BENGALURU: Researchers from the National Centre for Biological Sciences (NCBS), Bengaluru, have formed a potential hypothesis for evolution, based on the development of flies.
The study proposes that a new hypothesis can be found from the recent evolution of the US-based apple maggot fly in the 19th century, that could involve the rate of development in the brain as well as chemical changes. The fly, Rhagoletis pomonella, had originally infested native hawthorn fruit in the US.
However, following the introduction of apples in the US in the 19th century, the fly evolved into two species over the course of just a century and a half, one that infested regular hawthorn fruits and ones that evolved to infest only apples.
“Factors such as new environment, climate, competition and habitats are known to lead to the formation of different species. However, the changes that individuals undergo during evolution are still an area of study. The fly provided the researchers a unique opportunity to study a system currently forming a new species, than in the distant past,” a statement said.
The researchers studied fly species in Bengaluru, where they tried to find if changes in their brains could encourage them to further evolve. They monitored the brains of the developing pupae of the flies, to measure 14 chemicals (neuromodulators) in the brain like dopamine, serotonin and histamine.
“Surprisingly, even when we controlled their hibernation period, the apple fly developed the adult brain faster than the hawthorn fly. In addition, the apple fly brains, which developed faster, also showed reduced levels of neurochemicals. Our results suggest that changes in neurochemicals during specific stages of brain development could influence host choice in adult flies, providing a novel hypothesis for evolution,” said Hinal Kharva, lead researcher.
“Linking changes in brain development and neurotransmitters to an insect’s life cycle has interesting implications not only for generating new species, but for how changes in the environment, like climate change, could impact the choices that insects make -- like what plants to infest,” said Dr Shannon Olsson, who guided the study.