HORIZONTAL TRANSMISSION OF MYCOTIC INFECTION IN ADULT TSETSE, GLOSSINA-MORSITANS-MORSITANS

Adult Glossina morsitans morsitans exposed to wet conidia of Beauveria bassiana and Metarhizium anisopliae suffered high mortalities ranging from 90 to 100 % by 2 weeks post-exposure. Infected males maintained in the same cages with non-infected females throughout the experimental period transmitted the fungal infection to the females resulting in mortalities of 65 % with B. bassiana and 55 % with M. anisopliae. Likewise, infected females maintained together with non-infected males transmitted the infection to the males resulting in mortalities of 75 % with B. bassiana and 45 % with M. anisopliae. Female tsetse flies infected with B. bassiana and M. anisopliae and maintained in the same cages with non-infected females also transmitted infection to the non-infected tsetse resulting in mortalities of 62 % and 48 % with B. bassiana and M. anisopliae respectively. Infected tsetse exposed to non-infected tsetse of the opposite sex for only 30 min were also able to transmit the fungal infection. Pupae produced by female tsetse infected with B. bassiana and M. anisopliae exhibited higher pupal mortality than those produced by non-infected females. However, pupae exposed directly to dry spores of B. bassiana and M. anisopliae had no increase in pupal mortality but adults emerging from the B. bassiana-exposed pupae had markedly reduced longevity.