Stable flies,
Stomoxys calcitrans (L.), are the most important insect pests of cattle in the United States. However, adequate management strategies for stable flies (SF), especially for pastured cattle, are lacking. Microbial/symbiont-based approaches offer novel venues for management of insect pests and vector-born pathogens.
In this study, we investigated the effect of SF eggs and the bacterial community from the surface of eggs on SF oviposition. SF laid significantly more eggs on a substrate with con-specific fresh (< 2hrs old) eggs than on a substrate a) without eggs, or b) with con-specific old egg (20hrs old), or c) with surface sterilized con-specific eggs, or d) with eggs of house flies. Bacteria from the surface of fresh and old SF eggs were cultured, quantified, isolated, and identified by 16S rDNA analysis. The concentration of bacteria on the surface of fresh eggs was 6.9 ± 1.5 x 105 CFU/egg; the community on the surface of old eggs greatly increased (7.8 ± 2.5 x 106 CFU/egg) and represented
Staphylococcus saprophyticus,
Proteus vulgaris, and
Serratia spp. Additional oviposition bioassays revealed that the mixture of these bacteria alone (without eggs) stimulated SF oviposition. Our data demonstrate that the microbial community on the surface of SF eggs greatly affects SF oviposition behavior and likely produces semio-chemicals that depending on their concentration and/or composition either stimulate oviposition (fresh eggs) or suppress oviposition (old eggs). This study shows a promising starting point for exploiting SF oviposition behavior and SF-bacterial associations for development of novel approaches for SF IPM program.