Horizontal Transmission ofBeauveria bassiana(Hypocreales: Cordycipitaceae) andMetarhizium anisopliae(Hypocreales: Clavicipitaceae) inMusca domestica(Diptera: Muscidae)

Abstract

Beauveria bassiana Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin are fungi with potential for controlling Musca domestica L. However, the impact on this dipteral may vary depending on the fungal isolates and the methodology used. This study evaluated the pathogenicity of direct application and horizontal transmission of B. bassiana (CG240) and M. anisopliae (CG34) on adult M. domestica individuals. The impact of B. bassiana and M. anisopliae on M. domestica was evaluated at the concentrations 2 × 10(4), 2 × 10(5), 2 × 10(6), and 2 × 10(7) conidia/ml. Horizontal transmission was also estimated between sexes at different infection periods of the vector insect. The mortality of adult M. domestica individuals directly infected with B. bassiana was above 90%, and the mortality of those infected with M. anisopliae ranged from 25.50 to 97.78%. Horizontal transmission of B. bassiana caused the death of 100% of individuals, in turn, that of M. anisopliae killed 55% of male and 100% of female individuals. Horizontal transmission of fungi was negatively influenced by time. This study shows the potential of these fungi for controlling M. domestica, both with the direct implementation strategy and horizontal transmission. However, field studies are needed to evaluate the capacity to decrease the M. domestica population using these alternatives.

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

“…The lower survival time of female than male M. domestica infected with M. anisopliae through horizontal transmission is in accordance with the results of Quesada-Moraga et al 23 and Cárcamo et al 24 . Quesada-Moraga et al 23 observed that the aedeagus of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) had become infected with conidia after the flies were inoculated with the fungus.…”

“…Comparisons between the present study and Cárcamo et al 24 are however difficult to make due to the difference in the inoculation method. Dry formulations of conidia are generally better adapted for use in autodissemination strategies than liquid ones 36 and, therefore, the differences in the total mortality of the male recipient flies observed between the two studies could potentially be attributed to the present study using a dry conidia substrate to inoculate flies.…”

“…However, Cárcamo et al 24 observed a significant effect of sex on the total mortality caused by the horizontal transmission of their M. anisopliae isolate. The study showed transmission of the fungus from female donors to male recipients resulted in a mean mortality of 55% as opposed to the 100% mortality observed in female recipients.…”

“…Quesada-Moraga et al 23 observed that the aedeagus of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) had become infected with conidia after the flies were inoculated with the fungus. Cárcamo et al 24 suggested that this is also likely to occur in M. domestica and that the lower survival time in females infected via transmission from males is due to the increased pathogenic load transmitted to the females during copulation. Leemon and Jonsson 37 observed no evidence of M.…”

“…Reducing the non-target mortality would also facilitate the use of the fungus with other biocontrol agents and natural enemies. Transmission of M. anisopliae among host insects [18][19][20][21][22][23] , including M. domestica 24,25 , has previously been demonstrated but rates of transmission and the effects of infection can vary between strains 10,14,26 .…”