Researchers at the University of Exeter have found that older male burying beetles make better fathers than younger beetles. Researchers have observed that older male burying beetles demonstrate a greater frequency of protective behavior and overall parental care towards their offspring than their younger counterparts show towards their offspring. In other words, older male beetles invest more time into raising their offspring, whereas younger male burying beetles tend to be dead-beat dads that show little interest in the welfare of their offspring.
The reasons for this unequal participation in the upbringing of their offspring is rather simple. The older male beetle is past his prime, and he does not experience as many opportunities for reproduction as he did when he was younger and more fertile. Therefore, the older beetle has no other way of spending its time than to tend to the needs of its offspring.
The younger beetle, on the other hand, likely spends much of its time engaged in the act of reproduction, and therefore has fathered many different offspring. Naturally, the younger and more fertile beetle will produce such a high number of offspring that it cannot possibly tend to the upbringing of all of his young.
The researchers also noted that the older male beetle continued to nurture young beetles even if the older male beetle was unsure if the younger beetles were born from his seed. So apparently, older male beetles tend to become comfortable with the idea of adoption. The younger male beetles, with their superior swagger, proceeded to immediately abandon any young beetles that were not confirmed to be his offspring, and instead indulged in mate-seeking behavior.
Despite the noble decision on the part of the older beetles to nurture young beetles, the young beetles do not stand to gain any benefits from being reared by a nurturing father. Nor do the young neglected beetles demonstrate behavior that is in any way different from their nurtured counterparts. This is due to the fact that young beetles do not, by nature, depend on, or desire, the nurturing care of their fathers. Rather, the mother to the young beetles is solely responsible for fulfilling the role of nurturer to her offspring. The researchers involved with this study believe that the female beetle will ultimately prefer the older male as a mate since the older male is not concerned with the quantity of mates, and can therefore retire their need for sex in favor of the need for nurturing and support.
If Darwin’s theory of the survival of the fittest is true, then wouldn’t the female beetles in the above described study prefer the younger and more fertile males?