Engineered Fungi Lure and Eliminate Mosquitoes with Novel Scent Compound

Breakthrough in Biological Mosquito Control

Scientists have developed a novel approach to mosquito control using engineered fungi that produce an attractive scent compound to lure and eliminate disease-carrying insects, according to research published in Nature Microbiology. The modified Metarhizium fungi reportedly produce longifolene, a compound that mosquitoes find irresistible, leading them to their demise.

Breakthrough in Biological Mosquito Control
Fungal Engineering and Identification
Comprehensive Insect Testing
Behavioral Assays Reveal Attraction Mechanism
Infection Mechanism and Spore Tracking
Potential Applications and Future Directions

Fungal Engineering and Identification

Researchers worked with multiple Metarhizium strains, including M. robertsii obtained from the Agricultural Research Service Collection of Entomopathogenic Fungi in Ithaca, New York, and M. pingshaense TM1 isolated from grassland soil in China’s Tianmu Mountains. Sources indicate that thorough taxonomic identification was conducted through phylogenetic analysis of DNA sequences encoding the 5′ end of elongation factor 1-α.

The research team used advanced genetic techniques, including high-fidelity Taq DNA polymerase for all PCR reactions and maximum likelihood phylogenetic reconstruction with MEGA 7.0 software. Analysts suggest this careful identification process was crucial for ensuring the effectiveness of the engineered fungi.

Comprehensive Insect Testing

The study employed an extensive array of insect species to test the effectiveness of the longifolene-producing fungi. According to reports, researchers maintained colonies of A. albopictus mosquitoes, D. melanogaster fruit flies, G. mellonella larvae, tobacco whiteflies, cotton mealybugs, and parasitic wasps throughout their experiments.

Wild A. albopictus larvae were collected from August to October 2023 using oviposition traps in Jiangsu Province, with identification confirmed through both morphological characteristics and mitochondrial COI gene analysis. The report states this comprehensive approach ensured reliable testing across multiple insect species.

Behavioral Assays Reveal Attraction Mechanism

Researchers developed sophisticated two-choice assays to test insect responses to longifolene and the engineered fungi. The testing methodology involved placing stimuli and controls on opposite sides of Petri dishes and monitoring insect movement patterns. According to the research, response indices were calculated using the formula (O – C)/T, where O represents insects in the preferred zone, C represents those in the control zone, and T is the total number tested.

For mosquito testing, scientists used a custom-built two-port olfactometer with transparent PVC chambers connected by tubes. The report indicates that approximately 15 adult mosquitoes, sugar-starved for 12 hours before testing, were introduced into the apparatus and monitored for their chamber preferences over 30-minute periods.

Infection Mechanism and Spore Tracking

The research carefully documented how the engineered fungi infect target insects. Scientists used GFP-labeled M. robertsii strains to track spore attachment, germination, and infection processes. According to reports, they developed rigorous surface sterilization protocols using Triton X-100, ethanol, and sodium hypochlorite solutions to distinguish between loosely attached and successfully infecting spores.

Researchers examined spore behavior in insect guts through detailed histological investigations, fixing foregut tissues in formaldehyde, dehydrating them in sucrose solution, and creating 15-μm-thick slices for fluorescence microscopy. The study states this approach revealed critical information about how spores navigate the insect digestive system.

Potential Applications and Future Directions

This research represents a significant advancement in biological pest control, particularly for mosquitoes that transmit diseases like dengue, Zika, and malaria. The engineered Metarhizium fungi’s ability to produce longifolene creates a powerful attract-and-kill system that could reduce reliance on chemical insecticides.

Analysts suggest this approach could be particularly valuable in areas where insecticide resistance has developed, offering an environmentally friendly alternative. The research team’s comprehensive testing across multiple insect species indicates the potential for broader applications in integrated pest management programs.

While further field testing is needed, sources indicate this technology represents a promising new weapon in the ongoing battle against mosquito-borne diseases. The study demonstrates how understanding insect olfactory systems can be leveraged to develop more effective biological control agents.