Information

Reproductive strategies


Quantity or quality?

In Цcology, a distinction is made in principle between two naturally occurring reproductive strategies. The so-called r-strategists are characterized by their high reproduction rate (r = rate). An example of such a reproductive strategist is aphid. A female animal lays down to 100 eggs and thus provides for as many offspring. This is to the detriment of brood care: the eggs are left to themselves, which already leads to a decimation by predators even before hatching. With the overwhelming number of r-strategists, care or guarding of the brood is also not possible. Imagine the aphids trying to defend their offspring from ladybugs. She would either be eaten herself or her protection against several ladybirds would be useless anyway. Therefore, it may be beneficial to produce as many offspring as possible and to "hope" that at least one individual will reproduce.
Animals that only have a few offspring in comparison to the r-strategists are called k-strategists. Especially mammals but also bird species are characterized by this propagation strategy. Populations of k-strategists often reach the capacity limit (k), so that a high propagation rate would be rather disadvantageous for all individuals of this species due to limited resources.
A typical k strategist is the lion. Females give birth to a maximum of four young, mothered by the mother during the first two months of life and preyed on predators such as Hyten be protected. The effort is so enormous. All resources will be invested in raising the offspring, also because a loss for the population would be much worse than with r-strategists. Sometimes it takes years (primates) or decades (elephants) for a k strategist to reproduce.

R and K strategists in comparison

r strategists
(r = rate)
k strategists
(k = capacity)
Lifespan:shortlong
Number of offspringmany manylittle
broodno or very littlehigh effort
Time to first reproductionshortlong
PopulationsgrцЯeswayingconstant
Examples:Insects, fish, bacteria, parasitesMany mammals: primates, whales, elephants; but also birds