The witch hazel flies that became 150 years ago the flies that breed on apple fruits that were introduced to the US 400 years ago and the wasps that feed on them changed and became a separate species from those related to witch hazel
A team of researchers reported that the continued appearance of new species of fruit flies, and the serial decline of new species of wasps in an article published on February 6 in the journal Science.
The introduction of apples to America almost 400 years ago had a decisive effect on a change in the behavior of fruit flies, which led to a change and a corresponding change in the parasitic wasp that feeds on the fruit flies.
The result is a chain of reactions to the diversity of biology in which changes in one species caused changes in another species, which depends on it. "This is an excellent demonstration of how the specialization of one species opened up an opportunity for other species in the ecosystem to also specialize," said Jeff Feder, a biologist at the University of Notre Dame, who led the research team. "Biological diversity in a certain sense is a source of new biological diversity".
For nearly 250 years after the introduction of apples to North America, insects we refer to as horn flies, Rhagoletis pomonella, continued to congregate on the small red fruits of hawthorn plants to mate and lay eggs. Then in the middle of the 19th century, some wasps began to meet and lay eggs on apples as a substitute. According to Feder, the flies that were attracted to apples became genetically different from the flies that were attracted to thistle, and so did the wasps that feed on the flies' larvae (larvae).
The genetic differentiation was expressed in the variation in gene frequency between the flies as well as among the wasps from the corresponding populations, rather than all-or-nothing differences. This phenomenon is consistent with the process by which a new biological species is created.
"The Diachasma alloeum wasp that we studied is just one of several wasps that spend a significant part of their lives close to hawthorn and apple trees," Feder said. "We have strong evidence that one of the other wasps also began to develop a race specializing on the flies, but it's too early to say for sure."
"What is interesting is how quickly the populations can ecologically adapt to new habitats and develop into different species before our eyes," he said.
Feder said the research is important because it provides insights into solving Darwin's mystery of the origin of new species. "The clues can be found right under our eyes when we are sitting on the garden chair, making a barbecue and drinking a soft drink. We just have to open our eyes and see how new life forms begin to form on the old apple tree in our yard."
The research was supported by the National Science Foundation.