Volatiles Emitted From Eight Wound-Isolated Bacteria Differentially Attract Gravid Screwworms (Diptera: Calliphoridae) to Oviposit

Abstract

Bovine blood inoculated with bacteria isolated from screwworm [Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae)]-infested animal wounds was tested as an attractant for oviposition for gravid screwworms. Eight species of gram-negative coliform (Enterobacteriaceae) bacteria mixed with bovine blood singly or all species combined and incubated for various times produced volatiles that attracted gravid flies in a cage bioassay in varying numbers. In 15-min duration tests, volatiles from five species of bacteria (Klebsiella oxytoca, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, and Providencia stuartii) attracted more females than volatiles of the three species (Enterobacter cloacae, Enterobacter sakazakii, and Serratia liquefaciens). In 1-h duration oviposition tests, volatiles from the substrate using the same five species of bacteria attracted more females to oviposit than the other three species. Volatiles from 24-h incubation period elicited least attraction and oviposition whereas volatiles from the 48- and 72-h incubation period resulted in significantly more attraction and oviposition. Attraction and oviposition decreased significantly when the substrates were incubated for 96 h. Volatiles from substrate with all species of bacteria combined attracted a significantly higher percentage of flies to land and oviposit than those from substrates prepared with single species. It is possible that multiple active chemicals present in volatiles of the all-species substrate may act as synergists resulting in greater response than those observed with volatiles from single-species substrate. Before oviposition flies took a bloodmeal from the oviposition substrate. It is possible that the oviposition is moderated by two different factors in screwworm-first, by using a chemical cue to land on a potential oviposition site and second, by using a bloodmeal to stimulate oviposition.

Egg-Surface Bacteria Are Indirectly Associated with Oviposition Aversion in Bactrocera dorsalis

“…For Anopheles mosquitoes, volatile substances from larval habitats can induce oviposition at low concentrations but reduce oviposition at higher concentrations [16]. Similarly, blood inoculated with bacteria isolated from screwworms induced oviposition in female screwworms compared with the control [17]. Furthermore, studies have indicated that the oviposition behavior of flies can be affected by the egg surface bacteria of flies.…”

Microbial effects on the development of forensically important blow fly species

“…Thus different blow fly species may have evolved different relationships with the range of microbial species found on the corpse. Examples of such relationships have been demonstrated in previous studies, including species variation in levels of antimicrobial activity against specific bacteria [39] and ovipositional response to different bacterial species [40][41]. This relationship would extend to the temporal dimension as well, with microbial communities being dynamic through time [15,42] and species of blow flies laying eggs on the corpse at different times.…”

Proteus mirabilis interkingdom swarming signals attract blow flies

“…In the case of blow flies, volatile organic compounds released by bacteria are the primary mechanism governing their attraction, acceptance and colonization of such resources (Eisemann and Rice, 1987;Chaudhury et al, 2002Chaudhury et al, , 2010Morris, 2005). However, no one has demonstrated the role of these volatile compounds in the ecology of the bacteria from which they are released.…”