Microbial ecology of stable flies (Stomoxys calcitrans L.): Effect of a microbial community in the natural developmental substrate on stable fly oviposition behavior

The selection of a suitable oviposition site is very important for the successful development of insects. The oviposition behavior of stable flies (SF), Stomoxys calcitrans L., was studied by a series of two-choice tests using different oviposition substrates. Our results demonstrated that SF prefer to oviposit on aged (~ three weeks old) horse manure (AHM) than on fresh (< 1 day old) horse manure. Furthermore, AHM was clearly preferred for oviposition than sterile (autoclaved) aged horse manure (autAHM) confirming that the active microbial community plays a critical role in the SF oviposition behavior. Choice bioassays using a single plate, one half with AHM and the other half with autAHM revealed that SF are capable to distinguish a suitable substrate on a very small scale. autAHM inoculated with Citrobacter freundii AR3 (isolated from AHM) stimulated SF oviposition into a significantly greater degree than autAHM but into lesser degree compared to AHM. Our experiments show that SF are capable to select a very small and specific area for oviposition based on the suitable microbial community. Current experiments are focused on weekly analyzes of volatile compounds released from fresh and aging horse manure (six consecutive weeks), concurrent analysis of changes in the microbial community structure by culturing and metagenomic approach as well as corresponding SF oviposition behavior using two-choice tests. This study will lead to a better understanding of the SF oviposition behavior and the importance of a microbial community in this process. Our results will provide new information that may lead to the development of novel approaches for SF management.