Bacterial associations across house fly life history: Evidence for trans-stadial carriage from managed manure

Authors: ZUREK, KLARA - Kansas State University; Nayduch, Dana

Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2015
Publication Date: 1/1/2016
Publication URL: http://handle.nal.usda.gov/10113/61859
Citation: Zurek, K., Nayduch, D. 2016. Bacterial associations across house fly life history: Evidence for trans-stadial carriage from managed manure. Journal of Insect Science. 16(1):1-4.

Interpretive Summary: House flies associate with microbe-rich substrates throughout their lifetime. Since larvae utilize bacteria as a food source, degrading or digesting them in the process. However, some bacteria species survive and are present as third instar larvae become pupae and metamorphosis. During metamorphosis, many bacteria are again lost during destruction of the larval gut and construction of the new adult gut. It has been previously demonstrated that some bacterial species survive metamorphosis, being either left behind in the puparium (the pupal case) and/or present on the surfaces or in the gut of the newly-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 in order to assess trans-stadial carriage from this natural developmental substrate. All larvae (10/10), pupae (10/10) and puparia (10/10) cultures were positive for bacteria. Several bacterial species that were present in larvae also were present either in pupae or pupal cases. However, only four viable bacterial species were detectable in 6/10 newly-emerged adults reared from manure. Of note is the apparent trans-stadial 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.

Technical Abstract: House flies (Diptera: Muscidae; Musca domestica L.) associate with microbe-rich substrates throughout life history. Since 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 either left behind in the puparium and/or present on the surfaces 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 in order to assess trans-stadial carriage from this natural developmental substrate. All larvae (10/10), pupae (10/10) and puparia (10/10) cultures were positive for bacteria. Several bacterial species that were present in larva also were present either in pupae or puparia. However, only four viable bacterial species were detectable in 6/10 newly-emerged adults reared from manure. Of note is the apparent trans-stadial 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.