The influence of the hypoxia and hypercapnia on the blood-sicking mosquitoes larvae

In this article we are present the results of study of the influence of the hypoxia and hypercapniaon the larvae of blood-sucking mosquitoes of Anopheles, Culex and Aedes genera.The ability of Anopheles larvae to be alive under water of different temperature andoxygen concentration was analyzed. The larvae of the early developmental stages at decreaseof oxygen concentration in the water were died faster than older individuals. TheAn. atroparvus larvae are characterized by the greatest stability to hypoxia. Surprisingly,larvae of An. atroparvus and An. beklemishevi II age are highly resistant to oxygen starvationat oxygen concentration 8,3 mg/L. The experiments with carbon dioxide were spent attwo variants of water temperature: +10.С and +23.С. Death of all larvae occur after twofoldentry of carbon dioxide at the water temperature +23.С, and after threefold entry atthe water temperature +10.С. The longevity of C. p. molestus larvae IV stage correlateswith water temperature. The differences of viability of Culex and Aedes from Anophelesmost likely, are caused by the morphological differences of respiratory system.The larvae of Aedes and Culex genera in the last segment of the abdomen have a siphonwith a stigmal plate on the apex. Anopheles mosquitoes are characterized by a lackof siphon. Apparently, the larvae of Anopheles almost instantly fall into a stupor when acarbon dioxide entry on the water because the spiracles are close located to the trachealtrunks and tracheoles. The larvae of Aedes and Culex between the spiracle and the systemtracheoles have a sufficiently long tube, at the end of which, probably, there aregaseous composition receptors. Therefore, for the inflow of carbon dioxide to tracheolesrequires significantly more time and larvae have time to close the spiracles.For members of different genera were found different resistance to change in theconcentration of dissolved oxygen. Mosquito larvae of Aedes genus are resistant to completeabsence of oxygen for a longer time. At the same time, the larvae of mosquitoes An.beklemishevi and An. atroparvus II age characterized by more vitality at a high concentrationof dissolved oxygen in the water. Mosquito larvae genera of Aedes and Culex aremore resistant to hypoxia and hypercapnia, compared with Anopheles. The more viabilityof Culex and Aedes mosquitoes by the combination of hypoxia and exogenous hypercapnia,are caused by the presence of respiratory tube, a structure of stigmal plate andclosing apparatus. The resistance to hypoxia of mosquito larvae, all three consideredgenera, to the greatest extent on water temperature, which determines the intensity ofmetabolism.

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