Australian cattle farmers, especially those from the northern part of the continent, has had to contend with the serious threat that is the Buffalo fly. Now that the notorious insect is moving southward, the government relies on bacteria to stop this southward expansion.
Led by Dr. Peter James, a senior research fellow at the Centre for Animal Science and Postgraduate Coordinator with the Queensland Alliance for Agriculture and Food Innovation (QAAFI), the joint effort involving the academe, industry, and the Queensland government will rely on the bacteria Wolbachia to halt the fly's breeding cycle.
The Buffalo fly problem is a costly problem for the health of Australian cows, and subsequent production of beef in the area. An article from QAAFI places this trouble at about $100 million annually, going to treatments and production losses. The use of insecticides also remains a contested potential solution, facing local resistance coupled with the need to protect the "clean green" reputation Australian beef is known for.
Researchers have also noted that the buffalo fly has been steadily moving southward over the past 100 years, moving through Queensland to the northern part of New South Wales. Furthermore, data models show that this climate change-driven expansion would reach South Australia and south-west Western Australia by 2030.
Fighting the Buffalo Fly
The buffalo fly (Haematobia exigua) is an invasive species introduced in Australia's Northern Territory in the late 1830, coming in from Asia. It uses two separate mouthparts, cutting open the skin of mammals and sucking blood, with cows being among the most common victims. It causes large and painful sores, with affected animals experiencing severe distress, affecting their diet and affecting growth and health of the affected animals. The only break Australian mammals get is when winter sets in, weakening the buffalo fly and forcing them to leave into localized pockets to survive the cold season.
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Wolbachia, the proposed solution in a study published in Parasites & Vectors, is a kind of intracellular bacteria that mainly affects insects. It has been successfully used in mitigating dengue fever, which is transmitted by mosquitoes. However, it requires actually injecting the bacteria into the flies since Wolbachia is not transmitted sideways among flies but from parent to offspring. It posed a challenge to the team because, as Dr. James noted, the buffalo fly egg is extremely hard.
"When we started micro-injecting eggs, as is done with mosquitoes, we were blunting needles and damaging the eggs like you wouldn't believe. Needles were even breaking," Dr. James explained.
Introducing Wolbachia Through Adults and Pupae
"So from there we looked at micro-injecting adult flies or pupae, the idea being the bacterium would still spread through the insect and get into the germinal tissue of the females," Dr. James added. The project lead explains that the main thing is to introduce the bacteria into the fly population. Researchers are looking to use male flies as an alternate solution, since Wolbachia is a maternally transmitted microbe that passes through eggs.
Researchers are now looking at three possible solutions. If an infected male mates with a healthy female, they might have no offspring. Next, if a healthy male mates with an infected female and creates infected offspring, which will spread the bacteria to a larger part of the population. The last option is to breed and release sterile buffalo fly males, using them to affect clusters weakened during the winter season.
