Related Experiment Video
Updated: May 30, 2025
Drosophila melanogaster Larva Injection Protocol
Published on: October 19, 2021
A single entomopathogenic nematode infection assay for Drosophila melanogaster larvae
Sreeradha Mallick1, Eric Kenney1, Jacob Rashap1
1Infection and Innate Immunity Lab, Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.
Abstract:
The entomopathogenic nematodes (EPNs) Steinernema carpocapsae and Steinernema hermaphroditum can efficiently infect the fruit fly, Drosophila melanogaster. The EPN infective juvenile (IJ) stage is the free-living and non-feeding stage that seeks out suitable insects to infect. While previous studies have described successful infection of D. melanogaster larvae with a standard amount of 100 IJs, the pathogenicity of a single IJ nematode towards insects remains poorly understood. Given the variability in pathogenesis among individual IJs, investigating the ability of a single IJ to cause infection in fly larvae addresses a significant gap in our understanding of host-parasite interactions. This protocol aims to evaluate the infection efficiency of a single IJ of S. carpocapsae and S. hermaphroditum. This information contributes towards a better understanding of the EPN-insect interactions and promises to improve the use of EPNs in pest management strategies. The method is summarized below:•Individual third instar wild-type D. melanogaster larvae are infected with either a single IJ or 100 IJs of either nematode species. Uninfected control larvae are treated with sterile water.•Larval survival is monitored over time.•Survival curves are generated, and results are statistically analyzed to determine the effect of a single nematode on the fly larval mortality.
Insights
A single entomopathogenic nematode (EPN) can infect fruit fly larvae, but its efficiency is less understood. This study investigates the pathogenicity of one EPN infective juvenile (IJ) against Drosophila melanogaster.
Area of Science:
- Nematology
- Insect Pathology
- Host-Parasite Interactions
Background:
- Entomopathogenic nematodes (EPNs) like Steinernema carpocapsae and Steinernema hermaphroditum are natural insect pathogens.
- EPNs infect insects via their infective juvenile (IJ) stage, which is non-feeding and seeks hosts.
- Previous research focused on mass infections; the efficacy of a single IJ remains largely unknown.
Purpose of the Study:
- To evaluate the infection efficiency and pathogenicity of a single IJ of S. carpocapsae and S. hermaphroditum.
- To address the knowledge gap regarding the host-parasite dynamics at the single-nematode level.
- To provide insights for optimizing EPN-based pest management strategies.
Main Methods:
- Individual third instar Drosophila melanogaster larvae were exposed to either a single IJ or 100 IJs of S. carpocapsae or S. hermaphroditum.
- Control groups received sterile water without nematodes.
- Larval survival was monitored over time, and survival curves were statistically analyzed.
Main Results:
- The study quantifies the mortality rates induced by single EPN IJs in D. melanogaster larvae.
- Statistical analysis determined the significance of single IJ infections compared to mass infections and controls.
- Results highlight the variability and specific pathogenic potential of individual EPNs.
Conclusions:
- Understanding single IJ pathogenicity is crucial for EPN efficacy.
- This research clarifies the role of individual nematodes in host infection.
- Findings can refine the application of EPNs in biological control programs against insect pests.
