Horizontal transmission of Metarhizium anisopliae (Hypocreales: Clavicipitacea) and the effects of infection on oviposition rate in laboratory populations of Musca domestica (Diptera: Muscidae)

Abstract

BACKGROUND Effective control of house fly, Musca domestica (L.), populations currently relies on the use of chemical insecticides in most situations. Entomopathogenic fungi such as Metarhizium anisopliae (Metschn.) Sorokin may provide an alternative to chemicals and their efficacy may be enhanced by autodissemination amongst flies. This study assessed the capacity of M. anisopliae for transmission between adult M. domestica and the effects of infection on the fecundity of females. RESULTS Metarhizium anisopliae was transmitted between adult M. domestica flies with 91.67% - 100% mortality resulting across the three ratios of infected: non-infected flies tested (1:2, 1:5, 1:10). The mean lethal time (LT50) for female recipients mixed with infected male donor flies at the three ratios were 3.95, 4.79 and 5.65 days, respectively, whereas for male recipients mixed with infected female donors at the same ratios the LT50 were 4.98, 5.98 and 7.44 days, respectively. Infection with M. anisopliae significantly reduced the reproductive capacity of female flies during the first four days of infection with 25% less eggs oviposited by infected flies than those that were uninfected. CONCLUSION Autodissemination among house flies and reduction in oviposition in the early stages of infection could contribute significantly to the effectiveness of M. anisopliae used in biocontrol programs.