In August 2009, surprising reports of a rat-eating plant discovered in Palawan circulated on the international and local news circuit. According to media reports, a team of botanists led by British experts Stewart McPherson and Alastair Robinson found the plant in 2007 on Mount Victoria in Narra, Palawan, after a 2-month expedition.

The team, which included staff from Palawan State University, received word from two Christian missionaries who found the large, carnivorous pitcher plant in 2000. Their detailed findings were published earlier this year in the Botanical Journal of the Linnean Society after a 3-year study of all 120 species of pitcher plants.

According to GMANews.TV, the rat-eating plant is among the largest of the pitcher plants, with pitchers measuring 30 × 16 cm, twice the size of pitcher plants usually found in the area. Named after British nature filmmaker Sir David Attenborough, Nepenthes attenboroughii uses acid-like enzymes to dissolve its prey.

In his interview with Telegraph.co.uk, McPherson said that “the plant produces spectacular traps which catch not only insects but also rodents.”

“This is a spectacular discovery,” says Grant Singleton, IRRI rodent expert and Irrigated Rice Research Consortium coordinator. “We are often told about botanical extracts that are poisonous to rats, but perhaps we now have a natural rat trap!” Certainly, this newly discovered rat trap is a welcome addition to the arsenal used in controlling rats. Rodents are the most abundant and diversified order of living mammals in the world and can contribute to human disease and threaten public health.

Rodent-borne diseases—a comprehensive review

Dr. Singleton recently co-authored with Drs. Bastian Meerburg and Aize Kijlstra from Wageningen University, the Netherlands, a 50-page review on rodent-borne diseases and their risks to public health. In their article, published in Critical Reviews in Microbiology, the scientists stressed that rodents play a significant role in transmitting a large number of diseases to humans, and to animals that provide important sources of protein for humans. Risk levels of infection vary between different pathogens, and it is thus crucial to observe rodent populations more closely to predict future disease occurrences and to be able to identify new rodent-borne diseases.

Models that characterize changes in the demography and population density of rodents are needed to help predict expansion of rodent-borne diseases and thus allow planning, which will improve public health. The authors highlighted that possible effects of human activity and global climate change should be further investigated, because these might lead to rodents having different interaction patterns and habitats, which could then lead to infectious diseases emerging in areas that were previously not affected.

A key message that emerged in the article is the underreporting of rodent zoonoses or disease transmission. “Insufficient attention is paid to the diagnosis of these important diseases,” says Dr. Singleton. “In Asia, often common and treatable diseases such as leptospirosis and murine typhus are misdiagnosed. Some cases are simply diagnosed as fevers of unknown origin, while others are misdiagnosed as dengue or malaria. This is a tragedy given that many poor agricultural workers are at high risk of contracting rodent-borne diseases.”

The reviewers conclude that more research is needed to develop integrated prevention strategies, and to determine how to interrupt disease transmission cycles that involve rodents. With proper application of ecologically based rodent control methods, it is possible to reduce the dangers of rodent-borne diseases in areas where humans, food animals, and rodents live close to one another.

If this rat-eating pitcher plant can, in some way, help in catching rats, then it is a much-needed contribution to effective rat management and another interesting way of nature to maintain its checks and balances. However, Dr. Singleton explained, “The time it would take a pitcher plant to digest a rat would be sufficient for another generation of rats to be born! So, our quest for an effective method of rodent management continues, with management based on a strong understanding of the ecology and living habits of rodent pests offering the best promise.”

By Trina Leah Mendoza, photo by Alastair Robinson (reposted from Rat Trap, Rice Today, October-December 2009, and Discovered rat-eating plant, a solution for rat control?, RIPPLE, September-December 2009)

Links to articles:

Palawan discovery: A living rat trap

www.gmanews.tv/story/170117/Rat-eating-plant-foundin-Palawan

Rat-eating plant discovered in Philippines

www.telegraph.co.uk/earth/earthnews/6041241/Rateating-plant-discovered-in-Philippines.html