Why Are Guppies So Colorful? (Evolution Affected Their Coloration)

Image of colorful guppies

Guppies are also known as rainbow fish because of their vibrant colors. But why are guppies so colorful?

Guppies are colorful because of their reproduction preferences. Male guppies are more colorful than females. Their colors attract female guppies because they associate the vibrant colors of the males with fertility and health. However, wild guppies are drabber to protect themselves from predators.

The coloration of guppies is a perfect example of the evolutionary nature and the complexities thereof. So read on for answers to all your guppy color-related questions.

How Did Guppies Evolve?

As with most animals on earth, guppies are subject to something called natural selection. This is the subtle evolution over time whereby members of a species with particular physical and behavioral traits are more likely to survive and reproduce.

As they are more likely to survive and reproduce, they pass these traits on to the next generation. In contrast, less evolutionarily viable traits die with the individuals who fail to produce offspring.

For guppies, two main evolutionary factors affect their bright coloring:

  1. Reproduction preferences influence guppy coloration. This is why males are more colorful than females.
  2. Predation influences guppy coloration.

These two factors are actually in direct contradiction to each other. Let’s discuss this further.

Why Are Male Guppies So Colorful?

In the animal kingdom, the natural trend is for the males of a species to be more colorful than the females of that species. We see this a lot in birds, insects, and fish, but it also extends to some mammals, such as lions.

The evolutionary reason behind this is quite simple. For the males of a species to get a mate and reproduce, they have to look attractive to the females of that species. Colorful and vibrantly pattered appearances are what catch a female’s eye.

So, a male guppy is more colorful because he has to attract a mate. On the other hand, a female guppy is drabber because her role is simply to choose from the male guppies offering themselves to her.

Because the colorful males are more likely to procreate, they get the opportunity to pass their colorful genes onto the next generation of fish.

Recommended Further Reading:

How Do Male Guppy Colors Attract A Female Guppy?

Firstly, vibrantly colored male guppies are more likely to be seen and noticed by female guppies.

Secondly, female guppies will associate the bright colors of a male guppy with desirable qualities like health and virulence.

Thirdly, and this applies most strongly to wild guppies, colorful males have the ability to scare off or successfully avoid most predators. This is a skill that any female guppy would instinctively want to pass onto her offspring.

How Do Predators Influence Guppy Coloration?

In the wild, camouflage is typically the key to survival. If you stand out, you are more visible and, therefore, more likely to get targeted and killed by predators.

As you can imagine, the vibrant colored guppies that you see in a pet store tank would be like a neon sign that says “dinner” while swimming through freshwater rivers and lakes. So, in the wild, guppies tend to be less colorful than their captivity-bred counterparts, even the male guppies.

Due to how nature works, for the most part, the drabber males will escape predation long enough to reproduce successfully. So the successive generation carries genes that make them less colorful.

In addition, the drab color of females also helps them to fly under the predators’ radars. This gives them enough time to lay their eggs, which carry the less colorful male genes and their own drab genes.

Related Further Reading:

Why Do Colorful Male Guppies Still Exist In The Wild?

If colorful guppies are more likely to be killed, then why are the males colorful at all? Well, here we have the contradiction we mentioned earlier.

Just because the “flashy” males are more likely to become a bigger fish’s meal does not mean that the females don’t prefer them when given a chance. Thus, there is still this reproductive selection playing a part in evolution.

In addition, research has found that the rarest male guppy color and pattern combinations, no matter how vibrant, are more likely to survive in the wild. This is because their patterns confuse predators and make the guppies more difficult to target.

How Do Guppies Get Their Color?

If only males are brightly colored, then how does this work on a genetic level?

Guppies do not follow the same chromosomal inheritance pattern as mammals. In other words, they do not get half their genes from the male parent and half their genes from the female parent.

The science behind genetic inheritance in guppies is relatively complex, so we will not go into the details here. Suffice it to say that male guppies inherit most of their genes from their male parent, while the female fry only inherits a small portion of the male parent’s genes.

Interesting Further Reading:

How To Make Guppies More Colorful?

There’s very little you can do to make your guppies more colorful. The coloring is an expression of their genetic makeup, which you cannot change.

Feeding your guppy pigment-rich and nutritious foods may help to make their existing coloring more vibrant (they will be duller if their health is compromised), but it will not add colors that were not there to start with.

However, if you are worried because your male guppy fry looks quite drab, all you have to do is wait. Males only start showing their coloring once they get older. Conversely, when they reach a certain age, they once again begin losing color.

You can also play around with the lighting of your tank. A big part of a fish’s coloring has to do with reflecting and absorbing light waves.

So, your guppy might appear dull in one corner of your living room, while in another corner, they are brighter than they have ever looked.

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