A large number of insects eat only plants however it is still possible for harmful minute organisms to slip past through as an insect happily feasts on a leaf. But rather than get sick, they use a special technique to resist microbial infections. Researchers have observed the gut of a cotton leafworm and found a powerful peptide with antimicrobial properties that can kill pathogens eventually defending its host. Results of this research study may be applied to agriculture, health care and even as an alternative to common antibiotics in the future.

Yongqi Shao of Zhejiang University, author of the research on insect gut microbes said that their research has revealed the symbiotic association of insects with gut microbes owing to their evolutionary survival. He said that insects and microbes have evolved for over millions of years, according to Science Daily.  

Shao and Wilhelm Boland, senior study author from the Max Planck Institute for Chemical Ecology, focused their study on the cotton leafworm, Spodoptera littoralis. This worm is found widespread across temperate regions and is responsible for the destruction of large crop areas. The type of microbes inhabiting the cotton leafworm's gut varied widely during its larval stages. Young larvae had virulent Enterococcus species while older larvae had E. mundtii.

Phys also reported Shao's research. Boland mentioned that E. mundtii and the cotton leafworm have developed a symbiotic relationship. The microbe becomes dominant in the gut as it protects the worm against pathogens. He concludes that a protective association with bacteria that produces antibiotics is one of the most common techniques of insects to ward off microbial invaders.

Researchers plan to expand their study to include other insect species. They also plan to look for other toxic compounds that play an important role in host protection and development. It is also possible that findings could have positive implications for health and agriculture. Antimicrobial peptides may be used as food preservatives, to control insect pests and maybe even alternatives to conventional antibiotics.