Sequential utilization of hosts from different fly families by the fungal pathogen Entomophthora muscae
A. GRYGANSKYI (1), H. L. Liao (1), R. A. Humber (2), J. E. Stajich (3), B. Mullens (3), I. M. Anishchenko (4), R. Vilgalys (1). (1) Duke University, Durham, NC, U.S.A.; (2) USDA ARS BioIPM Research, Ithaca, NY, U.S.A.; (3) University of California-Riverside, Riverside, CA, U.S.A.; (4) M. Kholodny Institute of Botany, Kyiv, Ukraine
Dynamics of infection were described for the entomopathogenic fungus <i>Entomophthora muscae</i> growing on the plant feeding fly <i>Delia radicum</i> and the predatory fly <i>Coenosia tigrina</i>. Populations of infected flies were sampled in 2011-2012 in Durham, North Carolina, USA. Infections first appeared in the middle of March on the fly genus <i>Delia</i>, and later switched to of <i>Coenosia</i>. Optimal conditions for fungal infection were: average temperature 11-28°C, dew point 3-21°C, and rain 1-3 days before sampling. Occurrence of infected flies is correlated moderately well with average temperature, lowest temperature, and dew point (r = 0.33, 0.36 and 0.33 respectively) and is weakly correlated (r = 0.14) with relative humidity. Collected specimens were genotypically close to <i>E. muscae</i> and <i>E. scatophagae</i> but differed morphologically and karyologically. This suggests the broader range of these characteristics may occur in the still incompletely resolved <i>E. muscae</i> species complex. Genotyping of rRNA ITS region identified twelve genotypes in <i>E. muscae</i> population infecting both <i>Delia</i> and <i>Coenosia</i>. Transcriptomic analysis of mRNA from infected fly bodies reveals differences in gene expression on different stages of infection development and between host species. Results illustrate the complexity of insect-fungus relationships in this ecosystem that should be considered for development of biological control methods.
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