Bacteria species in mosquitoes may protect them from the effects of pesticides. Scientists believe that this species is naturally infecting these insects. The infection may be shielding them against different mosquito pesticides.
What the Wolbachia Bacteria Species Is
Studies show that this bacteria species may be the reason for pesticide resistance in mosquitoes. Recently, this bacterium has become an important tool in controlling mosquito populations. But researchers at the University of Reading, the National University of San Juan (Argentina), and the INBIOTEC-CONICET studied the effects of Wolbachia on common mosquitoes. They discovered that those with this bacteria species are less vulnerable to common pesticides.
Analyzing the Wolbachia bacteria species shows how vital the interaction between pesticides and mosquitoes is. Using new methods and specific target species is an ongoing trend these days. The process determines which species to target and where to use them.
Discovery About Culex quinquefasciatus
Mosquitoes generally transmit dangerous diseases like yellow fever, malaria, dengue, and Zika. Research shows they bite at least a million people around the world each year. Scientists are looking at Culex quinquefasciatus. This species is the southern house mosquito. A lab in Argentina has been rearing this species for many years in a controlled environment.
This mosquitospecies is widespread in hot climates. It transmits many diseases like SLEV (San Luis Encephalitis Virus), Venezuelan Equine Encephalitis Virus, and WNV (West Nile Virus). This mosquito also carries filarial worms in Asia, Africa, and South and Central America.The research team discovered that the larvae is naturally infected by the local Wolbachia strain. They then become less vulnerable to three bacterial insecticide species—Lysinibacillus sphaericus, Bacillus thuringiensis israelensis, and Bacillus wiedmannii bovar thuringiensis.
The Resistance
Wolbachia infections in mosquitoes are used in biocontrol programs. The aim is to prevent the transmission of dengue. The effects of the infection in pesticide resistance may affect the success of this control program. The insecticides affected are the following:
- Bifenthrin – This is a pyrethroid for larvicides and adult mosquito knockdowns.
- Bacillus thuringiensis var. israelensis –This is a bacterial insecticide.
- Temephos – This is an organophosphate.
- S-methoprene – This is an insect growth regulator.
Insecticides that target mosquitoes differ in the targeted life stages and modes of action. Mosquitoes are becoming resistant to the mentioned insecticides. Bifenthrin is a common option for killing adult mosquitoes. The bacterial insecticide is toxic when ingested. It kills mosquito larvae. Temephos is often used as a larvicide, especially against Aedes aegypti. S-methoprene is a juvenile hormone mimic. It gets rid of mosquitoes as they transform into the adult stage.
Scientists are attracted to the relationship between insecticide resistance and Wolbachia. The species of mosquito that was focused on was Culex quinquefasciatus. Studies were performed with deltamethrin and DDT. The results yielded that there was a neutral DDT susceptibility. Wolbachia also increases the mosquito’s susceptibility to deltamethrin.
The Wolbachia bacteria species can reduce mosquito vulnerability to bacterial insecticides in some species. It has neutral effects on Culex quinquefasciatus. Scientists are still studying the effects of Wolbachia on other insect species when it comes to insecticide resistance.