A chemical produced by the male genitals of this tropical butterfly is so attractive, scientists refer to it as an “anti-aphrodisiac. ”
New research published today in PLOS Biology outlines the genetic basics of man-made chemical fertilizers Heliconius melpomene butterflies. It is a good example of chemical markers, in which odor is used for communication. In this case, the chemical, known as ocimene, “acts as an anti-aphrodisiac pheromone, is passed from males to females during breeding to further courting of males thereafter,” wrote the authors in their paper.
Surprisingly, some plants make ocimene, but they use it for a different purpose. The new research highlights a specific case of convergent evolution. As well as identifying the genes Heliconius melpomene responsible for making the chemical, this is the first time scientists have recorded this chemical, terpene, in an animal.
Accordingly, the new inquiry dispels the previous credentials Heliconius melpomene ocimene from plants (experiments performed in 2007 sheall males coated with ocimene did not occur as often with males than those covered with control material). As the new research shows, however, these butterflies can do this chemical on their own.
Members of Heliconius melpomene they have an extremely long lifens for butterflies, living for about six months compared to the usual one month. They live in Central and South America and displays a wide range of wing color patterns, depending on where they are. These butterflies are poisonous, so is the patterns are a warning to potential predators. These patterns also play a role in sexual selection, as butterflies of this species select similar mates.
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“While the patterns have attracted the most attention, it has long been noted that the smell of these butterflies,” explained Kathy Darragh, lead author of the soil paper, in e-mail. “We now know that this scent is involved in companion protection, acting as an anti-aphrodisiac to deter future mating efforts from other men.” Darragh she did this research while doing her PhD at Cambridge University.
Humans are highly visual creatures, but many animals rely on a chemical signaling as their main means of communication. Orchids, for example, repetition the smell of female insects to attract males to pollinate. Anti-aphrodisiacs have also been reported in other insects, including the burial of beetles and plant insects.
Butterflies, with their amazing colors and patterns, clearly use visual cues to communicate, but that doesn’t mean they don’t use chemicals either. Darragh, now with UC Davis, wanted to study how chemical signals can play a role in butterfly communication.
“An interesting aspect of this, which was at the heart of the current study, is how butterflies can produce these chemicals which they use as signals.ling, ”she said. In other words, what genes do butterflies have that allow them to make these fertilizers? And are these the same genes used to make these fertilizers in plants? ”
Of course, ocimene is also produced by tropical plants to attract butterflies for pollination (more on this obvious nuisance in just a few). This is an example of a convergent evolution, in which two independent species evolve into a similar character. What is unique about this finding, however, is that plants and insects use this chemical for a variety of purposes (although it is still for chemical indications), and plants and insects use different genetic methods to produce it. In the new paper, the researchers identified a novel gene in Heliconius melpomene responsible for ocimene, which is not related to previously described genes in plants with the same function.
“Ocimene production has evolved independently through different genes in plants and butterflies, showing how different molecular mechanisms can form the basis of specific chemical production,” he said. Darragh. “Independent evolution of the same attraction, in this case pheromone production, many times, provides a good system to help us understand evolution. ”
Those plants use ocimene to attract insects, but this butterfly uses it as a repellent, a strange sight. The authors do not fully understand why, but they think it may have something to do with the way visual and olfactory information work together. In other words, context is important; a butterfly interprets the chemical as an attractor when it comes from a plant but as an anti-aphrodisiac when derived from other butterflies. The “smell itself doesn’t change,” said Darragh, “but the context does, and so does the sign.”
This is all well and good, but if a man successfully mates with a woman, why should he care about other lawyers? The answer is female Heliconius melpomene sperm storage for months, during this time they patiently fertilize the eggs. Subsequent courtship events would bring in new sperm. This has led to a male-to-male competition that has been witnessed and this strange arms race in which the genitals were stinky.
This gets even worse, as it creates situations in which eager females would like to raise hooks, but males do not want to do anything with them. Think of it as an insectoid version of sexual harassment.
At the same time, however, Darragh believes it may work to the benefit of women. The “anti-aphrodisiacs can also be honest signs of infection, reducing harassment by men while reckless women have more courtship,” she said. This benefits both men and women, “males do not spend time courting careless females, and females can reduce their harassment by males.”
I feel like this is an important lesson for us humans, but I can’t put my finger on it.