Nematodes containing bacteria may provide a natural pesticide solution against Europe's most invasive insect, the fire ants. The rate of the fire ant population is found abundant in Maine.


Nematodes, Transportation of Bacteria, and Fire Ant Colonies

The University of Maine experts determined that the cause of dead fire ants in numerous colonies they examined were nematodes. These colonies were located at Orono and Mount Desert Island.

The nematodes that infected the fire ants in Maine are called the biological community as roundworms. What the nematodes do is that they naturally harbor bacteria in their bodies, specifically in their digestive tracts. The study conducted by experts has investigated the capability of the nematodes to actually wipe out the invasive fire ants through the bacteria they migrated from the soil to the colonies. In addition, they also found a group of bacteria that is suspected to be involved with the fire ant extermination.

The nematode genuses that were involved in the killing of fire ants were the Serratia and Pseudomonas. According to the study published in the journal iScience, titled "Bacterial Transfer From Pristionchus entomophagus nematodes to the Invasive Ant Myrmica rubra and the Potential for Colony Mortality in Coastal Maine," these distinct nematode species were successful in transporting the bacteria across various fire ant colonies, increasing the mortality rate of the latter, and even inflicting other insects that had contact with them.

Nematode species that belong under the Serratia and Pseudomonas were proven to be harmful to insects that share ecological habitats. Moreover, they can also hurt bigger animals, as well as humans. However, the questions revolving around the nematodes morphology process and their life cycle remain.

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Nematode Bacteria Increases Mortality Rate in Ant Colonies, Potential Exterminator Against Invasive Fire Ants

University of Maine's animal and veterinary expert and author of the study Sue Ishaq said that the nematodes are a potential solution to gain biological control over the fire ants. However, the process of extermination is intriguing. Ishaq, along with their colleagues, presented in the study that the bacteria identified in the nematode's digestive regions and cuticles were carried directly to the bodies of fire ants. To prove the ability of nematodes in transporting the bacteria, the researchers fed the roundworms with fluorescent bacteria and let them interact with other insects, such as waxworms.

The experts observed that the adult nematodes were able to contain high rates of bacteria in their digestive tracts, but compared to the initial theory, they could not carry the bacteria through their exterior cuticles. In contrast to this observation, the young nematodes had more bacterial rates carried in their cuticles and less in their digestive tracts.

The observation between the young and adult nematodes was significant, but the experiment resulted in an unexpected outcome. Both the nematode variants, even though they carry the bacteria, were neither able to transmit the bacteria to the waxworm or cause any lethal effects toward the waxworm. PhysOrg reports that since the results from waxworms were not the same as the invasive fire ants, further studies will be conducted to specify the true correlation between the nematode bacteria with the mortality rate of fire ants.

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