Throughout the animal kingdom brilliant colours or elaborate behavioural displays serve as "advertisements" for the process of attracting mates. But, what do the ads promise and is there truth in advertising?

Researchers at Yale theorise that when males must provide care for the survival of their offspring, the males' "advertisements" will always be honest – and they may devote more of their energy to caring for their offspring than to attracting females.
The idea that males try to advertise their best qualities to attract females for mating isn't a new one, nor is the idea that they might be deceptive in what they are advertising. According to Natasha Kelly, a graduate student in ecology and evolutionary biology and lead author, their new model more closely predicts the requirement for honesty in advertising as a function of the male's suitability for parenting.
The peacock's tail, or the primping and posturing guy in a bar are "advertisements" or mating displays that take substantial energy to maintain. When a male's energy is heavily focused on keeping up his appearance, he may have little energy to devote to caring for offspring. But that may be OK – he may not need to tend to the kids.
Previous research suggested that, under certain circumstances, males could be dishonest about their parenting skills and still have high reproductive success. This new model, appearing 11 June online before print in the Proceedings of the Royal Society B, examines the reliability of males' mating signals when they must care for offspring – an aspect that was missing in earlier studies.
There are many species where males should, but do not have to, provide parental care – where females pick up the slack. These researchers focuses on those species where females can't pick up the slack and males pay the price of not providing care.
"This new work shows that when males can not escape the cost of their own failure to provide care, their advertisements will always be reliable," says principal investigator Suzanne Alonzo, assistant professor of ecology and evolutionary biology at Yale.
"The qualifier in this case is where males are obligated to provide care," says Kelly. "In that case, the quiet guy in the corner might be the better choice for fatherhood."