The r/K thing is a teensy bit different. That is more to do with offspring quality—with many vs few offspring.
The idea (from dietary energy restriction) is that organisms face resource-investment tradeoffs between self-maintenance and reproduction—and that circumstances and diet can affect where that tradeoff is made. If there isn’t enough dietary energy to support reproduction, what resources are available are devoted to maintenance—so the organism can live to reproduce another day.
It is a bit like K-selection taken to an extreme where no babies are produced at all—and all resources get invested in personal survival.
The r/K thing is a teensy bit different. That is more to do with offspring quality—with many vs few offspring.
The idea (from dietary energy restriction) is that organisms face resource-investment tradeoffs between self-maintenance and reproduction—and that circumstances and diet can affect where that tradeoff is made. If there isn’t enough dietary energy to support reproduction, what resources are available are devoted to maintenance—so the organism can live to reproduce another day.
It is a bit like K-selection taken to an extreme where no babies are produced at all—and all resources get invested in personal survival.
I have a page all about this general topic: http://cr.timtyler.org/why/