Bacterial Associations Across House Fly Life History: Evidence for Transstadial Carriage From Managed Manure

Abstract

House flies (Diptera: Muscidae; Musca domestica L.) associate with microbe-rich substrates throughout life history. Because larvae utilize bacteria as a food source, most taxa present in the larval substrate, e.g., manure, are digested or degraded. However, some species survive and are present as third-instar larvae begin pupation. During metamorphosis, many bacteria are again lost during histolysis of the larval gut and subsequent remodeling to produce the gut of the imago. It has been previously demonstrated that some bacterial species survive metamorphosis, being left behind in the puparium, present on the body surface, or in the gut of the emerged adult. We used a combined culture-molecular approach to identify viable microbes from managed manure residue and a wild population of house fly larvae, pupae, puparia, and adults to assess transstadial carriage. All larval (10/10), pupal (10/10), and puparial (10/10) cultures were positive for bacteria. Several bacterial species that were present in larvae also were present either in pupae or puparia. Four viable bacterial species were detectable in 6 of 10 imagoes reared from manure. Of note is the apparent transstadial carriage of Bacillus sonorensis, which has been associated with milk spoilage at dairies, and Alcaligenes faecalis, which can harbor numerous antibiotic resistance genes on farms. The potential of newly emerged flies to harbor and disseminate bacteria from managed manure on farms is an understudied risk that deserves further evaluation.

The gut bacteria across life stages in the synanthropic fly Chrysomya megacephala

“…4 ). Similar conclusion was also drawn in housefly M. domestica [ 36 , 38 ], which might result from a similar ecological niche [ 16 ]. Gut bacteria in these flies showed some difference at detailed taxonomic level, In dairy manure consuming M. domestica , Bacilli , Clostridia , Actinobacteria , Flavobacteria , and Proteobacteria were the most abundant classes [ 39 ] and Bacilli , Flavobacteria , Proteobacteria were also included as abundant classes in swine manure consuming C. megacephala (Fig.…”

“…However, the number of OTUs were generated more than twice as much as C. megacephala in the gut of polyphagous tomato fruit borer, Helicoverpa armigera (Hübner), indicating that diet and environment might affect gut bacteria of host insect [ 34 , 35 ]. The result that bacterial diversity of C. megacephala varied along with eggs, larvae, pupae and adults were accordance with that of other holometabolic dipteral insects, such as B. dorsalis and Musca domestica [ 25 , 36 ].…”

“…The relative abundance of gut bacteria in 1-d-larvae differed much in 5-d-larve (Table 2 and Additional file 6 : Table S5). The changes of bacterial community in young and old larvae might result from the manure feeding activity of larvae by manure transformation and bacterial digestion [ 36 ]. Fasting in the mature larvae might also play a role in this difference since mature larvae would experience a wandering stage to empty gut autonomously [ 41 ].…”

“…In some higher animals, gut bacteria Coprobacillus and Ruminococcus exhibited decrease in response to fasting [ 42 ]. Strikingly, pathogenic genera Wohlfahrtiimonas , swine manure associated Brevundimonas diminuta and Flavobacterium gelidilacus decreased significantly (Table 2 ) [ 26 , 36 ], which reduced health concerns. While, Pseudoclavibacter bifida increased significantly (Table 2 ) and it was an infection-associated organism that may cause chronic obstructive pulmonary disease [ 43 ].…”

Pseudomonads from wild free-living sea turtles in Príncipe Island, Gulf of Guinea

“…A. faecalis are environmental microorganisms that can also be found in the human fecal microbiota, being rarely responsible for human diseases (Chu and Harkness, 2016). Although they can present several resistant traits that can eventually disseminate through the environment to other animals and humans (Zurek and Nayduch, 2016), they were not considered relevant for this study, as are not associated with disease in turtles. Moreover, in De Vos et al (1997) Alcaligenes genus did not tested positive for oprI, contrary to our study.…”