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Updated: Jul 2, 2026
Systemic Bacterial Infection and Immune Defense Phenotypes in Drosophila Melanogaster
Published on: May 13, 2015
Sick of mating: sexual transmission of a pathogenic bacterium in Drosophila melanogaster
Tanner S Miest1, Margaret Bloch-Qazi
1Department of Biology; Gustavus Adolphus College; St. Peter, Minnesota, USA.
Abstract:
Internal fertilization protects gametes from inhospitable environments and ensures sufficient proximity for gamete union. However, close contact between individuals during mating also increases the risk of pathogen transfer. We developed an approach to transfer the entomopathogenic bacterium Serratia marcescens from males to females during courtship and mating in Drosophila melanogaster. We then examined the frequency of contamination and bacterial loads of females copulating with males for varying durations, showing that while courtship is sufficient for bacterial transmission, mating significantly increases the bacterial load received in a time-independent manner. S. marcescens transmission from contaminated males during mating was sufficient to establish rapid, systemic infection and death in mated females.
Insights
Male fruit flies can transmit the bacterium Serratia marcescens to females during mating. This pathogen transfer during mating leads to rapid infection and death in females, highlighting risks of sexual contact.
Area of Science:
- Microbiology
- Insect Pathology
- Reproductive Biology
Background:
- Internal fertilization offers reproductive advantages but increases pathogen transmission risks during mating.
- Understanding pathogen transmission during sexual contact is crucial for disease ecology.
Purpose of the Study:
- To investigate the transmission of Serratia marcescens from male to female Drosophila melanogaster during courtship and mating.
- To quantify bacterial loads and infection outcomes in females following exposure to contaminated males.
Main Methods:
- Males were experimentally contaminated with Serratia marcescens.
- Females were exposed to contaminated males for varying durations of courtship and mating.
- Bacterial loads in females were quantified, and survival rates were monitored.
Main Results:
- Courtship alone was sufficient for bacterial transmission, but mating significantly increased female bacterial load.
- Bacterial load increase during mating was independent of copulation duration.
- Transmission during mating led to rapid systemic infection and mortality in females.
Conclusions:
- Sexual contact in Drosophila melanogaster serves as a significant route for pathogen transmission.
- Serratia marcescens transmission via mating can cause lethal infections in females.
- The study demonstrates a direct link between reproductive behavior and disease spread in insects.
