New UNSW research confirms that in the battle for survival, some animals win not with brawn, but with bling, putting to bed a debate that has puzzled generations of scientists.
Peacock spiders are no bigger than the nail on your little finger but have one of the most remarkable mating rituals in nature.
Some male peacock spiders have an abdomen painted in bright yellows, reds and blues which, when they've found a potential mate, they lift and wiggle while kicking a long, hairy leg out in an alluring show designed to catch a female peacock spider's eye.
The show can last up to an hour and contains a dazzling array of dance moves, including some vibrations called 'rumble pumps'.
Hopefully the female spider likes it, because if she doesn't, she may well eat him for his troubles.
If she does, the lucky male gets a chance to mate and carry on his genes.
Displays like this appear across the natural world, puzzling scientists who can't work out why the animals bother.
Why do they evolve all that finery and waste all that energy on something that doesn't seem to make them stronger, and often makes their lives harder?
In other words, why has a peacock spider evolved to stand out when camouflage would be much safer?
And why do peacocks (the birds this time) bother with all that cumbersome finery when all it does is slow them down?
From dancing birds of paradise with just a hint of purple beneath their black satin feathers, to hammer-headed bats whose oddly shaped head makes a pleasing sound to females, incongruous displays are common in nature.
"Lots of animals express signals like these, even though they are not always appreciated, such as frogs croaking or crickets chirping," says UNSW ecologist and study lead author Pietro Pollo.
"There is a lot that might be going on around us, but we simply don't notice it because we are not well equipped to sense them.
"Using smells for communication is widespread in nature, but we don't have the nose to notice it."
Writing in the journal Ecology Letters , the team reviewed data from nearly 1200 papers and confirmed that the long-puzzled-over paradox might be less complicated than assumed.
The numbers show that despite potential downsides, the flashy and the garishly dressed are usually more successful.
The showier the creature the earlier it breeds, the more babies it has, and the more effective it might be at holding their territory, say the researchers.
In other words, despite "wasting" all that energy on dancing, croaking, or growing foot-long tail-feathers the colour of golden syrup, these show-boats are usually (but not always) fitter.
Next, the researchers tested the assumption that the showiest signals are mainly found on males.
The standard thinking is that it's the males of a species that are the bombastic, loud, or colourful ones, while females tend to be drabber (for a particularly stark example, compare the male Raggiana bird of paradise to the female).
But, in a finding that the authors were not expecting, the data suggest females exhibit these behaviours almost as much as males.
"This is surprising because most of the data available related to sexual signals has been collected from males," says Dr Pollo.
"People have assumed that females wouldn't and shouldn't be advertising their position and quality."
But they are, so why haven't we picked up on it?
Dr Pollo thinks there's some human bias creeping into the data and that female sexual signals have basically been ignored or explained away.
We could also just be incapable of seeing some of these signals because of how we've evolved.
"As we are better at seeing and hearing than we are at smelling or sensing electromagnetic fields, we end up being oblivious to many signals that animals around us are producing," Dr Pollo says.
"Because of this, researchers have more frequently studied visual and acoustic signals, which frequently occur in birds, especially in males."
Which means they show up in the data more.
Preconceptions might have also influenced the data in other ways, says Dr Pollo.
Researchers might see an ostentatious display and decide it's a sexual signal when in fact it means something totally different.
"Not every unusual characteristic we notice is necessarily used to attract mates as it is typically assumed," says Dr Pollo.
Vivid colours might signal to other individuals of the same sex that the bearer of that trait is strong and prepared to defend itself, thus avoiding costly and unnecessary fights.
More work needs to be done to fill in the gaps in the data and answer these lingering questions.
The next challenge, Dr Pollo says, is to explore subtler cues like pheromones, the secret signals we don't notice but which could prove just as powerful as any feather or dance.
