Influence of concentration of oxygen dissolved in water on viabilityof various stages of development of malarial mosquitoes Anopheles atroparvus (Diptera, culicidae)

The work purpose was studying of stability to asphyxia of preimaginal development stages of malarial mosquitoesAnopheles atroparvus depending on concentration of oxygen dissolved in water in different temperature modes. In experiments, larvaeand pupae of mosquitoes were in vessels with water without access to atmospheric air. They showed various speed of destruction ofpreimaginal development stages of mosquitoes under the set alternative conditions. The higher the water temperature, the less time larvaeor pupae remained viable, and this regularity was observed irrespective of the saturation of water with oxygen. At the same time inexperiments it was shown that in water sated with dissolved oxygen (7-8 mg/l) preimaginal stages remained viable much longer at alltemperature modes than in the conditions of О2 absence. Thus, larvae due to their branchiate and integumentary respiration and pupaeonly due to integumentary respiration in the thickness of water are capable to keep viability essentially longer in the conditions of isolationfrom atmospheric air. At alternative concentration of oxygen in water two opposite tendencies of speed of destruction of preimaginaldevelopment stages were fixed. At concentration of oxygen of 0 mg/l in three set modes of temperatures (15°С; 23°С; 30°С) anincrease of stability of individuals to asphyxia from I age to pupae was observed. In water sated with oxygen at initial concentration ofoxygen of 7-8 mg/l, on the contrary, larvae of younger age had greater viability in comparison with individuals of older age. Obviously,integumentary and branchiate respiration of larvae of older age plays a smaller role in the thickness of water, and, at the same time, forthey have a rather large supply of atmospheric air in tracheas when diving. Thus, at carrying out actions for destruction of preimaginaldevelopment stages of mosquitoes by means of asphyxia causing methods, it is necessary to consider temperature and water oxygensaturation, as well as the age structure of populations of insects.

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