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Scent turns male butterflies off sex
Marianna Nash 
On March 3, 2004, scientists identified methyl salicylate as an anti-sex hormone present in certain species of butterfly. The chemical functions in only these species, although it has been compared to the testosterone hormone in humans. The purpose of the hormone is to protect the mother and her larvae during pregnancy. The discovery was made during research on the species of butterfly Piernis napi, distinguished by its white wings and visible green veins. When the male and female butterflies mate, the male butterfly's sperm is transported to the female's body, carrying methyl salicylate. The hormone stays with the female for as long as she carries the male's offspring. The scent of the chemical repulses male butterflies who are not the father, causing them to stay away from the female during pregnancy (four to six days). While they do not know cognitively that she is "unavailable," they instinctively turn away from mates that have been "claimed" in this way. After this period of celibacy, the female can mate again with whichever male she chooses, and the process will repeat. The chemical is beneficial to the mother because it allows her to reproduce without interference (she has to protect her eggs, which she can only do by guarding them at all times). The process also benefits future larvae: while waiting for one set of eggs to hatch, females are able to evaluate the health and genetic promise of potential mates, from afar. Their choices are limited, because certain male butterflies, particularly the Heliconius, will physically battle other males for a female. The male that manages to stay in such a position to fertilize the female in spite of the others' assaults, will do so, regardless of the female's preference. Methyl salicylate does not work on mammals. Instead of scent, mammals usually choose partners by visual and touch perception. However, testosterone shares the same anti-sex function in male mammals. When given a choice between three objects, men in a series of experiments were recorded to rarely pick the object sprayed with another man's testosterone. Scientists are considering the employment of methyl salicylate in an eco-friendly insecticide. When sprayed on crops, they believe that it will prevent an infestation. The humane pesticide would be implemented as part of a new system of monitoring and protecting what farmers are called "Invasive Species." Another hope is that the organic chemical will replace toxic pesticides that damaged the environment. Between 2003-2004, many studies have been done on the sex pheromones of a varied pool of insects, including the scarab beetle, neotropical stink bug, gypsy moth, and plant bug. The female Asian Longhorned Beetle produces her own anti-sex agent. Sources: Viegas, Jennifer. Scientists Identify Anti-Sex Scent. 03 Mar. 2004. Discovery
Channel. 06 Feb. 2005 |