Relationships between chemical properties of larval media and development of two Stomoxys species (Diptera: Muscidae) from Reunion Island

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English. The development of two cattle pests, Stomoxys calcitrans L. and Stomoxys niger niger Macquart (Diptera: Muscidae), was studied in the laboratory using seven potential larval media from a dairy farm on Reunion Island. The media were six types of cattle feed and an old manure medium. Egg-to-adult survival, duration of development, and adult live weight at emergence were determined for both ßy species on each medium. The media were analyzed for pH, nitrogen, organic matter, and structural compounds (cellulose, hemicellulose, lignin). For S. calcitrans, immature survival was signiÞcantly higher on sugarcane leaves, Rhodes grass, and elephant grass; for S. niger, survival was signiÞcantly higher on the same substrates plus sugarcane tops. These substrates were characterized by slightly acid pH values (range, 5.4Ð6.0). In both species, there were signiÞcant bell-shape relationships between immature survival and substrate pH. The developmental time of both ßy species was signiÞcantly shorter on Rhodes grass, Rhodes grass hay, and elephant grass. These substrates were characterized by high cellulose contents and low soluble organic fractions. In both species, there were signiÞcant linear relationships between developmental time and cellulose content of substrates. Similarly, there were signiÞcant linear relationships between adult live weight and cellulose content of substrates. The C:N ratio of the most favorable substrates was highly variable. Although the relationships revealed in this study do not establish causation, it is suggested that pH and cellulose content may have direct and indirect effects on Stomoxys development.