Farmers, with the help of researchers in the field, have been desperately trying to develop new insecticides that can ward off pests looking to claim their crops. These products work with a varying degree of effectiveness. For one, the insect pests tend to develop tolerance and new solutions have to be developed, and of course there's always the issue of poisoning to humans and mammals. Spraying chemicals on crops might kill your pests and preserve yields, but if it comes at a compromise to human health, then we're spelling trouble here.
A new generation of safe insecticides might prove to be the most efficient, if we're to judge the latest findings made by an international team of researchers. The team successfully isolated for the first time a neuropeptide named natalisin that regulates the sexual activity and reproductive ability of insects. After blocking this neuropeptide, the researchers found that neither male or female insects were able to reproduce any longer. This neuropeptide is unique to insects and arthropods, so theoretically spraying it over crops won't affect humans and will in return kill off all pests simply by leaving them no means of reproducing any longer.
Neuropeptide is composed of short chains of amino acids in the brain of insects and arthropods and is part of their peptidergic system - a genetic network that uses small peptides as neurotransmitters to chemically relay messages throughout the body, particularly those related to sexual activity.
"Natalisin is unique to insects and arthropods and has evolved with them," said Yoonseong Park, professor of entomology at Kansas State University. "It appears to be related to a neuropeptide called tachykinin that is in mammals and invertebrates. While tachykinin is involved with various biological processes, including the control of blood flow in mammals, natalisin is linked to reproductive function and mating behavior in insects and arthropods."
The research followed natalisin interactions in fruit flies, red flour beetles and silk moths, each of them insects with four classic stages of development - egg, larva, pupa and adult. Natalisin distribution was manipulated using a genetic tool called RNA interference, or RNAi, which allowed the researchers to see what happens during each development cycle. They found that the absence of natalisin in the brain led to the insects' physical inability to reproduce as well as reduced their interest in mating.
"For example, we saw that knocking out the natalisin in the fruit fly makes them unable to mate," Park said. "The female is too busy grooming her body for the male to approach her. The male doesn't send a strong enough signal to the female to get her attention. We're not sure if that's because the male can't really smell her or because he is not developed enough to signal her.
This neuron knockdown might allow scientists to develop targeted pesticides that would be environmentally safe, because they wouldn't affect plants, animals or humans. This statement, however, warrants one or a couple of new studies altogether. What effects on the local biosphere would such a pesticide pose? If a large population of insects become sterilized, besides the targeted pests, how would this affect other animals that depend on these for food, for instance? Honeybees always come to mind.These are just a few important questions that need to be addressed.
If anything, however, the study sheds new light on how the brain functions with the neurosystem, and provides more information about the basic biology of the fruit fly, which is the model insect for research. The research was made in cooperation between the Kansas State University, South Korea's Institute of Science and Technology, Korea Academy and Slovakia's Slovak Academy of Sciences.
Findings appeared in a paper published in the journal Proceedings of the National Academy of Sciences.