A new study suggests that male zebra finches prioritize winning a mate above all other tasks, and that these intentions are reflected in dopamine-releasing brain cells.
The researchers found that the presence of a potential mate causes the males to drop what they are doing immediately shift their focus.
A male zebra finch is often engrossed in a task like finding water or refining the song taught to him by his father. The study shows that these activities quickly take a backseat the moment he perceives the proximity of a female.
The study was co-authored by Dr. Vikram Gadagkar, a lead investigator at Columbia’s Zuckerman Institute, and graduate student Andrea Roeser of Cornell University..
“The males stop worrying about anything else and, for the first time, we have found signs of that re-prioritization in the behavior of specific brain cells,” said Dr. Gadagkar.
“Our findings could help explain what our brains are doing when they shift gears as different opportunities arise and as our priorities change.”
Historically, Dr. Gadagkar and his team have been tracking male zebra finches as they practiced their songs to serenade females.
The researchers found that when a bird made a mistake while rehearsing, there was a notable decline in the dopamine – a chemical signal generated by particular brain cells.
“Dopamine seems to function as an internal error signal, helping the bird to realize that it has made a blunder and did not quite replicate the song it had memorized,” said Dr. Gadagkar.
Previously, the researchers had found that when birds get the song right, dopamine production is boosted and acts as an internal reward signal for their good performance.
For the current study, the researchers measured variations in dopamine in situations where a bird must choose between several objectives such as practicing its song, finding water, or pursuing a mate.
The experts discovered that the dopamine error signals, which previously played a role in tasks like finding water or practicing songs, were notably muted when courtship was in the picture.
In addition, the dopamine reward signal was amplified when the bird’s song succeeded in fetching return calls from a female.
“We think this is the first demonstration of a socially driven shift of dopaminergic error signals,” said Dr. Gadagkar.
“The big idea here is that your self-evaluation system, which you’re using to learn when you’re practicing, might be dialed down or switched off when you’re performing and your dopamine system instead becomes primed to receiving social feedback.”
“A big question for us now is whether these systems may be widely at play when it comes to learning many kinds of behaviors, including speaking, singing, playing an instrument and all kinds of behaviors where learning depends on internal self evaluations.”
“Now I want to know if this same circuitry might be much more general-purpose than anyone previously had thought.”
Zebra finches, native to the Central Australian grasslands, exhibit unique and fascinating courtship behaviors which are integral for mate selection and bonding.
Male zebra finches typically initiate the courtship process. During this phase, the males showcase their vitality and genetic fitness to attract potential female partners. They employ a combination of visual and auditory displays, including brightly colored feathers, dynamic dances, and melodic songs.
One of the most distinctive elements in their courtship is the male’s song. Each male zebra finch develops a unique song during their juvenile stage, primarily learned from their fathers or other adult males within the vicinity.
The courtship song is more complex and structured compared to their regular communication chirps. Males sing to attract females, with each song being distinctive, allowing the females to identify and choose their preferred mates.
Apart from singing, male zebra finches also engage in a dance display. They puff up their chests, flutter their wings, and hop around to garner attention from the females.
This dance, paired with their vibrant songs, creates a comprehensive display designed to entice and woo potential mates.
Female zebra finches play a critical role in mate selection. They evaluate the males based on their songs and displays, choosing a partner whose traits are most appealing or suitable for producing offspring.
Females may consider the complexity, volume, and pitch of the male’s song, as well as their overall health and vigor, before making a selection.
Once a female selects a mate, the pair forms a strong bond, often mating for life. This bond is reinforced through mutual grooming, feeding, and coordinated activities. The strong partnership ensures collaborative efforts in building nests, incubating eggs, and raising their offspring.
After the courtship and bonding, the pair engage in nesting behaviors. Male zebra finches actively participate in nest-building, collecting materials like twigs and feathers to construct a safe and comfortable environment for their eggs and future chicks.
The study is published in the journal Nature.
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