Juvenile hormone antagonists to combat against insects

Insects are responsible for millions of death around the globe and major economic losses annually, by damaging crops and stored agricultural products. According to the World Health Organisation mosquito is the deadliest animal upon earth.

Thus to save humanity from the detrimental effects of insects, use of insecticides is essential. One old concept is using chemical pesticides, which are hazardous to health and environment. Moreover, insects develop resistance to existing insecticides, complicating the controlling strategies. Other, more modern approaches are experimental DNA manipulation, designer bacterial infection and introduction of sterile males to control insect birth. However, many of these options threaten of eliminating insect species completely, and a great deal of tinkering with nature. Environmentalists think that the use of some of these methods could gravely affect ecosystems in unforeseen ways and thus may influence human health and environment. Thus development of novel and effective insecticides is urgently in need.

The most attractive strategy is to use “Insect-specific growth regulators,” which are compounds that regulate the growth of insects without posing any health risk to humans or environment. Juvenile hormone, a hormone in insects, is an attractive target for insect growth regulators because it exists in insects only and plays key roles in their development, reproduction and other physiological functions.

Recently an international team of scientists, including an entomologist at the University of California, Riverside, has made a detailed study about the mechanism of action of this hormone and devised a method to block it. They discovered antagonists of juvenile hormone antagonists (JHANs), in plants that counteract the hormone’s action. JHANs are known as make up plants’ innate resistance mechanism against insect herbivores.

The group along with Korean scientists screened 1,651 plant species and identified five JHANs from two plants that are effective against yellow fever mosquito larvae by specifically retarding the development of ovaries. The Korean researchers, led by Sang Woon Shin at Seoul National University, are testing the effect of these five molecules on other agricultural pests also.

These newly discovered herbal molecules could lead to the development of a new class of safe and effective pesticides to control mosquitoes and other agricultural pests.


Further reading:


Identification of plant compounds that disrupt the insect juvenile hormone receptor complex. Seok-Hee Lee, Hyun-Woo Oh, Ying Fang, Saes-Byeol An, Doo-Sang Park, Hyuk-Hwan Song, Sei-Ryang Oh, Soo-Young Kim, Seonghyun Kim, Namjung Kim, Alexander S. RaikhelYeon Ho Je and Sang Woon Shin. Proceedings of the National Academy of Sciences of the United States of America. doi: 10.1073/pnas.1424386112

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Arunima Maiti

Arunima Maiti

Biomedical scientist with special interest in reproductive biology.

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