Klein, M., Department of Entomology, ARO, Volcani Center, Bet Dagan 50250, Israel
Braverman, Y., Department of Entomology, Kimron Veterinary Institute, P.O.B. 12, Bet Dagan 50250, Israel
Chizov-Ginzburg, A., Department of Entomology, Kimron Veterinary Institute, P.O.B. 12, Bet Dagan 50250, Israel
Gol'berg, A., Department of Entomology, ARO, Volcani Center, Bet Dagan 50250, Israel
Blumberg, D., Department of Entomology, ARO, Volcani Center, Bet Dagan 50250, Israel
Khanbegyan, Y., Department of Entomology, ARO, Volcani Center, Bet Dagan 50250, Israel
Hackett, K.J., Agricultural Research Service, Insect Biocontrol Laboratory, U.S. Department of Agriculture, Beltsville, MD 20705, United States

Five beetle spiroplasmas, the Colorado potato beetle spiroplasma (CPBS, strain LD-1), the Cantharis carolinus spiroplasma (CCBS, strain CC-1), the Ellychnia corrusca firefly spiroplasma (FS, strain EC-1), the Diabrotica undecimpunctata corn rootworm spiroplasma (CRS, strain DU-1), and the Spiroplasma floricola fall flower spiroplasma (FFS), all associated with beetles, were fed to beetles (Maladera matrida and Carpophilus humeralis) and mosquitoes (Aedes aegypti and Culex pipiens). CPBS and CCBS were also injected into M. matrida. Attempts to recover spiroplasmas from regurgitates and hemolymph were conducted 1-10 days after their introduction. After day 1, orally administered spiroplasmas could not be recovered from M. matrida beetles; however, at 2-5 days, four out of five spiroplasmas were recovered from adult C. humeralis. Injected spiroplasmas survived in the hemolymph of M. matrida beetles for a relatively long period (at least 22 days). All five spiroplasmas were recovered from mosquitoes 1 day post feeding, but only two (CCBS and CRS) survived for five or more days. The results show short and variable persistence in orally challenged non-host insects, with general failure to pass the gut barrier. Such evidence should be considered when attempting to use these microbes in biocontrol programs.