 5, 10, and 15 g/ml, in enzymatic assays to assess changes in GST and AChE activity after 16 days. This study advances our understanding of the contagiousness of water-floating fern-conveyed insecticides and bioencapsulated AgNPs against therapeutically important insects, allowing us to recommend the proven materials as effective candidates to evolve the most recent and cost-effective pest management tools, and the long-term use of this larvivorous fish during wetlands and associated An. stephensi larval ecologies in various parts of the country is proposed.

Endemic Larvivorous Fish Fauna in Vicinities of Selected Water Bodies of Doon Valley (Uttarakhand)

Endemic Larvivorous Fish Fauna in Vicinities of Selected Water Bodies of Doon Valley (Uttarakhand)

A comparative study of consumption of Aedes aegypti and Aedes albopictus larvae by ornamental fishes to control their population in West Bengal

Aedes aegypti and Aedes albopictus are the carriers of a variety of diseases such as dengue, dengue hemorrhagic fever (DHF), chikungunya, zika virus, and yellow fever. An affordable way of vector management that effectively suppresses the mosquito population for a long time is the release of larvivorous fish. In this work, ornamental fish species are identified, and their potential larvicidal efficacy for biological control of Aedes mosquito larvae is assessed. The consumption rates of four ornamental fish species (Gold fish, Betta fish, Molly fish, and Guppy) for Aedes aegypti and Aedes albopictus larvae have been observed in the present study, and a comparison between the mean consumption rates of the four fish species for Ae. aegypti and Ae. albopictus has been recorded.The observation indicated practically no variance, and the intake rates for both types of larvae were almost same for the four species of fish. In contrast to guppy fish, the findings indicated that Goldfish, Black molly, and Betta fish had very high feeding rates. Therefore, in the near future, these fish can be thought of as efficient biological control agents for both Aedes aegypti and Aedes albopictus larvae.

Elucidating the status of malaria in Andaman and Nicobar Islands post-millennium 2000.

Malaria is a major vector-borne disease in the Indian sub-continent and has been pestering Andaman and Nicobar islands (ANI's) as well since British colonial times. A retrospective data mining technique has been adhered to assess the status of malaria for nineteen years from 2000 to 2019 in ANI's. The altered environment due to 2004 tsunami had increased malaria incidence significantly during (2005-2010). The Nicobar district recorded high incidence of malaria while the least in the north and middle Andaman district. Comparative high incidence of malaria was documented due to Plasmodium falciparum than Plasmodium vivax in the Nicobar district between 2005 and 2009. The declining trend of malaria-positive cases in ANI's was observed post 2010, articulating various initiatives taken by the local Andaman and Nicobar administration to curb this vector-borne disease. The initiatives were like (1) large-scale release of larvivorous fish, Gambusia affinis in the transient water pools, (2) outdoor application of DDT, (3) indoor application of Pyrethrum, (4) malaria awareness drive that led to the curbing of the proliferation not only the malaria vector but also other potential mosquito vector species as well, and (5) implementation of revised drug policy.

Comparison of larval eating capacity of two indigenous larvivorous fishes in malaria vector control in laboratory conditions in Dogbo district in south-western Benin, West Africa

Because of problems with insecticide resistance, alternative malaria control methods were necessary. These methods include the use of biological control agents, such as larvivorous fish. This study aimed to compare the larval eating capacity of two indigenous larvivorous fishes in malaria vector control in laboratory conditions in Dogbo district in south-western Benin. Larvae of Anopheles gambiae sensu lato mosquitoes were collected from breeding sites using the dipping method in July 2020 during the rainy season in Dogbo district. Alive Clarias gariepinus and Orechromis niloticus fishes were bought immediately once catched by fishers of Ganvié location in So-Ava district and carried by car from Ganvié location to the Laboratory. Laboratory evaluation for larvivorous efficacy was conducted. The results obtained in the current study showed that the larval eating capacity of Clarias gariepinus fish when this fish was fed was higher than that of Orechromis niloticus indigenous larvivorous fish in the laboratory conditions. Similar results were obtained when these different fishes were unfed. In a context of environmental crisis and global changes, environmentally friendly methods should be encouraged. The use of indigenous larvivorous fishes as predators to control malaria mosquitoes is obviously insufficient in the current study.

Comparison of larval eating capacity of two indigenous larvivorous fishes in malaria vector control in laboratory conditions in Dogbo district in south-western Benin, West Africa

Comparison of larval eating capacity of two indigenous larvivorous fishes in malaria vector control in laboratory conditions in Dogbo district in south-western Benin, West Africa

IMPACT OF HABITAT QUALITY VARIATIONS ON SOMEBEHAVIOURAL ASPECTS OF LARVIVOROUS FISH

Over 85 per cent of all known animal species belong to Arthropoda which includes the vectors of most important diseases. They affect our health either directly by bites, stings or indirectly throughdisease transmission. Several genera of Arthropods like mosquitoes, flies, ticks and mites play animportant role in human disease transmission. The most significant vector borne disease transmission is by blood feeding insects. Utilization of larvivorous fish in vector borne disease control programme is gaining momentum. Poecilia reticulata survives in all types of water bodies and can tolerate high degree of pollution. It is prolific breeder and surface feeder, carnivorous, thus efficient larvivorous fish. Present investigation reveals that low oxygen content in sewage water and surface feeding nature make it to stay at surface waters for longer time as compared to pond water.

Entomological outcomes of cluster-randomised, community-driven dengue vector-suppression interventions in Kampong Cham province, Cambodia.

Cambodia has one of the highest dengue infection rates in Southeast Asia. Here we report quantitative entomological results of a large-scale cluster-randomised trial assessing the impact on vector populations of a package of vector control interventions including larvivorous guppy fish in household water containers, mosquito trapping with gravid-ovitraps, solid waste management, breeding-container coverage through community education and engagement for behavioural change, particularly through the participation of school children. These activities resulted in major reductions in Container Index, House Index, Breteau Index, Pupal Index and Adult Index (all p-values 0.002 or lower) in the Intervention Arm compared with the Control Arm in a series of household surveys conducted over a follow-up period of more than one year, although the project was not able to measure the longer-term sustainability of the interventions. Despite comparative reductions in Adult Index between the study arms, the Adult Index was higher in the Intervention Arm in the final household survey than in the first household survey. This package of biophysical and community engagement interventions was highly effective in reducing entomological indices for dengue compared with the control group, but caution is required in extrapolating the reduction in household Adult Index to a reduction in the overall population of adult Aedes mosquitoes, and in interpreting the relationship between a reduction in entomological indices and a reduction in the number of dengue cases. The package of interventions should be trialled in other locations.