Never underestimate the power of the mosquito. This bothersome insect is not just a nuisance. Because of their direct role in spreading several deadly diseases, the mosquito has notoriously earned the title of the most deadly creature in the world. Malaria, dengue fever, West Nile virus, Zika virus, and several others are spread by mosquito bites.
The World Health Organization has reported that hundreds of millions of new cases of mosquito-related illnesses occur each year, with a fatality rate in the millions. Malaria is considered endemic in 91 countries.
Although the majority of mosquito-related illnesses occur in tropical and subtropical areas, the Centers for Disease Control and Prevention has declared mosquito-related illnesses (along with those caused by fleas and ticks) to be on the rise in the United States. In recent years, confirmed cases have tripled in number.
Keeping the mosquito population under control
Because of the devastation caused by mosquitoes, much time, effort, and research has been dedicated to reducing their numbers.
Insecticides are the most common method used to control the mosquito population. However, resources to produce and purchase these chemicals are often very limited in the areas that need them the most.
Scientists continue to investigate other more natural ways to keep the mosquito population in check.
Turtles: One predator of the mosquito
Several natural predators of the mosquito have been identified. One such example is the turtle. Turtles are aquatic and semi-aquatic reptiles. They eat a variety of things such as plants, tiny fish, and insects. Many species also feast on insect larvae, including that of the mosquito.
Could turtles help control the mosquito population?
A quick look at the mosquito’s life cycle will demonstrate how a turtle could help keep them at bay.
- First, adult female mosquitoes lay their eggs. They must lay their eggs in or near water. Areas with standing water (like ponds, streams, creeks, swamps, etc) are preferred. Any area with stagnant water for more than a week is a prime location.
- After the eggs hatch, the larvae emerge. These larvae are continuously feeding and growing. They go through a molting process four times, shedding their skin each time. The stages between moltings are known as instars. After the fourth instar, the larva becomes a pupa.
- The pupa is a period of resting and developing, similar to a butterfly in its cocoon.
- Finally, the pupa splits open and the adult mosquito emerges.
Turtles can help control the mosquito population. They thrive in areas of still water and many species feed off insect larvae, including that of the mosquito. They prefer larvae in the third and fourth instar. Some have actually been observed eating between 1000 – 2000 larvae per day.
Eating these more mature larvae will help interrupt the mosquito lifecycle, reducing the number of mosquitoes that reach adulthood.
The Red-Eared Slider
The red-eared slider is the most popular pet turtle in the United States. It is also very common in the rest of the world. This species of turtle likes calm, warm water and prefers to eat aquatic plants and insects.
Several studies have been conducted on the red-eared slider and its effect on the mosquito population.
A look at the research
In Honduras in 2007, researchers conducted studies to determine if turtles could help reduce mosquito numbers. Families in the area had cement water storage tanks that were used for laundry and household cleaning. Because of the stagnant water, these tanks were the perfect breeding ground for mosquitoes.
Scientists placed one red-eared slider in each of the tanks they were studying. The turtles were given small scraps of table food for supplemental nourishment, as well as something to float on.
The turtles eliminated virtually all of the mosquito larvae within each tank. Also, they kept the tanks mosquito-free for the entire two-year period of the study. The vast majority of the turtles remained healthy and happy. Families treated the turtles as pets and were glad to take care of them.
Another similar study was conducted in Louisiana in 2000. Mosquitoes were a major problem in certain residential ditches, especially those polluted by septic drainage. After some in-laboratory testing, red-eared sliders were placed in the ditches at a ratio of one turtle per every one meter of ditch. They were enclosed so they could not escape.
After five weeks, the turtles had reduced mosquito larvae and pupae by 99% (Marten, 2007).
Education and awareness is key
Do turtles eat mosquito larvae? Most species will gladly eat any insect larvae around them, including that of the mosquito. But could the turtle be useful in reducing the spread of mosquito-related diseases?
For some situations, like the families in Honduras, turtles would be invaluable. Small ponds and other similar aquatic areas would greatly benefit from having turtles in or near the water. Especially in locations where resources are limited, a turtle would be extremely efficient at reducing mosquito larvae.
However, several problems could occur when using turtles on a larger scale. First, as in the case of the Louisiana ditches, if the turtles were not enclosed, they could easily roam to other areas.
Also, having turtles in large numbers would require supplemental feeding which may not be feasible. Furthermore, the red-eared slider is considered an invasive species; large numbers could potentially endanger nearby plant and animal life.
Finally, turtles are commonly contaminated with Salmonella. This introduces another potential health concern.
The battle against mosquitoes is complex. Turtles are just one of the many weapons that can be used against them. Educating the public and creating awareness is crucial. Anything that can be done to reduce the mosquito population is important; a few well-placed turtles could truly make a difference.