1 time mating, a disadvantage perhaps?

[Keith]

I was thinking about roaches that mate only once, and can be pregnant the rest of their lives. For surplus breeding in captivity that is great, and even in the wild when your looking at increasing population numbers.

But let's take blaptica dubia for example. We all know males are usually more abundant than females, and have wings which makes them easily capable of finding plenty of females in the wild. But when a female only mates with 1 male in her entire life, and it doesnt even have to be males fight for her to insure the father is strong, the first male she encounters impregnates her.

First of all doesnt that not ensure healthy offspring if any male will mate? Second, if lets say you only have 5 females in an area the size of a room in a house, if the females only produce offspring form one male, genetic diversity wont be there after a while and inbreeding will surely occur, and as far as I know that's a bad thing in the animal kingdom. If females mated with a new male each time, at least genetic diversity would be abundant per area. Basically there just popping out clones their whole lives, it doesnt seem right.

If you take most snakes that lay lots of eggs or birth lots of young (just like roaches) even they have a new mate each year. So why for roaches most only mate once, some live many years.

 

[Zephyr]

It should be noted that many species, including Blaptica, that "mate only once", often will mate more than once in their lifetime. If the first male to mate with the female was healthy enough to produce a sufficient nuptial gift to both sustain the female and enough sperm to father a lifetime's worth of babies, clearly the female will not need to mate again, and inadvertently the "best" male has been chosen. If the female does not receive enough of a nuptial gift and enough sperm to ensure a life's worth of babies, she will mate again because she will inherently need to to reproduce. Genetic diversity isn't a problem in roaches, especially those that originated from small populations. Even some vertebrates (some species of island hawk, for example) can reach populations of less than 5 individuals with no detrimental effects. Coincidentally, the isolation of a population (which inevitably leads to inbreeding) is one of the ways speciation can occur. Almost every species on this planet has had to inbreed at some point in time...