Oddly enough

Dilemmas of life...

"A trait that's good for sex is often not good for surviving and a trait that's very good for surviving may not be good for sex".[...]
She says the classic example is the male peacock's tail, which is good for attracting females but weighs him down and affects his chances of survival when being pursued by a predator.

[W]hen females are not around, the males develop into sexually mature adults slowly, growing into relatively large adults with lots of energy stores. The researchers say this gives the male spiders a higher chance of survival when they set out on their search for female mates. When male spiders are surrounded by females, they focus their energy on maturing quickly, ending up both smaller and leaner because they have spent less time foraging.