Sequential Utilization of Hosts from Different Fly Families by Genetically Distinct, Sympatric Populations within the Entomophthora muscae Species Complex

Abstract

The fungus Entomophthora muscae (Entomophthoromycota, Entomophthorales, Entomophthoraceae) is a widespread insect pathogen responsible for fatal epizootic events in many dipteran fly hosts. During epizootics in 2011 and 2012 in Durham, North Carolina, we observed a transition of fungal infections from one host, the plant-feeding fly Delia radicum, to a second host, the predatory fly Coenosia tigrina. Infections first appeared on Delia in the middle of March, but by the end of May, Coenosia comprised 100% of infected hosts. Multilocus sequence typing revealed that E. muscae in Durham comprises two distinct subpopulations (clades) with several haplotypes in each. Fungi from either clade are able to infect both fly species, but vary in their infection phenologies and host-specificities. Individuals of the more phylogenetically diverse clade I predominated during the beginning of the spring epizootic, infecting mostly phytophagous Delia flies. Clade II dominated in late April and May and affected mostly predatory Coenosia flies. Analysis of population structure revealed two subpopulations within E. muscae with limited gene exchange. This study provides the first evidence of recombination and population structure within the E. muscae species complex, and illustrates the complexity of insect-fungus relationships that should be considered for development of biological control methods.

Comparative transcriptomics reveal host‐specific nucleotide variation in entomophthoralean fungi

“…; Gryganskyi et al . ), and the consistent difference in host range of houseflies and cabbage flies, respectively.…”

“…; Keller ; Gryganskyi et al . ). First, we use an RNA‐seq approach to obtain a genomewide reference transcriptome from E. muscae sensu stricto naturally infecting houseflies ( Musca domestica, Muscidae).…”

Robust manipulation of the behavior ofDrosophila melanogasterby a fungal pathogen in the laboratory

“…Interestingly, Group ii also includes a transcript whose translated product is homologous to the voltage-dependent calcium channel Cch1 in Saccharomyces cerevisiae, which is known to respond to environmental stress as well as mating hormones [45,46]. This is noteworthy given recent evidence that recombination occurs in E. muscae but is not yet understood when or how frequently E. muscae exchanges genetic material [24].…”

“…Findings from previous work examining host specificity of other E. muscae strains have not always been consistent. While some have found evidence for differences in infection efficiency between and local adaptation to varying hosts [24,50], others have demonstrated the capacity of a given E. muscae isolate to infect a variety of host taxa [26]. Our understanding of strain diversity and host specificity would greatly benefit from the collection of more molecular and ecological data for E. musace complex species and infected hosts.…”

“…In the wild, species within the E. muscae species complex have been observed to infect more than one host species [18,23]. However, recent molecular evidence suggests that there may be additional host specialization within some E. muscae complex species [24,25]. In the laboratory, a range of fly species can be infected and killed by E. muscae, though not all infected hosts manifest the stereotypical end-of-life behaviors, and susceptibility has not been found to track with host phylogeny [26,27].…”