When it comes to choosing a partner, guppies often go for couples with the most striking and interesting color patterns.
But why is that? It turns out that it's all about psychology.
In a new study, researchers at Florida State University found that these small tropical fish often choose a couple that physically stands out from the rest of the pack because of a common type of learning called habituation. Through habituation, the animals, in this case the guppies, stop responding to a stimulus after a prolonged exposure.
In other words, the female guppy is often immune to the charms of a male guppy that resembles all other male guppies. Some with unusual color patterns have a better chance of successfully attracting a partner.
"If they have seen certain patterns in the past, they have become accustomed to them," said Mitchell Daniel, a postdoctoral researcher who works with biological science professor Kimberly Hughes. "But when a male guppy comes with a novel pattern, they are not used to it, so they find that the male is more attractive, we have shown that this attraction to the unusual happens because of the habit, which means that the females Disconnect repetitive information, and pay more attention to things that look different. "
His study is published in the. Proceedings of the Royal Society B.
The team's research is based on a study Hughes conducted several years ago and found that the color patterns of the guppies seemed to influence the choice of partner. When Daniel came to work in Hughes' lab, he wanted to explore the psychological theory of habituation and if that explained how guppies women choose partners.
"It's been hard to understand," Hughes said. "Why do females have that preference? That has been a hard nut to break."
The researchers exposed female guppies to a large number of males with the same color patterns and traced their responses to exhibits of male courtship. In the guppy courtship, the male guppy performs a type of dance around the woman to express her interest. If the woman wants to participate in this courtship ritual, she will respond to the approach and move towards man.
Then, the researchers exposed the same female guppies to male guppies with very different color patterns to investigate the response. In some cases, they kept the group of guppies in isolation for a short period of time.
The researchers found that females usually preferred the new male guppies. But, they also found that male guppies with familiar patterns became interesting again for isolated guppies.
Through these experiments, the researchers demonstrated that this choice met four criteria that indicate habituation.
- First, the responsiveness of female guppies to a stimulus (male guppies with a familiar pattern) decreased with additional exposure.
- Second, the interest of females in males with new patterns was not affected by exposure to the family pattern, showing something called stimulus specificity.
- Third, they demonstrated what is called spontaneous recovery, which means that these same females became interested again in the family pattern once they were removed for a period of time.
- And fourth, they returned to be interested in the initial group of guppies after exposing themselves to guppies with a novel pattern, a phenomenon called detoxification.
"Nobody had linked this idea of habituation to the choice of a partner for novelty," Hughes said. "It's a good example of how ideas from different fields can be useful in explaining biology."
The variation of the color vision in guppies influences the preference of the female couple
Imperfect camouflage: how to hide in a variable world? Proceedings of the Royal Society B, rspb.royalsocietypublishing.or … .1098 / rspb.2019.0646
In the guppy courtship, the unusual male wins (2019, May 15)
recovered on May 15, 2019
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