A few words on mating preferences and the particulars of match-making in fish, in tribute to the new season of The Bachelor, scheduled to kick off this week.

Selection of mates based on physical appearance is a practice not unique to homo sapiens, rather, it is commonplace in many species of the animal kingdom. Even fish. Whilst a bold rainbow complexion, or a passion for performing death-defying stunts may not be preferred partner traits in humans, in the world of fish, these qualities can be a real turn-on.

Female guppies are selective about who they choose to mate with. They assess the ‘fitness’ of potential male suitors for a number of traits, with the fittest males being preferred as sexual partners. In guppies, females prefer bold, brightly coloured males who are more willing to dance with death – death, in this case, equates to swimming near a larger predatory fish. The theory is that a brightly coloured fish would regularly attract the attention of said predators. The brighter, bolder fish is handicapped by its ostentatious colouration and is more likely to be eaten than a duller coloured fish. As such, brighter and bolder fish need to be more informed about the whereabouts of predators, and must develop an aptitude for escaping them. The fact that a bold and brightly coloured male is alive and available to mate with a female, is indicative of its fitness. In the female’s mind, this is obviously a predator savvy guy that is able to avoid becoming a meal. The female guppy will therefore prefer to give her roses to males with brighter colours and a bolder streak (and a death sentence hanging over him) to be her partner, and mate with them in the hopes that those good traits will be passed on to her offspring. Perhaps a one-on-one, over orchestrated, channel 10-style date could win the guy with the good genes over?

Another mating behaviour in guppies similar to that in human relationships is ‘trading up’. Commonplace in relationships that have involved one party cheating on the other, trading up is essentially choosing to swap over to someone more attractive than the person with whom you are currently partnered. In an experiment looking at female guppy mating preferences, it was determined that the amount of orange colouration on a male was indicative of his attractiveness to females. The more orange, the better. Female guppies were presented with bachelor number 1, and then immediately afterwards presented with bachelor number 2. Generally, the females were less interested in the second guy UNLESS he was more orange than the first. Interesting…I wonder if that’s applicable for human males selecting female partners too? Is it the more orange, the better? Is the Bachelor even a red-head, fake tan kind of guy?

Maddison Howard