Objective:Rice fields are dynamic mosquito larval habitats with assemblage of different predator taxa,including the larva of the mosquitoes Lutzia.Entomological surveillance in the ricefields is essential to evaluate ...Objective:Rice fields are dynamic mosquito larval habitats with assemblage of different predator taxa,including the larva of the mosquitoes Lutzia.Entomological surveillance in the ricefields is essential to evaluate the potential of these predators as biological resource to regulate vector mosquito population.In view of this,a survey of ricefields for immatures of different mosquito species including Lutzia was conducted.Methods:Survey of selected ricefields was carried out to evaluate the species composition of mosquitoes.Laboratory evaluation of the immatures of Lutzia mosquitoes was carried out to assess its predation potential using mosquitoes and chironomid as preys.Results:The survey revealed the presence of five mosquito species belonging to the genera Anopheles and Culex and the predatory immatures of the mosquito Lutzia Juscana(Wiedemann,1820).The ratio of prey and predatory larva ranged between 1.46 and 4.78 during the study period,with a significant correlation on the relative abundance of the larval stages of Lt.Juscana and Anopheles and Culex larvae.Under laboratory conditions,a single IV instar larvae of Lt.fuscana was found to consume on an average 5 to 15 equivalent instars of Anopheles sp.and Culex sp.larvae per day depending on its age.The prey consumption reduced with the larval stage approaching pupation.When provided with equal numbers of chironomid and Anopheles or Culex larvae,larva of Lt.fuscana consumed mosquito larvae significantly more compared to chironomids.Conclusion: The survey results and the preliminary study on predation are suggestive of the role of Lt.Juscana in the regulation of vector mosquito populations naturally in the ricefields.Since Lt.Juscana is common in many Asian countries,further studies on bioecology will be helpful to justify their use in mosquito control programme.展开更多
文摘Objective:Rice fields are dynamic mosquito larval habitats with assemblage of different predator taxa,including the larva of the mosquitoes Lutzia.Entomological surveillance in the ricefields is essential to evaluate the potential of these predators as biological resource to regulate vector mosquito population.In view of this,a survey of ricefields for immatures of different mosquito species including Lutzia was conducted.Methods:Survey of selected ricefields was carried out to evaluate the species composition of mosquitoes.Laboratory evaluation of the immatures of Lutzia mosquitoes was carried out to assess its predation potential using mosquitoes and chironomid as preys.Results:The survey revealed the presence of five mosquito species belonging to the genera Anopheles and Culex and the predatory immatures of the mosquito Lutzia Juscana(Wiedemann,1820).The ratio of prey and predatory larva ranged between 1.46 and 4.78 during the study period,with a significant correlation on the relative abundance of the larval stages of Lt.Juscana and Anopheles and Culex larvae.Under laboratory conditions,a single IV instar larvae of Lt.fuscana was found to consume on an average 5 to 15 equivalent instars of Anopheles sp.and Culex sp.larvae per day depending on its age.The prey consumption reduced with the larval stage approaching pupation.When provided with equal numbers of chironomid and Anopheles or Culex larvae,larva of Lt.fuscana consumed mosquito larvae significantly more compared to chironomids.Conclusion: The survey results and the preliminary study on predation are suggestive of the role of Lt.Juscana in the regulation of vector mosquito populations naturally in the ricefields.Since Lt.Juscana is common in many Asian countries,further studies on bioecology will be helpful to justify their use in mosquito control programme.
