Bladderwort: How a Carnivorous Plant Could Be Used in Mosquito Control

By Grant Bolton, Ph.D.

Can you imagine being unexpectedly sucked into a room, the door shuts forever behind you, and you slowly dissolve into mush?

It sounds like something out of a horror film. Or it could be the nightmare of mosquito larvae who wander too close to plants in the genus Utricularia, also known as bladderworts.

Carnivorous plants have fascinated scientists and naturalists for centuries, and bladderwort is no exception. It is a rootless, aquatic plant with hundreds of little sacs attached to its underwater stems. These hollow sacs generate low pressure inside, and, when a tiny aquatic creature like a mosquito larva brushes up against a bristle, it opens the bladder, sucking in anything nearby and slowly digesting it.

With over 220 species of bladderwort worldwide, there has been interest in recent years in using this plant as a biological control method for mosquitoes that spread disease. A study published last week in the Journal of Medical Entomology explores the use of the bladderwort Utricularia aurea to help control three species of dangerous mosquitoes in India.

Bladderwort (visible at center and upper right) is a rootless, aquatic plant that uses small sacs to ingest and feed on small underwater creatures, including mosquito larvae. With over 220 species of bladderwort worldwide, there has been interest in recent years in using this plant as a biological control method for mosquitoes that spread disease. A study published in March 2024 in the Journal of Medical Entomology explores the use of the bladderwort Utricularia aurea to help control three species of dangerous mosquitoes in India. (Photo by Andrey Efremov via iNaturalist, CC BY-NC 4.0)

Bladderwort is a rootless, aquatic plant that uses small sacs to ingest and feed on small underwater creatures, including mosquito larvae. These hollow sacs, which can be seen here, generate low pressure inside, and, when a tiny aquatic creature like a mosquito larva brushes up against a bristle, it opens the bladder, sucking in anything nearby and slowly digesting it. With over 220 species of bladderwort worldwide, there has been interest in recent years in using this plant as a biological control method for mosquitoes that spread disease. A study published in March 2024 in the Journal of Medical Entomology explores the use of the bladderwort Utricularia aurea to help control three species of dangerous mosquitoes in India. (Photo by Naufal Urfi Dhiya’ulhaq via iNaturalist, CC BY-NC 4.0)

While traditional control methods include using insecticides in open water systems to control mosquito larvae, these chemicals can leach into drinking water and have negative effects on local ecosystems.

“After reading about bladderwort capturing mosquito larvae in laboratory conditions, I remember seeing bladderwort here in local large lakes,” says Ajeet Kumar Mohanty, Ph.D., lead author of the study and officer-in-charge at the National Institute of Malaria Research field station in Goa, India.

“When we sampled for mosquito larvae in these lakes, we never saw large populations of mosquitoes,” Mohanty says. His team then took bladderwort samples to his lab and studied the plant’s ability to capture mosquito larvae. Their recent paper looked at predation rates according to instar, or larval stage, in the mosquito species Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti. They found that, within 12 hours, 95 percent of first, second, and third instar larvae were trapped for all three species. The fourth instar, a non-feeding stage, only experienced 60-80 percent predation.

The researchers concluded that the capture rate is related to the larvae’s length and the bladder’s size. It was also the first report of fourth instar mosquito larvae being captured by bladderwort.

“After introducing the plant to the mosquito larvae for one hour,” Mohanty says, “we saw predation up to 50 percent. We don’t even see insecticide applications work that fast or efficient.”

That led Mohanty and his team to look at real-world applications in Goa. In India, construction sites often have large pits called curing water pits full of stagnant water. That’s prime real estate for mosquitoes.

“We are working on a study identifying breeding sites in urban areas for Anopheles stephensi, a major malaria vector in Goa,” Mohanty says. “These curing waters on construction sites are a preferred breeding site, and we took larval counts from them. Then we added bladderwort into these curing pits and took another count after 24 hours. We found that bladderwort was very active up until day seven, and the capture rate was 70 percent.”

Using bladderwort as a biocontrol tool has several advantages over other methods, including mosquito-eating fish, dragonflies, copepods (a type of crustacean), and tadpoles. The bladderwort can be cheaply and quickly propagated and grown for sustainable applications. It also doesn’t have to be planted in soil; it can be placed directly in a cistern, open water tank, or curing pit. The plants last for about a week, sucking in mosquito larvae the whole time.

Additionally, there are many local, native bladderwort species throughout various regions of the globe, so it isn’t necessary to introduce a non-native species to new locales. And, since bladderwort is highly resistant to insecticides and herbicides, it can be used alongside other traditional control methods.

However, there are a few disadvantages. Bladderwort is a seasonal plant whose activity and growth don’t always correlate with peak mosquito seasons. Plus, since it only lasts a week outside its natural habitat, plants must regularly be replaced for ongoing control.

“I believe this is the future of sustainable biocontrol of mosquito larvae,” Mohanty says. “We can simply introduce this plant to open water sources around homes and urban settings without using harmful substances. It can be a local, sustainable solution for communities.”

What might be a nightmare for mosquito larvae could be helpful in our integrated pest management toolboxes for controlling mosquito larvae. Bladderwort’s capabilities underscore the importance of integrating innovative, nature-based solutions into IPM strategies. This approach addresses public health concerns and promotes ecosystem conservation, paving the way for a future where sustainable practices are at the forefront of disease-vector control.

Grant Bolton, Ph.D., is a freelance writer and voice actor with a Ph.D. in entomology based in western Missouri. Email: grant@boltonvoices.com.