Scientists have discovered they can boost the reproductive success of zebrafish by pairing them on personality rather than appearance.
Experts at the University of Stirling, collaborating with the Autonomous University of Barcelona, conducted what is said to be the first study into the impact of animal personality and external coloration patterns on the reproductive success of a fish.
The team selected male and female fish on both their personality and coloration patterns and crossed both parameters to create four combinations: proactive, or bold, fish with clear defined coloration; proactive fish with undefined and unclear coloration; reactive, or shy, fish with clear defined coloration; and reactive fish with undefined and unclear coloration.
The scientists then counted a number of reproductive parameters – the number of eggs, survival of the eggs, embryos, and growth and survival of the larvae up to juvenile stages among others – to assess the success of the fish.
They found proactive fish had more success, regardless of their coloration, and concluded personality surpasses the effect of personal appearance.
Dr Sonia Rey Planellas, who led the study, said: “There is a lot of research on the impact of coloration patterns on sexual selection and reproductive success – and animals tend to choose mates that look better and have more defined coloration patterns, or those that look similar to them.
“Other studies link animal behaviour traits, or personality, with assortative mating and the fitness of the species.
“Our research explored both areas – coloration patterns and personality traits – to see if they were linked in some way and how they impacted the fitness of the species.”
“For all of the parameters of fertility and fitness of the species, proactive animals were the best, regardless of their external coloration pattern.
She added: “However, both parameters were additive, meaning that proactive fish with defined coloration patterns always achieved the best scores. This is also a very interesting result.
“Our research concluded that personality plays an important role that surpasses the effect of external appearance in the reproductive success under this conditions, and therefore, in the fitness of the species.
“This is important in understanding the evolutive drivers for the ecology and conservation of fish, and for the industry to select specific phenotypes that will perform better. It may also inform how we select fish for aquaculture, and the potential impact upon conservation.”
The study – Love at first sight: the effect of personality and colouration patterns in the reproductive success of zebrafish (Danio rerio) – is published in PLOS One.
Dr Rey Planellas worked with Professor Simon MacKenzie, director of research at the University of Stirling’s Institute of Aquaculture, and the study formed part of the thesis on zebrafish personality and phenotypic variability by PhD student Reynaldo Vargas, who is now working at the University of Panama.