Related Experiment Video
Updated: Mar 1, 2026
The Insect Galleria mellonella as a Powerful Infection Model to Investigate Bacterial Pathogenesis
Published on: December 11, 2012
Semiochemicals released from five bacteria identified from animal wounds infested by primary screwworms and their
Junwei J Zhu1, Muhammad F Chaudhury2, Lisa M Durso1
1USDA-ARS, Agroecosystem Management Research Unit, East Campus, UNL, Lincoln, Nebraska, United States of America.
Background:
The Primary screwworm, Cochliomyia hominivorax (Coquerel), is a serious pest feeding on living flesh of any warm-blooded animal, including humans. It was eradicated from the United States in the early 1980s using the sterile male technique. However, it was recently detected in populations of wild deer and pets in the Florida Keys of the US. For monitoring purposes, screwworm flies are normally trapped using attractant bait with liver. However, there has been little effort to develop an efficient monitoring system for detection of screwworm flies using a specific synthetic attractant blend. Several studies have shown that odors from animal wound fluids attract screwworm adults, particularly gravid females. Bacteria associated with animal wounds have been identified that act as a major source for this attraction. To understand what volatiles attract screwworms we inoculated bovine blood with previously identified bacteria. We identified volatile chemicals released from the inoculated blood and other selected media over time and assessed the effect of those chemicals on behavioral activity of adult screwworm flies.
Methodology/Principal Findings:
A total of 7 volatile compounds were collected from bacteria incubated in either broth or blood using solid-phase microextraction, and their chemical structures were identified by their characteristic mass spectrum fragments and confirmed by retention times in comparison to those of synthetic standards via gas chromatograph combined mass spectrometry analyses. Five major volatiles including dimethyl disulfide, dimethyl trisulfide, phenol, p-cresol and indole were detected from a mixture of 5 bacteria incubated in blood. The ratios of volatiles released differed among different incubation media, time and individual bacteria. A synthetic mixture containing the five compounds was demonstrated to be attractive to adult screwworm flies both in laboratory assays and field trapping trials.
Conclusions/Significance:
The results obtained from this study may assist in developing an efficient trapping system using the identified attractant blend to detect the infestation of primary screwworms. This is also the first study to explore the complex systems in volatile release profiles from 5 bacteria isolated from screwworm-infested animal wounds that are incubated with different media and incubation time, as well as individual and multi-species bacterial communities.
Insights
Researchers identified key volatile compounds from bacteria that attract primary screwworm flies. This discovery can lead to a more effective synthetic attractant blend for monitoring and controlling this significant pest.
Area of Science:
- Entomology
- Chemical Ecology
- Microbiology
Background:
- The primary screwworm fly (Cochliomyia hominivorax) is a dangerous parasite of warm-blooded animals, including humans.
- Eradicated in the 1980s, it has recently resurfaced in the Florida Keys, necessitating improved monitoring.
- Current monitoring relies on liver bait, but a specific synthetic attractant is needed.
Purpose of the Study:
- To identify volatile compounds produced by bacteria from animal wounds that attract screwworm flies.
- To develop a synthetic attractant blend for efficient screwworm fly detection.
Main Methods:
- Inoculated bovine blood with identified wound bacteria to identify volatile chemicals.
- Utilized gas chromatography-mass spectrometry to analyze volatile compounds.
- Assessed the behavioral response of screwworm flies to synthetic volatile blends in lab and field trials.
Main Results:
- Identified 7 volatile compounds, with 5 key compounds (dimethyl disulfide, dimethyl trisulfide, phenol, p-cresol, indole) detected from a bacterial mixture in blood.
- Volatile release varied based on media, time, and bacterial species.
- A synthetic blend of the 5 compounds proved attractive to adult screwworm flies in both laboratory and field settings.
Conclusions:
- The identified volatile blend can aid in developing an efficient trapping system for primary screwworm detection.
- This study provides novel insights into volatile profiles from wound-associated bacteria and their role in screwworm attraction.
