Growth and Survival of Larvae of Ephydra hians Say (Diptera: Ephydridae) on Unialgal Diets

Abstract

The algae Nitzschia latens Hustedt, Ctenocladus circinnatus Borzi, and two species of Oscillatoria were isolated from Mono Lake, which is near Lee Vining, CA, and used to produce cultures containing only one algal species (unialgal cultures). Survival to pupation and rates of larval growth and development were compared among larvae of Ephydra hians Say, which were reared on one of these algal species or on a diet prepared using the fish food Tetramin. It was found that larvae could be reared from the second larval molt to pupation when fed on a single species of algae. Larvae reared on Nitzschia showed significantly increased weight gain and survival compared with larvae reared on Ctenocladus. Growth performance was always ordered Nitzschia, Oscillatoria, then Ctenocladus. Larvae reared on Nitzschia or Oscillatoria developed significantly faster than those reared on Tetramin. The results indicate that single species of Nitzschia and Oscilatoria are adequate food sources for E. hians growth. Although larvae of this fly appear to be generalist algal herbivores, food quality varies between algal species.