Survival of female bush flies, Musca vetustissima Walker (Diptera: Muscidae), in relation to reproductive age

Abstract Survival rates of females of Musca vetustissima Walker were estimated as a function of their reproductive age, based on age-distributions of field females whose headwidths ranged from 1·5 to 2·5 mm. Females had a mean life expectancy of 140 day-degrees above 8°C, which was independent of fly size. They did not respond to baited traps during the first 15 day-degrees C of adult life. Thereafter, trappability varied with reproductive age but was affected by fly size only during the initial stage of the first ovarian cycle. Because ovarian development rates and female fecundity are dependent on fly size, the expected numbers of eggs laid by field females 1·5–2·5 mm in headwidth during their lifetime range from 28 to 106.